Retrofitting the Inhabited Built Environment of Cairo: Socio-Technical Factors of a Passive House in Cairo
. Mohamed Y. Elsarif .
Retrofitting the Inhabited Built Environment of Cairo: Socio-Technical Factors of a Passive House in Cairo
Presented to the Department of the Built Environment in partial fulfillment of the requirements For the degree of Master of Science
February 2016
Mohamed Yasser Amir ID /000678677 Word Count: 12510
University of Greenwich
Abstract
This research aims at developing skills for implementing realistic technical and social solutions for sustainable buildings with respect to delivering healthy, comfortable, efficient and eco-friendly structures. Greater Cairo was introduced as a city of interest in terms of retrofitting. As the existing building stock has been suffering from major deterioration in the past decades accordingly. However, the influence of time has been unkind to Cairo’s Egyptian housing stock as many aspects led to the physical deterioration of these structures. In the context of this dissertation, Mitigation of climate change is addressed through the improvement of energy efficiency and occupant comfort complying with EnerPhit standards as well as the use of solar active strategies.
This dissertation follows the “trias energetica” approach. Through implementing Passive house design measures on the building fabric components (walls, ceilings, openings. etc.) to reduce the cooling loads. Additionally, Solar Active measures are deliberated due to the geographical location of GCR and the high exposure to solar energy in GCR. Which leads to energy neutrality and an efficient use if the energy grid. In addition, a socio technical model was implemented, through investigating social behavioral patterns to identify and address the obstructions, motivators and energy behavioral connections found in the studies Egyptian housing typology.
Keywords: Passivhaus, EnerPHit, Residential Retrofit, Cairo, Energy Efficiency
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Acknowledgement
On the completion of this work, I would like to express my gratitude and appreciation to my supervisor, Dr. Spyridon Stravoravdis, whose advice and knowledge were of major assistance for this accomplishment. I sincerely appreciate the time and effort he's spent guiding me throughout the stages of the work. I also thank my dear friends and colleagues for accompanying me throughout this degree. Finally, and most importantly, I thank my family for their lifetime support and guidance.
-Mohamed Y. Elsarif-
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Table of Contents
Abstract …………………………………………………………………………………………..………iii Acknowledgments…………………………………………………………………………………...……iv List Abbreviations……………………………………….……………………………………………...viii List of Tables………………………………………………………………………………………....…...ix List of Figures……………………………………………………………………………….…………….x 1. Chapter 1: Introduction………………………………………………………………………..…...….1 1.1 1.2 1.3 1.4 1.5
Problem Overview Research Hypothesis Research Aims Research Objectives Target Audience
2. Chapter 2: Literature Review………………………………………………………………….………7 2.1 Overview of Structure 2.2 Egyptian Housing Stock Retrofitting & Retrofit Models 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7
Residential Retrofit GCR Building stock Housing Study for Urban Egypt by USAID in 2008 Housing Trilemma Egyptian Energy Efficiency Code in 2005 Egyptian Retrofit Models Modified Trias Energetica Process
2.3 Passive House concept and the Passive House Planning Package (PHPP) 2.3.1 2.3.2 2.3.3
Lowering household energy consumption and demand Passive house planning package (PHPP) PHPP at an international scale
2.4 Social Practice Theory; a socio-technical approach towards retrofit 2.4.1 2.4.2
The Energy Optimization Gap Rebound effect
3. Chapter 3: Methodology…………………………………………………..…………….……………30 3.1 Approach
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3.2 Data collection methods 3.2.1
Equipment used in inspection
3.2.2
Field survey Method
4. Chapter 4: Housing Typologies Selection Matrix in Cairo…………………………..…………...……..37 4.1 Current Energy Load of flats 4.2 Thermal Imagery Survey 4.3 Main Findings of the thermal imagery survey 4.4 Socio-technical Survey Results 4.4.1
Household standpoints about energy consumption:
4.4.2
Preliminary questionnaire results
4.4.3
Q-study results
4.4.4
Research ethics in choosing human participants
4.5 Strategy 1: Thermal Mass 4.5.1
Thermal imagery discussion
4.5.2
Results Discussion
4.5.3
Thermal imagery discussion
4.6 Results Discussion 4.6.2
Results and Discussion
4.6.3
Thermal imagery discussion
4.7 Ceiling 4.7.1
Thermal imagery discussion
4.8 External Renders 4.8.1
Results and Discussion
4.8.2
Thermal imagery discussion
4.9 Windows 4.9.1
Results and Discussion
4.10 Shading Strategies
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4.10.1
Results and Discussions
4.11 Airtightness 4.12 Correlation of the PH technologies with the Q-set and questionnaire 4.13 Passive design implementations 4.14 Questionnaire Development and Correlation with the PH technologies 4.15 Questionnaire results
5. Chapter 5: Results, Discussion & Recommendation………………….………………………………..66 5.1 Typology A1 results 5.2 Typology A2 results 5.3 The potential of solar active design 5.3.1
Solar active cooling technology
5.3.2
Conclusion and Recommendations
5.4 Limitations 5.5 Further Recommendations
6. References………………………………………………………………….…….…………………….76 7. Appendices ………………………………………………………………..………………………...…84
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List of Abbreviations
GCR - Greater Cairo Region USAID - The United States Nation for International Development GHG - Green House Gases A.C - Air Conditioned NGO - Non Profit Organizations RrtF. - Retrofit for the future programme EEEC - Egyptian Energy Efficiency Code UNDP - United Nations development programme SAC - Solar Active Conditioning PHPP.. Passive House Planning Package
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List of Tables
Table 2.2 - Exterior envelope requirements for air conditioned building in GCR Table 2.3 – Passive House Standards vs EnerPHit standards (Cotterell and Dadeby, 2012) Table 3.1-Tools used for the research Table 4.1- Main Elements of inspection Source (Author) Table 4.2- Selected Thermal Mass Technologies Source (Author) Table 4.3- Selected Intermediate floor configuration Table 4.4 Selected Ceiling technologies Table 4.5 Selected External Render technologies Table 4.6 Selection of window technology Table 4.7 Selection of Shading technologies Table 4.8- Ecotect criteria of the Airtightness layers Table 4.1 Occupant selection of technology
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List of Figures
Figure 1.1: World Wide economic mitigation by sector. (Source: Bernstein et al., 2007) Figure 2.1: Housing Trilemma diagram of poor energy performance. (source: Pelenur, 2013 ) Figure 2.2: (source:Egyptian Housing and research center, 2005) Figure 2.3: (a) Installed PV Cells, (b) Dimas Solar Thermosiphon installed on roof. (Source: Attia, 2010) Figure 2.4: Second monitoring period for the RPSH. (source: Attia, 2010) Figure 2.5: The three phases of the ''Trias Energitica'' Approach Figure 2.6: An integrated model of pro-environmental behaviour Figure 2.7: Energy Culture framework example. (source: Stephenson et at., 2010) Figure 2.8: Research model based on energy culture. Figure 3.1: Q study quasi-normal distribution. (source: Pelenur, 2009) Figure 3.2: Figure illustrates the structure of the methodology in relation to the other phases of this thesis. (source: Author) Figure 4.1: Typology description Figure 4.2: Main Image of the Selected Typology Figure 4.3: Figure 3 Current Energy Consumption of typology A1 Figure 4.4: Drawing details showing the main construction details of the selected typology Figure 4.5: Main Fabric Complications Source (Author) Figure 4.6: Modified Trias Energetica Source(Author) Figure 4.7: Thermal Image of the main elevation Figure 4.8: Thermal image inside Typology A2 Figure 4.9: Impact of Wool Insulation using ECOTECT Source (Author) Figure 4.10 Impact of Fiber Insulation using ECOTECT Source (Author) Figure 4.11 Impact of Polystyrene Insulation using ECOTECT Source (Author) Figure 4.12: Comparison between Thermal mass technologies Source (Author) Figure 4.13: Thermal Image inside Typology A2
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Figure 4.14: Thermal Image inside Typology A2 Figure 4.15: Impact of Polystyrene Insulation and ceramic finish using ECOTECT Source (Author) Figure 4.16: Impact of Fiber Insulation and parquet finish using ECOTECT Source (Author) Figure 4.17: Comparison between Thermal mass technologies Source (Author) Figure 4.18: Thermal Image inside Typology A1 Figure 4.19: Thermal Image inside Typology A1 Figure 4.20: Impact of Polystyrene Insulation using ECOTECT Source (Author) Figure 4.21: Impact of water pond technology using ECOTECT Source (Author) Figure 4.22: Comparison between Ceiling Technologies Source (Author) Figure 4.23: Eastern Elevation Figure 4.24: Figure 21 Thermal Image inside Typology A2 Figure 4.25: Comparison between external render technologies Source (Author) Figure 4.26 Thermal Image inside Typology A1 Figure 4.27 Thermal Image inside Typology A2 Figure 4.28: Impact of double glazed window using ECOTECT Source (Author) Figure 4.29: Impact of triple glazed window using ECOTECT Source (Author) Figure 4.30 Comparison between window technologies Source (Author) Figure 4.31: Comparison between Shading Technologies Source (Author) Figure 4.32: Modified Trias Energetica approach Figure 4.33: Typology A1 post-retrofit Figure 5.1: Typology A1; retrofit vs. pre-retrofit Figure 5.2: Typology A2; retrofit vs. pre-retrofit Figure 5.3: Potential Solar active strategies Figure 5.4: Estimated solar production on peaks and lowest production days (comsan, 2010) Figure 5.5: Typology A1 after solar active retrofit with lowest day average Figure 5.6: Typology A2 after solar active retrofit with lowest day average
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Figure 5.7: Typology A1 after solar active retrofit with highest day average Figure 5.8: Typology A2 after solar active retrofit with highest day average
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Chapter 1: Introduction
On the 13th of March, 2015; the Egyptian government announced investing £30 billion GBP as a panacea to Egypt’s crucial problems, targeting a new capital for Egypt to replace the existing capital Cairo (ECDC, 2015). This new capital was planned to accommodate more than 5 million inhabitants over 700 Sq km of land in the eastern desert of Cairo. Compare this to the 15 million people who live in the huge city of Greater Cairo. These areas are absorbing over 15% of the country’s population as the building structures accommodating them are suffering from dilapidation (Sims, 2010).
However, the world’s perception about energy consumption has shifted as the topic is becoming a significant challenge in the 20th century (Cotterell and Dadeby, 2012). According to the USAID, more than 35 million existing residences in the Egyptian housing stock compared to a few thousands of new dwellings annually added, most of which are excessively un-necessarily, the most effective solution for reaching the climate change act target would be by effectively retrofitting the existing stock. Ensuring a reduction in energy consumption whilst upgrading the functional usage of the unit. However, the question is, what are the existing practices we currently have knowledge of that could transform inefficient longstanding typologies to enhance the presentday quality of life without jeopardizing the life of future generations?
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Although several national energy codes and reports were published, none is found to offer a clear comprehensive methodology for understanding and assessing the existing fabric. On social basis, retrofitting seems more satisfactory for addressing the many tangible and intangible issues of Cairo’s complicated urban web rather than demolition and complete relocation leading to the loss of Cairo’s identity. On an environmental basis, retrofit has been verified as a more eco-friendly solution by saving tons of Co2 and addressing the scarcity of raw materials in the 20th century (Baeli, 2014). The term retrofit is used specifically to refer to upgrading of a building to enable it to respond to the imperative of climate change avoiding the dilapidation of these high value building that have become inhabitable.
Nevertheless, this dissertation follows the “Trias Energetica” approach and remodels it into a modified Trias Energetica approach. First, by implementing Passive house measures on the building fabric components (walls, ceilings, openings. etc.) to reduce the energy loads. Subsequently, compliance with the occupant’s energy practices and cognitive norms. Finally, Solar Active measures are deliberated due to the geographical location of GCR and the high exposure to solar energy in GCR. This should result in energy neutrality and an efficient use if the energy grid.
1.1 Problem Overview Egypt is the number one energy consumer in Africa leading to daily local electricity shutdowns, urbanization, economic growth and population growth all led to a rapid rise in energy consumption
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throughout the past decade (The Global Legislation Organization, 2015. The Residential Sector is estimated to consume almost half of the electricity produced by the Egyptian national grid (Attia and Evrard, 2013). According to Attia, 20 million apartments were estimated to consume 11 “Mtoe” of energy in the year of 2008. The residential sector is coping with uprisings in temperature with total dependence on mechanical equipment for maintaining thermal comfort. On the correspondent, there has been a constant rise in temperature degrees accompanied with long hot summers which acts as a natural response to GHG emissions (Boko et al. 2007). There are extraordinary opportunities to reduce the consumption of fossil energy in retrofitting existing buildings in Egypt. The peak load has reached 26140 kWh in the year of 2013/2014. Despite the low electricity consumption rates in Egypt (1120 kWh / capita in 2002), when compared to Northern Mediterranean countries, electricity consumption for residential purposes increased by 12% in 2007 (Michel, 2006). In summer of 2008, the total electric demand peaked to 21,530 MW, compared to 19,250 in 2007. Consequently, most governorates, especially in Upper Egypt, witnessed daily blackouts ranging from 5 to 8 hours. Analysts confirm that since the beginning of the long hot summers in the last decade, the hot seasons have been extended from April to October.
As a result, more than or half of the urban peak load of energy consumption is used to satisfy air conditioning demands alone. In 2008, annual sales of air conditioners (AC) It reached 150,000 units. Consequently, air-conditioning of buildings became the single largest consumer of electricity and it accounts for nearly 60% of nation's peak power demand and over 30% (6,500 MW) of annual energy consumption in the residential sector. The housing stock has a really poor record when it comes to converting sustainable design ideas into real time performance (AbdelRazek, 1998). Statistics establish that during the time period of “2006-2010”, an annual average 3
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of 765,000 air conditioning/fan units were sold respectively to compensate for the constructional deficiency (CAPMAS, 2009). This demand is expected to grow annually by more than 12% ((Georgy, 2007, ME, 2006/2007, ME, 2007). All of which resulted in a continuous loop of energy consumerists that further upsurges the consequences of the climate change phenomenon. (Figure 1.1)
Figure 1.1: World Wide economic mitigation by sector. (Source: Bernstein et al., 2007)
1.2 Research Hypothesis The prevailing cognitive norms of the GCR domestic built environment presents momentous potentials for optimizing energy consumption, therefore, achieve passive house/EnerPHit standards for their retrofits.
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1.3 Research aim The aim of this dissertation is to explore the potential of Passivhaus/EnerPHit Retrofit strategies of existing housing stocks in Cairo to optimize energy efficiency. Optimizing energy efficiency leading to the reduction of Co2 emissions, in result mitigate climate change.
1.4 Objectives In order to meet the aim of this dissertation, the following objectives have been set: 1. Critical review of the current literature about residential retrofit and energy efficiency. 2. Critical review of the available literature about Passive house strategies in hot climates and EnerPHit Standards. 3. Identify the relevant key energy performance aspects within the Egyptian energy efficiency code/ residential retrofitting code and investigate for future trends. 4. Reviewing of Cairo’s housing typologies and selecting an appropriate type. 5. Identifying the key issues such as thermal bridging, infiltration and moisture on the performance of the selected building typologies. 6. Critical review of the results observing the impact and developing the appropriate passive house technologies based on current interventions and occupant practices. 7. Evaluating the impact of the proposed Retrofit technologies on energy optimization of the selected typologies.
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1.5 Target Audience Domestic stock Inhabitants: This research concerns the existing housing stock inhabitants and the potential of optimizing energy consumption. National Governmental Policy Makers: The research results are directly related to the policy makers on a national scale who are organizing for the retrofit policies and energy optimization codes. Construction and built environment Industry: This research addresses architects, urbanists and engineers respectively. NGO’s: Organizations such as “Energy Saving Trust� may benefit from this research in terms of retrofit and social planning programs. Academics and researcher industry: This research targets academics that examine residential retrofitting in Greater Cairo Region. Furthermore, it concerns academics that study passive house designs in hot climates and its relation to the Energy Cultural Framework.
1.6 Summary Briefly, this research was driven by the interest of passive house performance in the hot weather of Cairo. In order to avoid the complications of optimization gaps and energy rebounds, a socio technical model was implemented. Social behavioral patterns were investigated to identify the obstructions, motivators and energy behavioral connections respectively.
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Chapter 2: Literature Review
2.1 Overview of Structure
In this chapter, the previous works and literature related to the scope of this dissertation is critically reviewed. The reviewed literature is divided into three main sections: 1- Egyptian Housing Stock Retrofitting & Retrofit Models Explaining the definition of residential retrofitting in respect to the case of the Egyptian Housing Stock, and critically appraising a number of studies and models related to the scope.
2- Passive House concept and the Passive House Planning Package (PHPP). Reviewing the Passive house energy performance standards in relation to residential retrofitting.
3- Social Practice Theory; a socio-technical approach towards retrofit. Reviewing energy consumption in homes through socio-technical approaches which requires a close examination of cultural, historical and radical approaches in retrofit designs.
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2.2 Egyptian Housing Stock Retrofitting & Retrofit Models Amongst various prospects to study the built environment, this dissertation narrowed down its focus to retrofitting the existing GCR housing stock, precisely air conditioned buildings, to optimize energy consumption. The scope was further narrowed down to compact detached units. GCR domestic built environment has a great potential for energy conservation. Further studies and downsides to the contemporary housing stock will be investigated in the following sections. 2.2.1 Residential Retrofit The standard definition of retrofit is the process where the building adapts to change by providing the same level of comfort using less energy through the installment of new components (Merriam-Webster, 2015). This dissertation focuses on minimizing energy consumption of air conditioned building with the least CO2 emissions as a key parameter. However, retrofit differs from renovation and refurbishment as they designate the commenced work in the buildings envelope to prolong the service life (Baeli, 2014). Ambitious and successful governments worldwide aim significant Co2 reductions targets from the existing housing stocks in the next couple of decades. Many incentives were induced to galvanize the construction industry to induce this transitional leap (Chiu et al., 2014). One of the most recent retrofit projects was the “Retrofit for the Future programme� which acted as a catalyst for the retrofit of over 100 residential units across the UK, targeting an 80% diminution of Co2 emissions of each unit (Baeli, 2014). An analysis was conducted on this programme surveying 37 post-retrofitted units. The key findings were that 3 of these achieved more than the desired 80% Co2
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emissions. An additional 23 post-retrofit units achieved between a 50% and 80% reduction in Co2 (Technology Strategy Board, 2013). Nevertheless, the defining approach in this dissertation is the implementation of a series of interventions and adaptations to enhance a building’s condition in terms of energy optimization, Co2 emissions and energy costs. 2.2.2 GCR Building stock The contemporary GCR residential built environment is composed of a multi-diverse set of typologies, sizes and eternities that accumulated through the epochs of history. In order to understand the nature of the miscellaneous housing stock in GCR, it is recommended to analyze the physical transformations and diversity in different regions. GCR has witnessed constant transformations within its housing stock both formally and informally to put up with fast pace of urbanization and the constant migrations from the countryside. These structures date back to the 1920s witnessing decades of foreign occupation and socio-economical interference leading to today’s identity (Myntti, 1999). Cairo’s housing stock significantly expanded to accommodate several architectural typologies and urban variations respectively. Nowadays, Cairo’s urbanscape is divided into two main types; A-Formal Neighborhoods with formal and informal housing stocks (Sims, 2010); •
Governmental social housing
•
Private units in desert cities
•
Units in old Historic Core
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B-Informal Neighborhoods with informal housing stocks (Sims, 2000); •
Units on former agricultural lands.
•
Units on former desert (State) lands.
2.2.3 Housing Study for Urban Egypt by USAID in 2008: A Housing study in in GCR was published by the United states agency for international development (USAID) on the 2nd of December, 2008. USAID conducted the housing study on GCR to analyze housing characteristics based on a detailed questionnaire charting 17,850 households compromising almost 60,000 housing units respectively. Although the GCHS has only surveyed 43% of the total households in GCR, the results of this publication significantly improved the general understanding of GCR’s housing profile. Key Findings of the USAID survey •
The general statistics underlined the “compactness” of existing stock, as the results established that the median footprint area was 95 m2, with a median height of 4 floors and the median number of units per building was 6 units respectively. The small sized, multiple story residential blocks dominate as 57% of the housing stock has a footprint of 100m2 or less. the median width of the street fronting the building was 6m wide.
•
Almost 85% of the surveyed units were composed of multiple apartments per structure, the remainder of the surveyed stock was either private residences or rural developments representing the smaller portion.
•
More than 57% of the housing stock had an Area/footprint of 100m2 or less.
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The median age of buildings was 38 years. 10
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81% of the buildings were considered structurally adequate.
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The median “street to height” ratio is 1.8.
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44 percent of the housing units were found to range from 65-90m2 with the highest reiteration rate. Units ranging from of 40-65 m2 and 90-120 m2 include 19 percent and 21 percent of the surveyed housing correspondingly. Housing with areas of 120-150 m2 represent 16 percent of surveyed units. Residential units that are less than 40 m2 represent 5.5 percent whilst the remainder of the units that are 150 m2 or greater represent 4.5 percent (USAID, 2008).
Subsequently, these records represent the reference point for the typical, most repetitive typologies which will assist further on choosing tested typologies in this dissertation. 2.2.4 Housing Trilemma The housing trilemma model was first mentioned by Pelenur (2013), stating three principal factors act as the utmost influential to todays depreciated housing stock in terms of energy performance; foremost, the historical basis for the residential stock has hindered the domestic energy standards; subsequently, the dawdling replacement rate for old houses; Finally, The heterogeneous physical and social domestic stock. These three factors represent the “housing trilemma” accordingly. (see Figure 2.1)
Figure 2.1: Housing Trilemma diagram of poor energy performance. (source: Pelenur, 2013 )
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With the aim of surpassing this Housing Trilemma and optimizing energy consumption of the housing built environment, domestic retrofit has to take place on a national scale with socio-cultural and energy optimization measures. The subsequent section will describe the proposed retrofit technologies and their potentials to optimize energy consumption.
2.2.5 Egyptian Energy Efficiency Code in 2005 The Egyptian residential standard rating system was developed by the UNDP in 2004, it is mainly a performance based sustainability rating system. ERSA encouraged passive measures as strategy to optimize energy in air conditioned buildings. According to the Egyptian Housing and Research Center (2005), the code established three main methods of assessment for code compliance; Component Prescriptive approach, component trade off approach and whole building performance. The selection these methods should be considered according to the design of the external envelope of the retrofit correspondingly. (See Figure 2.2)
Figure 2.2: (source:Egyptian Housing and research center, 2005)
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A. Code compliance methods for external envelope These three approaches are required to optimize the energy efficiency, thermal comfort and natural lighting respectively. Subsequently, the code was deliberated to regional concepts and benchmarks for residential retrofit in the GCR (Egyptian housing and research center, 2005).
Many further trials of residential retrofit in compliance with the energy efficiency code for but nonetheless, many downsides to the research were originated due to the lack of up-to-dated data based on existing residential prototypes. This resulted in several a collection of systematic approaches towards the solution without a proper assessment of the structures defects. For instance, Hanna’s researched neglected the different patterns of energy consumption through the energy consumption profile. Moreover, the Building defects weren’t properly identified and assessed (G.B., 2011). Thus, it is vital for this dissertation to generate a comprehensive assessment of the chosen typologies by representing both the social energy consumption patterns and structural defects correspondingly. Table 2.2 demonstrates the Exterior envelope requirements for air conditioned building in GCR:
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Table 2.2 - Exterior envelope requirements for air conditioned building in GCR
In an attempt to reduce growth in demand for electrical energy, the government issued the first Egyptian Energy Efficiency Building Code (IBC) for residential buildings in 2004 (HBRC, 2005). However, the code is not mandatory and the government was unable to adopt and enforce the new code until now. Adding to that, there were no guidelines provided in the code with regard to retrofitting existing buildings. For all that reasons, this study was conducted to assess the impact and potential of retrofitting existing buildings, on a community scale with low energy conservation measures. The emphasis was placed on residential middle-income housing since it has considerable potential for energy conservation measures that should start at once (Hussein, 1995).
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2.2.6 Egyptian Retrofit Models A. Attia’s model of retrofit: Shady Attia is one of the Egyptian contemporary “Sustainable building design and engineering� expertise. Attia conducted several experimental studies testing the potential of different domestic retrofit strategies in GCR. Attia and da Herde conducted an experimental study in 2010 to evaluate the potential of low-energy retrofits in Egypt. According to Attia and da herde (2010), residential buildings in GCR show relatively a high consumption of energy precisely in the heating and cooling sectors. Shady states that the chosen location and climate conditions represent an excellent opportunity for experimenting and exploring the feasibility of active solar retrofit strategies. (see figure 2.3)
(a)
(b)
Figure 2.3: (a) Installed PV Cells, (b) Dimas Solar Thermosiphon installed on roof. (Source:Attia, 2010)
Attia studies the Passive solar house techniques aiming at examining the potential of active solar retrofit strategies in minimizing the loads from the main energy grid. In a similar study, Attia focused on 3 main steps to lower the energy consumption by 80%; Envelope retrofit, solar protection, high thermal mass and ventilation strategies. 15
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Moreover, PV cells, domestic water heating and SAC were used as active solar strategies. the case study specifically compared between the case of an individual house in terms of the energy performance before and after retrofit These comparisons were conducted through energy consumption assessment, performance of the baselines using software’s like “TRNSYS” and a two-year monitoring following the international standard outline (ISO 9459-3 performance test for solar systems).
Figure 2.4: Second monitoring period for the RPSH. (source: Attia, 2010)
Shady stated that 55% of the total energy consumption was disbursed by the cooling loads, consuming 2736 kWh per annum. The cooling loads were estimated to reach 7.2 MJ. Per day at the hottest day of the summer. Furthermore, the annual heating load was measured to be concluded at 1616MJ with a maximum load of 9.2MH at the coldest day of the year.
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The surveys concluded that 4956 kWh of energy consumption per annum which is equivalent to 8177 Kg Co2 emissions increasing the potentials of climate change. The experimental results for renewable energy in GCR were intriguing as they covered a huge portion of the consumer’s annual energy consumption. According to figure 1, the solar photovoltaic cells showed a total energy production of 5777 kWh/year. During the winter season, the additional solar electricity production was fed into the national grid. Furthermore, the domestic water heating’s volume covered the family needs.
In a brief, active solar strategies for retrofit in GCR show remarkable prospects for both minimizing energy consumptions through the national energy grid in the GCR climate. Thus, the study recommends that centralized solar collectors should be optimized to supply domestic buildings both in solar air thermal cooling and DHW substituting Ac conditioning to achieve ultra-low-energy residential buildings in GCR. In another research, he further examined the application of these passive and active retrofit strategies on 3 different domestic typologies assessing the energy performance. This experiment resulted in a total reduction of energy use to 57 kWh.m2a (83%). Furthermore, this impacted the structure in means of quality of life, increasing property value and extending the physical life of the building for a several more decades. B.Gaps in Attia’s approach to retrofit Despite of the major success in the reducing the electrical energy demand, Attia’s research solely focused on testing an array of renewable technologies, overlooking occupant’s energy behavior as well as the prefiguration of societal patterns in relation with the selected technologies. Focusing on societal patterns afore quantifying
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individuals. Social practice theories present an opportunity to capture, analyze and redirect retrofit practices with more reliability: -
Physical significances due to alteration of spaces.
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Occupant dis-satisfaction due to external alterations (insulation).
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Occupant dis-satisfaction due to loss of internal spaces.
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Daily habits and cultural traits resulting in the Energy rebound (Opening/Closing windows).
User Incompatibility may result in a significant energy rebound. Furthermore, his approach hindered significant deliberations to assessing the structure through measuring fabric defects (thermal bridging, airtightness, u-values, etc.) and most importantly; how all these strategies work together.
2.2.7 Modified Trias Energetica Process This section introduces a modified version of the “Trias Energetica� process whereby a new factor was added which is the socio-technical aspect. Considering a socially oriented approach for choosing the technologies is vital in terms of addressing the mismatch between the expected and actual energy savings in post-retrofit results whether as an outcome of a defect in construction or an unanticipated socio-behavior [Guerra-Santin et al., 2013; Haas et al., 1998; Tweed, 2013; Zero Carbon Hub, 2013]. An Austrian study stated that the estimated energy consumption increased by 25% due to occupant behavior (Hass et al, 1998). In addition, a case study research based on two low energy domestic units in Switzerland, found that the post installation of solar active panels has exceeded what was expected by 54% in 3 years (Branco et al, 2004). 18
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Complexity of the technology used and the poor production quality was accredited as the main unconventionality (Branco et al, 2004). Conversely, these deviations are nevertheless vital to be investigated throughout preliminary examinations of the building typology (Guerra-santin et al. 2013).
Passive House Concept EnerPHit Standards Minimizing Energy Consumption Fabric First approach Controlling solar gains and shading to avoid overheating during the summer. Insulating the key junctions of the envelope’s construction and avoiding thermal bridges. Impact of Form Factor and material U-values. Achieving Thermal Comfort Airtightness, indoor air quality and an effective MVHR system. Meeting annual Space heat demands of maximum 25kWh/m2 Annual primary energy demand of maximum 120 kwh/m2
Social Practice theory Occupant's behavior towards energy Q-Methodology
Utilize Renewable Energy Sources Efficient use of Electricity Grid
Solar Active Air Conditioning Domestic Water Heating
Figure 2.5: The three phases of the ''Trias Energitica'' Approach
Figure (2.5) represents the 3 main phases for the modified “Trias Energetica” Approach. Focal prominence is given to the Passive house concept in hot climates, compliance with the PHPP main concepts were followed for achieving the passive house criterion and meeting the energy loads respectively. Proper assessment of structure conditions is given towards the building fabric subsequent to the “Fabric First Approach”. In sequence, a Socio-technical approach efficiently uses the incoming electricity which will correlate the selected technologies with the occupant behaviors further on throughout this dissertation. Finally, energy neutrality is achieved through 19
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“Solar Active Retrofit Strategies� based on the geographical advantage of GCR in the median hemisphere.
2.3 Passive House concept and the Passive House Planning Package (PHPP) 2.3.1 Minimizing household energy consumption and demand The Passive House is perceived as a comfort house (Colley, Antonelli and Hearne, 2013). The PH concept is one of the most established foundations of sustainable construction worldwide due to its minimalistic usage of energy through precise principles and criteria (Lewis, 2013). Adamson and Feist came up with the PH concept in 1988 defining the golden standard for energy optimization in homes, this later has been recognized by the consistent growth and added numbers of certified passive house structures surpassing 25,000 worldwide. Energy efficient implementations and injecting the voids in the structural main junctions cutting down the thermal conductivity, convection and noise levels significantly. Furthermore, EnerPHit retrofit standards have been developed to be certified through Passive House strategies (Lewis, 2013). Passive House strategies offers effective solutions to the existing domestic stock.
However, constructing a passive house requires meeting specific technical standards regardless of the regional location and local climate (Gibbons, 2011). This is accomplished predominantly through nine key concepts; Fabric First approach; Controlling solar gains and shading to avoid overheating during the summer; Insulating
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the key junctions of the envelope’s construction and avoiding thermal bridges; Impact of Form Factor and material U-values; Achieving Thermal Comfort; Airtightness, indoor air quality and an effective MVHR system; Meeting annual Space heat demands of maximum 15kWh/m2; Annual primary energy demand of maximum 120 kwh/m2. A Passive house standardized house uses 90% less heating demand compared to a conventional housing unit. If a retrofitted unit achieves the passive house criteria, thus, it will be certified as a Passive house. Nonetheless, it is extremely hard to comply with passive house standards in the case of a retrofit project. EnerPHit standards are nearly as hard to meet as the passive house standards. Several reasons affect the feasibility of achieving the passive house standards for old conventional buildings such as structural longevity, cost effectiveness, airtightness and thermal comfort during the whole lifespan of the structure and energy consumption respectively. On the other hand, Cotterell and Dadeby (2012) assure that EnerPHit standards can be fulfilled through passive house components and external fabric insulation. According to table (2.3), EnerPHit certification is considered as a more convenient preference for retrofit projects. Still, they require complying with specific mandatory requirements (Taylor, 2011). Table 2.3 – Passive House Standards vs EnerPHit standards (Cotterell and Dadeby, 2012)
Criteria
Based on PHPP Heating
Based on PHPP Heating
Passivhaus Standards
EnerPHit Standards
Heating demand
QH ≤ 15 kWh/(m2a)
QH ≤ 25 kWh/(m2a)
Window U-value
UW,installed ≤ 0.80 W/(m2K)
UW,installed ≤ 0.85 W/(m2K)
Glazing U-value
Ug ≤ 1.6 W/(m2K)
Ug ≤ 1.6 W/(m2K)
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U-value of external door
UD,installed ≤ 0.80 W/(m2K)
UD,installed ≤ 0.80 W/(m2K)
Ventilation
hHR,eff ≥ 75 %
hHR,eff ≥ 75 %
Primary energy demand
QP ≤ 120 kWh/m2a + ((QH - 15 kWh/(m2a)). 1.2)
QP ≤ 120 kWh/m2a + ((QH - 15 kWh/(m2a)). 1.2)
Airtightness
n50 ≤ 0.6 h-1fq
Limit value: n50 ≤ 1.0 h-1 Target value: n50 ≤ 0.6 h-1
Opaque Building Envelope
U ≤ 0.15 W/(m2K)
U ≤ 0.15 W/(m2K) Exterior Insulation
U-value of wall U ≤ 0.35 W/(m2K) Interior Insulation
U-value of Roof
U ≤ 0.15 W/(m2K)
U ≤ 0.35 W/(m2K)
Intermediate Floor
Minimum surface air temperature of 17 c
Minimum surface temperature of 17 c
Overheating
≤ 10% (T > 25°C)
≤ 10% (T > 25°C)
air
In order to meet the EnerPHit criteria, the envelope must be designed to have an annual heating load demand less than 25 kWh / m2a and similarly for the cooling loads (Passive House Institute, 2013). According to the Passive house institute, there are two typical certification procedures for meeting EnerPHit standards in conventional houses; -
Certification based on the heating demand requirement
-
Certification based on requirements for individual building components
Nevertheless, many drawbacks and disadvantages were found for the component approach due to the lack of convenient and PH certified components on an international scale (Taylor, 2011). However, in the case of a non-certified building component, a
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lengthy process of standardization is required meeting the required limit values. On the other hand, space heating demand represents more flexibility especially in the case of international projects.
2.3.2 Passive house planning package (PHPP) The Passive House Institute introduced the Passive House Planning Package (PHPP) first in 2005 as a consistent passive house design tool. Chronologically, PHPP has proven to provide reliable results in various climates and consequently it can be used as an international planning and verification tool (Lewis, 2013). PHPP is an energy balanced tool representing reliable foundations for Passive house designs in diverse climate zones.
2.3.3 PHPP at an international scale The Passive house planning package is based on physical properties of universal building physics, moreover, the consistency of the calculation worksheet was tested multiple times through scrupulous building measurements and dynamic comparative simulations correspondingly (Cotterell and Dadeby, 2012). According to Lewis (2012), the calculation measurements in hot areas was first introduced in 2007 and has been followed by a sequence of international studies from the time initiated to hitherto. PHPP is a user-friendly software for energy balance that provides reliable results for all climate zones including hot climates. Unpredictably, the calculation inputs for the rate of overheating, cooling and dehumidifying resulted in
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reasonable results requiring slight modifications. Calculations for shading and behavior of leaky fabric components in hot climates was also analyzed and validated. As a result of the various requirements for the retrofit of existing buildings, the PHPP addressed the precise requirements with energy efficiency measures as follows:
2.4 Social Practice Theory; a socio-technical approach towards retrofit Social practice theory is the leading approach in understanding energy consumption in homes through socio-technical approaches which requires a close examination of cultural, historical and radical approaches in retrofit designs (Shove et al., 2008). Although several technical solutions were developed to reduce energy consumption, the actual post operation of these technologies don’t usually go as planned resulting in a significant performance gap. Most current retrofit practices adopt purely technical models which set an array of technologies that overlooks the nature of occupant’s behaviours and properties of dwellings (Cole et al., 2010; Sunikka et al., 2012; Schweber & Leiringer, 2012). Buildings are not limited to technical issues but a set of social interactions with their home environment, a combination which demands new meanings and acknowledgment of the relationship between people and technology. This can prolong to the broader socio-cultural context as well. Many attempts throughout the past decades attempted to foray the application of energy retrofits in a phenomenological sense (Norberg-Schulz, 1971; Seamon, 1993; Tweed, 2000). This relationship was classified into three basic categories: embodiment, 24
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hermeneutic and alterity relations (Ihde, 1990). However, McCarthy& Wright (2004) refer to the interaction between technology and users as visual engagements, located creativity, hubs of value and a creation of sense. This requires understanding of two core concepts; -
The co-evolving nature of social and technological interactions (e.g. Elzen et al,. 2004)
-
The interweaving of technological components (walls, roofs, air ventilation, windows, etc.) within the social mesh (Schatzki, 2001). This leads to the acknowledgement of the main limitations and enablement’s for actions and technologies happening within a sequenced mandate.
The main advantage of this approach is that it doesn’t privilege neither of the social nor technical practices. As an alternative, it goes beyond the dualistic ideas of occupants and technology by investigating the social practices in coalition with existing building components (Schatzki, 2002)
2.4.1 The Energy Optimization Gap The Energy Optimization Gap is pronounced to be the existing energy gap of the current or the future consumption of domestic units. Weber conducted a study in 1997 demonstrating that the Energy Optimization Gap leading to a 30% loss of energy in the OECD countries. Four miscellaneous approaches were identified by Wislon & Dowlatabdi (2007): Attitude-based decision making for energy consumption and conventional and behavioral economics; sociology and phenomenology; Social and environmental phycology. Nonetheless, the concept of perceiving inhabitants as 25
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physical objects presumes that energy is consumed with a solitary purpose denudating the subjective conception of energy usage and its incidental nature (Lutzenhiser, 1992). Haas et al. (1998) conducted an investigative study for over 400 Australian domestic properties, they stated that the irrational usage of machinery hindered by the unseen energy led to the increase in the energy demands by 15-30% respectively. The measured room temperatures weren’t correlated with the ones found on the machinery sensors. This further was justified by the fact that the inhabitants usually open the windows in order to balance the indoor temperature. Burgess and Nye (2008) defined such energy as doubly invisible for the inhabitants. Preliminary models were investigated with the Living with Environmental Change programme in 2009, over 60 appropriate sociopsychological models, frameworks and concepts were presented to help understand the energy optimization gap (Darnton, 2008). The main findings of this programme was finding the correlative importance between the psychological variables and the energy consumption in households. Faiers et al. (2007) concluded that a wide range of punitive factors should be considered that extend beyond the single households; Individual cognitive abilities, occupants attitude, cultural principles and the social pattern of energy consumption. The rebound effect displays an additional behavioral challenge besides the energy optimization gap in housing stocks.
2.4.2 Rebound effect On occasion, Energy optimization and improvements counters spontaneously to a more energy-hungry building. This is called the rebound effect. The rebound effect can result in a direct means and indirect others; different house temperatures are a direct mean of rebound effects whilst the misuse and miss-choice of appropriate technologies. Thus, 26
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its vital to have a wide understanding of the social aspects of the households related to energy consumption in order to avoid consequences. Wilson and Dowlatabadi (2007) presented a primary cohesive model for pro-environmental activities. (see figure 2.6)
Figure 2.6: An integrated model of pro-environmental behaviour
Wilson and Dowtabadi’s model differentiates between the personal and contextual fields while identifying the interactions between them. Even though the models show full interactivity, the model does not present a straight forward application method (Wilson & Dowlatabadi, 2007). However, Lutzanhiser (1992) introduced the notion of a much simpler integrated energy cultural basis to comprehend behavior, that deliberates social norms and cultural background in conjunction with other econometrics. The energy culture framework was further backed by the Technology Acceptance 27
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Model which investigated the social behavior determination. Stephenson et al. (2010) correlated the Energy cultural framework to consumer energy behavior in one of his studies, this resulted in suggesting the ECF as an appropriate framework for detecting deficiencies for the chosen technological interventions. This framework is practical for assessing individuals, total households and community scale projects. The ECF demonstrates the main obstructions and motivators for energy efficiency potential; social and communal norms; cultural practices and shared expectations all are decisive factors in this equation respectively (Hargreaves et al., 2010; Rayner & Malone, 1998). For instance, the direction of the window opening in relation to the exterior shading, lifestyle adoptions and selections; household perception on aesthetics of technological interventions and the home heating behaviors respectively (Pelenur & Cruickshank, 2011; The Government office for science; 2008).
Figure 2.7: Energy Culture framework example. (source: Stephenson et at., 2010)
This figure encourages an inter-disciplinary, socio-technical approach without hindering the technical importance nor the economic assessment generating a long
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lasting change (Tweed 2013). Figure (2.7) altered this model to hypothetically addressing the main components of the energy efficiency gap. The household is unambiguously centered with three imperative areas of study; Cognitive norms such as social attitudes and behavior towards energy, followed by material culture (structure fabric and selected technologies) and energy practices respectively. Deprived of the consideration of the interlinked connection of this model, the household will not meet optimal energy savings and optimization. For instance, trials to alter the material culture without configuring it with the cognitive norms respectively.
Figure 2.8: Research model based on energy culture.
This diagram helps to achieve the main aim of this dissertation which evaluates the potential of Passive House strategies to optimize the energy performance in the domestic built environment without dwindling in the energy efficiency gap dilemma.
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Chapter 3: Methodology 3.1 Approach This dissertation is using a mixed approach by testing both empirical and theoretical approaches in the direction of viewing the potential of Passive house concepts as a viable solution for retrofitting existing housing stocks in Cairo to achieve energy optimization. The existing literature is critically reviewed on the early stages of the process by identifying the main concepts, noticeable researches, key codes and knowledge gaps in this area. Furthermore, empirical surveys were conducted with evaluative questions to measure the affectivity and the assessment of each measurement altering it into a recommendation correspondingly. Correlative studies are used to assess the relationship non-empirical theories and empirical surveys. Objectives number 1&2 are going to be met through a qualitative review of primary research sources such as governmental publications concerning deficits in Cairo’s housing stocks. Furthermore, a quantitative analysis of the existing energy consumption census on the residential sector in Cairo will be conducted. Objective number 3 is going to be met through a review of both primary and secondary resources, identifying key relevant codes and future trends through a number of governmental codes and publications. Secondary data will be reviewed initially through the university library using a range of information sources such as the OPAC system, academic and commercial abstracts, bibliographic databases, document analysis and Internet search engines. The current benchmarks and records will be tested through an on-line survey that will be conducted to gather primary source data from existing households related to energy consumption data per household. A systematic yet random sample survey will be conducted to gather Qualitative data about energy practices and cognitive. Quantitative studies are going to be conducted through 30
previous benchmarks, questionnaire results and academic studies around energy consumption in housing typologies to determine the most effective and repetitive typology to impact the most. To aid the search, a table of key terms will be constructed and the sources located will be associated with this. Additionally, a secondary cross-reference table will be developed so that data can be viewed from different perspectives.
Objective number 4 is consists of a set of qualitative studies about Passivhaus/EnerPHit standards by reviewing primary resources and certification standards. The collected data would be analyzed through considering the applicability of Passivhaus techniques/standards through a quantitative matrix correlated with variable aspects such as practicality, monetary values and building codes to select the appropriate Passivhaus elements in this dissertation. As the number of Passivhaus elements engaged in the defined activity increase, it is anticipated that a commercial spreadsheet package such as PHPP excel sheet would be appropriate, However, a more sophisticated analysis software’s such as DesignPH and Ecotect would be used to meet objective number 5. Results would be quantifying simulate the impact on energy efficiency and so on to mitigate the Co2 emission rate. Quantifying the surrounding microclimate into a number of factors (i.e. Street width, surrounding environmental analysis) affecting the selected typologies and using it as a factor in the equation.
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3.2 Data collection methods Data collection outlines the research objectives and hypothesis. This occurs by testing the hypothesis in alliance to the chosen objectives. The data collection in this dissertation both quantitative and qualitative. Two chief surveys are going to be conducted through two visits to the selected sample typologies; -
Initial survey; empirical surveys were conducted with evaluative questions to measure the two main aspects; the role of energy in the occupant’s daily behaviors and the uses of various residence spaces. Furthermore, the building fabric will be assessed through thermal image technology to detect main defects.
-
Evaluative survey to measure the social acceptance and the potential adaptability of the retrofitting interventions.
3.2.1 Equipment used in inspection Table 3.1-Tools used for the research
FLIR One Thermal Camera for IOS Temperature Specification Scene range temperature: Celsius to 100 Celsius
0
MSX Blending
32
iCelsius thermometer/sensor for IOS Temperature Specification Measurement range: -30 Celsius to 150 Celsius. Display resolution: 0.1 Celsius
3.2.2 Field survey Method A. Q Method Q is a fundamentally exploratory method that brings a sense of consistency to the energy viewpoints of the residential occupants in a statistical analysis [Smith et al., 1995]. The research conducted in this dissertation presents the first energy Q based analysis in the GCR domestic built environment. According to Pelenurs model (2009), The following common steps to a typical Q study were applied accordingly: I.
Categorizing and classifying the main areas of subjective discourse. The word discourse refers to the communal and household viewpoints on the residential energy consumption.
II.
Investigation of the household perspectives through a series of interviews and discussions with the relevant households. Other sources were reviewed such as magazines and newspaper editions creating a wide-ranging list of different viewpoints and perspectives that widely incorporates the residential energy consumption (brown, 2004; Watts & Stenner, 2012). 33
III.
A selection of the Q-set which represents the single utmost paramount statements.
IV.
Carrying out Q-sorts with the households by respectively ranking the Q-set using a Likerttype scale into a quasi-normal distribution as shown in figure --. However, other forms of distribution can be applied such as the free form distribution where the form of this distribution applies no implications (Brown, 1980; Watts & Stenner, 2012). This stage concludes qualitative analysis of the household viewpoints and decisions.
V. VI.
Execute a statistical individuality factor analysis with the Q-sorts. Qualitatively interpreting the consequential factors which signifies the emerging perspectives.
Figure 3.1: Q study quasi-normal distribution. (source: Pelenur, 2009)
Brown (1980) stated that a relatively minor Q-set shows a perceptive hyper-astronomical sum of sorting options and arrangements in statistical means with a qualitative lens. Thereby establishing energy consumption patterns within and amongst individuals is possible with the Q method (Barry & Proops,1999). Furthermore, questionnaires were developed and directed to measure the selected retrofit technology and energy preferences. The results of the questionnaire were correlated with the results of the Q methodology.
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B. Questionnaires In order to measure the subjective individuality of an occupant’s desire, a systematic questionnaire was established with 5 Likert item to choose from. According to Matthews & Ross (2010), the questionnaire provides a clear assessment of the various subjective views which complies with of households in different apartments. Furthermore, coding data is relatively easier to sort and develop through an appropriately structured questionnaire (Pallant, 2010). Additionally, semistructured interviews were done demonstrating different technologies and further amplification of the simulated impact on energy consumption. This Questionnaire mainly aimed at understanding the intent of the selected household samples to install the selected technologies. The questionnaire was influenced by two theories respectively; the Theory of Reasoned action and the theory of planned behavior respectively. However, it formally didn’t apply the models, to be specific, the questionnaire measured the aspiration and intent to approve of the desire to apply the chosen technologies. The word “desire” was intentionally used as it expresses the need of the technology regardless of the actual capability of doing so. For instance, A Solar PV system could be highly desired by an occupant but couldn’t actually purchase it for monetary reasons. These theories both propose that the utmost way to predict an individual is by their demonstrated degree of intentions (Kaiser et al., 1999; Kalafatis et al., 1999; Jackson, 2004). Ajzen and Fishbein developed the TRA in the late 1980s to TPB to comprise gauges or both action and intentions. PBC is defined as “the person’s belief as to how easy or difficult performance of the behavior is likely to be” (Ajzen & Madden, 1986). Thereby, a description box was placed to identify the variance concerning the motivations and obstacles to the selected technologies. (figure 3.2)
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Solar Active Retrofit
Figure 3.2: Figure illustrates the structure of the methodology in relation to the other phases of this thesis. (source: Author)
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Chapter 4: Housing Typologies Selection Matrix in Cairo Muhandeseen is located in the center of Cairo. Although Cairo is known for its diurnal temperature swings, the hot arid climate dominates most of the year extending from April to September (Attia & Herde, 2012) the chosen buildings were originally built on agricultural lands with a high built area density. Locational coordinates are 30.1 and 31.4 as a result (Google Earth, 2016). The weather data file was set accordingly.
Figure 4.1: Typology description
The selected base case typology is a typical compact detached residential building in al Muhandeseen. This building typically has 12 flats distributed amongst 6 floors. However, the assessment was narrowed down to assess the ground, third and the last floor to develop an overall assessment for the typology.
4.1 Current Energy Load of flats An Ecotect file was produced with all the necessarily information such as buildings architecture, materials, and energy loads respectively. Two unit typologies were chosen to be assessed in 4 different orientations according to their Floor lever. A Typical unit is composed of 6 zones 37
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(Bedroom 1, Bedroom 2, Bathroom, Kitchen, lobby and main reception respectively). Each zone has its own properties according to occupant’s behavior and the ongoing activity within. However, the main difference positions in the floor lever as each floor has different surroundings and environmental exposure respectively.
Figure 4.2: Main Image of the Selected Typology
Figure shows that the unit in the last floor contributes with almost double the load of that in a ground floor. Western and southern units consume the most energy followed by the north northern and eastern respectively. 12000.00 10000.00 8000.00 6000.00 4000.00 2000.00 0.00 North
East Typology A 1 Energy cons. kWh
West
South
Typology A2 Energy cons. kWh
Figure 4.3: Figure 3 Current Energy Consumption of typology A1
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Figure 4.4: Drawing details showing the main construction details of the selected typology
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4.2 Thermal Imagery Survey The thermal imagery inspection chosen to be undertaken on the 29th of January, 2016 around 7:00pm. The external temperature was 8 Celsius on that corresponding day whilst the internal temperature was around 18-23 Celsius accordingly. This timing was chosen to test the effect of direct solar radiation on the interior physics of the built environment. No existence of rain or condensation during the corresponding week. Inspection tested two typologies respectively; typology A1 and typology A2. In order to effectively assess the buildings fabric, the facades were scanned in separate images to maximize the in-depth of details accordingly. Access was possible to all parts of the building and main junctions were tested. Table 4.1: Main Elements of inspection Source(Author)
Heat Transfer through
Status
Description
Fabric
Exists
All key junctions were identified
Infiltration
Exists
Air leakage found through door, sealed windows and equipment installations.
Ventilation
Eliminated through closing ventilation units
All windows were closed and sealed
insolation
Solar radiation eliminated
Sun sets around 6pm before inspection
Incidental sources
Exists
Appliances were working.
Services
Exists
Heating systems were turned on prior to the inspection
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4.3 Main Findings of the thermal imagery survey The thermal survey resulted in determining the main defects of the selected typologies leading to the existing so-called energy hungry buildings. Figure one shows the main defects found in the inspected fabric accordingly. Thermal bridging transpires when heat flow sidesteps the insulation of the fabric through its structural components. However, the building isn’t insulated which means that the whole building in its contemporary state significantly allows heat flow. Windows also act as the greatest source of heat flow in the building, subsequently, R.C structural edges account for the second utmost potential source of thermal bridging particularly in the case of multi-story buildings.
Linear Thermal Bridging through the reinforced structural members. Insufficient windows and fitting techniques.
Low internal temperature surfaces High Energy Consumption
High fabric gains through roof and walls
Cold spots due to lack of ventilation and air movement
Figure 4.5: Main Fabric Complications Source (Author)
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4.4 Socio-technical Survey Results 4.4.1 Household standpoints about energy consumption: This research stage investigated a random yet systematic household questionnaire towards energy usage. This mainly was driven by involving the primary stakeholder’s principle to meet the paramount goal which is reducing residential energy demand. The resulting attitudes towards energy are considered vital as they act as a standpoint and a selection criterion for the technological interventions to assure avoiding unintended significances or conflict (Burgess & Nye, 2008). A preliminary 9-point based questionnaire was handed to the residents enquiring about general energy practices. Henceforth, for an extensive understanding of the household attitudes towards energy consumption, the questionnaire survey was applied towards a block (12 apartments) context.
4.4.2 Preliminary questionnaire results 12 units were surveyed accordingly. 6 surveys were done in typology A1 and the same for A2 accordingly. Average households had 4 occupant’s and children ranging from 15-25 years the average AC daily operation was 5 hours in one room and 9 hours in the master bedroom. The majority of the responses confirmed the results of the thermal imagery survey accordingly. 4.4.3 Q-study results A sum of 12 Q-sorts were concluded in El-Muhandeseen, it was vital for the research to engage various standpoints and category representative. Based on the results and experiences, further judgements were made to identify the specificity and the secondary factors serving the prevailing 42
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primary aspect. Brown (1980) stated that a specificity is defined as “a factor where respondents that load significantly on it also agree with the main dominant factor”. This allows investigating the prevailing standpoint from multiple sub-perceptions. This Q-study resulted in identifying three main factors in El-Muhandeseen;
Factor 1: We should consider being more energy efficient to save money, but we don’t know by what means to do so.
Factor 2: I usually don’t give much thought about energy optimization, but then again a renewable energy supply is beneficial and in favor.
Factor 3: I’m not ready to change my lifestyle and I don’t care how much energy I’m consuming.
7 household Q-sorts highly epitomized factor 1, accounting for more than 55% of the total households. Most households weren’t satisfied with their overall energy bills, nonetheless, they desired a more cost-effective unit. Highlighting an obvious desire of saving money and preserving energy was the central theme of this section. One occupant quoted; “I would rather heat only one room, however, I usually end up heating the whole house using the stove due to insufficient technologies”. 4.4.4 Research ethics in choosing human participants The design of this phase judiciously considered the ethics and insinuations of recruiting human participants in the questionnaires, Q-sorts and interviews respectively. The ethical code established by the UOC was respected as well as following the Blackwell’s précised guidelines. Throughout the various stages of this chapter, a signed consent was handed over to the residents outlining the purpose, main aims, outcomes and goals respectively. 43
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Figure 4.6 Modified Trias Energetica Source(Author)
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4.5 Strategy 1: Thermal Mass 4.5.1 Thermal imagery discussion Fig. 7 demonstrates a clear ongoing process of heat gains and losses through the through buildings envelope. Fig.8 shows that Slab concrete edges act as a thermal bridge leading to significant heat gains and losses. Furthermore, it is noticeable that the infill (red brick) has low thermal mass which has a great impact on the summer overheating.
Figure 4.7 Thermal Image of the main elevation
Figure 4.8: Thermal image inside Typology A2
The thermal mass positioning plays a vital role in the energy consumption in buildings as it limits the air infiltrations that contributes to the heat flow accordingly. According to the PH institute (2012), air infiltration significantly contributes to the energy optimization process. Commonly, a building with a high thermal mass has less internal temperature variations whilst a less mass building has more temperature variations which is considered unhealthy according to the passive house standards. Thermal mass is significantly energy effective in the case of diurnal climates. Table two demonstrates the three introduced thermal mass types for experimenting in the
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subsequent section accordingly; Fiber, Extruded Polystyrene and mineral wool.
Table 4.2 Selected Thermal Mass Technologies Source(Author)
Code
Insulation Type
Position
K (W/mK)
Thickness (cm) for a U-value of 0.1 W/m2K
F.G-1
Fiber
Internal –external
0.044
44
M.W-1
Mineral Wool
Internal –external
0.038
38
Internal –external
0.008
10
(Thermafiber)
E.P-1
Extruded Polystyrene foam (High density)
4.5.2 Results Discussion This section links the impact of three technologies on the energy optimization through insulation a base case of a wall composed of red Egyptian brick. Fig.10 shows an overall energy optimization of 6% reduction solely based on external fiber insulation. The total energy consumption was reduced from 7836kwh to 7369 kwh. On the other hand, the Polystyrene insulated wall showed an insignificant increase in energy consumption than that of the fiber insulated wall with a 6.1% reduction in total energy consumption (Fig 11). Likewise, the wool insulated wall showed the same almost the same performance. According to Attia & DeHerde (2009), Extruded polystyrene is considered one of the most appropriate insulation materials in the GCR region for its durable and resistive nature to the existing diurnal weather.
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Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7357.70 6845.00
R.B_Wool_Insulated 512.70
7836.60 R.B_No_Insulation
7216.20 620.40
Figure 4.9: Impact of Wool Insulation using ECOTECT Source (Author) Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7369.04 6855.44
R.B_Fiber_Insulated 513.60
7836.60 R.B_No_Insulation
7216.20 620.40
Figure 4.10 Impact of Fiber Insulation using ECOTECT Source (Author) Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7367.32 R.B_Polystrene_Insulated
6854.02 513.30 7836.60
R.B_No_Insulation
7216.20 620.40
Figure 4.11 Impact of Polystyrene Insulation using ECOTECT Source (Author)
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9000.00 8000.00 7000.00 6000.00 5000.00 4000.00 3000.00 2000.00 1000.00 0.00 Heating (Kwh) R.B_No_Insulation
R.B_Fiber_Insulated
Cooling (Kwh) R.B_Polystrene_Insulated
Total (Kwh) R.B_Wool_Insulated
Figure 4.12: Comparison between Thermal mass technologies Source (Author)
4.5.3 Thermal imagery discussion Fig.13 demonstrates a clear fragmentary process of heat gains and losses through the intermediate concrete slab floor. Additionally, fig. 14 the ceramic tile finish appears to have a direct impact on the overall temperature. The following section will study the impact of adding insulation and changing the floor finish to a common parquet finish.
Figure 4.13: Thermal Image inside Typology A2
Figure 4.14: Thermal Image inside Typology A2
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4.6 Intermediate floors As ensued in the thermal imagery survey, the ceramic floors contribute to creating cold spots in the internal environment which directly contributes to the thermal discomfort and heat gains and losses along with it. According to the EEEC and the PH institute, intermediate floors are not given much significance towards the total energy consumption. However, in the case of the selected typologies, intermediate floors show a great deal of contribution towards heat flow and air infiltration as shown in fig. 14. The subsequent section will assess the impact of three different floor sections towards the total fabric gains and energy consumption rates. Table 4.3- Selected Intermediate floor configuration
Abbreviation
Configuration
Position
C1
(Infill+Mineral tiles)
P1
(Infill+Mineral Wool+parquet)
Wool+ceramic
External / envelope
Reflectance percentage
whole
building
External
50
70
4.6.2 Results and Discussion This section links the impact the internal heat flow through intermediate floors and its impact on the total energy optimization process. Two factors are addressed in this section accordingly; the impact of the floor finish and the impact of internal insulation between floors. Fig 15 shows an additional 6% improvement in the of the energy optimization process solely through polystyrene insulation. Moreover, Fig.4.15 shows that the“Concrete_Polystrene_Parquet” shows a slightly higher energy performance than that of Fig. “Concrete_Polystrene_ceramic”.
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Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7369.04 Concrete_ Polystrene_Ceramic
6855.44 513.60
7836.60 Concrete_No_Insulation
7216.20 620.40
0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
9000.00
Figure 4.15: Impact of Polystyrene Insulation and ceramic finish using ECOTECT Source (Author) Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7367.32 6854.02
Concrete_Polystrene_Parquet 513.30
7836.60 7216.20
Concrete_No_Insulation 620.40
0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
9000.00
Figure 4.16: Impact of Fiber Insulation and parquet finish using ECOTECT Source (Author)
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9000.00 8000.00 7836.60
7000.00
7216.20
6000.00
7369.04 6855.44
7367.32
6854.02
5000.00 4000.00 3000.00 2000.00 1000.00 620.40
513.60
513.30
0.00 Heating (Kwh) Concrete_No_Insulation
Cooling (Kwh) Concrete_ Polystrene_Ceramic
Total (Kwh) Concrete_Polystrene_Parquet
Figure 4.17: Comparison between Thermal mass technologies Source (Author)
4.6.3 Thermal imagery discussion The following thermal images demonstrate a clear heat flow through the ceiling of the last floor (Typology A). Clearly, Fig 18 demonstrates The reinforced concrete slab floor allows heat flow to the external environment. Table 4 discusses the different scenarios of roof configurations in terms of fabric gains and energy consumption.
Figure 4.18: Thermal Image inside Typology A1
Figure 4.19: Thermal Image inside Typology A1
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4.7 Ceiling According to Dabieh et al., (2015), there are significant potentials in minimizing energy consumption through the direct shading and insulation strategies of the rooftop and avoiding direct solar radiation consequences. Dabieh conducted over 35 sample surveys to determine the most effective roof strategy in order to minimize heat gains respectively. The results of this experimental test displayed three techniques that minimized heat gains by over 50%; vault roofs, water pond roof and albedo coated roofs respectively. Complying with the case of domestic retrofit, the following section will test the techniques with minimum impact to reduce heat gains respectively; flat roof with albedo coating, water pond technique and adding simple thermal insulation.
Table 4.4 Selected Ceiling technologies
Abbreviation
Insulation Type
Position
K (W/mK)
Thickness (cm) for a U-value of 0.1 W/m2K
Alb.1
Flat Roof Albedo Coating
Internal –external
0.044
44
W.p
Water pond
Internal –external
0.038
38
M.W2
Mineral Insulation
Internal –external
0.02
28
Wool
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Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
7013.10 6678.10
Ceiling_Polystrene_Insulation
335.00
7109.50 6643.50
Ceiling_No_Insulation
466.00 0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
Figure 4.20: Impact of Polystyrene Insulation using ECOTECT Source (Author) Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
6920.44 6605.10
Ceiling_ Waterpond
315.34
7109.50 6643.50
Ceiling_No_Insulation
466.00 0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
Figure 4.21: Impact of water pond technology using ECOTECT Source (Author) 8000.00 7000.00 6643.506605.106678.10
6000.00
7109.506920.447013.10
5000.00 4000.00 3000.00 2000.00 1000.00 0.00
466.00 315.34 335.00 Heating (Kwh) Ceiling_No_Insulation
Cooling (Kwh) Ceiling_ Waterpond
Total (Kwh) Ceiling_Polystrene_Insulation
Figure 4.22: Comparison between Ceiling Technologies Source (Author)
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4.7.1 Thermal imagery discussion Fig.23 and Fig. 24 obviously show that the contemporary external renders were merely placed for aesthetical purposes having a minimal impact on the buildings heat flow. This allows for uncontainable heat flow through the external surfaces of the building.
Figure 4.23: Eastern Elevation
Figure 4.24: Figure 1 Thermal Image inside Typology A2
4.8 External Renders Multiple aspects contribute to the energy load of the selected building; solar radiation and ambient temperature are the dominant factors in the GCR climate. External Renders covering the red brick infill is the most common wall component in today’s GCR domestic built environment. Ranging from isolative renders, typical plaster, reflective renders and aesthetical coverings correspondingly. In fact, the type of external render has significant impact on the fabric gains. Table 5 experiments the application of Reflective coils and reflective paints on the fabric gains and losses of the selected typologies.
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Table 4.5 Selected External Render technologies
Code
Insulation Type
Position
Reflectance percentage
R1
Non-Reflective Paint
External / whole building envelope
10
S1
Reflective Paint
External / whole building envelope
70
4.8.1 Results and Discussion This section links the impact of the external impact on the internal heat gains and losses. Figure 25 shows slight variances between a reflective render and a non-reflective render accordingly. External render shows minimal contribution to the overall energy consumption.
8000.00 7000.00 6726.70 6717.67
6000.00
7061.70 7053.04
5000.00 4000.00 3000.00 2000.00 1000.00 0.00
335.00
335.37
Heating (Kwh)
Cooling (Kwh)
Low refelctivity 10%
Total (Kwh)
High reflectivity 60%
Figure 4.25: Comparison between external render technologies Source (Author)
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4.8.2 Thermal imagery discussion It is obvious from the corresponding thermal image suffers from poor fitting, moreover, the window has a low thermal conductivity. However, external wooden shutters provide protection from the direct solar gains which is vital. Attia et DeHerde (2009), stated that external solar protection of windows is vital for the eastern, western and southern facades respectively.
Figure 4.26 Thermal Image inside Typology A1
Figure 4.27 Thermal Image inside Typology A2
4.9 Windows Windows are considered the most significant source of thermal bridging in concrete structures. The corresponding thermal image shows the variation in surface temperature through the buildings structure due to various structural defects. Windows show a relatively poor performance in the case of the selected typology. Poor window performance may result several factors; poor on-site fitting (air infiltration), high glazing u-values and transmittance respectively. However, the following section experiments the impact of three window types on the hourly solar gains affecting 56
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the buildings envelope. Linking the effect of single glazed windows with wooden shutters, double glazed windows and double glazed windows with wooden shutters.
Table 4.6 Selection of window technology
Code
Window Type
Configuration
Visible transmittance (0-1)
Window U-value w/m2.K
W1
SingleGlazed_AlumFrame
Glass standard
0.753
6.00
W2
DoubleGlazed_LowE_AlumFrame
Glass StandardAir Gap -Glass standard
0.611
2.41
W3
TripleGlazed_LowE_AlumFrame
0.521
1.8
4.9.1 Results and Discussion This section compares between the impact three different window technologies on the total energy optimization process. Fig 28 shows that the double glazed window significantly saved 7.5% of more energy consumption than that of the contemporary single glazed window. On the other hand, the Triple Glazed window showed a minor addition to that of the double glazed. The triple glazed window saved 8.5% compared to the energy savings to the performance of the single glazed respectively.
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6773.30 6529.70
Single Glazed 243.60
6270.07 6104.77
Doule Glazed 165.30 0.00
1000.00
2000.00 Total (Kwh)
3000.00
4000.00
Cooling (Kwh)
5000.00
6000.00
7000.00
8000.00
Heating (Kwh)
Figure 4.28: Impact of double glazed window using ECOTECT Source (Author) Total (Kwh)
Cooling (Kwh)
Heating (Kwh)
6204.50 6071.50
Triple Glazing 133.00
6773.30 6529.70
Single Glazing 243.60 0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
Figure 4.29: Impact of triple glazed window using ECOTECT Source (Author)
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8000.00 7000.00 6773.30 6529.70
6000.00
6104.806270.10
6071.506204.50
5000.00 4000.00 3000.00 2000.00 1000.00 0.00
243.60
165.30
Single Glazing Heating (Kwh)
133.00
Double Glazing Cooling (Kwh)
Triple Glazing Total (Kwh)
Figure 4.30 Comparison between window technologies Source (Author)
4.10 Shading Strategies The existing literature on shading strategies has constantly verified the direct relation between shading devices and minimizing cooling energy loads in hot climates respectively. A study revealed that the shading strategies can contribute in minimizing the indoor thermal temperature by 1-2 Celsius accordingly (Ali and Ahmed, 2012). Shading strategies vary from vertical fins, wooden shutters, horizontal fins, venetian blinds and external window overhangs accordingly. Another common intervention found in the existing typology is the use of internal curtains which prevent direct solar radiation. Table 7 demonstrates the selected shading strategies whilst considering the impact of several shading strategies on the energy consumption of the domestic typology.
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Table 4.7 Selection of Shading technologies
Code
Shading
Position
W.S
Wooden shutters
External
C1
Curtains
internal
R.T
Terrace and rooftop shading
External
S.S
Street Fabric/overhangs shading
External
4.10.1 Results and Discussions Mainly in this section, four typical shading strategies were tested for impact on energy efficiency. Fig.31 shows that Thick fabric curtains have resulted to have almost the same impact as wooden shutters accordingly. Ali and Ahmed suggested that preferably, a combination of both wooden shutters and internal curtains would significantly decrease the absorption and act as an insulation layer in turn. Furthermore, the thickness and color of these technologies can be further investigated into to further reduce solar absorption. Energy consumption is directly proportional to the solar gains and absorption. Fig.31 shows shading strategies have reached a 2.7% decrease in energy consumption through the rooftop and terrace shading accordingly.
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8000.00 7000.00 6000.00
6485.80
6089.44
6731.30
6485.80
6714.70 6218.85
5000.00 4000.00 3000.00 2000.00 1000.00 245.50
129.41
228.90
0.00 Heating (Kwh)
Cooling (Kwh) Wooden Shutters
Roof top shading
Total (Kwh) Curtain
Figure 4.31: Comparison between Shading Technologies Source (Author)
4.11 Airtightness Table 8 shows the Ecotect criteria used for the airtightness layer. It is obvious from the thermal images that the fabric suffers from poor fitting, moreover, the window has a low thermal conductivity. However, external wooden shutters provide protection from the direct solar gains which is vital. In the final simulation, the airtightness layer was set to well-sealed considering the impact of concrete and the other technologies respectively. Table 4.8- Ecotect criteria of the Airtightness layers
Abbreviation
Insulation Type
Structural configuration
Air changes per hour (Ach)
A1
Airtight
External / whole building envelope
0.25 (ECOTECT)
A2
Well sealed
External / whole building envelope
0.5 (ECOTECT)
A3
Average
External / whole building envelope
1 (ECOTECT)
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Figure 4.32: Modified Trias Energetica approach
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4.12 Correlation of the PH technologies with the Q-set and questionnaire The questionnaire aimed at assessing the desire of adopting the selected retrofit technologies in dwelling. Fig energy proficient PH technologies as well as 3 behavioral factors were encompassed in the questionnaire. The questionnaire used a seven point Likert item that range between strongly recommended to not compulsory. This was used to evaluate the response rate of the subsequent questions: “I have the desire to adopt this PH technology/Energy behavior in the next tie period�. Furthermore, he participating households were asked to fill a box if they have already implemented the technology or behavior in their unit. Table 4.1 Occupant selection of technology
Typology A1
Typology A2
Thermal Mass
Extruded Polystyrene
Extruded Polystyrene
Intermediate floor
Extruded Polystyrene/Parquet
Extruded Polystyrene/Parquet
Ceiling
Water pond + Extruded Polystyrene
External Renders
Windows
Double Glazing
Double Glazing
Shading
Rooftop + terrace shading +street
terrace shading +street curtain
curtain
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4.13 Passive design implementations 24 simulation amalgamations and technological sets were conducted to determine the impact of each technology on the selected typologies. A correlation of the tested technologies and interventions was conducted to be adopted within the two optimized prototypes. This selection ensued according to the constants and variables matrix, previous simulation results and postsimulation questionnaire. A combination of tested technologies was adopted to comply with each of the two selected units in order to calculate the effectiveness of the passive measures on energy optimization accordingly. The simulation was based on 4 orientations North, west, east and south.
Figure 4.33: Typology A1 post-retrofit
4.14 Questionnaire Development and Correlation with the PH technologies This questionnaire aimed at quantifying the subjective views and desire of adopting the simulated technologies in the selected units. Energy proficient PH technologies as well as 4 behavioral factors were encompassed in the questionnaire. The questionnaire used a seven point Likert item that range between strongly desired to not desirable. This was used to evaluate the response rate 64
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of the subsequent questions: “I have the desire to adopt this PH technology/Energy behavior in the next tie period�. Furthermore, the participating households were asked to fill a box if they have already implemented the technology or behavior in their unit (See appendix).
4.15 Questionnaire results The questionnaire was distributed amongst 12 households inhabiting the last floor unit (Typology A1) and the ground floor (typology A2) respectively. The households were asked to tick a box next to suitable proposed technologies to adopt in their units to quantify the desires link between cognitive norms, material culture and energy practices accordingly. The questionnaire was purely based on desire without the inclusion of economical complications. The surveyed occupants showed the most interest towards the installation of the photovoltaic and the usage of the rooftop space as a recreational area accordingly. Thus, technology S.P and R.T well highly desirable. Although the topic of thermal mass seemed enigmatic somehow, nonetheless, more attention was given especially after careful explanation to the households the advantages and the impact of applying thermal mass on the buildings envelope. 4 out of 6 households recommended changing the windows to double glazing whilst a single household had the desire to install triple glazing. On the other hand, one household saw no reason in changing the existing windows. Shading strategies were adapted and developed from the existing interventions on three main scales; internal, external and urban scale respectively.
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Chapter 5: Results, Discussion and Conclusion
5.1 Typology A1 results The application of technological set 1 typology A1 displayed a major reduction in its four orientations using passive measures and complying with passive house strategies. A1-East showed the most potential in reducing energy demands amongst the four orientations. Witnessing a 50% optimization in total energy consumption. According to fig -- , the pre-retrofit consumption was 8764 Kwh/annum, 4322 Kwh/annum was saved after applying technological set 1 accordingly. Furthermore, A1-south showed the second highest potential in energy reduction by 45%. The pre-retrofit simulation showed a total consumption of 9088.6Kwh. The implementation of technological set 1 reduced the total consumption to 5049 Kwh. A1-north was third by reducing energy consumption for over 41%. The pre-retrofit 9929 kwh/annum to 5889.4 Kwh/annum respectively. On the other hand, A1-west showed the least response to the selected passive technologies with a 35 % reduction. The western facing unit had an original energy demand of 9813 Kwh/annum which seems convenient compared to the other 4 orientations. Despite of implementing the same technological set as the other orientations, A1-west was only reduced to 6285 Kwh/annum. This demonstrates that each orientation will have to test a variation of technological sets based on its environmental surroundings for the utmost optimization.
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12000.00 10000.00 9929.50 8000.00
9813.10 8764.80
6000.00
6285.67
5889.43 4000.00
9088.60
5049.05
4442.90
2000.00 0.00 North
East Rerofit (Kwh)
West
South
Pre-retrofit (Kwh)
Figure 5.1: Typology A1; retrofit vs. pre-retrofit
5.2 Typology A2 results According to figure ‌ The application of technological set 2 on typology A2 displayed a further significance in reducing energy consumption in its four orientations using passive measures compared to typology A1. Once more, A2-East showed the most potential in reducing energy demands amongst the four orientations. Witnessing approximately a 58% optimization in total energy consumption. According to fig 5.32, the pre-retrofit consumption was 4751 Kwh/annum, 2738 Kwh/annum was saved after applying technological set 2 accordingly. Moreover, A2-south showed the second highest potential in energy reduction by 55%. The pre-retrofit simulation showed a total consumption of 5155.7Kwh/annum. The implementation of technological set 1 reduced the total consumption to 2325 Kwh/annum respectively. Surprisingly, A2-west was third this time by reducing energy consumption for over 50%. The pre-retrofit 5757 kwh/annum to 2885
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Kwh/annum respectively. On the other hand, A1-North showed the least response to the selected passive technologies with a 48 % reduction. The western facing unit had an original energy demand of 5797 Kwh/annum which seems convenient compared to the other 4 orientations. Despite of implementing the same technological set as the other orientations, A1-west was only reduced to 3102.8 Kwh/annum. This further proves that each orientation will have to test a variation of technological sets based on its environmental surroundings for the utmost optimization.
7000.00 6000.00 5000.00
5797.10
5155.70
4751.70
4000.00 3000.00
5757.80
3102.80
2000.00
2885.00 2325.00
2013.50
1000.00 0.00 North
East Rerofit (Kwh)
West
South
Pre-retrofit (Kwh)
Figure 5.2: Typology A2; retrofit vs. pre-retrofit
Figure 5.3: Potential Solar active strategies
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5.3 The potential of solar active design 5.3.1 Solar active cooling technology The intensity of the sun in GCR is significant as it falls in the Sahara. GCR belongs to the global sun belt. According to (Comsan, 2010), GCR has an average annual solar irradiation of approximately 3000 hours, resulting in a production of 1970-3200 kwh/m2 of renewable solar energy accordingly. Hence, photovoltaic panels show great prominence in the GCR region as a constant source of renewable energy (Omran, 2000). According to a study conducted by Attia (2009), A 26 m2 array of solar collectors resulted in an approximate energy supply of 6115 Kwh/annum during a post-retrofit monitoring period. The subsequent section will test the potential of solar cooling technology on the chosen location. This solar energy formula is tested on an area of 120m2 as the residents stated that they only want half of the roof area as solar collectors.
Solar Energy Production
Lowest production:1970 kwh/m2
Peak Production:3200 kwh/m2
Area used= 120m2 (50% of roof area)
236400 kwh
384000 kwh
Energy production Per Flat 19700 kwh 32000 kwh Figure 5.4: Estimated solar production on peaks and lowest production days (comsan, 2010)
Implementing photovoltaic panels on area of 120m2 resulted in covering the primary consumption of the unit with 10000-30000 kwh/annum of plus energy accordingly. this can be used in adapting to technologies such as SAC and DWH respectively. Excessive electricity can be sold to the national grid
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20000.00 15000.00 10000.00 5000.00 0.00 -5000.00
North
East
West
South
-10000.00 Typology A1 (Kwh)
Solar Active energy optimization (Lowest)
Figure 5.5: Typology A1 after solar active retrofit with lowest day average 20000.00 15000.00 10000.00 5000.00 0.00 North
East
West
South
-5000.00 Typology A2(Kwh)
Solar Active energy optimization (Lowest)
Figure 5.6: Typology A2 after solar active retrofit with Lowest day average 400000.00 300000.00 200000.00 100000.00 0.00 North
East
West
South
-100000.00 Typology A1 (Kwh)
Solar Active energy optimization (Highest)
Figure 5.7: Typology A1 after solar active retrofit with highest day average
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450000.00 400000.00 350000.00 300000.00 250000.00 200000.00 150000.00 100000.00 50000.00 0.00 -50000.00
North Typology A2(Kwh)
East
West
South
Solar Active energy optimization (Highest)
Figure 5.8: Typology A2 after solar active retrofit with highest day average
5.3.2 Conclusion and Recommendations To recapitulate, this dissertation intended on experimenting the potential of Passive House/EnerPHit retrofits in the optimizing energy consumption of the GCR domestic built environment from a socio-technical insight. Focusing mainly on a set of cultural and locational based technologies complying with the socio-technical research model founded on cognitive norms, material values and energy practices correspondingly. Throughout the critical review of the current literature around domestic retrofit, a substantial amount of research was conducted regarding preliminary approaches and concepts to both local and international Passive House schemes. A Knowledge gap was situated in the correlation between the Passive House strategies and the cognitive norms of GCR’s Domestic built environment. This dissertation was profound on evading the customary implementation of an array of technologies without considering the social attitudes towards energy consumption which may transpire in a significant energy rebound. This further on aspired the necessity of adopting a socio-technical approach with an appropriate research model to assess the selected technologies for compliance with the material culture. This 71
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led to three core surveys in this dissertation; Identifying the energy practices and general data about households, Thermal imagery survey for assessing the material culture complications and finally the post-simulation survey to rate the selected technologies according to occupant’s standpoints. Furthermore, the relevant key energy performance aspects were identified of the EEEC, PH and the EnerPHit respectively assessing the selected typologies. GCR’s domestic built environment was assessed in a quantificational sense to determine the most adaptive and reiterated typologies creating benchmarks for future adaptations. This dissertation was further limited to investigating the potential of a passive house on two units (ground floor and last floor unit) of a Compact detached apartment in El-Muhandeseen accordingly. There was no trace of previous thermal imagery inspections in the GCR domestic Environment, thus, this thermal imagery inspection significantly contributed with its findings affecting the perceptions towards the domestic energy consumption rates and fabric performance. Multiple complications were found in the existing fabric such as the existence of thermal bridging phenomena through R.C slab edges predominantly in protruded terraces which allows significant heat flow. Furthermore, the exterior shell of the buildings envelope (walls-floors-ceiling-windows) has a relatively low thermal resistivity leaving the internal environment vulnerable to fabric gains and losses due to GCR’s diurnal climate. In process, occupants rely much on inefficient air conditioning units without heat recovery systems to achieve a state of comfort resulting in high the state of energy-ravenous buildings. Finally, most external and internal renders of the buildings envelop are purely aesthetical with no relevance to energy conservation, however, internal ceramic tiles are widely used creating heat storage and cold surfaces. The modified Trias Energetica approach adopted in a modified version encompassing three main pillars; Passive house strategies, a socio-technical selection of technologies that comply with 72
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occupant energy practices and finally solar active strategies to deduct energy from the national grid. A number of 17 various technologies were individually simulated in terms and collectively compared energy optimization impact. The process was explained to the surveyed households and the impact of each technology on energy performance respectively. Occupants were required to respond to the proposed questionnaire and rate each technology based on the desire of adopting these technologies. Basically, two sets were selected according to each unit as a result. A total of 2 base case simulations were led to assess the impact each selected set on four different orientations respectively. As expected, a range of different results were concluded, significant enormous range between 35% savings to over 55% percent savings between typology A1-west and A2-East accordingly (fig). As a result of this experimental phase, one unit had a reduction of 58%, 2 units had a deduction of 50-55%, followed by 1 unit with a deduction of 48%, 2 units resulted in a 4045% deduction and finally one unit had the least response to the technological set as it was reduced by 35%. The East-West axis showed the significant metamorphosis in the simulation results as the eastern units showed the highest response in all typologies whereas the western units showed the slightest response correspondingly. The North-South axis showed a reasonable judicious response with an 4% difference between both. The last phase of the Modified Trias Energetica approach neutralized the energy consumption through installing Attia’s proposed SAC technology to replace the cooling loads with solar renewable energy. The results verify the hypothesis of this dissertation: “The prevailing cognitive norms of the GCR domestic built environment present momentous potentials for optimizing energy consumption, therefore, achieve passive house/EnerPHit standards for their retrofits�.
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5.4 Limitations: Many complications were found in obtaining benchmarks for the current energy consumption models and building census in GCR. This had the ripple effect on multiple aspects in the dissertation. A simulation-based approach was conducted to determine the energy consumption of the selected typologies deducted a significant part of the word count. Moreover, this sociotechnical approach was infrequent to find in the literature review, consequently, most of the data conducted was on first basis acting as a preliminary benchmark basis which could’ve saved more time and space if it was provided by the local government. Wider comparisons on various typologies would’ve been beneficial, however, it wasn’t conceivable due to the limit of word count and time limitation. Time limitation was vital in the research process. As the research was progressive, more questions and proposals arose requiring further investigation. For instance, the MVHR strategy was surprisingly declined by the surveyed occupants due to the perception of control and insufficient place for the unit. Finally, the main constraint in this research the insufficiency of the testing equipment’s GCR, this severely delayed the systematic approach. Yet, the research was able to meet its hypothesis, aims and targets.
5.5 Further Recommendations Although the last phase of the Modified Trias Energetica approach neutralized the energy consumption through the use of renewable solar energy, it is believed that further energy optimization could be achieved through an earlier stage of the Modified Trias Energetica approach through further customization of technological sets specifically complying with each orientation
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respectively. The comprehensive sequence and socio-technical approach developed in this dissertation resulted in achieving energy neutrality accordingly. This comprehensive approach should be further implemented on the other typologies (B&C) and their sub-typologies respectively in four different orientations (N,W,E & S). The dynamic insulation for heat recovery developed by -- should be tested within the technological set to further improve the energy optimization in the first two stages of the MTE approach. Carrying out further thermal imagery inspections is vital towards understand the nature of energy efficiency problems in GCR. The relation between airtightness, concrete structures and energy optimization in hot climates should be studied more in depth.
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Appendices Appendix – A
Questionnaire set “1”: 1) Gender: Male/Female 2) Age: <15 , 15-25 , 25-60 , >60 3) Household/no. of occupants per household: ≤3
,
4
,
5 ,
over 5
4) Hours of AC operation: 2-4 hrs ,
4-6 hrs , 6-8 hrs
Describe: …………………………………………………………………………….. 5) How many rooms with AC installed 1
,
2
,
3 , 4
Name the rooms: ………………………………………………………………………… (Living, bedroom …) 6) How many hours spent in room ‘1’ on a daily basis <2 ,
2-4
,
4-6
,
>6
7) How many hours spent in room ‘2’ on a daily basis <2 ,
2-4
,
4-6
,
>6
8) How many hours spent in room ‘3’ on a daily basis <2 ,
2-4
,
4-6
,
>6
9) If you experience discomfort, which of the following best describes it:
Air flow issues
Loss of AC cooled air due to heat flow in summer
Cold surfaces and loss of internal heat during winter season
Direct incident sunlight leads to internal space heating
Hot/cold air infiltration through windows 87
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Questionnaire set “2”:
Rate the overall desire to adopt the selected technologies (Desirable / not desirable) 1) Thermal mass on the whole building envelope
Desirable
Neutral
Not desirable
2) Intermediate floor insulation
Desirable
Neutral
Not desirable
3) Ceiling insulation
Desirable
Neutral
Not desirable
4) External reflective renders
Desirable
Neutral
Not desirable
5) Double glazed windows
Desirable
Neutral
Not desirable
6) Single glazed windows
Desirable 88
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Neutral
Not desirable
7) Triple glazed windows
Desirable
Neutral
Not desirable
8) Roof water pond
Desirable
Neutral
Not desirable
9) Shading with wooden shutters
Desirable
Neutral
Not desirable
10) Shading with internal curtains
Desirable
Neutral
Not desirable
11) Terrace and rooftop shading
Desirable
Neutral
Not desirable
12) Street fabric/overhangs shading
Desirable
Neutral 89
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Not desirable
13) Air tightness
Desirable
Neutral
Not desirable
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Appendix – B
Typology selection process This section roughly outlines a quantitative and a qualitative analysis of the existing housing stock in greater Cairo. Census, descriptive data and comparative tables are applied on a quantitative scale are used to choose 3 main typologies for testing “energy efficiency experiments” on a regional scale. However, it has to be understood that despite of any rigid categorization, the housing stocks matrix will not be able to capacitate all the existing variations and typologies in the Cosmopolitan of Cairo. Table 1 Reiteration rate according to GCR classifications
Table 1 profusely shows that the informal housing stocks have been dominating the residential sector during the past decades in Greater Cairo. 63% of the Greater Cairo’s population in habitat informal developments and per urban Cairo (Sims, 2010). The following figure explains the
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constants and variable on which the selected typologies were chosen.
Selection Criteria for Constants
Variables 100 â&#x20AC;&#x201C; 120
Median Size
Street Width Ratio Urban Density
m2
Wind Exposure Category
Age of the Structure
Construction System and Materials
Form Aspect Ratio
Reinforced Concrete and
Number of Occupants Floor Level
Figure 1Constants and variables for housing selection Source (Author)
The selected typologies all should be exposed to a set of analogous conditions such as ventilated volume, wind exposure, sun orientation, construction system and materials to assure the objectivity the comparison. The selected units roughly reflect their prevalence in these areas; -
High Reiteration rate according to occupation.
-
Typicality meeting a set of variables such as geometry, average sizes, number of occupants, shape of the building and street to height ratio which is recognized to have the largest impact on energy demand.
-
Dissimilar height/floor levels in each typology according to Sun/wind exposure.
-
Age of the structure detects the fabrics condition and infiltration rate.
-
Different Form/Aspect ratio.
Simultaneously, it is important to address existing stocks in its different variations to reflect the impact on locational disparities inside greater Cairo. However, the selected typology ought to fall in a well-defined urban boundary for the community impact to be easily assessed further in this dissertation. Moreover, the neighborhood of the sample typology should contain a population between 5000 and 30000 respectively. 92
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Figure 2Form Factor and selection criteria
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Table 2Simulation Matrix
However, the research further narrowed down to typology A for more specific results due to the time limit and word count. This simulation map was created to guide the further Ecotect simulation. However, it will be developed due to the progressive nature of this dissertation. 94
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Further details
Typology A plan
Conceptual Isometric displaying the position of the insulation to avoid thermal bridging
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Appendix - C Passive house planning considerations
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