Low energy Cooling systems in Buildings by NIYAS MOIDU

INTEGRABILITY OF LOW ENERGY COOLING SYSTEMS IN BUILDINGS

Dissertation Submitted by Niyas Moidu Reg No:113701206

B. Arch, VII Semester, Section A

FACULTY OF ARCHITECTURE MANIPAL UNIVERSITY NOVEMBER 2014

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FACULTY OF ARCHITECTURE MANIPAL UNIVERSITY

CERTIFICATE

We certify that the Dissertation entitled “Low energy Air-conditioning systems & its uses in large span buildings”, that is being submitted by Niyas Moidu (113701206) in the VII th Semester of B.Arch undergraduate programme, Faculty of Architecture, Manipal University, Manipal is a record of bonafide work, to the best of our knowledge.

Faculty in Charge

Director

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CONTENTS CHAPTER 1- INTRODUCTION 1.1 BACKGROUND ………………………………………………………………8 1.2 RESEARCH QUESTION………………………………………………………8 1.3 AIM……………………………………………………………………………….8 1.4 OBJECTIVES OF THE STUDY ………………………………………………9 1.5 SCOPE AND FOCUS OF STUDY……………………………………………9 1.6

RELEVANCE

THE

STUDY……………………………………………….10 1.7 LIMITATIONS…………………………………………………………………..10 1.8 METHODOLOGY………………………………………………………………11

CHAPTER 2- LITERATURE REVIEW 2.1 DEFINTION…………………………………………………………………….13 2.1.1 WHAT IS A SOLAR AIR CONDITIONER? ..................................13 2.1.2 SOLAR POWERED AIR CONDITIONER………………………….13 2.2 EMERGENCE AND HISTORY OF SOLAR ENERGY…………………….13 2.3 HOW DOES SOLAR AIR CONDITIONING WORK? ……………………..14 2.4 AIR CONDITIONING IN BUILDINGS ………………………………………16 2.5 SOLAR AIR CONDITIONING………………………………………………..16 2.6 ECONOMIC VIABILITY AND ENVIRONMENTAL BENEFITS ………….18

CHAPTER 3 3.1 INTRODUCTION………………………………………………………………20 3.2 SOLAR THERMAL COOLING……………………………………………….20 3.3 CONCENTRATED SOLAR POWER………………………………………..21 3.3.1 ADVANTAGES………………………………………………………..22 3.3.2 TECHNICAL POTENTIALS………………………………………….23

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3.4 APPROACHES TO CONCENTRATING SOLAR POWER (CSP)………..24 3.4.1 PARABOLIC TROUGH……………………………………………… 25 3.4.2

CENTRAL

RECEIVER

TOWER…………………………………….26 3.4.3

LINEAR

FRESNEL

3.4.4

FRESNEL

REFLECTORS………………………………...27 LENS……………………………………………………...28 3.4.5 DISH ENGINE SYSTEM…………………………………………….29 3.5 LAYOUT OF SOLAR COOLING INSTALLATIONS………………………..31 3.6 MAIN COMPONENTS IN A SOLAR ASSISTED AC SYSTEM…………… 33 3.6.1

SOLAR

COLLECTORS

FOR

COOLING

SYSTEM……………….33 3.6.2 HOT WATER & CHILLED WATER STORAGE…………………...35 3.6.3 CHILLER……………………………………………………………… 35 3.6.4 FAN COILS…………………………………………………………… 38 3.6.5 COOLING TOWER…………………………………………………..39 3.7 POSITIONING OF SOLAR PANELS………………………………………..39 3.8 BUILDING INTEGRIBILITY…………………………………………………..40 3.9 PRINCIPLES OF BUILDING INTEGRATION………………………………41 3.10 STATUS AND SCOPE OF SOLAR COOLING IN INDIA………………...41

CHAPTER 4 - CASE STUDIES 4.1 QATAR 2022 SHOWCASE STADIUM………………………………………44 4.2 KAOHSUING NATIONAL STADIUM, TAIWAN……………………………..49 4.3

ESTADIO

MINEIRAO,

BRAZIL……………………………………………….53

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CHAPTER 5 – CONCLUTIONS 5.1 CONCLUSIONS………………………………………………………………57 5.2 REFERENCES………………………………………………………………..58

Figure 1(a) Parabolic trough (b) Wind tower....................................................11 Figure 2 parabolic Trough collector.................................................................18 Figure 3-Principles for Solar driven cooling.....................................................21 Figure 4 Heat fluxes of a thermally driven cooling system..............................22 Figure 5 Parabolic trough collector : tracks the sun on one axis.....................25 Figure 6 parabolic trough system - Half-driven string.....................................26 Figure 7-Parabolic trough system - schematic................................................27 Figure 8 Solar power tower..............................................................................28 Figure 9-Linear Fresnel reflector: Multiple mirrors move on one axis to focus the sun to a fixed linear receiver......................................................................29 Figure 10-Fresnel lens based CPV: Multiple small units on a heliostat..........29 Figure 11 parabolic dish concentrator: tracks the sun in two axes.-...............30 Figure 12- Solar cooling system......................................................................32 Figure 13-Basic layout of a solar cooling plant utilized during summer & winter .........................................................................................................................32 Figure 14-Flat plate collector...........................................................................34 Figure 15-A vacuum tube collector..................................................................35 Figure 16-: Schematic Diagram of hot water tank for solar assisted air conditioning system.........................................................................................36 Figure 17-Principle of an absorption chiller.....................................................37 Figure 18-Principle of an adsorption chiller.....................................................38 Figure 19-Cooling Tower..................................................................................40 Figure 20-Digriam and angle of installation.....................................................41 Figure 21-Design Option – Arup Associates....................................................46 Figure 22-Roofing Structure for shade............................................................47 Figure 23-Solar heat Collector set outside the stadium..................................47 Figure 24-Environmental Sketch.....................................................................48 Figure 25-(a) Plan and Section (b) Picture shows the solar panels fitted on rooftop................................................................................................51

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ACKNOWLEDGEMENT

In conducting this report, I have received munificent help from many quarters, which I like to put on record here with deep gratitude and great pleasure. First and foremost, I am highly obliged to my Dissertation Faculty in charge, Ar.Sahana and my guide Ar. Abhishek VK who allowed me to encroach upon his precious time from the very beginning of this work till the completion. His expert guidance, affectionate encouragement and critical suggestions provided me necessary insight into the research problem and paved away the way for the meaningful ending of this report work in a short duration, A special thanks goes to my father Er.Moidu MK, who gave suggestion about the topic and by providing me various articles and project reports from the companies. I have to appreciate the guidance given by other faculties and the review of the other panels. Their advices and feedback has helped me to go

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about the study in the right direction. I would like to express my gratitude towards my Director Mr. Nishant H. Manapure and my college Faculty of Architecture for their kind co-operation and encouragement which help me in completion of this dissertation.

ABSTRACT According to the World Bank, the Middle East is one of the largest consumers of energy per capita in the world now and an estimated two-thirds of that in the summer months is used for driving air-conditioning. The demand for energy consumption for the purpose of air conditioning has been increasing. As the cooling devices are usually electrical powered, the demand for electrical power increases and reaches the capacity limit during the summer time. This study of low energy cooling systems aims at the typologies, functionality and working of cooling systems in large span buildings. With the advent of new solar technologies, low energy cooling systems provide the right answer and satisfy the requirements to make energy efficient buildings. Solar cooling system installations have increased substantially in the last decade and there are a number of installations with successful working records, especially in Europe. Case studies are conducted as an analytical study to see the systems workability in existing situations.

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CHAPTER 1

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1. INTRODUCTION 1

BACKGROUND

By the end of 2011, about 1000 solar cooling systems were estimated to be installed all over the world. According to the World Bank, the emirates is one of the largest consumers of energy per capita in the world now

and an

estimated two-thirds of that in the summer months is used for driving airconditioning. The demand for energy consumption for the purpose of air conditioning has been increasing. As the cooling devices are usually electrical powered, the demand for electrical power increases and reaches the capacity limit during the summer time. But the more innovative way is to use solar energy for driving the air conditioning systems at the location where the temperature is high. A cooling system for building through absorption refrigeration makes direct and efficient use of solar heat, replacing the use of natural gas or electrical energy for vapor compression refrigeration. In 2007, the US Energy Independence and security act provided funding for innovative solar air conditioning research and development programmes and has resulted in a wide number of new technologies that actually use solar thermal power . 2

RESEARCH QUESTION:

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How to efficiently use the concentrating solar collectors for the purpose of air conditioning systems in large span buildings for a better thermal comfort. 3

AIM:

To study the efficient use of solar collectors for the purpose of air cooling systems in Outdoor spaces for a better thermal comfort. The topic focuses on providing alternate energy generation systems mainly on the air conditioning systems making buildings independent of the grid & reducing the load on existing infrastructure or controlling the excessive use of resources .

OBJECTIVES OF THE STUDY

The objective of the study is to understand the ideology of a solar cooling system based on the use of concentrating solar collectors and also the steadily growing market of solar cooling systems coupled with concentrating solar collector technologies for air-conditioning which are still infrequent. 

To Study the various methods and techniques for air cooling systems.



To study the different typologies and their limitations.



To collect data regarding the above mentioned resources.



To study the feasibility of the air cooling systems in the present buildings.



To study any alternate methods to be used during the failure of CSP.

SCOPE AND FOCUS OF STUDY Study the performance of the HVAC system, while maintaining comfort

conditions in the stadiums/outdoor spaces in low-velocity displacement underseat supply ventilation. 

Focus on Low energy concepts to create thermal comfort



Apply innovative , green highly efficient cooling technology

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

Produce electrical energy by using concentrating collectors.

The cooling strategy in stadiums ensures outdoor comfort for the players and the fully solar powered cooling systems keep the comfort level high.

1.6 RELEVANCE OF THE STUDY Why the use of solar thermal energy for air-conditioning in buildings? There is a large interest from end users according to first observation. Making cold from heat seems to be an interesting technology that appeals to many end users. Main opinions for solar assisted cooling originate from an energy saving perspective. 

Application of solar assisted cooling saves electricity and thus



conventional primary energy sources. Solar assisted cooling also leads to a reduction of peak electricity demand, which is a benefit for the electricity network and could lead to additional cost savings of the most expensive peak electricity when applied on a broad scale.

Other arguments originate from a more technical perspective: 

Solar energy is almost available at the same time when the cooling is required, this argument holds for both, solar thermal and solar electric based systems. 1.7 LIMITATIONS:



The study is limited to the use of concentrating Collectors for the purpose of air cooling systems.

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

The use of solar collectors allows the production of heat at higher level of temperatures compared to the standard collection technologies used in buildings (i.e. Flat plate collectors).



And also the study of absorption chillers which are used by the concentrating collector w0hich collects solar thermal heat from the sun by means of a heat transfer fluid (HTF).

Figure 1(a) Parabolic trough (b) Wind tower

1.8 METHODOLOGY 

Identifying the various techniques in the working of a Solar concentrating collectors.



Literature study done through Journals, Articles, & videos regarding parabolic trough particularly single axis transmitting collectors which are mainly used for air conditioning purpose.



Referring live research articles based on the same topic.



Contacting companies like Gardener Tao bold and POPULOUS who are responsible for the installations of solar thermal collectors and finding an innovative way to fight the desert heat in Middle Eastern countries for better thermal comfort in stadiums.



Comparative analysis of various live case studies done.



Formulation of the final report.

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Chart 1: Methodology

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CHAPTER 2 LITERATURE REVIEW:

2. LITERATURE REVIEW 2.1

DEFINITION

2.1.1 WHAT IS A SOLAR AIR CONDITIONER? Solar Air conditioning refers to any cooling system that uses solar energy for the purpose of providing active or passive cooling of a structure or a building. Solar air-conditioning can be done through various methods including solar Thermal energy and by use of photovoltaic conversation i.e sunlight to electricity.Solar air-conditioning plays an important role in the increasing zero energy and energy plus building designs. 2.1.2 SOLAR POWERED AIR CONDITIONERS PV electrically supplied compressor air conditioning systems are often improperly included in a discussion concerning solar air conditioners. However, a more correct definition of a solar a/c unit is an apparatus dependent entirely on the sunâ&#x20AC;&#x2122;s thermal energy to produce a cooling system without significant need of electricity.

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This concept does not include evaporative cooling and the use of solar chimneys and other approaches. Nor does it include so-called passive solar methods involving building design to lower cooling costs such as ventilation and insulation improvements. 2.2 EMERGENCE & HISTORY OF SOLAR ENERGY In today’s age of global warming & the gradual reduction of our valuable natural resources, solar energy can be considered as an advantage to our endangered society. Therefore it is important to know what solar technologies are along with its history of origin. Such knowledge is not only beneficial for the sustainability of our future but will also help us to make maximum utilization. Conflicting to what people may think, solar energy is actually an age old technology. It’s first known use can be traced back to 7th century B.C. The earliest solar power came in the form of glass pieces used to converge sun’s rays for fire. Although the initial use of solar power was mostly in the form of venerating the sun as a god who sustained life, the ancient Greeks and Romans saw the greater potential of the sun. They built their cities and houses in a solar reflexive manner and used glass to trap sunlight for warmth and energy. In the year 1767 a Swiss environmentalist Horace –Benedict de Saussure tried to ascertain the usefulness of sunlight and the heat generated by it by inventing what is now known as a solar collector. He tried to capture the heat by making an insulated pine-wood box covered with three glass layers. 2.3 HOW DOES A SOLAR AIR-CONDITIONING WORKS? Solar thermal collectors fixed on the top of the buildings provide thermal energy by collecting the sun’s energy on plate collectors and heating the recirculated heat transfer fluid within the system. The produced heat is then used in conjunction with e.g. absorption or adsorption air conditioner to provide a renewable source. Both ab-and adsorption process are thermally driven processes, the only difference is that, in absorption process vapor is

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taken by liquid while in adsorption process, vapor is attached on the porous solid material. Currently, most of the solar cooling systems are driven by absorption conditioners. However, due to simple vapor-solid operation, adsorption conditioners seem to provide a promising alternative. A Concentrated solar power is used for collecting the thermal energy for the purpose of Air Conditioning systems particularly a Single Axis Tracking Concentrating Collector. The use of SATC collectors allows the production of heat at a higher level of temperature in an area. Concentrated solar power systems use mirrors to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Electrical power is produced when the concentrated light is converted to heat, which drives a heat engine connected to an electrical power generator or powers a thermochemical reaction. Types of concentrated solar power: 

Parabolic trough



Enclosed trough



Fresnel Reflectors



Dish Engine System



Solar Power Tower

According to the ongoing investigation it has also been suggested to use Wind towers which is less expensive and more sustainable than when CSP is used in large scale. Wind Tower is the first hybrid solar-wind renewable energy technology in the market. The structure is comprised of a tall hollow cylinder with a water injection system near the top and wind tunnels containing turbines near the bottom. In the new proposed systems, solar energy is captured by high temperature solar receivers i.e. the trough system with single axis tracking method. Solar absorption cooling – or solar air conditioning using an absorption chiller – is one of the most efficient and cost effective solutions for commercial air conditioning and space heating. The world's first air conditioners used thermal

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energy to provide cooling, and this technology is common in the northern east coast USA.

Figure 1: (a) parabolic trough

(b) Wind tower

2.4 AIR CONDITIONING IN BUILDINGS Active cooling of interiors using cold generating systems becomes necessary in particular when the internal and external cooling loads of a building can no longer be dissipated effectively via night time cooling or sustainable technologies. To meet this demand of thermal comfort, the cold can be produced by using conventional compressor technologies, like simple solar cooling technologies. Solar cooling technologies produce cold from heat. 2.5 SOLAR AIR CONDITIONING The power to operate solar cooling can be drawn from the heat harvested by solar collectors or the waste heat from a coupling process. The use of solar energy is recommended when a significant proportion of the cooling load derives from the external loads. In the cases where the cooling demand is at the highest coincides almost exactly with the time of maximum output of the system, which in turn is determined by the solar radiation. The electricity consumed by solar cooling systems is restricted to that needed to operate fans and pumps, so depending on how the electricity was produced, they contribute only minimally to the production of anthropogenic CO2.it is recognized that the production of green electricity has relatively little global warming potential. On other benefit is that the use of solar cooling systems

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helps relieve peak loads within electricity network, which in turn helps to avoid any overloading in the grid. Technology

Absorption

Adsorption

DEC

One Stage

Two Stage

Refrigerant

Water

Sorption agent

Lithium

Silica gel

Cold carrier

Bromide Water

Water

Cold temp. range

6-20 degC

chloride 16-20 degC

Hot temp. range

75-100 degC

140-170 degC

65-95

55-100 degC

Cold output range

15-20000 kW

170-23000 kW

degC 70-350 kW

6-300 kW

per unit COP

0.6-0.7

1.1-1.4

0.6-0.7

0.5-1.0

Silica gel order lithium

Table 1: Summary of Solar-thermal cooling processes

There are two types of solar air conditioning system: open and closed. The cold systems include adsorption and absorption chillers, which produce cold water. DEC systems (desiccant evaporative cooling), also referred to as sorption supported air conditioners, are open systems which generate cold air. In contrast to compression cooling systems, the sorption cooling systems and DEC systems do not involve mechanical compression of the refrigerant. Rather the refrigerant is taken up (sorption) by a hygroscopic solid or liquid and then driven out of the sorbent again through the application of heat. To maintain the alternating process of sorption and desorption it is necessary to continuously apply heat, for example in the form of solar thermal energy. Absorption chillers operate on a liquid substance. Adsorption chillers work within a solid. In addition to the systems available on the market, there are also steam jet cooling systems which are currently undergoing testing. Systems of this type use steam to compress the working substance.

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Figure 2 parabolic Trough collector

2.6 ECONOMIC VIABILITY AND ENVIRONMENTAL BENEFITS The first cost (investment cost including planning, assembly, construction and commissioning) for solar assisted cooling systems is significantly higher than corresponding cost of best practice standard solutions – this is a very wellknown fact for almost all solar energy systems and many other systems using renewable energies. The first cost of solar assisted cooling installations is between 2 & 5 times higher compared to a conventional state of the art system depending on local conditions, building requirements, system size, and of course on the selected technical solution. In recent studies, first cost for total systems ranged from 2000 € per kWcold to 5000 € per kWcold and even higher in some particular cases. This large range is due to different sizes of systems, different technologies, different application sectors, and other boundary conditions.

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CHAPTER 3

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3.1 INTRODUCTION The world demand of energy for air conditioning is continually increasing. Air-conditioning is one of the major consumers of electrical energy in many parts of the world today. Nearly all air-conditioning systems in use are built around vapour compression systems driven by grid-electricity. However, most ways of generating electricity used today has some kind of negative impact on the environment, whether it is emissions of carbon-, sulphur-, and nitrogen dioxide (fossil fuel plants), radioactive waste (nuclear power), destroyed rivers and water falls (hydropower) or noise pollution (wind power). Therefore it is desirable to reduce or at least to prevent the increase of electrical demand. Solar air-conditioning might be a way to reduce the demand for electricity. As traditional cooling devices are electrically powered, demand for electrical power in summer keeps increasing and reaches the capacity limit in some countries. Because most of the electrical power stems from fossil fired power plants this trend also increases the emission of CO2. A more innovative approach to provide cooling is to use solar energy in a heat driven active absorption cycle for air conditioning. The high correlation between the availability of solar energy and the need for cooling in a building provides an advantage to solar driven cooling. 3.2 SOLAR THERMAL COOLING Solar energy can be converted into cooling using two main principles

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

Electricity generated with photovoltaic modules can be converted into cooling using well-known refrigeration technologies that are mainly based on vapour compression cycles.

 

Electricity generated with solar thermal collectors can be converted into cooling using thermally driven refrigeration or air-conditioning technologies. Most of these systems employ the physical phenomena of sorption in either an open or closed thermodynamic cycle.

3.3. CONCENTRATED SOLAR POWER (CSP): 1.

Concentrated solar power systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Concentrated Solar power (CSP) systems use combinations of mirrors or lenses to concentrate direct beam solar radiation to produce forms of useful energy such as heat, electricity by various downstream technologies.

Figure 3-Principles for Solar driven cooling

In the present day, the first principle –solar electricity driven cooling- is mainly used for solar driven refrigerators while second principle – solar thermally driven cooling – is the one mainly applied for air-conditioning and comfort cooling in buildings.

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Figure 4 Heat fluxes of a thermally driven cooling system

Figure 4. Heat fluxes of a thermally driven cooling system and definition of the thermal Energy Efficiency Ratio, EER thermal. The useful cold is produced at a low temperature level, TC.The driving heat is supplied at a high temperature level, TH. Both heat fluxes flow into the machine and have to be rejected at a medium temperature level, TM.

Why use solar thermal energy for air-conditioning of buildings or refrigeration applications? As a first observation it can be said that there is a large interest from end users. Making cold from heat seems to be a magical technology that appeals to many end-users. Main arguments for solar assisted cooling (SAC) originate from an energy saving perspective: 

Application of SAC saves electricity and thus conventional primary



energy sources. SAC also leads to a reduction of peak electricity demand, which is a benefit for the electricity network and could lead to additional cost savings of the most expensive peak electricity when applied on a broad



scale. SAC technologies use environmentally sound materials that have no ozone depletion and no (or very small) global warming potential.

Other arguments originate from a more technical perspective: 

Solar energy is available almost at the same time when cooling is needed; this argument holds for both, solar thermal and solar electric



based systems. Solar thermal systems used for production of sanitary hot water and heating have large collector areas that are not fully used during

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summer. They can be used for SAC and thereby reduce risk of 

stagnation situations of the solar collector system. Comparatively low noise and vibration-free operation of thermally driven chillers.

3.3.1 ADVANTAGES SAC application has some other advantages that are often difficult to translate in an economic advantage, but may be important to be considered by policy makers: 

Application of SAC systems may lead to (primary) energy savings and thus help to reduce the dependence of finite energy fuels, which have



to be imported in many countries. Correspondingly, application of SAC systems will lead to reduced CO2 emissions and thereby contribute to a reduction of climate change and



related effects. SAC systems using thermally driven cooling cycles show additional environmental benefits since they typically employ refrigerants with no ozone depletion potential and no or a very small global warming



potential. SAC systems can be used also for all heating applications in a building or industry. The large solar collector field also provides heat for other purposes than cooling and thus helps to avoid consumption of fuel (or



electricity) for heating applications. SAC systems can contribute to grid stability in regions with a considerable share of daily electricity consumption from the grid for airconditioning with conventional techniques

3.3.2 TECHNICAL POTENTIALS

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Potentials on the technical level range from new and advanced materials through improved components to more efficient and more reliable systems. Work on components concerns advanced cooling cycles on the one hand and advanced solar collectors, which are well adjusted to the needs of thermally driven cooling on the other hand. Important advanced components are: 

Integration of the generator of a thermally driven cooling machine in the solar collector will lead to reduced heat transfer losses and to more compact systems. Also, space in a technical room will be saved.



Overall, such concepts aim at high efficiency at reduced system cost. Double-effect cycle absorption technology, which achieves high efficiency at high operation temperatures, will be extended also for the small capacity range and thus offer solutions with high overall efficiency



for applications in the range of small capacity. Single-axis tracking solar thermal collectors to produce heat at temperatures in the range of 150°C to 250°C are still a rather new technology and important cost savings may be achieved by development of advanced materials (e.g. for reflectors) and advanced



production technologies. Non-tracking collectors have achieved a high level of technical maturity. However, improvements towards higher operation efficiency at temperatures of 80°C to 110°C are still possible and advanced production technologies will allow for reduction of cost.

3.4 APPROACHES TO CONCENTRATING SOLAR POWER (CSP) CSP systems capture the direct beam component of solar radiation. Unlike flat plate photovoltaics (PV), they are not able to use radiation that has been diffused by clouds or dust or other factors. This makes them best suited to area with a high percentage of clear sky days in location that do not have smog or dust

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The configurations that are currently being used are,     

Parabolic trough Solar power tower Linear Fresnel reflectors Fresnel lenses Dish engine system

3.4.1 PARABOLIC TROUGH Parabolic trough shaped mirrors produce a linear focus on a receiver tube along the parabola’s focal line as illustrated in the figure. The complete assembly of mirrors plus receiver is mounted on a frame that tracks the daily movement of the sun on one axis. Relative seasonal movements of the sun in the other axis result in lateral movements of the line focus, which remains on the receiver but can have some spill at the row ends.

Figure 5 Parabolic trough collector : tracks the sun on one axis

Trough system using thermal energy collection via evacuated tube receivers are currently the most widely deployed CSP technology. In this configuration, an oil heat transfer fluid is usually used to collect the heat from the receiver tubes and transport it to a central power block.

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Figure 6 parabolic trough system - Half-driven string

In parabolic trough collector, long, U-curved mirrors focus the rays of the sun into an absorber pipe. The mirrors track the sun on one linear axis from north to south during the day. The pipe is seated above the mirror in the center along the focal line and has a heat-absorbent medium running in it. The sunâ&#x20AC;&#x2122;s energy heats up the oil, which carries the energy to the water in a boiler heat exchanger, reaching a temperature of about 400Â°C. The heat is transferred into the water, producing steam to drive turbine. A study supported by Japanese government found an annually-averaged collector efficiency using supercritical CO2 as the working fluid, higher than water/vapor. The Shape and Material of the collector differ from different designs as well. The collector is generally composed of one bent glass mirror, with either silver or aluminum coated on the backside of the glass. The glass is about fourmillimeter thick and low in iron, maximizing the reflectance of incoming sunlight.

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Figure 7-Parabolic trough system - schematic

3.4.2 CENTRAL RECEIVER TOWER The solar power tower, also known as 'central tower' power plants or 'heliostat' power plants, is a type of solar furnace using a tower to receive the focused sunlight. A central receiver tower system involves an array of heliostats (large mirrors with two axis tracking) that concentrate the sunlight onto a fixed receiver mounted at the top of a tower, as shown in the figure. This allows sophisticated high efficiency energy conversion at a single large receiver point. Higher concentration ratios are achieved compared to linear focusing systems and this allows thermal receivers to operate at higher temperatures with reduced losses. A range of system and heliostat size have been demonstrated. Design: 

Some of the conc. solar towers are air cooled instead of water cooled,

 

to avoid usage of limited water in the desert type areas. Flat glass is used instead of curved glasses which are more expensive. Thermal storage to store the heat in molten salt containers to continue



producing electricity while the sun in not shining. Steam is heated to 500 degC to drive the turbines that are coupled to generators which produce electricity.

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ď&#x201A;ˇ

Control systems to supervise and control all the plant activity including the heliostat array positions, alarms, other data acquisition and communication.

Figure 8 Solar power tower

Usually installation use from 150 hectares to 320 Figure: Solar power tower

3.4.3 LINEAR FRESNEL REFLECTORS Linear Fresnel reflector (LFR) systems produce a linear focus on a downward facing fixed receiver mounted on a series of small towers as shown in the figure. Long rows of flat or slightly curved mirrors move independently on axis to reflect the sunâ&#x20AC;&#x2122;s rays onto the stationary receiver. For thermal systems, the fixed receiver not only avoids the need for rotary joints for the heat transfer fluid, but can also help to reduce convection losses from a thermal receiver because it has a permanently down facing cavity. The proponents of the LFR approach argue that its simple design with near flat mirrors and less supporting structure, which is closer to the ground, pout weights the lower overall optical and thermal efficiency. To increase optical and ground use efficiency, compact linear Fresnel reflectors (CLFRs) use multiple receivers for each set of mirrors so that adjacent mirrors have different inclinations in order to target different receivers. This allows higher

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packing density of mirrors which increases optical efficiency and minimizes land use.

Figure 9-Linear Fresnel reflector: Multiple mirrors move on one axis to focus the sun to a fixed linear receiver.

Linear Fresnel reflector solar collector helps to reduce the cost significantly. It weighs 3 kg/m2, only one third of the parabolic trough mirror. It has a much lower concentrating temperature, at 285 degC. 3.4.4 FRESNEL LENS A conventional lens is expensive and impractical to manufacture on a large scale. The Fresnel lens overcomes these difficulties and has been employed extensively for CPV systems. A Fresnel lens is made as a series of concentric small steps, each having a surface shape matching that which would be found on a standard lens but with all the steps kept within small thickness. A plastic material is usually used and arrays of multiple lens units are typically mounted on a heliostat structure as shown in figure. This is also a point focus approach requiring accurate sun tracking in two axes.

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Figure 10-Fresnel lens based CPV: Multiple small units on a heliostat

Table 1-Figure: Figure showing the efficiency of parabolic troughs, Fresnel systems & Solar tower

3.4.5 DISH ENGINE SYSTEMS The dish/engine system is a concentrating solar power (CSP) technology that produces relatively small amounts of electricity compared to other CSP technologiesâ&#x20AC;&#x201D;typically in the range of 3 to 25 kilowatts. Dish/engine systems use a parabolic dish of mirrors to direct and concentrate sunlight onto a central engine that produces electricity. It is the most powerful type of collector which concentrates sunlight at a single, focal point, via one or more parabolic dishes arranged in a similar fashion to a reflecting telescope focuses starlight, or a dish antenna focuses radio waves. Parabolic dish systems consists of a parabolic shaped point focus concentrator in the form of a dish that reflects solar radiation onto a receiver mounted at the focal point

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Figure 11 parabolic dish concentrator: tracks the sun in two axes.-

Dish systems offer the highest potential solar conversion efficiencies of all the CSP technologies, because they always present their full aperture directly towards the sun and avoid the cosine loss effect that the other approaches experience. Advantages: 

Good efficiency. By concentrating sunlight current systems can get better efficiency than simple solar cells.



Very high temperatures reached. Conversion efficiency approaching 30% has been achieved. This is the highest conversion efficiency of the concentrating solar power technologies.



A larger area can be covered by using relatively inexpensive mirrors rather than using expensive solar cells.



The solar parabolic dish engine system has only a very minimal water requirement. The engine is air cooled, so no cooling water is needed.

Disadvantages: 

Concentrating systems require sun tracking to maintain Sunlight focus at the collector.

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ď&#x201A;ˇ

Inability to provide power in diffused light conditions. Solar Cells are able to provide some output even if the sky becomes a little bit cloudy, but power output from concentrating systems drop drastically in cloudy conditions as diffused light cannot be concentrated passively.

ď&#x201A;ˇ

Heat to electricity conversion requires moving parts and that results in maintenance.

3.5 LAYOUT OF SOLAR COOLING INSTALLATIONS A typical solar cooling system consists of a common solar thermal system made up of solar collectors, a storage tank, a control unit, pipes and pumps and a thermally driven cooling machine. Most collectors used in solar cooling systems are high efficiency collectors which are available in the market today.

Figure 12- Solar cooling system

The available solar energy, in the form of solar radiation flux, is utilized by a solar panel, in order to produce a high temperature fluid that is accumulated in a storage tank. The chiller, the real heart of the process, uses the hot fluid of the storage tank to produce a cold fluid; the cold fluid can then be used in a normal cooling plant similar to an electric refrigerator. The thermal storage tank then acts as a buffer and enables the optimization of the asynchronous heat absorption during the hours of solar radiation and the cooling that may be needed during a different time period making this component indispensable.

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Figure 13-Basic layout of a solar cooling plant utilized during summer & winter

Solar assisted air conditioning systems may be classified into closed or open systems: ď&#x201A;ˇ

Closed systems : These are thermally driven chillers, which provide chilled water that is either used in air handling units to supply conditioned air or that is distributed via a chilled water network to the particular rooms to operate decentralized room installations. Absorption and adsorption chillers are the equipment available in the market for this purpose.

ď&#x201A;ˇ

Open Systems : Open system includes mainly desiccant cooling system, which uses water as a refrigerant in direct contact with air. The thermally driven cooling cycle is a combination of evaporative cooling with air dehumidification by a desiccant. The common technology applied today uses rotating desiccant wheels, equipped either with silica gel or lithium chloride as sorption material.

3.6 MAIN COMPONENTS IN A SOLAR ASSISTED AC SYSTEM

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The main components in a solar air conditioning system can be divided as follows,     

Solar Collector Hot water & chilled water storage Chiller Cooling towers Fan coils

3.6.1 SOLAR COLLECTORS FOR COOLING SYSTEMS 

Flat Plate solar Collector : Flat plate collectors are the most widely used kind of collectors for domestic water heating systems and solar space cooling. A typical flat plate collector consists of an absorber, transparent cover sheets, and an insulated box. The absorber is usually a sheet of high thermal conductivity metal such as copper or aluminum with tubes either integral or attached. Its surface is coated to maximize radiant energy absorption and to minimize radiant emission. The insulated box reduces heat loss from the back or the sides of the collector. The cover sheets, called glazing, allow sunlight to pass through the absorber but also insulate the space above the absorber to prevent cool air to flow into this space.

Figure 14-Flat plate collector



Evacuated Tubes : Glass evacuated tubes are the key component of the evacuated tube heat pipe solar collectors. Each evacuated tube consists of two glass tubes. The outer tube is made up of extremely strong transparent

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borosilicate glass that is able to resist impact from hail up to 25mm in diameter. The inner tube is also made of borosilicate glass, but coated with a special selective coating, which possesses excellent solar heat absorption and minimal heat reflection properties. The air is evacuated from the space between the two glass tubes to form a vacuum, which eliminates conductive and convective heat loss. The vacuum tube solar panel has been around for several years and has proved to be both reliable and dependable. The solar radiation is absorbed by the selective coating on the inner glass surface, but is prevented from reradiating out by the silver coated innermost lining which has been optimized for infrared radiation. 93% of the sun lights energy hitting the tubes surface is absorbed while only 7% is lost through reflection and re emission. The heat transferred to the tip of the heat pipe is in turn transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is places in direct sunlight on a summer day, the tip temperature can reach 250 degC, so the system easily heats domestic hot water cylinders to 60 degC even in cooler weather.

Figure 15-A vacuum tube collector

3.6.2 HOT WATER & CHILLED WATER STORAGE: The main purpose of storage in a solar assisted air conditioning system is to overcome mismatches between solar gains and cooling loads. The most common application is the integration of a hot water buffer tank in the heating

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cycle of the thermally driven cooling equipment. In a solar assisted air conditioning system that uses absorption chiller, there are 2 possible places for integrating thermal storage.

Figure 16-: Schematic Diagram of hot water tank for solar assisted air conditioning system.

3.6.3 CHILLER The core of solar cooling plants are the chillers. If the solar panels provide the necessary energy input to the plan, chillers are those machines that are able to produce cooling by utilizing the hot water coming from the solar panels. Generally, a chiller is a machine that removes heat from a liquid via a vapor compression or absorption refrigeration cycle. Most often water is chilled, but this water may also contain 20% glycol and corrosion inhibitors. There are many types of chillers but absorption or adsorption chillers have been used for decades and have been mainly powered by electric motors, steam or gas turbines.

ď&#x201A;ˇ

Absorption chiller : Absorption chillers thermodynamics cycle is driven by a heat source. This heat is usually delivered to the chiller via steam, hot water or combustion but in the sunny climates, solar energy can be used to operate absorption chillers. Compared to electrically powered chillers, they have very low electrical power requirements, very rarely above

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15kW combined consumption for both the solution pump and the refrigerant. However, their heat input requirements are large. However, absorption chillers, from an energy efficiency point of view, excel where cheap heat is readily available such as heat provided by solar thermal panels in sunny regions. Absorption chillers are the most widely used chillers throughout the world. A thermal compression of the refrigerant is achieved by using a liquid refrigerant solution and a heat source, thereby replacing the electric power consumption of a mechanical compressor. For chilled water above 0 degC as is used in air conditioning a liquid H2O solution is typically applied with water as a refrigerant.

Figure 17-Principle of an absorption chiller

ď&#x201A;ˇ

Adsorption chillers : Adsorption chillers apply solid sorption materials instead of a liquid solution. Instead of absorbing the refrigerant in an absorbing solution, it is also possible to adsorb the refrigerant on the internal surfaces of a highly porous solid. This process is called adsorption. Systems available in the market today use water as a refrigerant and silica gel as a sorption material. The machines consist of two sorption one evaporator and one condenser. The capacity of the chillers ranges from 50 to 500kW chilling power.

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Figure 18-Principle of an adsorption chiller

 Desiccant cooling system: Desiccant cooling systems are basically open cycle systems, using water as a refrigerant in direct contact with air. The thermally driven cooling cycle is a combination of evaporative cooling with air dehumidification by a desiccant, i. e. a hygroscopic material. For this purpose, liquid or solid materials can be employed. Only water is possible as a refrigerant since a direct contact to the atmosphere exists. The common technology applied today uses rotating desiccant wheels, equipped with silica gel or lithium chloride as sorption material. Solar assisted desiccant cooling uses solar thermal energy to dry out or regenerate the desiccant.

Comparison of the main sorption and desiccant technologies Systems Absorption

Adsorption

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Advantages

Disadvantages

• Only one moving part

• Low COP

(pump) with possibly

• It cannot achieve a

no moving part for a

very low evaporating

small system

temperature

• Low-temperature heat

• The system is quite

supply is possible No moving parts

complicated • High weight and poor

•Low operating temp.

thermal conductivity of

can be achieved

the absorbent

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Desiccant

• Thermal Coefficient of

• Low operating

Performance (COP) is

pressure requirement

quite high compared to

makes it difficult to

other heat operating

achieve air-tightness

systems Environmentally

• It cannot function

friendly, water is used

properly in a humid

as the

area

working fluid

• It is not appropriate

• Can be integrated

for an area where

with a ventilation and

water is scarcity

heating system

3.6.4 FAN COILS A fan coil system is a heat exchanger with a fan that simply circulates indoor air over it. The heat exchanger is supplied with chilled water. Each of the fan coil units have a thermostatically controlled built-in fan that able to draws air from the indoor space and then blows it over finned tubes of the heat exchangers where chilled water for cooling is circulated. The cold medium is produced by the absorption chiller. Generally fan coils can be ceiling mounted, concealed or recessed vertical floor units.

3.6.5 COOLING TOWER A cooling tower is a device where cooling water is brought into contact with ambient air to transfer rejected heat from the coolant to the ambient. There are 2 basic types of cooling tower: open-circuit systems, where there is direct contact between the primary cooling-water circuit and the air, and closed circuit systems where there is only indirect contact between the 2 fluids across heat exchanger walls. Open circuit systems are commonly known as ‘open cooling towers’, ‘wet cooling towers’ or just as ‘cooling towers’. A

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characteristic feature of all such systems is, that they mostly use latent heat transfer where the coolant, which has to be water, is cooled by evaporating about 2-3% of the coolant itself.

Figure 19-Cooling Tower

3.7 POSITIONING OF SOLAR PANELS: The direction and angle that the panel faces can have a big impact on its performance by affecting the amount of light that hits the panel each day through the year. Some solar panels move continuously to track the sun but most will not go to the expense and difficulty of implementing that. To get it right we have to make sure that the panels get hit by the maximum amount of light. This happens when the sun is directly above the panel.

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Figure 20-Digriam and angle of installation

3.8 BUILDING INTEGRIBILITY: Buildings and their processes account for one half of all energy consumption. When the energy required to mine, produce, deliver and assemble materials for the construction of buildings. For developed countries to carry on enjoying the comforts sustainability must be the cornerstone for design philosophy for the years to come. Rather than reducing usage of non-renewable resources to create less pollution, we need sustainable building designs that run on renewable sources of energy to provide most/almost of their own energy needs and future pollution. . Building integrated Photovoltaics has many additional benefits: 

The building itself becomes the support structure.



System electrical interface is easy



BiPV components displace conventional building materials and labor, reducing the net installed cost of the PV system



Architecturally

classy.

Well

integrated

systems

will

increase

marketplace

3.9 PRINCIPLES OF BUILDING INTEGRATION: Unlike any other building installation, building integrated photovoltaics can affect a lot of essential parts of the design process: 

Layout and orientation

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

Form and Massing



Layout and height of surrounding buildings



Energy strategy



Building structure and modularity



Selection and assembly of other building materials



Capital and running costs



Construction integrity and detail



Appearance and architectural expression

3.10. STATUS AND SCOPE OF SOLAR COOLING IN INDIA Space cooling and refrigeration are highly energy-intensive processes. Cooling demands in various sectors are maximum mainly during day time when solar energy is also prevalent; this is more so in the hot summer season. Most parts of India get abundant sunshine throughout the year. Solar cooling/refrigeration is, therefore, the most relevant application for our country, especially in view of the rapidly increasing demand for energy and shortage of electric power. It is estimated that cooling consumes about 35,000 MW of electricity for various end-uses. Part of this is from conventional power plants in areas where electricity is easily available and the rest is being generated through DG sets which consume a significant amount of highly subsidized diesel leading to noise and air pollution, besides heavy CO2 emissions. The applications of cooling include domestic refrigeration, comfort/ space cooling in various sectors, industrial refrigeration and process cooling, cold storages with deep freezing, vaccine storages in PHCs, etc. The capacity range of systems varies from a few Watts to thousands of kilowatts. Solar cooling/air-conditioning systems have the potential to catering to all the above sectors. However, this is an emerging technology and faces many growth barriers, which are different from other heating and cooling technologies. Standalone solar cooling systems:

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These systems with intermittent heat storage has also been developed by M/s Thermax Ltd, Pune, under a publicâ&#x20AC;&#x201C;private partnership with MNRE. The system of 30-ton capacity using indigenously made concentrating parabolic troughs has been developed and demonstrated at the solar energy center, MNRE, for the purpose of air conditioning of office complexes. It is a standalone system for day time use and can take care of intermittent clouds through small heat storage. The system has been found to be useful for offices and institutions working during day time when solar radiation is also available. Smaller systems with air cooled condensers have also been developed.

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CHAPTER 4 Case Study

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4.1 QATAR 2022 SHOWCASE STADIUM

Project data: Year of Completion – 2010 Country – Qatar Location – Al Thumaama, Doha Capacity – 500 Seats Architect - Arup Associates, UK

The Qatar showcase stadium is located at Al Thumaama in the city of Doha, Qatar. The Stadium is designed as a showcase model stadium for the Qatar 2022 FIFA world cup bid by the Arup associates. Arup Associates design for 2022 FIFA World Cup Qatar Showcase is a distinctive building that was a major driver in Qatar’s sustainability plan. As part of the bid, Arup Associates has designed a 500-seater model stadium that will be carbon zero and be a development platform to refine these technologies for application across Qatar and potentially across all arid regions.

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The Showcase was commissioned in order to demonstrate to FIFA and the world-wide audience that the harsh climate over the summer months is no longer a barrier to hosting global events. It is an investigation into innovative, cutting-edge solutions for creating a controlled microclimate over and around the football field, and other public spaces. The Showcase serves as a proofof-concept for innovative cooling and climate control technologies. The Showcase is based on three key aspects: an exciting architecture and structure which develops traditional passive design ideas to a new energysaving and comfortable architecture; photovoltaics that convert the energy of the sun into electricity; capturing and converting the sun’s heat into cooling for summertime air-conditioning using under-seat supply. The Showcase, Qatar’s model stadium, is complete after a construction period of only 4 months, with its key design elements – a revolving canopy roof, summer-time air-conditioning and solar energy systems – now operational and supplying zero-carbon energy and cooling from the sun.

Figure 21-Design Option – Arup Associates

The revolving roof canopy: The compelling rhythmic geometry of the Showcase’s canopy roof plays an important part in the sustainability strategy of the stadium. The canopy roof moves to provide cooling shade within the building and insulated against the hot sun in summer. It is the first roof of its type and is already considered a pioneering move towards a more environmentally responsible approach to stadia architecture. On approaching the Showcase, there is a “solar farm” made up of photovoltaic panels and Fresnel parabolic mirrors which focus the

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sun’s energy onto pipes that, in this case, have water running in them, capturing the sun’s energy.

Figure 22-Roofing Structure for shade

Power from the Sun: Just outside the Showcase is a photovoltaic installation- a sun farm, connected to the structure’s electrical system and the national grid. The venues’ solar panels will operate year-round, continuously exporting electrical energy to the national grid. On a match day, the higher electrical demand will bring electricity back into the facility from the national grid. This national grid electricity, together with generators using biofuels, provide robust and reliable power for both technical and general power, so the events are assured power during the World Cup. The amount of electricity generated in this way from the sun exceeds the amount of electricity imported for events over the year, making the facility zero carbon for electricity.

Figure 23-Solar heat Collector set outside the stadium

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On the site, next to the photovoltaic panels is an array of solar heat collectors. These represent the latest generation of solar heat collectors and have a series of motorised mirrors that track the sun, focussing the sunâ&#x20AC;&#x2122;s power onto collecting tubes which have hot water circulating in them. They collect this energy in the form of heat, which is converted into cooling for the Showcase environment, and electricity to supply lighting, power and other functions within the space. The solar energy heats water to 200C and is converted to cooling water by machines called absorption chillers. These have been used for the last 100 years in industrial cooling systems. The cooling is then stored in eutectic tanks beneath the showcase for use in the evening when itâ&#x20AC;&#x2122;s circulated into the air-handling units.

Figure 24-Environmental Sketch

Figure: 25 (a) Thermal modelling

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(b) Partial section and elevation

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The air-handling units supply this air to the area beneath the spectatorâ&#x20AC;&#x2122;s seats. This cools the seating area and flows down to create cooling for the players. Importantly, the surfaces of the Showcase are designed to remain cool throughout the match to help to stabilise the heat gains from lights and people.

Figure 26-Drawing showing how the solar heat collectors provide cooling.

Figure 27-Drawing showing under seat cooling.

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4.2. KAOHSUING NATIONAL STAIDUM, TAIWAN

Project data: Year of Completion – May 2009 Country – Taiwan Location – Zuoying, Kaohsiung Capacity – 55,000 Architect - Toyo ito # Solar panels – 8,844 Panels (Roof top)

The Kaohsiung National Stadium formerly known as world games stadium is a multipurpose stadium in Zuoying District, Kaohsiung, Taiwan . It is currently the largest stadium in Taiwan in terms of capacity. The stadium has a capacity of 55,000 people. The stadium, designed by Japanese architect Toyo Ito, makes use of solar energy to provide its power needs. The stadium's semi spiralshaped, like a dragon, is the first stadium in the world to provide power using solar energy technology. The solar panels covering the vast external face of the stadium are able to generate most of the power required for its own operation, as well as additional power that can be saved. The solar-powered stadium built in Taiwan for the 2009 World Games is the epitome of engineering ingenuity, eco-friendliness, renewal energy and beauty. The stadium incorporates 8,844 solar panels, supported by spiraling steel girders and covering every square inch on the roof. The rooftop panels

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generate enough energy to power the building’s 3,300 lights and two giant television screens. On hot days, the stadium generates more power than it needs, so the Taiwanese government sells the excess capacity. The panels will generate about 1.14 million KWh per year, preventing 660 tons of annual carbon dioxide emissions. Other green features in the stadium include permeable pavement that is used throughout the complex, and all of the raw materials used in the main stadium are 100 percent recyclable/reusable and made in Taiwan. The stadium can power 80 percent of the surrounding neighborhood with its solar array that is connected to the grid during days when the stadium is not being used. When it was built in 2009, it was touted as the world’s largest solar-powered stadium. Viewed from high above, the stadium is said to appear dragon-like with its thousands of solar “dragon scales,” covering an area of 14,155m square.

Figure 25-(a) Plan and Section

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(b) Picture shows the solar panels fitted on rooftop

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In this large solar powered stadium, the solar power system generates 1.1 mKw/h units of electricity which translates to 660 tons less carbon emission. The unique character of arched roof Kauhuing stadium is the biggest challenge of solar power system. To accommodate the shape of the roof in increased brightness for the stadium they used photovoltaic system using 4422 frames for 8844 world first translucent solar modules customized for the stadium in both looks and functionality. The translucent solar modules are connected to the photovoltaic inverter which has the highest inversion rate in the world of 98%. The World Games Stadium is oriented on a north-south axis, on a slight northwest-southeast 15-degree angle, with its spiral shape creating an open "C.â&#x20AC;? The design allows the main spectator stand to be effectively sheltered from the southwestern summer wind and the northwestern winter wind. The orientation also provides shelter from sunlight. The roof structure uses a lightweight earthquake-resistant design that includes spiral high-strength steel girders and precast concrete using a special energy-efficient insulation. Interior spaces were designed for improved air circulation to decrease the load of air conditioner. The generators will meet the stadiums power needs for lighting and air-conditioning. Moreover, any new materials used to build the main stadium are 100% reusable and all made in Taiwan. During sports games, the stadium is able to provide electricity. While during non-game days, the stadium is able to store extra energy that can later be sold to the surrounding neighborhood.

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Figure 27-Roofing structure

Figure 28-Roofing structure in Kaohsiung Stadium

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4.3 ESTADIO MINEIRAO, BRAZIL

Project data: Year of Completion – 1965 Year of Renovation - 2010 Country – Brazil Location – Belo Horinzonte, Brazil Capacity – 62,547 Architect – Eduardo Mendes Guimaraes (1959), BCMF (2010), GMP Certification – LEED certified

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Mineirão established in 1965 in Belo Horizonte, is the largest football stadium in the state of minas Gerais, Brazil. It served as a venue in the 2013 FIFA confederations cup and the 2014 FIFA world cup. The stadium, located in the Brazilian city of Belo Horizonte, has been equipped with a 1.4MW solar array on its rooftop. Electricity generated by the plant will be used into the grid and won’t be directly consumed by the stadium. The solar project required a total investment of €12 Million of which €10 million was provided as a loan from German bank KfW while CEMIG provided the remaining €2.5 million. Martifer solar built the rooftop PV plant as part of the Minas Solar 2014 program for CEMIG and their partners, German bank and minas arena. The 1.4 MW plant will offset 139.7 tons of carbon dioxide emissions each year, which is sufficient energy to power more than 2,700 inhabitants in Brazil on an annual basis. The 1.4 MW PV installation at the Mineirão stadium was built on an area of approx. 10,000m2, which covers more than 85% of the stadiums rooftop. There are 5910 solar modules installed in a fixed position which totals an estimated production capacity of more than 1.6 GWh on an annual basis. With this capacity, the PV plant will offset 139.7 tons of carbon dioxide each year, which is sufficient energy to power more than 2,700 inhabitants in Brazil on an annual basis. After the renovation the roof support consisted of a flat lattice structure with a bracing system made of tubular steel profiles anchored in each of the facades concrete porticos. The solar panels in this building was installed in the outer circle of the rooftop on a galvanized steel support.

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Figure 29-: (a) Roof structure

(b) Section

Figure 30-Plan

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CHAPTER 5 CONCLUSION

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5.1 CONCLUSION The demand for energy consumption for the purpose of air conditioning has been increasing. As the cooling devices are usually electrical powered, the demand for electrical power increases and reaches the capacity limit during the summer time. But the more innovative way is to use solar energy for driving the air conditioning systems at the location where the temperature is high especially in the desert area. Air-conditioning is the dominating energy service in buildings in many countries. In fact, in many regions of the world, the demand for cooling and dehumidification of indoor air is growing due to increasing comfort expectations and increasing cooling loads. Conventional cooling technologies exhibit several clear disadvantages:   

Energy consumption is high Cause high electricity peak loads In general, they employ refrigerants, with considerable global warming potential

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The utilization of solar energy to work heat-driven cooling machines is a way to address these problems. The utilization of solar energy to work heat-driven cooling machines is a way to address these problems. Solar cooling system installations have increased substantially in the last decade and there are a number of installations with successful working records, especially in Europe. Some of the major solar cooling installations at the international level have been shown above in the case study. Experience shows that many problems of real operation rise at the system level rather than at the level of components. The evaluation of successful design strategies and successful system layouts in different climates will be very important. Talking about the application I solar assisted air conditioning systems, the primary need is further reduction of costs in order to increase the overall competitiveness of the entire system.

5.2 REFERENCES BOOKS 1. Jacobson, Mark Z. and Delucchi, Mark A. (2010). "Providing all Global Energy with Wind, Water, and Solar Power, Part I: Technologies, Energy Resources, Quantities and Areas of Infrastructure, and Materialsâ&#x20AC;?. Energy Policy. 2. "The

surprising

history

sustainable

energy".

Sustainablehistory.wordpress.com. Retrieved 2012-11-01. 3. "Energy Sources: Solar". Department of Energy. Retrieved 19 April 2011. WEBSITE 1.

http://seedengr.com/An%20Overview%20of%20Solar%20Assisted %20Air-Conditioning%20System.pdf

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http://mnre.gov.in/file-manager/UserFiles/Sun-Focus_April-June2014.pdf

http://ec.europa.eu/energy/intelligent/projects/sites/ieeprojects/files/projects/documents/solco_solar_cooling_conclusions_an d_recommendations_en.pdf

http://www.arupassociates.com/en/case-studies/qatar-showcase/

http://acboy.org/solar-air-conditioner/

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