Project report on trombe wall by VINAY KUMAR

Trombe Wall System

A Project Report

Submitted by

GANJI VINAY KUMAR Reg: No: 1130100362

B. Arch IV Year

SCHOOL OF PLANNING AND ARCHITECTURE VIJAYAWADA November 2016

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SCHOOL OF PLANNING AND ARCHITECTURE VIJAYAWADA DECLARATION I declare that this project report entitled “TROMBE WALL SYSTEMS” is the result of my work and prepared by me and that it has not formed the basis for the award of any degree, diploma, associate-ship or fellowship of any other university or institution previously. Due acknowledgement have been made whenever anything has been borrowed from other sources.

Date: Name: GANJI VINAY KUMAR Roll No: 1130100362

ABSTRACT Green building and sustainable architecture are new techniques for addressing the environmental and energy crises. Trombe walls are regarded as a sustainable architectural technology for heating and ventilation. The reviews discuss the characteristics of Trombe walls, including Trombe-wall configurations, and Trombe-wall technology. The advantages and disadvantages of this sustainable architectural technology have been highlighted. The building sector accounts for approximately 40% of total global energy usage. Energy consumption for space heating and cooling makes up 60% of the total consumed energy in buildings. This study presents a comprehensive technical review of passive wall systems in building envelopes while discussing their respective capabilities in optimizing energy efficiency. Different types of energy efficient walls such as Trombe Walls, Autoclaved Aerated Concrete Walls, Double Skin Walls, and Green Walls are explored. Furthermore, novel concepts for optimizing energy efficiency in building envelopes are also introduced. The energy and environmental performance is compared for buildings with and without Trombe walls. The performances of several constructions of Trombe walls are studied. And efficiency of trombe wall is also calculated by changing the size, location, colours, materials, orientation, etc. When the building with Trombe walls is used, the annual final energy saving during heating is around 20%. For the electrical heating and optimum core thickness, the energy ratio is around 6 and the energy payback time is around 8 years. Finally the utilization of passive wall systems to save energy while improving the building environmental impacts is discussed. And recommends the passive heating concept to the stakeholders of the building so as to conserve the energy requirement for room air heating and cooling purposes. Keywords: Passive wall systems, Trombe wall, Sustainable architecture, Energy conservation, Passive building, Energy efficiency, building facades, Low â&#x20AC;&#x201C; tech retrofitting, passive solar heating and cooling.

GRAPHICAL ABSTRACT

LIST OF TABLES Table1. - Effects of colours on the performance of the solar wall.

Table2. - Schedules of the people presence, use of the installed light, and use of the instilled electric equipment, supported operative temperature during heating.

Table3. - Constructions with their layers used in Trombe walls

Table4. - Properties of the core material used in Trombe walls (Their thicknesses are optimized during these investigations) and of some house envelope material 18 Table5. - Thermo physical properties of building materials Zurcher and Frank

Table6. -The absorption coefficients of absorbing surfaces (OzÄąÄąk, 1985).

Table7. - The weather data of Erzurum.

Table8. - Parameters of the building.

Table9. - Annual heat gain from solar energy through Trombe wall.

Table10. -Material properties of the classic and the proposed tombe wall

Table11. - Comparision between the classic and proposed trombe wall in terms of energy consumption, energy saving and co2 reduction.

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LIST OF FIGURES Figure 1- Classic trombe wall .................................................................................. 1 Figure 2 - Unvented Trombe wall (left); vented Trombe wall in winter mode(center);and vented Trombe wall in summer mode(right). ............................... 7 Figure 3 – (a)The review approach. (b) Functionality of the Trombe wall ................ 8 Figure 4 - Working principle of WIHP .................................................................... 8 Figure 5 - Various configurations of a solar wall: (a) without ventilation; (b) winter mode with air thermo-circulation; (c) summer mode with cross ventilation. .......... 11 Figure 6 - (a) The original Mozart house design in France and (b) basic modified Mozart house without Trombe walls. ..................................................................... 17 Figure 7 - (a) Analyzed house with two Trombe walls and (b) plan schematic of the Mozart house. ........................................................................................................ 18 Figure 8 - The percentage of electricity used in the house to achieve different tasks: (a) the basic building and (b) the house with Trombe walls when the Trombe core material is clay brick 1220 with ıc = 0.45 m (both houses are heated by electricity). .............................................................................................................................. 19 Figure 9 - A conventional Trombe wall during (a) winter and (b) summer. ............ 25 Figure 10 - PV-Trombe wall for (a) winter heating and (b) summer cooling. ......... 26 Figure 11 - Schematic plan view of single on the south –east wall of size(5mX3m) Figure 12 - Vented Trombe wall retrofitted zone building for simulation using TRNSYS ............................................................................................................... 26 Figure 13 - Room air temperature for different retrofits on south-east wall. ........... 27 Figure 14 - Heating potential for different retrofits on south-east wall. .................. 27 Figure 15 - Working principle of a traditional trombe wall and energy gain Figure 16 - Monthly energy flows for a Trombe wall. ............................................ 32 Figure 17 - The solar radiation map of the Erzurum, Turkey. (EIE,2008). ............. 33 Figure 18 - Outdoor temperature and montly average daily incident solar radiation on the horizontal surface for Erzurum. .................................................................. 34 Figure 19 - (a) Ground Floor plan (b)Second Floor plan ...................................... 35 Figure 20 - Section of the building. ........................................................................ 35

viii Figure 21 - The schematic view of Trombe wall in plan and section. ..................... 36 Figure 22 - Investigated wall constructions with different materials. ...................... 36 Figure 23 - Monthly solar gain of concrete trombe wall with various colours Figure 24 - Monthly solar gain of brick trombe wall with various colours Figure 25 - Monthly solar gain of areated concrete trombe wall with various colours .............................................................................................................................. 36 Figure 26 - Psychrometric chart of Saint Katherineâ&#x20AC;&#x2122;s yearly temperature showing comfort range according to ASHRAE standard 55-2004. ....................................... 39 Figure 27 - Ground floor plan for the case study showing the test room location and orientation

Figure 28 - Cross section in the proposed Trombe wall. ................. 40

Figure 29 - Winter average daily indoor and outdoor temperature showing the performance of the proposed Trombe wall compared to the classic Trombe wall and the base case. ......................................................................................................... 41 Figure 30 - Summer average daily indoor and outdoor temperature showing the performance of the proposed Trombe wall compared to the classic Trombe wall and the base case. ......................................................................................................... 41 Figure 31 - . Different modes and adjustments of the Trombe wall during summer and winter days and nights. .................................................................................... 43

TABLE OF CONTENTS ABSTRACT………………………………………………………………...iii GRAPHICAL ABSTRACT……………………………………………….iv LIST OF TABLES…………………………………………………………v LIST OF FIGURES………………………………………………………..vi 1.

INTRODUCTION………………………………………………….1 1.1

Background of the study

1.2

Aim & objectives of the study

LITERATURE REVIEW…………………….……………………5 2.1

List of references used in study

2.2

Summary of review of paper –I………………………………6 2.2.1 Introduction 2.2.2 Problem Statement 2.2.3 Objectives of the paper 2.2.4 Data used 2.2.5 Analysis 2.2.6 Results 2.2.7 Way forward

2.3

Summary of review of paper –II……………………………..10 2.3.1 Introduction 2.3.2 Problem Statement 2.3.3 Objectives of the paper 2.3.4 Data used 2.3.5 Analysis 2.3.6 Results 2.3.7 Way forward

2.4

Summary of review of paper –III……………………………16 2.4.1 Introduction 2.4.2 Problem Statement 2.4.3 Objectives of the paper

x 2.4.4 Data used 2.4.5 Analysis 2.3.6 Results 2.3.7Conclusion 2.5 Conclusion (overall summary)…………………………………21 3.

CASE STUDIES…………………………………………………..22 3.1 List of case studies 3.2 Presentation of case study I…………………………………….23 3.2.1 Introduction 3.2.2 Location 3.2.3 Climate 3.2.4 Exclusivity of the case 3.2.5 Data used 3.2.6 Analysis 3.2.7 Result 3.2.8 Conclusion 3.3 Presentation of case study II…………………………………...31 3.3.1 Introduction 3.3.2 Location 3.3.3 Climate 3.3.4 Exclusivity of the case 3.3.5 Data used 3.3.6 Analysis 3.3.7 Results 3.3.8 Conclusion 3.4 Presentation of case study III………………………………….38 3.4.1 Introduction 3.4.2 Location 3.4.3 Climate 3.4.4 Exclusivity of the case

xi 3.4.5 Data used 3.4.6 Analysis 3.4.7 Results 3.4.8 Conclusion 3.5 Conclusions of case study…………………………………….45 4.

BIOGRAPHY……………………………………………………...46 4.1 Profile 4.2 Philosophies and thoughts/concepts

CONCLUSION…………………………………………………….49

REFERENCES…………………………………………………….50

1. INTRODUCTION

1.1 Background of the study A Trombe wall is a south facing wall of a building which is thick and is usually painted black to absorb heat. If in the southern hemisphere of the world, this wall would be the north wall of the building because that is the winter sun side. A pane of glass or plastic glazing is installed on the exterior of the wall offset a few inches which creates an air space between the pane and wall.

Figure 1. Classic trombe wall

2 During the winter, this set up allows the wall to heat up during the day because the glass does not allow heat to escape easily. At night, the wall cools down and this results in heat being let off into the building. During the summer, this same wall can be used to cool the building. There is usually a vent at the top of the wall open to the outside and an overhang above the wall which blocks the higher summer sun. The vent allowing heat in the the house during the winter is closed and the summer vent is open. This creates a solar chimney which creates coolness in building. This idea of a passive way of heating a building was first patented by Edward Sylvester Morse in 1881 with his design of a versatile vent system. The Trombe wall is named after a French engineer name FĂŠlix Trombe who made this passive heating system popular in the 1960's. Further interest emerged particularly in the US in the 1970's which was aided by researchers at Los Alamos National Laboratory in New Mexico. Since the classic Tromble wall was made popular, different configurations have been developed to adapt the Trombe wall to various climates, purposes, and seasons. Some of these different configurations include the zigzag, water, solar hybrid, composite, and fluidized Trombe walls. Trombe walls since the 1960's have been look on by governments and research facilities as a great alternative for fossil fuels in home heating. This heating also is practical in places where gas heating is not practical. In China for example, the National Natural Science Foundation of China and the National Technology Research and Development Program of China has granted funds to research for improved Trombe walls. Basic design Trombe walls may be constructed with or without internal vents. Non-vented walls rely on conduction through the wall to heat the space behind the wall, while vented walls allow the user to actively or passively circulate room air past the heated side of the wall for more immediate heating. Vented Trombe walls may use passively or actively controllable flaps to prevent convection in the undesired direction, as when the wall cools at night in winter or heats during the day in summer. In climates that

3 have higher summer temperatures Trombe walls may also be designed with external vents to improve the shedding of heat at night. Vented walls offer the advantage of being able to shed more heat earlier in the evening when it is more commonly required while higher heat capacity non-vented walls offer the advantage of improved overall diurnal stability. Views differ among the passive solar community as to which is more advantageous. A simplistic rule of thumb that is often used when designing dense masonry walls is that heat will be absorbed and lost at around two hours per inch. Common variations Common modifications to the Trombe wall include: 

Exhaust vent near the top that is opened to vent to the outside during the summer. Such venting makes the Trombe wall act as a solar chimney pumping fresh air through the house during the day, even if there is no breeze.



Windows in the Trombe wall. This lowers the efficiency but may be done for natural lighting or aesthetic reasons. If the outer glazing has high ultraviolet transmittance, and the window in the Trombe wall is normal glass, this allows efficient use of the ultraviolet light for heating. At the same time, it protects people and furnishings from ultraviolet radiation more than do windows with high ultraviolet transmittance.



Electric blowers controlled by thermostats, to improve air and heat flow.



Fixed or movable shades, which can reduce night-time heat losses.



Trellis to shade the solar collector during summer months.



Insulating covering used at night on the glazing surface.



Tubes or water tanks as part of a solar hot water system.



Fish tanks as added heat capacity.



Using a selective surface to increase the absorption of solar radiation by the wall.

1.2

Aim & objectives of the study

The main objective of my research study is to know about the energy efficient equipmentâ&#x20AC;&#x2122;s in buildings and equipmentâ&#x20AC;&#x2122;s uses renewable energy which are harmless to environment. In present days, building sector accounts approximately 40% of total energy usage. Energy consumption for space heating and cooling makes up to 60% of the total consumed energy in buildings. All these things lead to energy crisis and it ultimately leads to pollution, global warming, greenhouse gas emitting, etc. Trombe wall is one among the passive wall systems which is energy efficient and uses renewable energy, saves lot of energy consuming by buildings. And it is definitely pay back after some period of time, without any cause to environment. The objectives of the study are 1. To know in detail about trombe wall functioning and applications. 2. To know different types of trombe walls and its techniques by changing colours, materials, position, orientation and size. 3. To know its efficiency in different climates and how its performance can be maximized. 4. To know trombe walls annual efficiencies and their payback time in different locations. 5. And to what all new techniques implemented on trombe wall and its parameteric methods.

5 2. LITERATURE REVIEW

2.1 List of references used in study 1. H. Omrany, Ali G., Amirhosein G. , K. Raahemifar , J. Tookey (2016). Application of passive wall systems for improving the energy efficiency in buildings: A comprehensive review, Renewable and Sustainable Energy Reviews (62)1252–1269. 2. O. Saadatian , K. Sopian, C.H. Lim, Nilofar Asim, M.Y. Sulaiman (2012). Trombe walls: A review of opportunities and challenges in research and development, Renewable and Sustainable Energy Reviews (16) 6340–635. 3. M. Bojic, K. Johannes, F. Kuznik(2014). Optimizing energy and environmental performance of passive Trombe wall, Energy and Buildings (70) 279–286.

2.2 Review of Application of passive wall systems for improving the energy efficiency in buildings: A comprehensive review - Hossein Omrany, Ali Ghaffarianhoseini, Amirhosein Ghaffarianhoseini, Kaamran Raahemifar, JohnTookey.

2.2.1 Introduction Maintaining building's indoor climate and environment is responsible for consuming 30-40% of global energy. This percentage varies between countries as the result of social and economic situations, concentration on energy requirements and the approach towards utilizing building energy codes, availability of main energy resources and climatic conditions. Recent studies estimate that 41% of total US primary energy demand is consumed by the building climate control, close to the figure of 40% within the European Union.

2.2.2 Problem Statement The building sector accounts for approximately 40% of total global energy usage. Energy consumption for space heating and cooling makes up 60% of the total consumed energy in buildings. Significance of achieving energy efficiency in buildings has been well reflected in European regulations where 3 out of the10 priority measures in the Action Plan for Energy Efficiency are related to buildings. The recent recast of the EU Energy Performance of Buildings Directive requires all new buildings in the EU to consume ‘nearly zero’ energy after 2020.It requires buildings energy efficiency to be raised to a higher level through ‘the coherent application of passive and active design strategies in order to reduce the heating and cooling loads’, ‘raising equipment energy efficiency’, and ‘the use of renewable energies’.

2.2.3 Objectives of the paper A primary measure to minimize the BICE energy use is to enhance the thermal and energy performance of the building envelope. This enhancement is achievable through enforcing active, passive or combined energy management measures. In recent years passive strategies have held prominence. Researchers have proposed

7 innovative solutions aiming to improve the energy performance of building envelope components. This paper presents a wide spread technical reviews of the wall component in building envelope and discusses about its respective improvements from a BICE efficiency perspective. The scope of this research is limited to the use of passive strategies in the wall component.

2.2.4 Data used Primary list of passive walls developed based on Passive solar walls ,Autoclaved Aerated Concrete (AAC) Walls ,Double skin faรงades ,Green wall ,Wood-framed wall systems ,Phase Change Materials (PCMs) Wall systems, Trombe Walls ,Intelligent Faรงades ,Climate Adaptive Building Shells ,Solar chimney, Biophilic ,Unglazed transpired solar faรงades ,Kinetic Faรงades ,Lightweight concrete (LWC) walls ,Walls with latent heat storage Passive-house curtain walls.

2.2.5 Analysis This research presented a comprehensive technical review of passive walls systems in building envelopes, while discussing their respective potentials towards optimizing energy efficiency. These Walls normally constitute the largest portion of the building envelope.

Figure 2.Unvented Trombe wall (left); vented Trombe wall in winter mode(center);and vented Trombe wall in summer mode(right).

Consequently walls create a route for thermal transmission as a result of their large surface area, allowing solar radiation to pass through the building in bright sunlight. Conversely they also provide a large surface that facilitates thermal radiation in cold environments. In high-rise buildings with a high ratio of wall to envelope, the

8 thermal performance of walls can be even more crucial. Highlighting the functionality of walls in buildings, appropriate selection of wall type is a fundamental measure to reduce the energy consumption. They can be achieved by different types of walls such as Trombe walls, AAC walls, double skinned walls, pcm wall systems, green wall systems. Correspondingly their advantages and dis advantages are compared which can be helpful in their selection for different climatic conditions. These can be operated in different modes with climate.

Figure 3 .(a)The review approach. (b) Functionality of the Trombe wall

Figure 4. Working principle of WIHP

2.2.6 Results This paper is a review of different passive wall systems and explored their potentials towards improving the thermal performance and reducing the energy

9 consumption of buildings. The results concluded that Trombe walls ,DSFâ&#x20AC;&#x2122;s and AAC have been recognized as a wall system capable of significantly reducing building energy consumption and careful consideration of design parameters improves the overall energy performance of the wall. This performance is further enhanced through integrating other strategies namely BIPV into the wall system.

2.2.7 Way forward This paper identified and reviewed energy-efficient concepts with promising potentials for integration in the building envelope. It is concluded that; the discussed solutions hold promises for the future trends of energy-efficient buildings. As these concepts are still under research, future studies are expected to excessively quantify the corresponding benefits of their application for generalization purposes.

2.3 Review of Trombe walls: A review of opportunities and challenges in research and development - Omidreza Saadatian n, K. Sopian, C.H. Lim, Nilofar Asim, M.Y. Sulaiman

2.3.1 Introduction Green building and sustainable architecture are new techniques for addressing the environmental and energy crises. Trombe walls are regarded as a sustainable architectural technology for heating and ventilation purposes.

2.3.2 Problem Statement Fossil energy is an essential component of daily life whose environmental impact and fast-increasing price are two important concerns in the millennium. For instance, two price increases, which occurred from 1973 to 1983 and from 1998 to 2008, affected the social and economic aspects of many lives . Moreover, the depletion of natural resources generated interest in renewable energy sources, such as the sun, wind, etc.. Solar energy plays an important role for numerous people in different walks of life. Solar energy can be used in remote and undeveloped areas to meet the requirements of schools, clinics and other buildings. Buildings are reasons for 33% of the world’s total greenhouse-gas emissions. In the building industry, the importance of solar energy is more obvious when the role of architecture, the use of renewable energy, and climatic design are taken into account.

2.3.3 Objectives of the paper The main aim of the article is to show the significance of passive trombe wall systems in modern building industry. •

Application of Trombe walls in buildings and

•

Characteristics of Trombe walls, including Trombe-wall configurations, and Trombe-wall technology.

•

The advantages and disadvantages of this sustainable architectural technology in present era.

2.3.4 Data used Configuration of Trombe walls Nine different types of Trombe walls: (1) a classic and modified Trombe wall; (2) a zigzag Trombe wall; (3) a solar water wall; (4) a solar trans wall; (5) a solar hybrid wall; (6) A Trombe wall with phase-change material; (7) a composite Trombe wall; (8) a fluidized Trombe wall; and (9) a photovoltaic Trombe wall.

Figure 5.Various configurations of a solar wall: (a) without ventilation; (b) winter mode with air thermo-circulation; (c) summer mode with cross ventilation.

2.3.5 Analysis Trombe walls have various accessories that help increase efficiency. Important accessories include vents , fans , and insulation . Certain intrinsic Trombe wall parameters contribute to the wallâ&#x20AC;&#x2122;s efficiency. Size, thickness, color, wall materials, coating materials, and glazing specifications are among the important Trombe wall parameters that affect the wallâ&#x20AC;&#x2122;s efficiency. 2.3.5.1 Vent effects Classic Trombe walls could be categorized in two types: vented and unvented. For vented Trombe walls, two thermos circulation vents are installed at the top and bottom of the wall to assist heat circulation. These vents are designed to control the heat loss. The higher the temperature of the air space, the greater is the heat loss. As

12 the air in the air space becomes warm and lighter, it enters the room through the upper vent, and cool air replaces it through the lower vent. 2.3.5.2 Fan effects The feasibility of using fans to assist the circulation of heat through the vents is questionable. A thermal network computer simulation was performed by, on a Trombe wall with a thermostatically controlled fan. The thermostatically controlled fan started when the outside wall temperature exceeded 29 .1⁰C. The results revealed that the fan’s performance depends on parameters such as the wall’s thickness and climate. 2.3.5.3 Size effects The size of Trombe walls or, more precisely, the ratio of the Trombe wall’s area to the total wall area has been proposed as a parameter of Trombe-wall efficiency. Based on a study , the ratio of Trombe wall area to the wall area (a) has a direct effect on thermal efficiency . 2.3.5.4 Thickness and colour effects Generally, the optimal thickness of a Trombe wall is related to latitude, climate and heat loss. The thickness of the mass is one parameter that contributes to the effectiveness of Trombe walls. For example, with concrete, there is a lag of 120 min to 150 min for heat delivery from outside to inside for each 10 cm. Insufficient wall thickness results in excessive interior temperature swings, while increasing the thickness will increase costs. In this regard, in India, Agrawal and Tiwari have proposed a 30–40 cm thick concrete Trombe wall for optimal results 2.3.5.5. Insulation effects A classic Trombe wall possesses low thermal resistance and loses a large amount of heat at night. In hot weather and particularly in well-insulated buildings, Trombe

13 walls might function as a source of undesired heat gain and overheating due to reverse heat transfer. To prevent reverse heat transfer, Trombe walls should be properly insulated. A study suggested that proper insulation is necessary for maximizing the ventilation rate of a building integrated with Trombe walls during summer. 2.3.5.6. Colours effects

Table1.Effects of colours on the performance of the solar wall.

2.3.5.7. Glazing effects The use of proper glazing materials is another important subject in Trombe wall design. In glazing, not only the material is important. The thickness and the number of the glazing layers are also relevant factors. Normally, glazing is either single or double. 2.3.5.8. Advantages of Trombe walls •

Trombe walls not only provide thermal comfort in the spaces connected to the wall, but also in adjacent spaces.

•

A Trombe wall can reduce a building’s energy consumption by 30% and decrease the moisture and humidity of interior spaces in humid regions.

•

In addition to being environmentally friendly, Trombe walls can enhance thermal comfort and save energy even in arid and desert areas

14 2.3.5.9. Disadvantages of Trombe walls •

Trombe walls have low thermal resistance.

•

Trombe walls suffer from an inverse thermo-siphon phenomenon .

•

In Trombe walls, heat transfer always proceeds uncertainly. The amount of heat gained is unpredictable due to changes in solar intensity .

•

Trombe walls are not sufficiently beautiful, and the aesthetic value of the walls.

2.3.6 Results Trombe walls are proven to be a suitable passive-energy solution to current environmental and energy crises. Various Trombe-wall configurations are exist. Using different configurations, a variety of Trombe walls can be produced. Nine types of Trombe wall are cited most frequently by scientists. Vents, fans, and insulation are three Trombe-wall components that have significant effects on efficiency. These components should be used carefully to avoid reverse flow. A fan is a useful appliance that improves the efficiency of the vented Trombe wall by up to 8%. Moreover, size, thickness, colour, wall materials, coating materials, and glazing specifications contribute to the efficiency of Trombe walls. With regard to wall materials, any material that possesses a high storage capacity can be used in Trombe walls. However, the use of lightweight materials with high storage capacity reduces the size of the mass wall, which structural designers prefer.

2.3.7 Way forward The sociological study of the awareness of the benefits of Trombe walls is recommended, particularly among a building’s stakeholders. Additionally, research on the preferences of building users in different countries with respect to Trombe walls is suggested. Moreover, studies on the social and cultural impediments, such as aesthetic issues, that discourage individuals from using Trombe walls should be undertaken for different nations.

15 From the perspective of economics and engineering, research on the optimal thickness of various materials, such as stone, brick, adobe, concrete, etc., for different climatic regions is suggested. Research on the distance between wall and glazing for different climatic regions is also recommended. Additionally, the importance of the thickness of the glazing and the effects of glazing thickness on the performance of the Trombe wall should not be overlooked. In all suggested research, costs and benefits as well as engineering issues should be considered.

2.4 Review of Optimizing energy and environmental performance of passive Trombe wall. - Milorad Boji´ca, Kévyn Johannes, Frédéric Kuznik.

2.4.1 Introduction The energy and environmental performance is compared for buildings with and without Trombe walls. The indicator for environmental performance is a sum of primary operating energy for heating during winter and the annualized embodied energy consumed by using the Trombe walls.

2.4.2 Problem Statement Passive trombe wall should be used to save energy and to use renewable energy for heating of buildings partly or completely instead of fossil energy. In this direction, passive Trombe walls are used by a building to capture energy of the sun and use it for space heating partly or completely instead of electricity or natural gas.

2.4.3 Objectives of the paper The main aim of the article is to optimization of design of a two passive Trombe walls . •

building would use the lowest annualized life cycle primary energy for heating.

•

The performances of several constructions of Trombe walls are studied that differ only in the type and thickness of the core layer.

•

The energy per-formances of these buildings are compared to that without Trombe walls.

2.4.4 Data used In this research, thermal behavior of two houses is simulated. Each house is built according to a “Mozart” house design – the famous house design in France .

17 The first house is without Trombe walls denoted as the basic house . The second house is with two Trombe walls located at the south side of the house at the part of the external wall of the living room. Each house is used by one family. The house has 10 rooms . There are one living room of 36.5 m2, three bedrooms of 10.9 m2, 11.1 m2, and 10.1 m2, one bathroom of 7.2 m2, kitchen of 9.5 m2, two anterooms of 5.7 m2, and 4.8 m2, and storage room of 2.6 m2. The total floor area for all these rooms is 99.6 m2, where the living area of 97.1 m2 is obtained without the storage room. The performances of six variants of Trombe walls are studied. Each variant consists of a window, frame, a massive (accumulation) wall, and an air space between the window and the massive wall. The window has two glass panes with a light opaque window shade between them. The between-glass window shade serves as a thermal insulation during night. Consequently, it is on during night if low outdoor temp is 19 â&#x2014;ŚC and it is off during day. The frame is from PVC. The massive wall has three layers: outer mortar layer, core layer, and inner mortar layer.

2.4.5 Analysis

Figure 6. (a) The original Mozart house design in France and (b) basic modified Mozart house without Trombe walls.

Figure 7.(a) Analyzed house with two Trombe walls and (b) plan schematic of the Mozart house.

Table.2. Schedules of the people presence, use of the installed light, and use of the instilled electric equipment, supported operative temperature during heating season.

Table.3. Constructions with their layers used in Trombe walls

Table.4. Properties of the core material used in Trombe walls (their thicknesses are optimized during these investigations) and of some house envelope material

Figure 8. The percentage of electricity used in the house to achieve different tasks: (a) the basic building and (b) the house with Trombe walls when the Trombe core material is clay brick 1220 with Äąc = 0.45 m (both houses are heated by electricity).

2.4.6 Results In both houses, electricity is used to cover space heating, lighting, and operation of different electrical equipment, the per-cents of used electricity for different tasks are shown in Fig. 3. The house with Trombe walls has 0.45 m layer of clay brick 1220 as the Trombe core material. Compared to the house without Trombe walls, it can be seen that the house with Trombe walls uses cap-tured solar energy to save around 14% of all electricity, and around 20% of electricity for space heating. For maximum primary energy saving and minimum benefit to environment, the core layer in Trombe walls has to have the optimum thickness. The existence of Trombe wall on the house would generate the saving of primary operating energy up to 21% compared to that for the basic house. The amount of used embodied energy depends on the density of the core material, then using the core material with low density and low embodied energy inside Trombe wall may save up to 5% of primary energy.

2.4.7 Conclusions These investigations revealed that the building with Trombe walls in Lyon, France, by using solar energy may save around 20% of the operating energy during heating compared to that used by the building without Trombe walls. Due to the fact that different types of heating consume different amounts of primary energy while embodied primary energy in Trombe walls does not change, the space heating by electricity saves (up to 15%) more primary energy than that by using natural gas (up to 11%) so it is more beneficial to environment that the houses with electrical heating are equipped with Trombe walls.

2.4.8 Way forward The sociological study of the awareness of the benefits of Trombe walls is recommended, particularly among a buildingâ&#x20AC;&#x2122;s stakeholders. Additionally, research on the preferences of building users in different countries with respect to Trombe walls is suggested. From the perspective of economics and engineering, research on the optimal thickness of various materials, such as stone, brick, adobe, concrete, etc., for different climatic regions is suggested. In all suggested research, costs and benefits as well as engineering issues should be considered.

2.5 Conclusion (overall summary) Trombe walls are proven to be a suitable passive-energy solution to current environmental and energy crises. Building with Trombe walls, by using solar energy may save operating energy (a definite amount, which varies place to place) during heating compared to that used by the building without Trombe walls. Various Trombe-wall configurations are exist. Using different configurations, a variety of Trombe walls can be produced. Nine types of Trombe wall are cited most frequently by scientists. Vents, fans, and insulation are three Trombe-wall components that have significant effects on efficiency. These components should be used carefully to avoid reverse flow. A fan is a useful appliance that improves the efficiency of the vented Trombe wall by up to 8%. Moreover, size, thickness, colour, wall materials, coating materials, and glazing specifications contribute to the efficiency of Trombe walls. With regard to wall materials, any material that possesses a high storage capacity can be used in Trombe walls. However, the use of lightweight materials with high storage capacity reduces the mass of the wall, which structural designers prefer. The fact says that different types of heating consume different amounts of primary energy while embodied primary energy in Trombe walls does not change, the space heating by electricity saves (up to 15%) more primary energy than that by using natural gas (up to 11%) so it is more beneficial to environment that the houses with electrical heating are equipped with Trombe walls.

22 3. CASE STUDIES

3.1 List of case studies 1. Energy conservation in honey storage building using Trombe wall,Gwalior,india. 2. Heat gain through Trombe wall using solar energy in Erzurum,a cold region of Turkey. 3.Ventilated Trombe wall as a passive solar heating and cooling retrofitting approach; a low-tech design for off-grid settlements in semi-arid climates.

3.2 Presentation of case study I – Energy conservation in honey storage building using Trombe wall - Arvind Chel, J.K. Nayak, Geetanjali Kaushik.

3.2.1 Introduction With the severe energy crisis over worldwide, the utilization of energy has become a vital issue and the conservation of energy has acquired prime importance. The energy is required in a building for room air heating, cooling, ventilation, lighting, etc. However, the maximum energy is utilized in buildings for room air conditioning. The building energy requirement can be reduced to great extent if proper passive solar features are incorporated in the building during the design level. The use of passive building concept for achieving thermal comfort inside a building is a growing concern world over for the building energy conservation. A Trombe wall concept is one of the passive heating examples for heating of a honey storage building. A conventional Trombe wall comprises a south-facing massive thermal wall with a clear outer glazing and a convective air cavity inbetween them. It has been used worldwide and had many improvements in the past decades due to advantages, such as simple configuration, high efficiency, zero running cost.

3.2.2 Location Honey storage building located at Gwalior (India) (latitude: 268140n, longitude: 788150E, elevation: 207 m above MSL)

3.2.3 Climate Gwalior has a sub-tropical climate with hot summers from late March to early July, the humid monsoon season from late June to early October, and a cool dry winter from early November to late February. Temperatures peak in May and June with daily averages being around 33–35 °C (93–95 °F), and end in late June with the onset of the monsoon. Winter in Gwalior starts in late October, and is generally very mild with daily temperatures averaging in the 14–16 °C (58–62 °F) range, and

24 mostly dry and sunny conditions. January is the coldest month with average lows in the 0 Â°C range (32 Â°F) and occasional cold snaps that plummet temperatures down to zero.

3.2.4 Exclusivity of the case Energy conservation, mitigation of CO2 emissions and economics of retrofitting for a honey storage building with trombe wall for winter heating application. During winter months, the room air temperature of building falls below the required temperature range of 18â&#x20AC;&#x201C;27 8C which is suitable for honey storage. So, the room air temperature range is maintained in the building using a 2.3 kW capacity electrical oil filled radiator (or room air heater) which accounts for the major energy consumption of the building on an annual basis. On account of which there are significant CO2 emissions into the atmosphere from the honey storage building. Hence, this case study was conducted to recommend the passive heating concept to the stakeholders of the building so as to conserve the energy requirement for room air heating.

3.2.5 Data used In this paper, the thermal performance of a single zone honey storage building integrated with Trombe wall is analyzed using TRNSYS software. In this software, the building model is prepared based on the inputs like building construction details, thermal properties of materials, details of Trombe wall and orientation of building. The simulation results of the retrofit building show that Trombe wall is sufficient to maintain room air temperature suitable for honey storage. The TRNSYS software was used by Valerio and Stefano for obtaining the thermal performance of retrofitted building in Rome. They obtained reduction in CO2 emissions by a considerable amount because of significant energy saving due to retrofitting of building.

3.2.6 Analysis The honey has a shelf life of 2 years. It is important to store honey in sterilized and sealed airtight containers. The honey storage temperature should be maintained

25 between 18 and 30 8C. The constructional details and the orientation of the existing honey storage building 1. The storage building has a store room with an attached bathroom. 2. All external walls are three-layered with middle layer composed of 22 cm thick brick wall and both the side walls are cement plastered. The plaster thickness is 1.5 cm for inside layer and 2.0 cm for outside layer. The height of each wall is 3 m. 3. Roof is also a three-layered structure having inside layer of limestone tile (15 cm thick), middle layer of cement mortar (2.5 cm thick) and outermost layer of cement plaster (2.5 cm thick). The roof has a length of 7.13 m and width of 3.05 m.

Figure 9 . A conventional Trombe wall during (a) winter and (b) summer.

4. The ground is made of first layer of cement mortar (10 cm thick), second layer of sand gravel (25 cm thick) and the last layer of soil or mud phuska (40 cm thick) after this layer it is assumed that ground is exposed to a boundary maintained at 25 8C. 5. There are two identical windows on the north-west wall. The dimensions of window are height of 0.914m and width of 1.828 m. Window is made of plywood of thickness 2.5 cm. The windows open inside. Windows are not provided with overhangs. 6. A single steel door is on the south-east wall. The dimensions of door are 2.134 m height and 0.914 m width. The door is made of 0.5 cm thick GI metal sheet. The door opens inside.

Figure 10. PV-Trombe wall for (a) winter heating and (b) summer cooling.

3.2.6.1 Building orientation & simulated building. The orientation of building is mentioned with respect to due south. The honey is stored in store room and the other room is rarely used as bathroom during day. The building is simulated using TRNSYS software. The results of this software are validated using experimental data.

Figure 11.Schematic plan view of single on the south-east wall of size (5 m T3m).

Figure 12. Vented Trombe wall retrofitted zone building for simulation using TRNSYS.

3.2.6.2 Thermal performance of building using TRNSYS The thermal performance of existing single zone honey storage building is obtained using TRNSYS software. The room air temperature of the building was predicted for harsh winter conditions for the month of January using the input climatic parameters like ambient air temperature and solar radiation data and the building design parameters with constructional details of Trombe wall and roof. The

27 simulation results of retrofitted building with vented Trombe wall show that the room air temperature is in the range of 18.5â&#x20AC;&#x201C;22.8 8C for harsh winter of January month. The results show that room air temperature is maintained highest in case of vented Trombe wall.

Figure 13. Room air temperature for different retrofits on south-east wall.

Figure 14.Heating potential for different retrofits on south-east wall.

Hence, it is recommended to retrofit the existing building with vented Trombe wall on south-east wall. 3.2.6.3 Assumptions The following assumptions are made during modeling of the building using TRNSYS software. 1. The building is a single zone building since the bathroom usage is only once in a day.

28 2. The building is mainly used for storage; hence low infiltration gain with 1.5 EACH. 3. Doors and windows are assumed to be always closed for simulation of building. 4. Roof is assumed horizontal, since the roof slope is negligible to drain out roof water. 5. Only the room air heat capacity is considered and rest all isothermal masses are neglected. 6. The absorptivity of wall and roof surfaces is 0.6 and each material layer is assumed to be homogeneous. 7. The black surfaces are assumed to have absorptivity 0.9. 8. The outside and inside heat transfer coefficients are constant and the values are 22 and 6Wm2 K1, respectively, for both horizontal and vertical surfaces. 9. The ground surface of building is assumed to conduct heat to the boundary maintained at 25â °C. 10. All passive heating concepts like wall painted black, Trombe wall and direct gain using glass window are assumed to be retrofitted on south-east surface with area 15 m2 (5 m x3 m).

3.2.7 Results The thermal performance of the building for the month of harsh winter condition for different passive building heating concepts has the following key results. 1. When all walls are painted black individually then comparison showed that northeast wall is least concerned for heating and south-east wall has maximum heating effect among all walls. Roof has maximum heating effect as compared to south-east wall. When south-east wall is painted black, room air temperature predicted in the range of 14.9â&#x20AC;&#x201C;18.5 8C for harsh winter month (January).

29 2. When south-east wall is retrofitted to unvented Trombe wall, simulation results show that room air temperature predicted to be in the range of 15.4â&#x20AC;&#x201C;19.1 8C in harsh winter month. This needs improvement like providing vents so that during daytime air gets heated and circulated into the building to heat room air and during night time close these vents and shade the Trombe wall using movable insulation to avoid heat loss to ambient. During night time, the heat absorbed by the wall in daytime gets lost inside the building by convection and thereby heats the inside room air temperature. 3. When the south-east wall is retrofitted with vented Trombe wall the results were promising; room air temperature predicted to be in the range of 19â&#x20AC;&#x201C;23.3 8C for harsh winter (January) month. This room air temperature range is suitable for honey storage inside the building to avoid crystallization of honey. 4. When south-east wall is converted into direct gain concept for the existing building then the room air temperature is predicted to be in the range of 15.8â&#x20AC;&#x201C;19.7 8C for harsh winter month. Hence, this option is not sufficient to maintain room air temperature above 18 8C for honey storage.

3.2.8 Conclusions The investigation of Trombe wall for honey storage building has proven its importance for natural heating of building in winter months. The use of Trombe wall passive heating of building provides an opportunity for conserving considerable amount of electrical energy for heating room air for honey storage requirement. The recommendations for retrofitting the honey storage building are based on the thermal performance results of TRNSYS. The following recommendations can be made for honey storage building for winter conditions to maintain inside zone temperature above 18 8C and below 30 8C for better performance of honey storage building. 1. The south-east wall surface is completely black painted with mat finish. 2. The vented Trombe wall of size 5 m width and 3 m height is retrofitted on southeast wall.

30 3. During winter climatic conditions, the two vents of Trombe wall are kept open during the day and closed during the night. Also, during night the vents are covered with night movable insulation cloth. 4. During summer climatic conditions, completely shade the Trombe wall with the movable insulation in order to avoid heat gain through Trombe wall. The stakeholders are already using desert cooler during summer for 12 h during daytime for room air cooling in the month of March, April, May and June. During summer, it is preferred to go for shading of roof of the building to cut the excessive heat gain.

3.3 Presentation of case study II – Heat gain through Trombe wall using solar energy in a cold region of Turkey. - Turkan Goksal Ozbalta and Semiha Kartal.

3.3.1 Introduction A great amount of energy consumption occurs in buildings due to indoor heating, cooling, ventilation and lighting. Among these, the energy consumed for heating in buildings has the biggest proportion (40%) of consumption. For that reason, it is crucial to decrease the energy consumption and its environmental effects. It is also inevitable to use clean, inexhaustible and emission free sources for energy gain in order to provide energy efficiency and conservation. One of those sources is solar energy utilized in architectural applications for sustainability. In this context, proper structure elements need to be considered for utilizing solar energy in active or passive ways and for decreasing energy losses. By using passive solar devices in the building design, the energy requirement of buildings can be reduced to a great extent. In passive design, the direction and location of buildings and the characteristics of building materials are the criteria which need to be taken into account.

3.3.2 Location Erzurum, a city in the coldest region of Turkey. Coordinates: 39°54′31″N 41°16′37″E. It is situated 1757 meters (5766 feet) above sea level.

3.3.3 Climate Erzurum has a humid continental climate (Koppen climate classification Dfb) with cold, snowy winters and warm, dry summers with cool nights. The average maximum daily temperature during August is around 27 °C (81 °F). The highest recorded temperature is 36.5 °C (97.7 °F), on 31 July 2000. However, the average minimum daily temperature during January is around −15 °C (5 °F); temperatures fall below −30 °C (−22 °F) most years. The lowest recorded temperature is −37.2 °C (−35.0 °F), on 28 December 2002

3.3.4 Exclusivity of the case In Turkey, energy consumption for heating is extremely high because heat insulation applications on building walls/roofs are not wide spread and solar energy is not used efficiently for energy gain. Therefore, solar energy gain for buildings through Trombe

wall for winter heating application on a sample building in

Erzurum, Turkey, was investigated. According to TS 825 regulation, Erzurum (latitude: 39°55’N, longitude: 41°17’E, altitude: 981 m) which is located in cold climatic zone (zone 4) having 4888 heating degree-days has great heating load. In addition, solar radiation rate is high in Erzurum due to the altitude. Therefore, solar energy can be potentially utilized for heating in this region. It is aimed at showing the passive use of solar energy with architectural elements and the impact of material choices on energy gain. Using renewable energy has a growing importance in case of decreasing energy demand of buildings and reducing CO2 emissions for sustainability.

3.3.5 Data used

Figure 15.Working principle of a traditional Trombe wall and energy gain.

Figure 16.Monthly energy flows for a trombe wall.

3.3.5.1 Un utilizability method (UU method) UU method establishes the limiting cases of zero and infinite capacitance building. A real building that lies between these two limits. The first case is that construction materials have the capacity of infinite heat storage. In the latter one, construction

33 materials do not have the capability of energy storage. By using UU method, it is possible to calculate auxiliary energy requirement for direct gain systems and applied

for collector storage wall systems (Trombe wall) by amendments.

Calculations were carried out by using monthly average values. And from that annual auxiliary energy required for trombe walls. 3.3.5.2 Utilizability concept Utilizability can be thought of as a radiation statistics that has been built into its critical radiation levels. The f and f concepts can be applied to a variety of design problems for heating systems, combined solar energy-heat pump systems and many others. The concept utilizability has been extended to apply to passively heated buildings, where the excess energy (un utilizable energy) that cannot be stored in a building structure can be estimated.

Table 5. Thermo physical properties of building materials Zurcher and Frank (1998).

Table 6. The absorption coefficients of absorbing surfaces (OzÄąÄąk, 1985).

Figure 17. The solar radiation map of the Erzurum, Turkey. (EIE,2008).

Figure 18.Outdoor temperature and montly average daily incident solar radiation on the horizontal surface for Erzurum.

Table 7. The weather data of Erzurum.

3.3.6 Analysis Building construction details In the study, a two storey building with 118.7 m2 floor area of which structural system is reinforced concrete carcass was selected. Trombe wall was applied on the south facade of this building. The height of the south oriented Trombe wall is 2.7 m and its width is 9.1 m. Trombe wall consists of double glazing (6 â&#x20AC;&#x201C; 16 - 6 mm) and a massive wall is constructed with reinforced concrete, brick and autoclaved aerated concrete in different thicknesses and surface colours. The wall thicknesses are 25 cm in reinforced concrete, 19 cm in brick and 15 cm in AAC. Also, inner plaster is 2 cm; outer plaster is 3 cm. Wall surface colours were deduced as dark, natural and light due to different absorption coefficients of those colours.

35 It was deduced that double glazing was installed in front of massive wall. The effective heat storage capacity of the building was accepted as 59.35 MJ/K.

Figure 19. (a) Ground Floor plan (b) Second Floor plan

Figure 20. Section of the building.

Table 8. Parameters of the building.

Figure 21.The schematic view of Trombe wall in plan and section.

Figure 22.Investigated wall constructions with different materials.

Figure 23 .Monthly solar gain of Figure 24 .Monthly solar gain of Figure 25. Monthly solar gain of Concrete trombe wall brick trombe wall with various aerated concrete Trombe Various colour. Colour. Wall with various colour.

Table 9. Annual heat gain from solar energy through Trombe wall.

3.3.7 Results In this study the efficiency of Trombe wall application for heat gain from solar energy in Erzurum was calculated.The annual energy requirement of the sample building was calculated by insulating it in accordance with TS 825 rules Qyear = 22390 kWh. In order to decrease energy consumption of the building, it was found out that solar energy gain through the 24.5 m2 south oriented Trombe wall is about 6041, 4532, 2183 kWh/year for concrete wall; 4609, 3686, 1607 kWh/year for brick wall; and 2923, 1776, 976 kWh/year for aerated concrete wall with different colour intensity of wall surfaces (dark, natural, light respectively). As a result of this work, it indicated that annual heat gain through solar energy on dark, natural and light coloured concrete Trombe walls in Erzurum was found out to be 26.9, 20.2 and 9.7% respectively; on brick Trombe wall, it was calculated as 20.5,16.4 and 7.1%respectively, while on autoclaved aerated concrete wall it was determined to be 13.0, 7.9 and 4.3%. The results proved that the varied absorption coefficient depending on the colour of outer surface affects the solar energy gain.

3.3.8 Conclusion Trombe wall application needs to be taken into account inevitably for the design of buildings in order to provide energy gain from renewable sources such as solar energy

for the environment and sustainability. The Trombe walls provide

significant heating to the buildings without paying energy cost.

3.4 Presentation of case study III – Ventilated Trombe wall as a passive solar heating and cooling retrofitting approach; a low-tech design for off-grid settlements in semi-arid climates - Marwa Dabaieh, Ahmed Elbably

3.4.1 Introduction The world is experiencing one of its most serious energy crises in decades (IEA,2014). By 2050, global temperatures are anticipated to continue to rise and greenhouse gas emissions are expected to be more than double if we carry on with our energy inefficient building methods. Many countries have become more import reliant and gradually more effected by the problems associated with fuel poverty. Today’s buildings consume more than 40% percent of the world’s primary energy, which are responsible for 30% of greenhouse gas emissions. This is more energy than any other sector of the world’s economy, including transportation and industry. Domestic heating and cooling alone consumes one fifth of total fossil fuel energy production worldwide, meaning our homes add to many environmental problems like greenhouse gas emissions, which contributes to man-made global warming. Accordingly, we pay a high environmental cost for our future.

3.4.2 Location A residential building located in Saint Katherine in Sinai, Peninsula, Egypt. It is located at a latitude of 28.7 North and a longitude of 34.1 East at an elevation of 1586 m.

3.4.3 Climate Koppen-Geiger

climate

classification

system classifies

its

climate

as cold

desert (BWk). It has the coldest nights of any city in Egypt. Its humidity is very low. In terms of climatic characteristics, Saint Katherine is located in a semi-arid climate zone with extreme differences in temperature between the day and night in both summer and winter. It is characterized by hot dry summers with a maximum average temperature of 29.7 C and a minimum average of 22.4 C and mild to cold winters with a maximum average temperature of 18.6 C and a minimum average of

39 5.2 C. Summer midday temperatures can reach up to 34 C, while in winter, night temperatures can fall to around 0 C commonly accompanied by frost. The average solar radiation intensity is 5.4 W/m2 and the average wind speed is 0.7 mph. The prevailing winds come from the Northwest. Saint Katherine is characterized by relatively low annual rain fall ranges from 7075 mm to 10,018 mm. Typically, snow falls from late December until mid-February

3.4.4 Exclusivity of the case In the coming years, it is anticipated that if we continue with the same pace of energy consumption, communities will continue to face three major challenges; a mounting increase in energy demands, pollution, and global warming. On a local scale, Egypt is experiencing one of its most serious energy crises in decades. The energy consumed in indoor cooling and heating is the biggest portion of total energy consumption in residential buildings. This paper is an experimental simulation study for building retrofitting in off-grid settlements in semi-arid climates, using Trombe wall as a low-tech passive heating and cooling solution.

3.4.5 Data used This study applied an experimental simulation method for retrofitting using parametric simulation modeling by means of Design Builder software.

Figure 26 .Psychrometric chart of Saint Katherineâ&#x20AC;&#x2122;s yearly temperature showing comfort range according to ASHRAE standard 55-2004.

Figure 27. Ground floor plan for the case study showingthe test room location and orientation.

Figure 28 .Cross section in the proposed trombe wall.

Table 10.Material properties of the classic and the proposed tombe wall

3.4.6 Analysis Study show how retrofitted buildings using a low-tech resilient trombe wall design can increase its efficiency and reduce cooling and heating loads. Proposed trombe wall design showed a significant improvement in indoor temperature that affected thermal comfort range both in summer and winter compared to both the base case and the classic trombe wall. The proposed trombe wall ensured a satisfactory thermal comfort with minimal temperature difference to the standard comfort. 16%

41 of the year is outside the comfort range for the proposed trombe wall compared to 66% for the base case and 62% when using the classic trombe wall. During spring and autumn the room retrofitted with the proposed trombe wall showed no need for heating or cooling. Cold nights in autumn and hot days in spring were still within the comfort range.

Figure 29. Winter average daily indoor and outdoor temperature showing the performance of the proposed Trombe wall compared to the classic Trombe wall and the base case.

Figure 30 .Summer average daily indoor and outdoor temperature showing the performance of the proposed Trombe wall compared to the classic Trombe wall and the base case.

Table 11.Comparision between the classic and proposed trombe wall in terms of energy consumption, energy saving and co2 reduction.

During winter, the simulation for proposed Trombe wall showed 152 h outside the comfort range during January and February with average lowest temperature 19.1

42 C, compared to 2566 h outside the comfort in the case of the classic Trombe wall with average lowest temperature 16.5 C. During peak winter days, the measurements on the 16th of January, when the lowest outdoor temperature was 4.7 C, the lowest recorded temperature indoors for the proposed Trombe wall was 17.6 C, compared to 13.9 C for the classic Trombe wall and 13.1 C for the base case, where the minimum comfort in winter according to ASHRAE standard 55 is 20.3 C.

For summer performance, the base case was outside the comfort range for the whole summer season with an average temperature of 29.4 C and the same for the classic Trombe wall with an average of 29.6 C. The proposed Trombe wall reduced the total number of cooling hours to 1072 h with an average temperature of 26.3 C. The highest indoor temperature recorded for the new Trombe wall proposal case on the 24th of July was 28.7 C compared to 30.1 C for the classic Trombe wall and 32.3 C for the base case when the outdoor temperature was 35 C. The highest comfort summer temperature according to ASHRAE standard 55 is 26.7 C.

The average heating load in winter season when using the classic Trombe wall is 20,160 kW h compared to significant difference in heating load reduction for the proposed Trombe wall to be 202 kW h, when the average heating load for the base case is 33,256 kW h. The average cooling load in summer season was reduced when using the proposed Trombe wall to be 1814 kW h compared to the classic Trombe wall which is 23,970 kW h when the existing cooling load for the base case is 22,391 kW h with marginal small difference to the classis Trombe wall operation. This reduction in heating and cooling loads was accompanied by a significant reduction in energy consumption in case of proposed Trombe wall is 2016 to kW h to reach an energy savings of 53,631 kW h and reduction in CO2 emissions of 144,267 kg of CO2. The classic Trombe wallâ&#x20AC;&#x2122;s energy consumption is 42,551 kW h, with an energy saving of 13,096 kW h and a 35,228 kg reduction in CO2 Emissions.

Summer daytime

Summer night time

Winter daytime

Winter night time

A: Wooden shutters, B: Glass panel, C: Rammed earth wall, D: Wool insulation panel, E: Lower vent for north cool air, F: Trombe wall lower vents, G: Trombe wall upper vents, H: Wool curtain, I: Trombe wall top vent. Figure 31. Different modes and adjustments of the Trombe wall during summer and winter days and nights.

The Trombe wall works as a method of passive heating in winter and is adjusted to act as a solar chimney for passive cooling in summer. It is important to mention that the computer simulation results have been obtained under the assumption that the building would be operated correctly; especially when it comes to opening and closing the Trombe wall air vents. To overcome the inverse thermosiphon phenomena and heat transfer from inside to outside especially during winter nights, we introduced several solutions like thermal insulation, using goat wool curtains and sheep wool insulation for the upper and lower vents.

3.4.7 Results The annual heating energy load for the base case is 33,256 kW h. This value is obtained by assuming that the starting point of using a heater is 20.3 C. The heaters in Saint Katherine are powered by electricity in some houses and connected to the main grid; whereas, in remote areas, the majority of homes are powered by diesel or charcoal depending on local availability. In such remote areas, 1 kg of diesel is needed to produce 10 kcal (1 kW h = 0.866 kcal) and emits 2.69 kg CO2. The total cost of the proposed Trombe wall when manufactured locally is calculated to be 3600 EGP, while the classic Trombe wall costs 2300 EGP, including materials and labor (equivalent to 420 and 270 Euro, respectively, at the time of this study). According to calculations, the proposed Trombe wall is a reasonable investment relative to its efficiency. It has a comparatively short payback,7 months, in relation to a buildingâ&#x20AC;&#x2122;s 70 year average lifespan.Which is less than what other researchers have reached. This calculation has been made only for the retrofitted room and not for the entire building.

3.4.8 Conclusion Building retrofitting represents the largest unexploited source of energy savings and CO2 reduction potential in Egypt at this moment. Using Saint Katherine in Egypt as a case study, a modified Trombe wall technique is applied to offer an efficient lowtech solution for off-grid residential buildings in semi-arid climates. Our proposal aimed to introduce an economically viable, energy efficient Trombe wall design with a low carbon impact. Residentsâ&#x20AC;&#x2122; social acceptance of passive technologies is also a key aspect for the success of this proposal. This is especially pertinent when it comes to manually adjusting the system in different seasons. The methodology applied in this study should also be followed by a best practice manual that integrates applicable passive and low-tech, cost-effective retrofitting strategies or off-grid settlements.

3.5 Conclusions of case study (overall summery) Trombe wall application needs to be taken into account inevitably for the design of buildings in order to provide energy gain from renewable sources such as solar energy for the environment and sustainability. The use of Trombe wall passive heating of building provides an opportunity for conserving considerable amount of electrical energy for heating room air for a particular building requirement. Building retrofitting represents the largest unexploited source of energy savings and CO2 reduction potential at this moment. The Trombe walls provide significant heating to the buildings without paying energy cost and it will definitely payback after some period of time. The recommendations for retrofitting the building are based on the thermal performance results of TRNSYS. 1. By varying the wall surface paint which in particular direction from sun,the efficiency of trombe wall may increase. 2. The vent size of Trombe wall also may increase the performance of wall. 3. During winter climatic conditions, the vents of Trombe wall are kept open during the day and closed during the night. Also, during night the vents are covered with night movable insulation cloth. 4. During summer climatic conditions, completely shade the Trombe wall with the movable insulation in order to avoid heat gain through Trombe wall. During summer, it is preferred to go for shading of roof of the building to cut the excessive heat gain. Residentsâ&#x20AC;&#x2122; social acceptance of passive technologies is also a key aspect for the success of trombe wall applications. This is especially pertinent when it comes to manually adjusting the system in different seasons..

46 4. BIOGRAPHY

4.1 Profile Edward mazria Nationality – American Known for – Green building architecture Published works 

The Passive Solar Energy Book, Rodale Press 1979



It’s the Architecture Stupid!, Solar Today Magazine, May/June 2003



Turning Down the Global Thermostat, Metropolis Magazine, October 2003



Blueprint for Disaster, On Earth Magazine, Summer 2005

His building designs have been published in Architecture, Progressive Architecture, Metropolis, Architectural Record, Landscape Architecture, Architectural Digest, Process, Kenchiku Bunka, Public Garden, Solar Today, ArchitectureWeek, Texas Architect, The Wall Street Journal and the New York Times. Awards - American Institute of Architects (AIA) Design Awards AIA Design Innovation Award Design Futures Council Senior Fellow Commercial Building Awards from the Department of Energy Landmark Designation Award from The Albuquerque Conservation Pioneer Award from the American Solar Energy Society Outstanding planning award from the American planning association Edward Mazria is an architect, author and educator. After receiving his Bachelor of Architecture Degree from the Pratt Institute in 1963 he spent two years as an architect in the Peace Corps in Arequipa, Peru. He later worked with the firm of Edward Lara bee Barnes in New York before completing his master's degree and beginning a teaching and research career at the University of New Mexico in 1973. His architecture and renewable energy research at both UNM and the University of Oregon established his leadership in the field of resource conservation and passive heating, cooling and daylighting design. His design methodology, developed at that

47 time and presented in The Passive Solar Energy Book, is currently in use worldwide. Since forming the architecture and planning firm Mazria Associates, Inc. in 1978, he has completed award winning architecture and planning projects from the day-lit Mt.

Airy

Public

Library

in North

Carolina to

the Rio

Grande

Botanic

Garden Conservatory in New Mexico

4.2 Philosophies and thoughts Edward mazria is an internationally recognized architect, author, researcher, and educator. over the past decade ,his seminal research into the sustainability, resilience, energy consumption, and greenhouse gas emissions of the built environment has redefined the role of architecture, planning, design, and building, in reshaping our world. He is the founder of Architecture 2030, a think tank developing real-world solutions for 21st century problems. Mazria issued the 2030 Challenge and introduced the2030 Palette, a revolutionary new platform that puts the principles behind low-carbon/zero carbon and resilient built environments at the fingertips of architects, planners, and designers worldwide. In 2014 he presented the Roadmap to Zero Emissions at the Organization of Economic Cooperation and Development and UN Framework Convention on Climate Change calling for zero emissions in the built environment by 2050, and drafted the 2050 Imperative, endorsed by professional organizations representing over 1.3 million architects in 124 countries worldwide. In 2015 he launched the China Accord, which has been adopted by key international firms pledging to plan, design and build to carbon neutral standards in China; and delivered the opening presentation at the UNFCCC COP21 â&#x20AC;&#x153;Buildings Dayâ&#x20AC;? titled The 2 Degree Path for the Building Sector.

Recently, he developed Achieving Zero, a framework of incremental actions that cities and governments can put in place to ensure carbon neutral built environments by mid-century, and the Zero Cities Project (with the Carbon Neutral Cities

48 Alliance, Urban Sustainability Directors Network, New Buildings Institute, and Resource Media) to implement the framework. Mazria speaks nationally and internationally on the subject of architecture, design, energy, economics, and climate change and has taught at several universities, including the University of New Mexico, University of Oregon, UCLA, and the University of Colorado-Denver.

5. CONCLUSIONS Trombe walls are proven to be a suitable passive-energy solution to current environmental and energy crises. Building with Trombe walls, by using solar energy may save operating energy (a definite amount, which varies place to place) during heating compared to that used by the building without Trombe walls. Various Trombe-wall configurations are exist. Vents, fans, and insulation are three Trombe-wall components that have significant effects on efficiency. These components should be used carefully to avoid reverse flow. A fan is a useful appliance that improves the efficiency of the vented Trombe wall by up to 8%. Moreover, size, thickness, colour, wall materials, coating materials, and glazing specifications contribute to the efficiency of Trombe walls. With regard to wall materials, any material that possesses a high storage capacity can be used in Trombe walls. However, the use of lightweight materials with high storage capacity reduces the mass of the wall, which structural designers prefer. The fact says that different types of heating consume different amounts of primary energy while embodied primary energy in Trombe walls does not change, the space heating by electricity saves (up to 15%) more primary energy than that by using natural gas (up to 11%) so it is more beneficial to environment that the houses with electrical heating are equipped with Trombe walls.The use of trombe wall passive heating of buildings provides an opportunity for conserving considerable amount of energy.

6.REFERENCES 1. H. Omrany, Ali G., Amirhosein G. , K. Raahemifar , J. Tookey (2016). Application of passive wall systems for improving the energy efficiency in buildings: A comprehensive review, Renewable and Sustainable Energy Reviews (62)1252–1269. 2. O. Saadatian , K. Sopian, C.H. Lim, Nilofar Asim, M.Y. Sulaiman (2012). Trombe walls: A review of opportunities and challenges in research and development, Renewable and Sustainable Energy Reviews (16) 6340–635. 3. M. Bojic, K. Johannes, F. Kuznik(2014). Optimizing energy and environmental performance of passive Trombe wall, Energy and Buildings (70) 279–286. 4.Arvind Chel, J.K. Nayak, Geetanjali Kaushik(2008). Energy conservation in honey storage building using Trombe wall. Energy and Buildings (40)- 1643–1650. 5. https://en.wikipedia.org/wiki/Gwalior#Climate 6. Turkan Goksal, Ozbalta and Semiha Kartal (2010). Heat gain through Trombe wall using solar energy in a cold region of Turkey. Scientific Research and Essays (5) - 2768-2778. 7. https://en.wikipedia.org/wiki/Erzurum 8. Marwa Dabaieh , Ahmed Elbably(2015). Ventilated Trombe wall as a passive solar heating and cooling retrofitting approach; a low-tech design for off-grid settlements in semiarid climates. Solar Energy (122) 820–833. 9. https://en.wikipedia.org/wiki/Sinai_Peninsula 10. https://en.wikipedia.org/wiki/Trombe_wall 11. https://en.wikipedia.org/wiki/Edward_Mazria 12. http://architecture2030.org/about/leadership/