Performance studies of various designs of buildings by using different heating and cooling concepts.

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PERFORMANCE STUDIES OF VARIOUS DESIGNS OF BUILDINGS BY USING DIFFERENT

HEATING AND COOLING CONCEPTS

by

NEERAJALUGANI

Thesis submitted

in fulfilment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

Centre for Energy Studies

INDIAN INSTITUTE OF TECHNOLOGY, DELHI

HAUZ KHAS, NEW DELHI-11001 6 INDIA

AUGUST, 1995

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Dedicated to

My Parents

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CERTIFICATE

The thesis entitle "PERFORMANCE STUDIES OF VARIOUS DESIGNS FOR PASSIVE HEATING AND COOLING CONCEPTS" submitted by Ms. NeerajaLugani to Indian Institute of Technology, Delhi for the award of degree of Doctor of Philosophy is a record of bonafide research carried out by her. She has worked under our guidance and fulfilled the requirement for the submission of this thesis, which has attained the standard required for the Ph.D degree of this Institute. The results presented in this thesis have not been submitted elsewhere for the award of degree or diploma.

Dr. G. . Tiwari

3t

9't Assistant. Professor Centre for Energy Studies Indian Institute of Technology Hauz Khas, New Delhi - 16 Date :

Prof. H.P. Garg Centre for Energy Studies Indian Institute of Technology Hauz Khas, New Delhi - 16

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ACKNOWLEDGEMENT

I take it as my foremost duty to express my deep sense of gratitude and indebtness to my supervisor Prof. H. P. Garg, and Dr. G. N. Tiwari, Assistant Professor, Centre for Energy Studies, I. I. T., Delhi for their gifted guidance simulating suggestion and deep personal interest through out the research work.

I wish to sincerely thank Dr. Tiwari and his family for all encouragement, guidance and assistance extended to me.

The help extended by Prof. N. K. Bansal, Dr. S. N. Garg of Centre for Energy studies, staff of Solar Distillation Laboratory and Solar Energy Laboratory have gone a long way in materializing this work in its present form.

I must express my heart felt thanks to Dr. Kuldeep Chander and his family and Dr. A.K. Singh for their active co operation and kind help during course of work.

Special thanks are also due to Mr. B.B. Kumar Chief Engineer National Building Construction Corporation, Mr. Abuzar of Steel Authority of India Limited who guided and helped me in my career advancement.

Were I to put a name to each finger that pointed a way during my course of research, I would exhaust the page and still would have left many unacknowledged. To all those, few for whose direction brought an avenue to concrete end and many whose suggestions culminated in dead ends, but the paths to which had been the best teacher, I express my heartfelt gratitude.

Beyond words, some people make a difference by their mere presence, my father- Padamshree R.S. Lugani for his strength of purpose and sense of direction and my staunch stoic and stable force that kept the flame alight through the storm of momentary depression and euphoria of achievements my mother-Smt. Krishna Lugani whose patience, is fused into each moment of work.

0

-161"-4 NEERAALUGANI

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ABSTRACT

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ABSTRACT

The architects and planners face numerous problems for designing thermally comfortable buildings due to diverse nature of parameters constituting the weather. The problems are not unique in nature. Weather parameters are the variables of time and space.

The time and space dependent problems related to planning of buildings have been studied with a special reference to Indian context. They are broadly synthesized below.

i) Balancing of thermal load by making modifications and using cost effective techniques of buildings located at places where regular sources of artificial sources of energy do not exist.

ii) Conservation of energy in buildings with high and low occupancy.

iii) Levelling of thermal load in ancient buildings,i.e, when sources of artificial sources of energy do not exist.

iv) Performance of suitable heating concepts for Cold and Sunny climates.

v) Development of an integrated approach for passive cooling and heating techniques in six different climatic zones of India.

The solutions of such problems need to be found within the bounds of socio-economic,cultural and technological aspects. Planners under the constraints of resources are required to put in concerted efforts for maximizing the thermal comfort at minimal cost.

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Inspite of the technological advancements and the placement at the highest pedestal of the schemes for power generation to meet the additional requirement, the accomplishment of this dream in the near future appears to be remote. Even in the times to come, the planners and architects shall continue to remain involved in the development of infrastructural facilities at places where the regular source of artificial energy may be nonexistent. Inflationary tendencies in the monetary system are likely to make the use of artificial energy prohibitive.

Such constraints make it imperative that planners and architects arraign their inputs for optimal use of existing resources of energy. There is also a requirement to maximize the use of inexpensive and inexhaustible source of sun's energy. Diminishing reserves of fossil fuels warrant the exhaustive review of the methodologies adopted for design of buildings.Extensive use of the design concepts needs to be made under these constraining circumstances.

The study has been undertaken by taking into account the above indicators and the possibility of the use of passive and active concepts for cooling and heating of buildings examined. Mathematical models have been formulated and computer solutions of energy balancing equations obtained by converting the non- linearities of the heat flow into linearities.Sensitivity analysis of various cooling and heating systems, by deploying them singly or in combination, has also been carried out.The concept of orientation,use of locally available materials ,clustering of buildings, selection of proper shading devices, courtyard concepts, have been studied for providing thermal comfort in buildings to obviate the use of artificial energy.

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The study has been undertaken by considering the existing buildings including those having historical and cultural importance. Certain modifications in terms of design concepts have been suggested and taken into account while deriving the thermal load. Conservation of energy and development of integrated approach for heating and cooling of buildings for six climatic zones of India, form a part of the study.

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PRELUDE

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PRELUDE

The human body reacts sharply to any variation in the thermal parameters.

The activity accelerates or decelerates depending upon the upward or downward change in the thermal environment. There is a desired level of thermal environment for the man to be physically comfortable and the activity level at peak. Any temperature variations beyond 23°C ± 4°C is likely to affect the human body, resulting in thermal discomfort.

Thermal environment of a place is a function of geographical and topographical conditions. The places near the equator of the earth are generally warmer than the places near the poles (North & South). Because of its location near the equator, the climate of Indian sub-continent can be classified into following six categories (Table Al).

Table A 1: Criteria for classification of climates (Bansal et aL[1989]) Case Climate Mean

monthly temp.°C°'

Relative Humidity

% age

Precipitation mm

No of clear days.

I Hot and Dry > 30 < 555 < 5 > 20 II Warm and

Humid

> 30 > 55 > 5 < 20 II Moderate 25-30 < 75 < 5 < 20 IV Cold and

Cloudy

< 25 > 55 > 5 < 20 V Cold and

Sunny

< 25 < 55 < 5 > 20 VI Composite This applies when six months do not fall in any category

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Man's desire to seek protection against climate's onslaught led to the necessity of shelter. Later on, with advancement of knowledge acquired about the parameters constituting the weather, he became restive to achieve thermal comfort. This mundane desire of the man led to the advent of various design concepts for construction of shelters. In the ancient times, the man made all out efforts to exploit the knowledge acquired in the field of sun energy. Attitude towards orientation of shelter with respect to radiation from the sun and movement of air became more and more pressing. In hot climates, thicker walls made of non-heat absorbing local materials were found more useful. The size of windows and other openings was decided to permit the desired amount of sun radiation. The windows were oriented in the direction of the wind. Acquisition of knowledge about emissivity and reflectivity of materials and colours helped in choosing the proper building materials. The man learnt to make use of water film for producing cooling effect and the concept of small court-yard inside the building served as a pool of cool air.

In cold climatic conditions, extensive use of wood was made for construction of walls, roofs and floors. Thermal qualities of wood helped in conservation of energy.

All such inexpensive techniques found their application when artificial sources of energy were non-existent. Full exploitation of thermal properties of building materials and knowledge in the realm of solar energy and wind movement, was made for creation of appropriate thermal environment. Classical examples of such explorations are found in Hawa Mahal in Jaipur and Taj Mahal in Agra in India.

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The acquisitive nature of man to seek more and more comfort led to the discovery of different artificial sources of energy, i.e., fossil fuel like petrol and coal, tidal and hydropower. Artificial wind drafts are generated by running propellants with the help of new found sources of energy to dry the human sweat.

Added knowledge in the scientific field and myriad inventions helped in creating desired thermal environment inside the shelter.

Depletion of fossil fuels compelled him to search alternative sources of energy. Realization of a fact that the sun is a non-expensive and inexhaustible source of energy, made him concentrate his mind to explore the possibility of using this source. Sun's energy has found its application mainly in three fields (Walter et al. [1992)).

i) Refrigeration where the temperature ranges 0°C - 10°C

ii) Thermal energy application where the temperature ranges 10°C -150°C.

iii) Concentrators where the temperature ranges from 150°C to more.

The quantum of sun's energy is colossal and adequate to provide for energy needs of the future.Enough strides have been made and its application has found way in the field of water heating, distillation, construction of green houses and solar buildings.

Transportation of solar energy takes place through building components or by mechanical means. The energy is received and stored for utilization in the present and near future and then transported at the right place. This

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transportation of energy is referred to as passive and active means of cooling and heating the building.

The author during the course of service in different organizations, has been closely associated with the design and planning of buildings having high and low occupancy.lt was felt that full use of solar energy has not been made in Indian context and most buildings need artificial lighting even during the day time . Installation of mechanical and electronic gadgets for creating the proper thermal conditions in such buildings is imperative. Use of expensive techniques like airconditioning and airheating are prohibitive in terms of initial cost and recurring expenditure .More over, inhospitable weather conditions and absence of regular source of artificial energy, inspired the author to explore the possibility of using of inexpensive and simple techniques for creating proper thermal environment.

The author has come across places of cultural and historical importance where adequate use of orientation concepts and choice or suitable local building materials has been made to create comfortable environment.

The study undertaken considers the problems being faced by architects and planners for creation of proper thermal environment in different weather conditions without in incurring huge expenditure.lt aims at developing analytical procedures ,mathematical models and finding computer based solutions for such problems.

To understand the exact nature of the problem and to carry out its synthesis,an effort was made to find out the present status of the art by scanning and reviewing the existing literature on the subject.Historical background of

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various heating and cooling concepts, heat and mass transfer relationship and energy balance equations have been studied in depth. The study of existing literature has led to recoginition of following categories of problems.

Category 1

The areas where weather remains hot and dry for most part of the year and the winter season is for a short spell, the buildings at such places need to be Cooled for major portion of the year. The conservation of energy has to be

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esorted to in the winter season. A cinema hall located in hot and dry zone has een considered as a case study for the synthesis of such problems.

Category II

Creation of proper thermal environment in buildings at places where for most part of the year, the weather remains cold and humid,forms the second category of problems being faced by architects and planners. For such areas

Irelevance of energy concepts, penetration of solar energy , creation of sunspaces needs investigation.

Energy conservation in terms of Rs./KWhr has been studied by considering the case study of a non-airconditioned cinema hall at Jodhpur and a duplex house (low occupancy building) at Patnitop in Jammu and Kashmir state of India having cold and cloudy weather.

Category III

Several places where buildings have to be constructed are located in remote areas and the artificial sources of energy are nonexistent. In such areas

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the building design needs rigorous application of various orientation concepts.

Application of evaporative, earth air tunnel, courtyard and shading concepts for cooling, has been studied by considering the case of an ancient building,i.e., Raja Mahal in Banaras (India).

Category IV

There are places which witness extreme cold and sunny climate, i.e., like that of a place called Leh in Jammu and Kashmir state of India.At such places artificial sources of energy are not available. Thermal performance of a solarium has been analysed for load levelling in the living spaces.

Category V

Indian weather conditions are given in

Table Al.

An integrated approach by making use of passive cooling and heating for six climatic zones of India has been developed.

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Performance studies of various designs of buildings by using different heating and cooling concepts.