Environmental Guidelines for Residential buildings in Delhi

University of Westminster, College of Design, Creative and Digital Industries School of Architecture and Cities MSc Architecture and Environmental Design 2018/19 Sem 2&3 Thesis Project Module

Environmental Guidelines for Residential buildings in Delhi thesis 18/19

Environmental Guidelines for Residential buildings An adaptive envelope to improve the energy performance of residential building blocks in Delhi

Athiya Bhalla September 2019

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19

ABSTRACT The issue being the increasing temperatures of the metropolis city of Delhi, National Capital Region of India. Delhi undergoes various challenges because of the rising temperature, with the future prediction getting worse due to increase in Global warming and urban heat island effect. Also, Delhi being the 5th most populated city in the world has a need of densification, which leads to high demand of resources and energy consumption. The aim is to optimise environmental housing qualities along with climatic comfort and energy utilisation by using different combinations of strategies and create an adaptive envelope. This is being done by providing guidelines for a typical residential tower in Delhi. Considering the apartment facing four orientations in three different seasons.

The methodology followed would involve studying a typical residential high-rise block by fieldwork and analytical simulations which would further develop a base case. The base case is then analysed to develop the envelope of the building. This can be done by creating various combinations of design solutions such as shading, ventilation , insulation preceded with analytical studies. Focusing on facades by using balconies as buffer and spill out spaces helping the design furthermore. The research findings developed by using different strategies helped in achieving better thermal comfort from the existing base case and reduce the energy consumption in the most problematic summer season.

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19

TABLE OF CONTENTS ABSTRACT .................................................................................................................................. 3 1. Introduction ......................................................................................................................... 10 1.1

General background ............................................................................................... 12

1.2Theoretical background ................................................................................................... 12 1.3 Context .......................................................................................................................... 12 1.4 Problem Statement ........................................................................................................ 12 1.5 Hypothesis ..................................................................................................................... 13 1.6 Methodology .................................................................................................................. 13 1.7 Summary of the results................................................................................................... 13 1.8 Structure ........................................................................................................................ 14 2. Literature Review and Theoretical background ..................................................................... 16 2. Literature Review and Theoretical background ..................................................................... 18 2.1 Residential high rise building ......................................................................................... 18 2.1.1 Urban form building................................................................................................. 18 2.1.2 Aspect Ratios, Orientation and Solar Access ............................................................. 18 2.1.2 Urban Heat Island Effect (UHI) ................................................................................. 18 2.2 Thermal comfort ............................................................................................................ 19 2.3 Energy efficiency requirement of a residential building................................................... 19 2.3.1 Need of rationalisation of energy consumption........................................................ 20 2.4 Envelope design ............................................................................................................. 20 2.4.1 Building envelope components ................................................................................ 21 2.4.3 Role of building envelope in reducing energy consumption ..................................... 21 3. Context ................................................................................................................................ 23 3.1Location .......................................................................................................................... 24 3.2 History of Delhi .............................................................................................................. 24 3.3 Urban growth and population ........................................................................................ 24 3.4 Climate ........................................................................................................................... 27 3.5 Seasonal Analysis............................................................................................................ 27 3.6 Vernacular Architecture of Delhi..................................................................................... 29 3.6.1 examples of vernacular residences .......................................................................... 30

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 3.6.2 Shading devices in Vernacular buildings in delhi ...................................................... 31 3.6.3 Envelope design of vernacular buildings................................................................... 31 3.7 Precedent ( case study) .................................................................................................. 32 3.7.1 Introduction............................................................................................................. 32 3.8 Problem statement ........................................................................................................ 32 4. Fieldwork ............................................................................................................................. 35 4.1 Analysis methodology..................................................................................................... 36 4.1.1 Instruments used in fieldwork.................................................................................. 36 4.1.2 Introduction............................................................................................................. 39 4.1.3 Post occupancy evaluation ....................................................................................... 39 4.1.4 Spot measurements ................................................................................................. 39 4.1.5 Continuous Monitoring ............................................................................................ 40 5.Analytical studies .................................................................................................................. 42 5.1 case study analysis ......................................................................................................... 43 5.1.1 Strategy 1 ................................................................................................................ 43 Moreover, strategy one talks about night time ventilation that is opening of windows at night time. .................................................................................................................... 43 5.1.2 Use of FANS ............................................................................................................. 43 5.1.3 Strategy 2 ................................................................................................................ 45 5.1.4 Strategy 3 ................................................................................................................ 47 .1.5 Findings from the case study...................................................................................... 47 a)

Energy Balance ................................................................................................... 47

b)Radiation Analysis ..................................................................................................... 48 c)Daylight Analysis ( UDI ) ............................................................................................. 48 5.2 Base case........................................................................................................................ 48 5.2.1 Methodology .......................................................................................................... 48 5.2.2Parameters ............................................................................................................... 49 a)Seasons ..................................................................................................................... 49 b)Orientation................................................................................................................ 49 c)Condition ................................................................................................................... 49 5.2.3 Inference from case study........................................................................................... 49 5.3 Design strategies ............................................................................................................ 49 5.3.1 Window to wall ratio............................................................................................... 49 5.3.2 Openable aperture .................................................................................................. 51

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 5.3.3 Shading strategies.................................................................................................... 51 6. Research outcomes and Design Applicability ........................................................................ 59 6.1 Research outcome .......................................................................................................... 59 6.1.1 Free Running ........................................................................................................... 59 6.1.2 Aircon ..................................................................................................................... 65 7. Conclusions .......................................................................................................................... 69 7.1 Context fieldwork and analytical analysis........................................................................ 69 7.2 Research outcomes ........................................................................................................ 69 ................................................................................................................................................ 71 8. References ........................................................................................................................... 73

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 Table of Figures FIGURE 1: Combination of physical spaces and envelope .................................................................................................. 19 FIGURE 2: Representing in India on the world map. Latitude 28 N Longitude 77 E ............................................................. 24 FIGURE 3 : Urban growth and densification 1995.............................................................................................................. 25 FIGURE 4: Urban growth and densification 2015 .............................................................................................................. 25 FIGURE 5: Representing in India on the world map. .......................................................................................................... 27 FIGURE 6: Climate typology in India. Delhi with composite climate. .................................................................................. 27 FIGURE 6: Monthly Average Climate Data representing summer season. .......................................................................... 27 Though the latest studies have said that temperature goes 35 in these peak summer months .......................................... 27 FIGURE 7: summer typical week temperature (TAS ) ......................................................................................................... 28 FIGURE 9: Average Vertical radiation chart ....................................................................................................................... 28 FIGURE 10: Representing average climate data for monsoon season . ............................................................................... 28 FIGURE 11: Average relative humidity for Delhi ................................................................................................................ 29 FIGURE 12: Representing average climate data for winter season . ................................................................................... 29 FIGURE 13: Vernacular building. Residential blocks with environmental features .............................................................. 30 FIGURE 14: Examples of vernacular architecture in residential buildings of Delhi. Depicting ventilation an shading strategies ....................................................................................................................................................................................... 30 FIGURE 15: Shading devices fro vernacular buildings in Delhi. ........................................................................................... 31 FIGURE 16: Features for environmentally functioning houses in old times of Delhi ............................................................ 31 FIGURE 17: Case study, Wellington aparments , gurugram................................................................................................ 32 FIGURE 18: Multi story residential building in Delhi .......................................................................................................... 32 FIGURE 19: Typical residential apartment block, U shaped block with central courtyard .................................................... 32 FIGURE 20: Surface temperature recording device ........................................................................................................... 37 FIGURE 21: Tiny Tag data Logger ...................................................................................................................................... 37 FIGURE 22: Anemometer, temperature measuring device ................................................................................................ 37 FIGURE 23: plan and fieldwork images ............................................................................................................................. 39 FIGURE 24: Case study spot measurements on a plan. Including three rooms, kitchen bedroom and living room ............... 40 FIGURE 1: Representing in India on the world map. .......................................................................................................... 41 FIGURE 1: Continuous monitoring for 10 days ; fieldowork ............................................................................................... 41 FIGURE 26: Representing winter TAS analysis ................................................................................................................... 43 FIGURE 27: Representing mid season TAS analysis for strategy 1 ...................................................................................... 43 FIGURE 28: Representing summer TAS analysis for strategy 1 .......................................................................................... 43 FIGURE 29: Representing summer season TAS analysis for strategy 2. ............................................................................... 46

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 FIGURE 30: Representing mid-season TAS analysis for strategy 2. ..................................................................................... 46 FIGURE 31: Representing mid-season TAS analysis for strategy 3. ..................................................................................... 47 FIGURE 32: Representing mid-season TAS analysis for strategy 3. ..................................................................................... 47 FIGURE 33: Energy Balance of internal gains from EDLS TAS.............................................................................................. 48 FIGURE 34: Radiation Analysis.......................................................................................................................................... 48 FIGURE 35: UDI daylight analysis (lux) .............................................................................................................................. 48 FIGURE 37: Window to wall ratio (north).......................................................................................................................... 50 FIGURE 38: Window to wall ratio (south).......................................................................................................................... 50 FIGURE 39: window to wall ratio (east) ............................................................................................................................ 51 FIGURE 40: openable aperture for summer season........................................................................................................... 51 FIGURE 41: Sun path Diagram .......................................................................................................................................... 52 FIGURE 42: Strategy for Glazing ratio ............................................................................................................................... 52 FIGURE 43: Strategy for Vertical shades ........................................................................................................................... 52 FIGURE 44: Strategy for balcony (transitional spaces) ....................................................................................................... 52 FIGURE 1: Strategy for balcony ( transitional space ) ......................................................................................................... 52 FIGURE 46: Representing in India on the world map. ........................................................................................................ 53 FIGURE 47: Sun path for shading strategy......................................................................................................................... 54 FIGURE 50: shading strategy 2 with horizontal fins ........................................................................................................... 55 orientation ...................................................................................................................................................................... 55 FIGURE 49: shading strategy recessed balcony ................................................................................................................. 55 . ...................................................................................................................................................................................... 55 FIGURE 49: shading strategy recessed balcony ....................................................................... Error! Bookmark not defined.

FIGURE 51: Combination of strategies for south orientation ........................................................................................... 56 FIGURE 52: Sun path for east and west orientation........................................................................................................... 57 FIGURE 57: Combination of various shading strategies to improve thermal comfort ................ Error! Bookmark not defined.

FIGURE 53: vertical shading (fins) with 2 meter protruding balcony .................................................................................. 58 FIGURE 54: Vertical fins with varying balcony ................................................................................................................... 58 FIGURE 55: vertical fins with protruding balcony. ............................................................................................................. 58 FIGURE 58: Best case scenario for north orientation - Guidlines ........................................................................................ 60 FIGURE 59: temperature variation for best case scenario in summer season ( may- august) – north orientation ................ 60 FIGURE 60: Best case scenario for South Orientation guidelines ....................................................................................... 62 FIGURE 61: temperature variation for best case scenario in summer season ( may- august) – south orientation ............... 62 FIGURE 62: Best case scenario- guidelines for east orienation........................................................................................... 63

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 FIGURE 63: temperature variation for best case scenario in summer season ( may- august)- East orientation .................... 64

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1. Introduction

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1.1 General background

understand the passive study. Furthermore a study of vernacular architecture would help to create and develop strategies As the vernacular buildings were built long back according to the climatic studies way before when there were no need for mechanical cooling or ventilations.

1.2Theoretical background

Climatic conditions affect Delhi aggressively with rise in temperature , population and pollution and with the use of resources is increasing day by day. The climate of Delhi has become too harsh in summers causing tremendous deaths. The scorching heat and scarcity of water have caused a lot of people to die. A climatic analysis with temperatures, humidity, rainfall, solar radiation and wind speed will help to understand the climate of Delhi in a detailed way.

This thesis would mainly focus on the residential sector of delhi including midrise and high rise residential tower blocks whereas the main focus being the energy consumption is increasing day by day. The growth in population and the climate getting worse is the main reason for energy consumption increasing rate. AS These buildings use the maximum amount of energy emitting greenhouse gas which is hazardous for the environment. There is a huge need for decreasing the energy consumption by the residential sector for improvement. To further do to and help in decreasing energy loads which are basically through air conditioners in this very hot climate is by designing climate responsive buildings or solar passive towers and come up with energy efficient solutions. The main idea of this thesis is to work on the envelope and derive guidelines by using a combination of various shading strategies, improving thermal mass , better insulation of the building. By carrying out various analysis based on thermal performance study , comfort frequency and evaluation it becomes easier to quantify scientifically.

After such studies it becomes easier to University of Westminster

The envelope of the buildings plays a crucial role in affecting the energy demands inside the apartment. It has been observed in various projects how the envelope of the building provides a tremendous amount of benefit to the interiors. As the envelope controls the insulation, thermal mass, exterior walls materiality, etc. In the warm climate of Delhi , the cooling loads in the buildings are too high. Therefore the need for creating strategies in the envelope would help decrease the loads in future 1.3 Context Delhi being a developing country with the urban growth rate rising at a peak there is a demand for land utilisation and a need for high rise towers to accommodate as much people. A number of people have been migrating for villages in search of jobs and houses and with the shortage of houses the cost goes higher. The old traditional dwellings of delhi were mostly bungalows and multi-story house. With the tremendous amount of population growth there is a need for going vertically high with residential apartments.

1.4 Problem Statement Delhi being a developing country with an increasing population and needs of people.

There is a lack of environmentally designed buildings. The energy consumption is

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 getting higher day by day by neglecting basic environmental principles while designing a building. The use of glass facade leads in in efficient buildings consuming more and more energy . the cooling’s have reached 400 kwh/ sq m in some apartments as per the fieldwork and it is of great importance to lower down the energy consumption to last longer on this earth.

Also , residential sector had a high consumption of resources making it more important to curate guidelines with passive environmental strategies to reduce the loads. The design of the buildings do not compliment with the surrounding environment which makes in environmentally ineffective and does not achieve comfort increasing the energy loads. The passive design 1.5 Hypothesis As land utilisation is very important which lead to the growth of residential towers in Delhi and theoutsikrits. There is a great demand to reduce the energy consumption levels of residential sectors. Which is done by providing environmental guidelines for the same. With the help of climatic conditions and solar analysis. As the climate being extremely hot the free running thermal comfort frequency isn't very good whereas by improving thermal mass, insulation and shading strategies according to the orientation the comforts have improved upto 30% . as the temperatures of Delhi getting worse day by day it is impossible to achieve comfort by passive strategies . therefore the aim further was to decrease cooling loads to improve the energy performance of the building.

The results show great improvement in the cooling loads as they have decreased up to 25% and gone under the benchmark by NBC ( National Building Code) . The hypotheses also says that west orientation does not achieve any comfort so it is University of Westminster

advisable to not have windows or bedrooms, living rooms and kitchens facing the west orientation.

1.6 Methodology The methodology followed in this thesis study is based on research , analysing and then creating environmental guidelines for a residential block in deli.

This involves studying about the climatic conditions of Delhi which further lead to to the research question of over exhaustion of energy resources in Delhi with the use of air conditioners most time of the day and night .A literature review about the vernacular architecture and the way strategies were used in the earlier time when there was no mechanical cooling . therefore a study about materiality , insulation and shading strategies to keep the indoors cool. Therefore, the next step was to analyse an apartment from a typical residential block of delhi. Measurements and analytical analysis was done in order to see the cooling loads an environmental performances of each room. Furthermore, the next step was to create guidelines for each orientation in the three seasons namely summer , mid season and winter in the living room, bedroom and kitchen.

1.7 Summary of the results The purpose of the research was to analyse the existing scenario of the residential sector of Delhi and create guidelines with the help of passive strategies used on the envelope of the building to reduce the energy consumption or the cooling loads.

Delhi having an extremely hot climate it was impossible to achieve comft in a free running state therefore the main idea was to reduce cooling loads.

The fieldwork was to analyse a case study in the existing area which resulted with consumption of air conditioners for long duration and with high amount of cooling 13

Environmental Guidelines for Residential buildings in Delhi thesis 18/19 loads .therefore to create guidelines a base case was developed which was developed with inference from the case study defining the same rooms sizes with a similar layout and same schedule of people and understanding their lifestyle with various surveys and simulaticla analysis. Further a base case was developed to analyse further and generate guidelines which depended on the three season in four orientations and in two conditions . the tests were conducted with strategies like different window to wall ratio in each orientation , moreover, openable area ratio and leading to the shading devices playing a crucial impact.

This resulted with each orientation having a combination of WWR and shading strategy and resulted in 20% drop in cooling loads when compared to the existing scenario.

1.8 Structure The thesis is divided into 7 chapters Introduction Literature review Context Case study - fieldwork Guidelines digital analysis Conclusion

scenarios .The climate analysis of delhi . it focuses on the three seasons with summer season being the most problematic with high temperature. Also refer to the high demand of energy with growing population.

The chapter has another part which includes the history and vernacular architecture of delhi. This explains the use of envelope to increase thermal comfort inside buildings with the use of thermal mass and shading strategies in the old times.

Moving forward with the third chapter which helps in analysing the current state scenario of residential buildings of delhi.

This is done by conducting fieldwork analysis followed by stimulation work to discover and help creating guidelines for a better environmentally efficient building.

The last and the most crucial chapter being the guidelines derived from the inference of the case study. It is based on analytical work done in TAS to reduce the energy consumption with better envelope design using strategies of reducing the glazing ratio, improving thermal mass and combination of shading strategies in each orientation for summer season .

The Literature review is about the research conducted about residential sector of delhi with the kind of energy consumption taking place. It focuses on the envelop design of residential sector and how it can be improved with the following green building benchmarks of delhi. It talks about thermal comfort needed and how it can be achieved with various strategies of different kinds.

The envelope being the major research and focus on this dissertation. Moreover, it focused on majorly two aspects the first one being thermal comfort and the second being conservation of energy consumption by creating guidelines for the envelope of the building.

The next chapter focuses on the context of the study understanding various issues and challenges faced in the current building University of Westminster

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2.

Literature Review Theoretical background

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19

2. Literature Review and Theoretical background The following chapter will try to find the problems and concerns faced by the people with respect to the buildings design , climate and comfort. Focusing on the literature review about buildings having high energy demands and the need to reduce it. The main objective is to work on the envelope of the building which acts as a barrier between the interior and exterior.

2.1 Residential high rise building Delhi being the capital city of India, witnessed a great amount of expansion due to the migration from the villages on the outskirts in search of work and a better living life dylte. This creates urban sprawl and more demand of housing with rising costs of land. Moreover with the city increasing horizontally and increasing the size of the city increases traffic , pollution as people commute every day from afar.

In Delhi a high rise structure is generally a building with 7 to 10 floors. Also according as the fire fighter reach is limited and not considered well developed , buildings more than 15- 25 m is considered as a high rise building. Whereas most of the high rise buildings in India are in mumbai , Delhi and the national capital region buildings go highest upto 25 m and have about 1500 constructed high rises ( NBC 2017 ) 2.1.1 Urban form building 2.1.2 Aspect Ratios, Orientation and Solar Access

In Delhi climate, buildings should be oriented in such a way that its longer axis should remain in east-west direction. In this orientation, the walls will receive less solar radiation in summer and more solar University of Westminster

radiation in winter in comparison to other orientations. This orientation minimizes the heat load in summer and is a very effective passive cooling strategy.

The walls should be thicker having time lag over 8 hours. Cavity walls or composite walls are also very helpful in controlling the heat transfer from outside to inside the building. When the air movement is necessary, the advantage of prevailing breeze should be taken by grouping the buildings in relation to the wind direction.

Fenestrations should be made on the walls perpendicular to the wind direction. Direct sunlight must be excluded from the fenestration and window shades should be designed in such a way so that it cuts the summer sun but permits winter heat inside the building. Roofs should also be properly insulated so as to minimize heat transfer from the roof to the inside of the building.

2.1.2 Urban Heat Island Effect (UHI)

There is an amount of change in the level of temperature from rural areas to the urban areas ,the temperature rises about 7-8 C in the urbanized localities. The urban heat island effect rises with the increase in density of buildings and reduces the amount of vegetation and greenery. (Dorer, 20120 ) The urban heat island effects the central city way more than the rural surroundings and the climate globally.mostly in hot and humid climates the temperature rises significantly in the urban areas (Santamouris, 2001) Therefore the buildings urban climate and thermal performance is much worse than that of houses in the suburbs . Thermal performance of buildings is often ignored while looking at the development of cities.

This affecting the climate by decoupling with the temperatures. Moreover the reduced greenery also increases the amount of pollution.

Furthermore, the urban heat island effects most is the result of energy consumption in the buildings especially during summer and 18

Environmental Guidelines for Residential buildings in Delhi thesis 18/19 mid season. This makes it worse for the buildings environmental qualities and reduces thermal comfort for the occupants (N Gaitani, M. Santamourisa, C Cartalisa,I Pappasb, F Xyrafic, E Mastrapostolia, P Karahalioua, Ch Efthymiou . 2014).

Moreover there is a high potential for the buildings to adaption to the urban environment and climate change with the help of sustainable developments.

For naturally ventilated buildings Indoor operative temperature = (0.54 x outdoor temperature ) + 12.83 Therefore the comfort band provided for Delhi by ECBC states of the temperature lying between 25- 30 C to be in comfort.

Moreover, in a place like Delhi, about more than 60% of the occupants stay in no comfort in summer and monsoon. As the actual sensation goes way above the standard . whereas with the use of personal environmental controls , like metabolism , clothes and more it varies.

2.2 Thermal comfort Thermal comfort is measured by dry bulb temperature, wet bulb temperature, relative humidity, and resultant/operative temperature. The definition of thermal comfort means that how a human body is conditioned to experience satisfaction with the environmental conditions around.

Thermal comfort depends on the feeling of the human body. This totally depends on the environmental conditions of the surroundings depending on the psychology and behavioural aspects. The thermal comfort varies with the change in metabolic rates, mean radiant temperature , air velocity (Anderson, T, 2012) A Building design is designed in such a way that it gets moulded according to the environmental conditions over a period of time. More over people gets accustomed to the change in environmental temperatures and work through a larger temperature range without experiencing thermal discomfort. This results with adaptive thermal comfort for naturally ventilated buildings. Adaptive thermal comfort provides and opportunity to reduce energy used in buildings and can work with moderate temperature.

Operative temperature used to find out the comfort is derived by the following equation Thermal comfort equation according to ECBC (Energy conservation building code 2017) University of Westminster

FIGURE 1: Combination of physical spaces and envelope

The use of Fans , air conditioners have become a necessity in a place like Delhi with external temperature rising to 50 C last summer. This increases the energy consumptions 2.3 Energy efficiency requirement of a residential building The building sector in India consumes about 40% of the total energy consumption in India. . whereas residential buildings consume about 75% of the total consumption of energy. Moreover, the rise in energy consumption in residential buildings have been rapidly growing with the growth in population and increasing global warming and the urban heat island

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 effect. The energy from 50TWh in 1995 has increased by four times by 2015 . in the time period of 20 years such rapid consumption of energy further projections states that in the coming years the growth would reach upto 600-900 TWh in another 10 years .

Further considering the increase amount of energy consumption through buildings refers to the heat gains in the buildings. The energy efficiency of a building is derived by analysing various aspects of the building which includes the spatial layout , occupancy schedule, materiality, and facade characteristics like window balconies etc (BEE ECBC 2017)

2.3.1 Need of rationalisation of energy consumption

There is a huge demand of energy in the building sector . the first aim to reduce the energy demands would focus on the design of the building should be in accordance with the environmental conditions and topographic, solar energy which would help in increasing the efficiency of the building.

Moreover the enveloped and the outer coat of the building should be well insulated to help in reducing the thermal load. opaque materials such as the walls , roos doors should have complete air tightness. Another factor depending on increasing thermal comfort depends on the orientation of the building and the way the unit is designed as which room needs to face less solar radiation and which needs high solar radiation. The orientation of the building also depends on the ventilation as in the air movement as to which direction being the best suitable for ventilation and placement of windows and transitional spaces.

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2.4 Envelope design Envelope design of a building corresponds to internal and external heat loads as well as ventilation and daylight benefits. Envelope of a building is designed while considering all aspects such as environmental, socio cultural and aesthetic design. In residential buildings the main focus point being the right kind of shading devices, materiality and the window ratio to profive the maximum benefits. The design aims to include various features including maximizing daylight , reducing the amount of glare and controlling direct sunlight, reducing heat gain during the hot season.

(Dasgupta, 2007; Tvaronavicius and Tvaronaviciene, 2008; Sobotka and Rolak, 2009). Zavadska and Antucheviciene (2006) defined sustainable development as “a set of indica- tors in the multi criteria analysis to include environmental, social and economic aspects of sustainability�.

Envelope design of a building plays a crucial role in to restrict the heat gains in a hot city like delhi. This not only helps in reducing energy consumption but also improves daylight and ventilation of the apartment. Further study has been referred to Energy Conservation Building Code (BEE ECBC 2017) Moreover, the most key aspect and concern regarding the energy efficiency of the building depends on the amount of solar radiation and the radiant temperature. As it is considered to be the most important climate factor, being responsible for the maximum heat gain through solar. Solar gain is also responsible for abundant daylight , lightning up the space. The energy exchanges between the interior and exterior happens due to solar radiation and convection.

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 2.4.1 Building envelope components

A building involves various features and elements and is stated either simple or complex depending on the aesthetic v=importance and design value . the functionality of the building plays a major role Thermal mass being an essential component which has the ability to absorb store and release heat depending on the climatic conditions The vernacular architecture used thermal mass to improve thermal comfort of the interiors by having 500 mm thick walls protecting from the harsh sun. the use of materials with high thermal absorbs and stores the heat delaying the effect of peak exterior wall temperature. This helps the interior wall temperature to stay cooler with delayed transfer of heat. This mechanism helps to achieve better comfort as it improves and reduces the energy consumption.

Furthermore the study focuses on shading devices and transitional spaces to improve the thermal comfort. As the envelope consists of a well designed shading device according to the orientation .

As every climate has different needs for shading devices. The places having hot humid climate has a high demand.

Shading of buildings needs to be considered minutely with each orientation of the building. The sun angles should be considered in retrospect. As an example 10%- 11.3% of energy consumption can be saved with the help of external devices to shade and improving the envelope of the building. The effectiveness of shading devices has been proven in the studies conducted by the Energy conservation codes with the right configuration of glazing improves the envelope and makes it way more efficient.

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2.4.3 Role of building envelope in reducing energy consumption

The building envelope is considered to be the skin of the building which protects the interiors with its covering creates a thermal barrier between the enclosed conditioned spaces. This results in minimizing the transfer of heat from exterior to interior.

Furthermore the parameters used while designing environmental guidelines.

Most of the residential buildings have energy performance index from 200 - 400 kwh/sq m per year . therefore there is a great requirement to reduce the energy loads . as the benchmark according to ECBC is 120-290 kwh/sq m . in these residential buildings the energy demand is high due to the internal heat gains. There are various reasons for internal heat gain in the building envelope, equipment , occupancy , infiltration and low insulation . therefore the cooling demands can only be reduced by curating appropriate design considerations and passive strategies for the envelope of the building. The most significant procedures incorporated in better a design would be focusing on the orientation, the shading strategies and the materiality of the building . this would further help in recovering the energy loss and reducing energy consumption. A study in Hong Kong stated that an energy efficient envelope could save as much as 35% of the total cooling loads

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3. Context

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 3.1Location

3.3 Urban growth and population

The site to be focused on is located in Delhi, India.

Which lies on 28N Latitude and 77 E longitude.

Delhi has a composite climate in India.

Where the summers are extremely hot whereas the winters are extremely cold.

Delhi has an area of about 1484 sq km with a population of 19 billion and counting.

In a place like Delhi where the population has grown tremendously in the last 10 years. Being the capital city of a developing country , Delhi has undergone a massive increase in population and infrastructure.

This causes the urban areas being hotter than the surrounding rural area. The man made structures absorbs heat during the day and release at night causing heat island effect.In recent years there is a rise in air pollution in Delhi due to the growing industries and population. The city is going through its worse with increased number of vehicles on the road, greenhouse gas emissions , industrial pollution. The size of Delhi has almost doubled from 1991 to 2011 becoming way more dense. It has also extended to neighbouring areas in search of land. The periphery of Delhi have become way more dense incorporating the rural areas into urban areas leaving no land for agricultural activities .Due to the rapid growth of urban areas there is a need for land utilisation with the right kind of infrastructure to accommodate these people moving to the city.

FIGURE 2: Representing in India on the world map.

Latitude 28 N Longitude 77 E

3.2 History of Delhi Delhi is tend to have a very strong history with various kinds of building architecture found in the city. First was the Muslim period which created an impact on the buildings of Delhi. Furthermore Rajput architecture also gave a lot to design in Delhi. The details it provided for example The Hawa Mahal, which was covered with small openings on the entire facade and made of stone giving very high thermal mass.

Moreover the architectural style of the british combined with the Mughal and rajputs.

Central delhi is surrounded by roundabouts and trees on either side to provide the maximum airflow

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FIGURE 3 : Urban growth and densification 1995

FIGURE 4: Urban growth and densification 2015

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 3.4 Climate The overall climate of Delhi is subtropical , with a very hot summer starting from april to july with very high temperatures , the mdi season being the monsoon season with high relative humidity and high precipitation in the months of july and august. The winter season stays only for a short duration mainly in December January and February with the minimum temperature going till 5 degree

FIGURE 6: Climate typology in India. Delhi with composite climate.

3.5 Seasonal Analysis summer This graph shows the monthly average data of Delhi, India in the past. The summer months being April, may, June and July with the highest temperatures. The graph shows that in these summer months there is no comfort achieved and is mostly out of comfort for most of the time.

In the past few years the temperature in these months have crossed 40 C making it extreme and unbearable for the people living in the country.

FIGURE 6: Monthly Average Climate Data representing summer season.

FIGURE 5: Representing in India on the world map.

This graph shows a typical summer week of summer from 16th may to 26th may. The graph shows high temperatures throughout .

This helps to see the temperature variables in the current summer week.

Its observed that the average temperature lies between 30- 35 C Though the latest studies have said that temperature goes 35 in these peak summer months

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 Whereas, north and south gets the same amount of vertical radiation from about 2kwh/sq m to 2.5 kwh/sq m. This results in shading all the four orientations to avoid solar gains.

FIGURE 7: summer typical week temperature (TAS )

This is a sun path diagram for summer by grasshopper ladybug. This analysis shows that the temperature reaches up to more than 45 C in summer with all orientations having harsh solar throughout the day. Also north achieves the maximum sun during some hours of the day and needs to be shaded.

FIGURE 9: Average Vertical radiation chart

Mid-season/ monsoon The graph above depicts the temperature during the mid season which is also monsoon in Delhi. The temperatures being warm and not to extreme in this season.

The monsoon season is from august to October end. Due to rainfall the temperature drop slightly but the humidity levels rises the most during the season of monsoon

FIGURE 8: Sun path diagram for summer season The graph below shows vertical radiation in the climate of Delhi. This graph shows the vertical radiation east and west is the highest in summer season , from April to august. Therefore it shows the need to shade east and west orientations completely in summer season.

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FIGURE 10: Representing average climate data for monsoon season .

The maximum rainfall occurs during the months of July august and September with the maximum number of days. The

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 precipitation going more than 200 mm in the month of July. 1 monthly average precipitation data With the warm temperatures and high precipitation in these months, the relative humidity also rises as shown in the graph above. This shows the monthly average precipitation data. The relative humidity being the highest in the monsoon season which is from july to september end.

FIGURE 11: Average relative humidity for Delhi

Winter

FIGURE 12: Representing average climate data for winter season .

The winter season of Delhi is for a very short period of time as noticed in the above graph. The winter months are December, January and February. In these months the temperature drops to 5 degrees maximum.

Whereas the average temperature stays between 10 - 15 C .

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3.6 Vernacular Architecture of Delhi Vernacular architecture basically means structures made by using traditional materials in a functional manner to meet the needs of people, ongoing since those earlier times. Vernacular buildings are very responsive in respect to the climatic conditions of the particular region. With time these buildings evolved focusing more on the need of the space and growth of people.

Delhi is located on the latitude 28N and 77 E longitude with an area of about 1484 sq km Delhi has three seasons , hot and dry , warm and humid and cool and cloudy .

Vernacular architecture is inspired by the climatic conditions of each region and is very responsive to the climate. Indian vernacular buildings are made with using the local and traditional material to meet the needs of people.

The vernacular architectural design consists of vernacular design features like having an open space or courtyard or balcony in front of the building to improve the cross ventilation and give a sense of openness to the building , also a passive strategy of having a chajja also known as an overhang or an extended roof to protect from the high solar radiation of winters .Another strategy being the overhang of a window . moreover vernacular buildings used traditional materials and sustainable materials with high thermal mass to keep the inside of the building cool and protect it from the hot climate.

A verandah or an open space in the middle which would help in blocking the afternoon sun going to into the rooms. Louvres / bling made of wood which would be adaptive and selectively operable . another very important strategy was creating an air gap in the ceiling to keep the interiors cool.

The vernacular architectural design consists of vernacular design features like having an open space or courtyard or balcony in front of the building to improve the cross ventilation and gvive a sense of openness to 29

Environmental Guidelines for Residential buildings in Delhi thesis 18/19 the building , also a passive strategy of having a chajja also known as an overhang or an extended roof to protect from the high solar radiation of winters .Another strategy being the overhang of a window . moreover vernacular buildings used traditional materials and sustainable materials with high thermal mass to keep the inside of the building cool and protect it from the hot climate.

A verandah or an open space in the middle which would help in blocking the afternoon sun going to into the rooms. Louvres / bling made of wood which would be adaptive and selectively operable . another very important strategy was creating an air gap in the ceiling to keep the interiors cool.

The vernacular buildings generally has elongated plans with u shaped clusters the building is shaped according to the wind direction of the area. The most exposed area would face the prevailing winds. This acts as ventilation strategy in vernacular buildings also helps in excess heat loss for thermal comfort and enhanced natural ventilation which is one of the essential requirements to ovr ome high temperatures and humidity..

had double stories and wasn't a high rise building. The Tarqa housing has large overhangs and elements to proetch from the hot and dry climate of Delhi. Therefore shading and materiality were the main aspects to be studied improved The most common evolution in the residence sector in delhi was the introduction of gated housing complexes with multi story buildings which helped in providing facilities as car park as in Delhi an average family has 2 cars. Also safer areas for the children and elderly to spend time in the evenings.

FIGURE 13: Vernacular building. Residential blocks with environmental features

3.6.1 examples of vernacular residences

YMCA staff quarters is a great example of md rise development for middle class typology of people. This building is a great example of traditional indian villages to modern urban settings with the use of traditional materials and building style.

Most of the rural population move to the city in search of work and opportunities.

The YMCA is a small scale housing project has exposed brick exteriors, which depicts a good amount of thermal mass. Al according to the rationality of delhi, there were elements like courtyards, verandahs, Further another example of housing developed from vernacular architecture ead the Tara Group housing which was designed by Charles Correa. This building University of Westminster

FIGURE 14: Examples of vernacular architecture in residential buildings of Delhi. Depicting ventilation an shading strategies

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 3.6.2 Shading devices in Vernacular buildings in delhi

Vernacular buildings refers to traditionality of the people the materials the style of architecture. That architectural features used are climate responsive and responding to the environment context. These features used provides a good solution and savings upto 1-5% with the use of passive solar design according to the building orientation , ratio, proportion, natural ventilation, daylight .

(Mingfang 2002) Shading devices acting as another medium to control the solar gains with horizontal or vertical shading.

The horizontal components used in vernacular buildings were canopies , awnings , horizontal louvres, overhangs. Whereas the vertical components used were vertical louvres , projecting fins. These devices helped in reducing the heat gains by solar and provides comfort in the interiors. These shading elements also provides sufficient daylight in the interiors while giving an aesthetic value to the building. In the Mughal era of the architecture of buildings considered inclines and deep shades to cover more surface. Another aspect of mughal architecture was to create selfshading therefore providing deep shade and carvings. For south orientation , horizontal shading devices are the best suited whereas for east and west orientation vertical shading devices were considered

3.6.3 Envelope design of vernacular buildings

The vernacular buildings envelopes is also designed according to the climatic zone and are quite massive in construction. The thick walls are either made of mud or backpacked bricks , but all have lightweight roofs . massive walls have high thermal mass have the property of storing and radiating heat, by providing proper thickness and air tightness these walls are effectively used to modulate the indoor temperature .

Thickness of such walls is around 500 mm.

The more evolved vernacular houses are made using brick and surkhi( mortar to bind the bricks and for plastering the walls ) It has been observed that a wall of 350 mm to 500 mm thickness made up of bricks and mortar gives a time lag of 10-15 hours. (source)

FIGURE 16: Features for environmentally functioning houses in old times of Delhi

FIGURE 15: Shading devices fro vernacular buildings in Delhi.

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3.7 Precedent ( case study) 3.7.1 Introduction

Eventually a case study was done to understand the lifestyle of occupants and other aspects of the building and apartment.

The case study is a typical residential apartment building which is located on the gold course road which has a number of residential buildings similar the the WELLINGTON APARTMENTS. The welling apartments has 14 floors with 4 bedroom hall kitchen apartments . therefore it is a mid rise block which we would be analysing further.

FIGURE 18: Multi story residential building in Delhi

The building to be analysed further was a C shaped block with a central courtyard which was accessible for all residents of the building.

An apartment was to be analysed to understand the working of the apartment and the qualities it had. Therefore an apartment facing all four orientations , north , south , east , and west was studied

FIGURE 19: Typical residential apartment block, U shaped block with central courtyard

3.8 Problem statement

FIGURE 17: Case study, Wellington apartments , gurugram.

There are a lot of issues and problems faced due to various reasons . the increase in populations with higher demand of resources and land leads to land utilization by going vertical rather than spreading further destroying the agricultural land.

The increase in population and temperature also demands a lot of energy. Especially in

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 the summer season there is high cooling demand in summer and mid-season..

Therefore there is a need to reduce energy consumption by passive strategies Another issue which comes across is the occupants of the apartment require natural ventilation with the help of more open transitional spaces and bigger balconies in the monsoon which is in mid-summer due to high humidity.

Summer climate resulting with high radiation in the east and west . therefore there is a need to shade it completely t reduces solar gains. And also use more passive strategies in these orientations The main strategy would be increasing thermal mass which would be useful in all seasons of Delhi. With the extreme temperatures have more mass would

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4. Fieldwork

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 portable . the surface temperature device covers a range of -50 ĚŠC -700 ĚŠ 4.1 Analysis methodology The methodology to analyse the case study was done in 4 steps Step 1 - fieldwork analysis The fieldwork analysis was done in the month of May , which is during the summer season.

Spot measurements, post occupancy evaluation, and continuous monitoring was done to understand the lifestyle of people and the schedule of occupants using each space at each interval of time.. This helped to further evaluate the apartment to understand the energy demands Step 2 This involved the TAS analysis to see thermal comfort and the amount of cooling loads required Step 3 UDI analysis to check the right amount of daylight in the apartment Step 4- was to check the ventilation of the apartment if it was meeting the required air

Tiny tag Data Loggers The data loggers are used to log continuous measurements for over a very long period.

In this case the data loggers were installed in the apartment for 10 days. This gives exact temperatures and humidity for the duration it is set for in the desired interval of time.

1 kitchen and 1 dining and living room which had a balcony.

The user typology was the apartment was mostly family with 4 to 6 people staying in each flat.

These are some images from the fieldwork which shows that there is a large amount of light falling in the apartment , also there a good amount of thermal mass percent with brick walls of 115mm plastered and painted in white.

The exterior images of the residential building shows that the balconies are quite exposed and the occupants are covering to protect from solar.

The windows seems to have a lot of glare due to a large

4.1.1 Instruments used in fieldwork

Anemometer The anemometer is a device used to measure the temperature , relative humidity, and wind speed . this device is used for spot measurements due to is mobility and easy usability, the anemometer can measure temperature upto 50 C and wind speed upto 25m/s with a best air velocity accuracy of Âą2%.

Surface temperature device This infrared thermometer is used to measure the material temperatures. This helps in checking the materials spot temperature. It is quite small and easily

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FIGURE 20: Surface temperature recording device

FIGURE 22: Anemometer, temperature measuring device

FIGURE 21: Tiny Tag data Logger

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 4.1.2 Introduction

The apartment where the fieldwork was done was facing the south orientation, The area of the apartment was 125 sqm with 4 bedrooms

FIGURE 23: plan and fieldwork images

4.1.3 Post occupancy evaluation

Fieldwork consisted of a major study which was to analyse the lifestyle of people for which a survey has been conducted. This survey helped in understanding the use of balconies ,air conditioners etc. The survey conducted was in summer seasons on 26th May, when the maximum temperature was University of Westminster

46 C and lowest was 31 C. the post occupancy evaluation gave a lot of information Therefore the post occupancy evaluation resulted with understanding the duration of consumption of air conditioners, during the day and night And also thermostat set point of air conditioners by the users/ occupants. Further another question answered by the occupants were the duration of use of balcony and the time when its used. The survey also helped to understand the occupant schedule as how many people are present in the apartment at what time.

Therefore, the post occupancy resulted with the 40% consumers using air conditioners for more than 10 hours a day with a set point of 24 C . Moreover , a feature about homes in Delhi to increase thermal comfort is the use of ceiling fans.

Mostly curing the entire fieldwork study the fans were on as this helped to speed up the airflow and make the place. It is also mentioned in by the occupants in the survey conducted on 26th may that due to very high temperatures , the set point of air conditioners have been set to 18-20 C Another result being the use of transitional spaces which in summer time was less than 2 hours or negligible whereas in winters it was occupied for about 5 hours a day during the morning and afternoon sun to gain with low temperatures on the outside.

Furthermore the occupancy for that matter said that house was 24 hours occupied and was never to be left unoccupied with about a family of 4-6 people in every apartment.

Another interesting aspect was the kitchen which did not have any artificial cooling like air conditioners or even fans. Whereas it has high cooking hours for about 6 hours a day .

4.1.4 Spot measurements

The spot measurements were taken on Sunday 26th May when the highest temperature was 41 and lowest was 30 C . it was a sunny day.

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Spot measurements were conducted in the fieldwork analysis to see the current temperatures of the three rooms which were to be further analysed.

The kitchen had no mechanical cooling and had 1 window for ventilation. The temperature of the kitchen was 34 C Room 2 was the living room which had air conditioning , a window and a balcony the internal temperature measurement by the device was 30 C Room 3- the bedroom which had a temperature of 29 C in spite of the aircon being on most of the time. The bedroom consists of a window which is not open for most of the time of the day.

There were four occupants at this time of the day in the house.

FIGURE 24: Case study spot measurements on a plan.

Including three rooms, kitchen bedroom and living room

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4.1.5 Continuous Monitoring

Further analysis was done by placing the data loggers for continuous monitoring of the three rooms discussed on the previous page.

The continuous monitoring was done for 10 days in the month of may. In the typical 10 days of summer.

The comfort band for summer being 25-30 C according to the comfort band by NBC(National Building Codes) The observation says that the temperature inside mostly remains constant due to the use of aircons in the apartment throughout day and night Whereas at certain times there is a drop in the temperature meeting the external temperature, this could be possible when the windows are open and the with no occupancy in the room, majorly during night time.

The overall conclusion proves that there is overheating due to high temperatures and occupancy inside the apartment. As

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 mentioned above in the post occupancy analysis, high number of occupancy.

Considering the kitchen, as people in india majorly cook all the meals at home and kitchen being in use for more than 6 hours a day. The operative kitchen temperature is always to be expected higher than the other rooms in the apartment..

Therefore, these observations made by data loggers helps in reaching the conclusion to develop the research to check night time ventilation for getting better results.

FIGURE 1: Representing in India on the world map.

FIGURE 1: Continuous monitoring for 10 days ; fieldowork

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5.Analytical studies

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 5.1 case study analysis

the airflow. This helps in cooling the internal space in the day time.

5.1.1 Strategy 1

EDSL TAS analysis conducted in the 3 seasons to check the amount of comfort achieved without the use of aircons.

Considering free running strategy.

As noticed in the fieldwork, the internal temperature drops by increasing ventilation and opened windows during evening hours.

Strategy one being night time ventilation, as the temperature drops at night. By changing the aperture schedule, by opening windows from 22:00 to 5:00 during summer and mid season. Where as in winters changing the aperture schedule by opening windows 2 hours during mid day to retain the heat during night time when the temperature drops.

Summer typical week analysis resulted with 98% overheating with no comfort due to high temperature.

Operative comfort lying between 25 C - 30 C for naturally ventilated buildings. Also, similar scenario during mid season/ monsoon due to high relative humidity results in overheating.

This results with increasing ventilation to achieve more comfort.

5.1.2 Use of FANS

Ceiling fans are used to create a wind flow which makes the room cooler and more comfortable. As the air generated by the fan helps in evaluating the sweat and moisture in the room . According to the post occupancy evaluation, people responded that with the use of fan the air conditioners work in a much better way as fans reduce the temperature by 2-3 C and increase thermal comfort. As the occupants of residences in Delhi use fan as a mandatory medium of cooling the environment .

Therefore keeping the air conditioner set point at 24 C with the use of fan make them the environment comfortable.

Moreover the use of fan also helps in reducing the energy consumption by air conditioners as fan consumes energy less than a tube light. Whereas setting 24 degrees without a ceiling fan results in discomfort whereas , setting the aircon temp to 24 C while using a ceiling fan helps to circulate the cold air providing comfort.

Whereas , winter results in comfort by the aperture strategy. Winter results in 92% comfort.

Moreover, strategy one talks about night time ventilation that is opening of windows at night time.

The reason why windows cannot be open during the day time is the high temperature outside reaching 40-45 C. this introduces the use of ceiling fans. Delhi being hot in summers and humid in the monsoon season has a great importance of ceiling fans used in every house. Further Ceiling fans help to improve the ventilation inside improving

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FIGURE 26: Representing winter TAS analysis

FIGURE 27: Representing mid season TAS analysis for strategy 1

FIGURE 28: strategy 1

Representing summer TAS analysis for

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 Therefore the use of a fan during the day helps in increasing comfort as opening the windows is not feasible in such a hot climate.

5.1.3 Strategy 2

Now, that the winters have achieved comfort by with the help of strategy 1 and results with no heating. The focus would only be mostly summers and mid season.

As summer having really high temperatures and mid season with high temperature and high humidity.

According to the fieldwork and post occupancy analysis which proved that most of the occupants living in these residential apartments use air condition for almost more than 10 hours a day. The post occupancy evaluation resulted with occupants setting the aircon thermostat at 24 degrees Celsius. Delhi having really hot summers has a high requirement of air conditioners.

In mid-season , living room gives a cooling load of 96 KWH/sq. m and bedroom with 73 KWH/sq m This strategy concludes with high cooling loads in both seasons , summer and monsoon and therefore need for passive strategies to reduce cooling loads in these apartments.

Moreover, another observation depicts with operative temperatures being in comfort but not being stable at 24 degree Celsius. The graph shows the living room and bedroom having temperatures between 25- 30 degree Celsius

Strategy 2, would help to analyse the current cooling loads experienced in these apartments of this residential tower to furthermore reduce the cooling loads further by using various other strategies leading to creating guidelines for each orientation.

Therefore , by setting the thermostat at 24 degree celsius , we achieve very high cooling loads.

As the benchmark according to NBC ( National Building Codes) for HVAC is 120-290 KWH/ sq M per annum.

In summer, the living room gives a cooling load of 311 KWH/ sqm , whereas the bedroom results with a cooling load of 140 KWH/sqm.

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FIGURE 29: Representing summer season TAS analysis for strategy 2.

FIGURE 30: Representing mid-season TAS analysis for strategy 2.

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5.1.4 Strategy 3

Strategy 3 was based on the optimum condition required by the benchmark NBC to set thermostat, which was 27.5 degree Celsius.

The indoor comfort conditioned for air conditioned residences between 25- 30 degree with optimum condition at 27.5 degree C .

FIGURE 31: Representing mid-season TAS analysis for strategy 3.

This simulytical analysis was carried out to see the decrease in cooling loads by setting the thermostat higher within the standards.

As the hypothesis was the cooling loads to be lower whereas it resulted with the thermal comfort to be very poor. The strategy helped reduce the cooling loads in summer and mid season whereas resulted with temperatures higher than the comfort band.

The cooling loads drop down to 245 KWH/ sq m in the living room and 193 KWH/ sq m in the bedroom in summer season , following the required bench mark of HVAC in India.

Whereas, mid season the cooling loads have dropped to 80 KWH/sq m in living room and 61 KWH/ sq m in the bedroom.

Mostly in summer with temperature being too high, the living room and the bedroom was mostly out of comfort resulting in overheating in both rooms.

Whereas , another observation said that the mid season was benefitted as the cooling loads had reduced by the use of strategy 3 ,with the living room and bedroom was mostly in comfort.

FIGURE 32: Representing mid-season TAS analysis for strategy 3.

5.1.5 Findings from the case study a) Energy Balance

The energy balance of the apartment results in the maximum gains through solar radiation. Whereas also depicts gain through occupancy and equipment which is not much of a concern. The requirement to reduce solar gains inside the apartment is to provide a good strategy of shading which would help reduce the energy consumption the apartment . therefore further strategies and improvised shading would help to reduce the maximum gains , which are through solar. Also another strategy being to increase the G value of the glass for better performance. This graph below shows a result from the EDSL TAS

Further to conclude, the strategy helped in mid season with low cooling loads and providing comfort.

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 software. c)Daylight Analysis ( UDI )

FIGURE 33: Energy Balance of internal gains from EDLS TAS.

The UDI daylight analysis conducted in the case study to to confirm adequate light in the apartment. As the diagram below shows sufficient daylight in the apartment. Where as the UDI near windows is quite high 9more than 2000 lux) which results in glare and provides a need to shade the windows or reduced since the size of the windows.

Also moreover, increasing shade in such a way that it does to disturb the daylight inside the apartment

b)Radiation Analysis

Furthermore , radiation analysis was also conducted to prove high radiation onto the windows and exposed balcony.. This depicts the radiation over 150 kwh . the balcony having glass which gets the maximum radiation and increases heat inside the apartment. this FIGURE 35: UDI daylight analysis (lux)

5.2 Base case Developing Guidelines for a better design to reduce the cooling loads in the apartment by considering the seasons from summer to mid season to winter. The analysis and design strategy would consider all orientations as different orientations have different demands. Developing guidelines in Delhi for any typical residential apartment to improve the energy performance of the apartment by reducing the cooling loads .Furthermore , the study would be conducted in two conditions.

These guidelines developed by studying the case study and taking inference from it to develop a base case for analysis.

FIGURE 34: Radiation Analysis

5.2.1 Methodology

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 5.2.2Parameters a)Seasons

As Delhi witnesses various climatic conditions, all three seasons are considered while developing guidelines.

Most of the design guidelines consider the summer season as it's the most problematic season with extremely high temperatures reaching up to 45-50 C. Moreover summer season being the longest season has been studied and analysed in detail. b)Orientation

Orientation plays a crucial significance while designing the guidelines as each orientation has its own qualities and disadvantages which needs to be considered. Therefore the guidelines would vary for each orientation.

North South East West

the bedroom having an area of 21 sq m , living room 45 sq m and kitchen with an area of about 9 sq m.

2. Furthermore , creating a simplified unit layout by using sizes from the existing case study. The simplified unit layout with an area of about 150 sq m. this unit includes 4 bedrooms, a living room and a kitchen.

3. Moreover, the fieldwork helped to understand the schedule of people.

The number of people staying in the apartment with the schedule of number of people staying indoors at which specific hours of the day.

4. The fourth and the last inference from the case study to develop our base case would be the construction materials used with specific u values.

Considering the wall - 12 mm plaster 200mm brick block with a U value of 2.28 .

Free Running Air Conditioning

For glazed windows single clear glass was used , with a u value of 5.8 and g value of 1 .

Furthermore , for flooring the material used was 150mm RCC with 40mm polyurethane foam for insulation with a u value of 1.28.

All the construction materials and values were extracted considering the typical residential buildings of delhi. The materials used traditionally were only kept in consideration.

5.2.3 Inference from case study

5.3 Design strategies

The case study of wellington apartments helped in creating a base case for creating guidelines.

The inference of the case study was to develop a simplified version of an apartment to study it in a more detailed way. There are four inputs which were derived from the case study.

5.3.1 Window to wall ratio

c)Condition

2 conditions mainly considering , free running and air conditioning. As the idea is how by creating effective guidelines for free running , cooling loads could be decreased.

1. The first step was to define the room sizes of the base case. Considering the same room area as a case study, with

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In order to design guidelines, the first step is to determine the window to wall ratio. As according to the benchmark by NBC ( National building codes) the window to wall ratio of a residential building shouldn’t be more than 40%. Therefore following the benchmark , 20% , 30% and 40% window to wall ratio was tested. The test was conducted in the four orientations , north , south , east , west for the three rooms which 49

Environmental Guidelines for Residential buildings in Delhi thesis 18/19 were studied in detail. The living room , bedroom and the kitchen.

North Orientation According to the north orientation, the simulation conducted is considering the three percentage ratios, 20% 30% 40%.

The graph below shows the results of all the simulations conducted. The simulation being conducted for summer season from month of April to August which is the most problematic with high temperatures as discussed above in the climate analysis.

Bedroom and kitchen achieved no comfort where as the living room had about 40% of thermal comfort.

Taking into account 30% window to wall ratio, comfort increased from 4% to 10% in the living room ,and 2% in the bedroom , with the kitchen still not being in comfort.

The maximum ratio of 40% gives the maximum results with the maximum thermal comfort frequency in all the three rooms which were being tested. The living room receiving the maximum comfort out of the three rooms.

Therefore, this resulted with having 40% window to wall ration WWR in the north orientation.

FIGURE 37: Window to wall ratio (north)

This graph below shows that maximum comfort frequency is achieved with 20% window to wall ratio. Whereas the maximum comfort frequency achieved is comparatively way less than north orientation due to high vertical solar radiation during summers.

FIGURE 38: Window to wall ratio (south)

East Orientation The eat orientation in summers is also found to be really problematic but somehow better than the south. The sun path shows lower temperatures in the east as compared to the other orientations.

Therefore the east orientation in summers gives better results. As per the window to wall ratio, its observed that 30% window to wall ratio results best comfort frequency compared to 20% and 40% ratio percentages.

The living room achieving the maximum comfort with 23% thermal comfort frequency whereas the bedroom and kitchen with 5-10% comfort. Due to high temperatures in summer, free running temperature does not show comfort for more than 25%

South Orientation As per the climate analysis south receiving maximum sun results with small window to wall ratios. Furthermore, a TAS analysis conducted to analysis the best window to wall ratio for the bedroom, living room and kitchen oriented towards south orientation.

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 in comfort by opening the windows during the day time to gain heat through solar radiation , with ventilating at the same time.

Therefore, winter needs an open ability of 50% of the windows to achieve the maximum comfort and follow the schedule of windows which has already been shown in the above case study.

5.3.3 Shading strategies FIGURE 39: window to wall ratio (east)

5.3.2 Openable aperture

The process goes further down to designing an openable of the windows. This mostly would be based on seasons rather than orientation of the apartment. Openable aperture of the window plays a major role as the amount of ventilation is totally dependent on the open ability.

Summer Season Summer season facing the most issues of overheating is focused more in this strategy of open ability of windows. As summer being hotter with temperatures need the maximum ventilation. Therefore by a simulations conducted by TAS to achieve maximum thermal comfort , the graph below shows the best results achieved with the maximum ventilation, therefore by 100% operability of windows in all the three rooms, bedroom, living room and most importantly kitchen.

FIGURE 40: openable aperture for summer season

Winter Season In the season of winter, as proved in the case study before that winter stays mostly University of Westminster

The design strategies proposed here is for summer season from end of April to the end of August, during the major summer months, now that we know in summer temperatures go really high and free running buildings is not an option. But the main idea is to reduce the cooling loads and the use of air conditioners in the apartments of residential buildings . therefore design guidelines have been proposed to increase thermal comfort in free running and then consider the best case scenario, to check reduced cooling loads in each orientation .

The design strategies include the use of shading mainly by using fins / screens , by providing shade by recessing or protruding balconies.

A number of strategies have been used with different combinations to come up with the best case in each orientation .

North Orientation Different shading strategies applied to come up with a best case scenario to test further with using air cons and resulting with better cooling loads.

First, the sun path shading mask study helps to discover the kind of shading required for each orientation , in this case north orientation . the shading masks focussed on providing vertical orientations.

As discussed earlier by referring to the window to wall ratio being 40% for north orientation and 100% operability of windows in summer for the best kind of ventilation. All these various inputs required in the simulation conducted by TAS to get the best case scenario.

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FIGURE 41: Sun path Diagram

FIGURE 42: Strategy for Glazing ratio

FIGURE 43: Strategy for Vertical shades

FIGURE 44: Strategy for balcony (transitional spaces)

FIGURE 45: Strategy for balcony ( transitional space )

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FIGURE 46: Combination of strategies for thermal comfort

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 South Orientation South orientation being one of the most problematic orientations with the maximum amount of solar and need for more shade to provide comfort. As proven before about excess daylight near windows by the honeybee UDI analysis. Therefore shading the windows and reducing the window to wall ratio to 20% provides better comfort compared to the current situation.

Various combinations to be tested again , in the orientation of south to come up with the best combination strategy of vertical or horizontal shade.

Another method of figuring the kind of shade to be provided is derived by the shading mask analysis which results with a huge amount of horizontal shade and louvres to project the exposed balcony and provide better thermal comfort frequency as shown in the diagram below.

FIGURE 47: Sun path for shading strategy

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FIGURE 48: window to wall ratio for south orientation

FIGURE 50: shading strategy 2 with horizontal fins orientation

FIGURE 49: shading strategy recessed balcony

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FIGURE 51: Combination of strategies for orientation

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 7.3.3 East Orientation Similarly, as per the other two orientations , deciding the best case scenario for further analysis to get better cooling loads in summer. The idea different strategies applied to achieve better performance in the apartment

FIGURE 52: Sun path for east and west orientation

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FIGURE 53: vertical shading (fins) with 2 meter protruding balcony

FIGURE 54: Vertical fins with varying balcony

FIGURE 54: Vertical fins on the balcony design FIGURE 55: vertical fins with protruding balcony.

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 7.3.4 West Orientation After a number of tests done to achieve some comfort in the west, it resulted with no thermal comfort frequency at all. Proven above in the climate study, the sun in the west has the highest temperature, mostly during the summer season. Therefore west being the most difficult to get into comfort.

All the study and analysis done on the west facade leads to only one result which says that the rooms which are most occupied at all times mainly the bedroom, living room and kitchen which are being focused on in this dissertation are not located on the west facade.

6. Research outcomes and Design Applicability 6.1 Research outcome Post the analysis and use of different combination of shading strategies. The strategy with the maximum comfort achieved would further be tested with air conditioners to achieve better results.

The best case scenario is further tested by simulitical analysis by TAS with the same occupant schedule, and efficient use of windows. This analysis has been done in the summer months from May to august. As the summer being mostly in discomfort.

horizontal shade, overhang, recess, screens, louvres to come up with the best case.

Therefore the conclusion depicts best case for each room would be horizontal shade .

Adaptive ventilation for the kitchen as it does not have an air conditioner or mechanical ventilation. As needs to be shaded as well as ventilated most of the time. The kitchen achieves most comfort which is 40% thermal comfort frequency.

Moreover various strategies of shading were tested for the living room to achieve its best comfort. It was observed that in the north orientation with 40% window to wall ratio the living room needs an overhang/ balcony of 1m to achieve the comfort of 28%. similarly with the bedroom , facing the north didn't need much shading as the north didn't get much of solar as studied above. Therefore with no overhang and only screen it could achieve comfort of 20% .

6.1.1 Free Running

North Orientation Various combinations of shading strategies have been tested to develop a best case guideline for apartments facing the north orientation.

The analysis period being the months of summer from april to august which care considered to be maximum times in discomfort.

The strategies considered while providing shade was mostly based on solar angles. 4 combinations used with vertical shade,

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 FIGURE 58: Best case scenario for north orientation Guidlines

FIGURE 59: temperature variation for best case scenario in summer season ( may- august) – north orientation

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 South Orientation Further down , the south orientation being a problematic orientation as it achieves the least comfort even with the best case scenario. As studied above in the climatic study of Delhi. Its proven that the south achieves the maximum amount of solar.

Therefore, it requires the least amount of glazing with window to wall ratio being 20% and the operability of windows being 100%. The best results achieved for the south orientation is shown in the image below. The kitchen having vertical louvres as there is high vertical radiation. Also the living room is recede to 500mm with a balcony/transitional space of 2m to completely shade it vertically as well as horizontally. Moreover the bedroom gets the best comfort when recessed 500mm and protruding balcony of 1m.

The thermal comfort frequency with each room stays from 10%-15%.

The graph below shows the maximum comfort achieved in the summer season, with the hottest months from april to august. The temperature variation lies between 30-35 C. As mentioned in the previous chapters about high temperatures and high internal gains in Delhi. The best case would further be tested with the second condition which is with thermostat temperature 24 C to confirm that the environmental guidelines have helped in reducing the energy consumption / cooling loads of the apartment

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FIGURE 60: Best case scenario for South Orientation guidelines

FIGURE 61: temperature variation for best case scenario in summer season ( may- august) – south orientation

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 East Orientation The analytical simulations conducted by EDSL TAS resulted with the best case scenario in east orientation by shading it completely and provide indirect sunlight.

The bedroom and living room with a recess of 1meter and a balcony of 2meters . Also another strategy was to shading the balcony completely by vertical louvres. Therefore this strategy helped in achieving the maximum comfort and gave the best results . also the kitchen required vertical louvres and an adaptive overhang shade. The thermal comfort frequency achieved in the east orientation were about 30% in Further the graph shown below shows improvement with the temperature's dropping from the first case and resulting with temperature variation from 30-35 C. Further When tested with thermostat the cooling loads would drastically drop.

FIGURE 62: Best case scenario- guidelines for east orienation

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FIGURE 63: temperature variation for best case scenario in summer season ( may- august)- East orientation

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 helps in achieving low cooling loads with comfort. The graph below shows the temperatures of living room and bedroom being in comfort completely, whereas the kitchen which does not have an aircon but as compared to the earlier results , the temperatures have dropped giving better results.

South Orientation In the south orientation the resultant temperature being higher due to high amount of radiation. Further the cooling loads decreased by 20-30% from the existing scenario analysed in the case study.

The cooling load for the living room being 288 kwh / sq m and bedroom load being 120kwh/ sqm . this results with 20-25% less than current loads experiencing by delhi

6.1.2 Aircon

As Delhi having exceptionally high temperatures, with high occupancy in each apartment it makes it impossible to achieve thermal comfort with passive environmental strategies. further to reduce the energy consumption , the guidelines were tested in the case to the temperature how the occupants set the thermostat set point being 24 C .

The EDSL TAS analysis conducted with the best case scenario of each orientation to confirm the guidelines benefits and reduced cooling loads from the current situation , studied in the case study

East Orientation Similarly the same application to the east orientation. The new guidelines for east orientation helps in improving the cooling loads specially in the month of summer and reducing the energy consumption. The cooling load for the living area results with 236 kwh/ sq m and bedroom load is 140 kwh/ sq m which is way less and therefore achieving positive results. The best orientation for a residential tower in deli would preferable north or east.

North Orientation In North orientation the annual cooling load has decreased by 20% with 245 kwh/m2 in the living room and 132 kwh/m2 in the bedroom. This reduced cooling loads , still achieves comfort in the two rooms with air conditioners. This proves that the guidelines proposed for this orientation University of Westminster

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FIGURE 66: Summer Analysis result for North Orientation

FIGURE 66: Summer Analysis result for North Orientation

FIGURE 64: Summer Analysis result for East Orientation

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19

7. Conclusions The thesis was conducted to create guidelines for a residential tower in Delhi.

The main objective of the guidelines was to increase thermal comfort inside the apartment by using the envelope of the building and improving it with passive strategies. The guidelines for the envelope of the building involved glazing ratios , thermal mass with material properties and with the help of shading devices. This study includes six chapters. With an introduction of the issues and problem statement followed by the methodology. Furthermore a literature review which included the benchmarks and energy efficiency and envelope design of a building which helped in developing the thesis further. Chapter 3 discusses about the context where is the thesis study on . the urban growth and climate analysis of Delhi . it also includes another subdivision which is based on the earlier times the architecture of the city. It focuses on the vernacular architecture of Delhi and how they created and efficient envelope with help of shading strategies and high thermal mass. Chapter 4 is based on the fieldwork study based in a typical residential tower of Delhi to check its environmental aspects and cooling requirements. Further, chapter 5 contains all the analytical investigation firstly done on residential building and further which helped to derive a base case and was further analysed. Finally the last chapter summarises and provides a conclusion to create guidelines for a typical residential tower in Delhi.

7.1 Context fieldwork and analytical analysis Delhi being in a very dangerous condition with high temperature , high population and increasing pollution. Increase in population leads to increase in the energy consumption. Therefore this thesis focused on the reduce in energy consumption in residential buildings with analysis’s University of Westminster

existing residential typology of Delhi and improving the envelope of the building with better glazing , thermal and shading properties. These effective environmental improvements have been used in earlier times . references taken from vernacular architecture of Delhi , where the use of window sizes , thermal mass and various shading strategies helped to have a comfortable interior space . Also a case study conducted to analyse the existing residential typology with field word. The fieldwork including the schedule of people , spot measurements, continuous measurement for a period of 10 days to understand the scenario thoroughly. measuring the internal temperature and various intervals of time. Also a post occupancy evaluation survey which helped in understanding the lifestyle of people staying in Delhi. This resulted with high internal gains and high use of energy consumption in the months of summer and mid-season. The cooling seasons as per Delhi climate are from April till October.

Therefore the high demand of energy.

7.2 Research outcomes This research develops the guidelines created for each orientation of the building.

The guidelines involve window to wall ratio, the glazing percentage ,also as to check which open ability be the best suited in each orientation. The Envelope guidelines also focuses on the shading strategy to be used in each orientation and its adaptability according to the seasons.

So the conclusion about the north orientation says does it needs 40% window to wall ratio with a 100% open ability of windows for maximum ventilation when open for all the three rooms. Whereas the shading strategy would vary from room to room with the bedroom having no shading as in the north there is not much requirement for shade whereas the living area requires a protruded balcony of 1 m to

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 provide shade and also helps the bedroom next to the living room. Moreover, kitchen requires louvres adaptive to the. Season and time of the day . the need for horizontal louvres helps in providing shade in the kitchen while providing 24 hours ventilation due to no air-conditioning.

Furthermore the resultant guidelines for south orientation required a good amount of shading to provide more comfort in order to reduce cooling loads. Therefore south orientation having relatively lesser window sizes with the window to wall ratio being 20% with an operability of windows being 100% in summers and 50% in winters. The bedroom results in having 1 meter protrude and 1 m recessed balcony for the most comfort reducing cooling loads in problematic seasons .

The east orientation focusing on vertical as well as horizontal shading to completely block the sun with providing indirect sunlight inside the apartment . this was done by. Creating a perforated screen or louvres covering the balcony. Further the window to wall ratio for eat orientation.

East orientation achieved best results with considering 30% window to wall ratio. The east orientation considering vertical shade requires fins of 300 mili meters for provide shade and also a balcony of 1 m recess and 2 m protrude to provide complete shade.

Furthermore these strategies where tested with the current scenario considering the amount of cooling loads required . these guidelines have helped in reducing the cooling loads for about 20% per annum.

Further below on the next page is a chart of the final guidelines for Delhi residential typology to reduce the energy consumption.

The guidelines haves been creating only on the envelope of the building as it is a crucial and most significant way

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 8. References

High- Rise Buildings – Needs & Impacts CIB World Building Congress (2007).

Available from http://www.irbnet.de/daten/iconda/CIB504 7.pdf. Accessed April 13, 2019 Climate and housing form — a case study of New Delhi Available from https://www.sciencedirect.com/science/arti cle/pii/037877889190079I . Accessed April 14, 2019 Urban Growth of New Delhi. Available from https://earthobservatory.nasa.gov/images/9 2813/urban-growth-of-new-delhi.

Accessed April 13, 2019 High- Rise Buildings – Needs & Impacts CIB World Building Congress (2007).

Available from http://www.irbnet.de/daten/iconda/CIB504 7.pdf. Accessed April 13, 2019 Ashok B. Lall,Madhu Pandit, Navneen Kulshreshta, Paul (2003) Climate and housing form- A case study of New Delhi. [online] Available at: (https://www.sciencedirect.com/science/art icle/pii/037877889190079I https://www.researchgate.net/publication/2 61627774_Building_environmental_assess ment_methods_Applications_and_develop ment_trends) [Accessed July 2019] Shreya O. and Anoop K. (2017)Transition from Vernacular to Modern Architecture : Gurgaon ,India. [online] Available at: https://www.researchtrend.net/ijet/pdf/77%20113.pdf [Accessed July 2019]

Addressing India’s Local concerns with a sustainable approach to building tall [online] Available at: http://global.ctbuh.org/resources/papers/do wnload/1309-addressing-indias-localconcerns-with-a-sustainable-approach-tobuilding-tall.pdf [Accessed july 2019] Amelia Taylor Hochberg (2017) https://archinect.com/news/article/129791 024/charles-correa-legendary-indianarchitect-dies-at-84 [Accessed July 2019] Neha Gupta (2017) Exploring passive cooling potentials in Indian vernacular architecture [online] Available at: http://www.insightcore.com/journal/201702-01Exploring%20passive%20cooling%20pote ntials%20in%20Indian%20vernacular%20 architecture-Gupta.pdf [Accessed July 2019] Charles Phillips (1398) Battle of Delhi Indian History [online] Available at: https://www.britannica.com/event/Battleof-Delhi-1398 [Accessed July 2019] Somini Sengupta (2018) In India summer heat may soon be literally unbearable [online] Available at:https://www.nytimes.com/2018/07/17/cl imate/india-heat-wave-summer.html [Accessed July 2019] http://delhiarchitecture.weebly.com/architecture-andidentity.html# D.G Leo Samuel, K.Dharmasastha Thermal comfort in traditional buildings composed of local and modern construction materials [online] Available at: https://reader.elsevier.com/reader/sd/pii/S2 21260901730078X?token=9C4D7C406F8 764FC6DBA1D2E82F87D0DA523199B3 E3866D2EC539642745B033E7336AD58 480EB182CF99700D87CF7D1B [Accessed July 2019]

Sudhir J. and Peter W. (2008) University of Westminster

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Environmental Guidelines for Residential buildings in Delhi thesis 18/19 Sanyam Bahga and Gaurav Raheja (2018) Frontiers of architectural research [online] Available at: https://reader.elsevier.com/reader/sd/pii/S2 095263518300530?token=DD4182F7F6A EBD3F1F7F6BEEE9A0BC5C4AA48C71 0E7FB6C6BBF7544D1B4D3D827EC3C0 2FB65472D73A15A10AE83A6C31 [Accessed July 2019] Sawdust Stepping back in time; New Delhi, Vernacular Architecture [online] Available at: https://www.sawdust.online/do-you-knowtrivia/stepping-back-in-time-new-delhivernacular-architecture/[Accessed July 2019] Jitendra Kumar Tracing the histories : A survey on the vernacular histography in pre-colonial india [online] Available at: https://www.academia.edu/10256053/Trac ing_the_Histories_A_survey_on_the_Vern acular_Historiography_in_Precolonial_India[Accessed July 2019] Design Determinants of Building envelope for sustainable environment (2016) [online] Available at: https://www.researchgate.net/publication/3 08664481_Design_Determinants_of_Build ing_Envelope_for_Sustainable_Built_Envi ronment_A_Review [Accessed July 2019] Abdul H. and Firoz A. (2016) Bio climatic design strategies for buildings in Delhi , India [online] Available at:https://www.ijltemas.in/DigitalLibrary/ Vol.5Issue4/01-07.pdf[Accessed July 2019]

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8. Appendix

8.1

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