renewable energy systems in buildings pdf.doc

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RENEWABLE ENERGYSYSTEMS INBUILDINGSCHAPTER 1

INTRODUCTION

More than 90 per cent of our time is spent in buildings i.e. either in the office or at home.

Energy used in buildings (residential and commercial) accounts for a significant percentage of a

countrys total energy consumption. This percentage depends greatly on the degree of

electrification, the level of urbanization, the amount of building area per capita, the prevailing

climate, as well as national and local policies to promote. Recent studies have shown that in

India, the buildings sector accounts for nearly 30-35% of total energy consumption. This

includes the residential and commercial sector.The building sector encompasses a diverse set of

end use activities, which have different energy use implications. Space heating, space cooling

and lighting, which together account for a majority of building energy use in industrialized

countries, depend not only on the energy efficiency of temperature control and lighting systems,

but also on the efficiency of the buildings in which they operate. Building designs and materials

have a significant effect on the energy consumed for a selected set of end uses In terms of

Potential in savings, the residential sector offers a saving potential of almost 30% while

commercial sector offers a saving potential of almost 40%.The most common method of

harnessing renewable energy in buildings is with the use of technologies which rely on naturally

occurring renewable resources such as water, wind, sun etc. These primarily include Solar Photo

Voltaic (PV) cells and Solar Water Heaters (SWH). Solar PVs help convert suns energy into

electricity. Solar PV panels can be used can be used to provide a certain percentage of energy

requirements in a buildings, thereby reducing the pressure on grid electricity. Solar PVs can be

installed on rooftops, porches etc. Or can be integrated into the various glazing systems on

buildings facades or rooftops. Solar PVs can be used to directly supply electricity to a building or

can be clubbed with a battery bank to store excess electricity generated for later use. Solar Water

Heater can be placed on rooftops and used to heat water and store it for later use. Using

renewable energy systems helps in reduction of Green House Gas (GHG) emissions. Since thesystems use suns energy or wind energy, they act as a clean source of energy which is available

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RENEWABLE ENERGYSYSTEMS INBUILDINGSfree of cost. It is important to develop, promote and adopt these technologies in order to help

avert/ mitigate dangers due to climate change.

1.1 ENERGY EFFICIENCY

The ratio of energy input to the calculated or estimated amounts of energy required to

cover the various requirements relating to the standardized use of a building serves as the

measure of energy efficiency. According to EU Directive "Energy Performance of Building

Directive" (EPBD), the following thermal and electrical forms of energy are considered when

determining the energy efficiency of a building:

Heating

DHW (domestic hot water)

Cooling

Ventilation

1.2 WHAT IS ENERGY EFFICIENCY OF A BUILDING?

The energy efficiency of a building is the extent to which the energy consumption

Per square meter of floor area of the building measures up to established energy consumptionbenchmarks for that particular type of building under defined climatic conditions. Building

energy consumption benchmarks are representative values for common building types against

which a buildings actual performance can be compared. The benchmarks are derived by

analyzing data on different building types within a given country. The typical benchmark is the

median level of performance of all the buildings in a given category and good practice represents

the top quartile performance. Comparisons with simple benchmarks of annual energy use per

Square meter of floor area or treated floor area (kWh/m2/annum) allow the standard Of energy

efficiency to be assessed and priority areas for action to be identified. Benchmarks are applied

mainly to heating, cooling, air-conditioning, ventilation, Lighting, fans, pumps and controls,

office or other electrical equipment, and electricity consumption for external lighting. The

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RENEWABLE ENERGYSYSTEMS INBUILDINGSbenchmarks used vary with the country and type of building. The measure of heat loss through a

material, referred to as the U-Value, is also used as a way of describing the energy performance

of a building. The U-value refers to how well an element conducts heat from one side to the

other by rating how much the heat the component allows to pass through it. They are the

standard used in building codes for specifying the minimum energy efficiency values for

windows, doors, walls and other exterior building components. U-values also rate the energy

efficiency of the combined materials in a building component or section. A low U-value

indicates good energy efficiency. Windows, doors, walls and skylights can gain or lose heat,

thereby increasing the energy required for cooling or heating. For this reason most building

codes have set minimum standards for the energy efficiency of these components.

1.3. ENERGY EFFICIENCY MEASURES FOR BUILDINGS

Energy efficiency measures for buildings are approaches through which the energy

consumption of a building can be reduced while maintaining or improving the level of comfort in

the building. They can typically be categorized into:

Reducing heating demand

Reducing cooling demand

Reducing the energy requirements for ventilation

Reducing energy use for lighting

Reducing energy used for heating water

Reducing electricity consumption of office equipment and appliances

Good housekeeping and people solutions.

1.3.1 REDUCING HEATING DEMAND

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RENEWABLE ENERGYSYSTEMS INBUILDINGSHeating demand can be reduced by:

Limiting the exposed surface area of the building

Improving the insulation of the buildings fabric

Reducing ventilation losses

By selecting efficient heating systems with effective controls

1.3.2 REDUCING COOLING DEMAND

Energy use in typical air-conditioned office buildings is approximately double that of

naturally ventilated office buildings. The need for air-conditioning or the size of the systems

installed can be reduced by:

Controlling solar gains through glazing

Reducing internal heat gains

Making use of thermal mass and night ventilation to reduce peak temperatures

Providing effective natural ventilation

Reducing lighting loads and installing effective lighting controls.

1.3.3 REDUCING ENERGY REQUIREMENTS FOR VENTILATION

When the cooling demand is sufficiently reduced by implementing the above measures, it

may be possible to reduce heat gains so that air-conditioning is unnecessary and comfort

conditions can be maintained through the use of natural ventilation. The energy required for

ventilation can be minimized by:

A building design that maximizes natural ventilation

Effective window design

Use of mixed mode ventilation

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RENEWABLE ENERGYSYSTEMS INBUILDINGS Using efficient mechanical ventilation systems.

1.3.4 REDUCING ENERGY USED FOR LIGHTING

This can be accomplished through:

Making maximum use of daylight while avoiding excessive solar heat gain

Using task lighting to avoid excessive background luminance levels

Installing energy-efficient luminaries with a high light output to energy ratio

Selecting lamps with a high luminous efficiency

Providing effective controls that prevent lights being left on unnecessarily.

1.3.5 REDUCING ENERGY USED FOR HEATING WATER

This can be achieved by:

Installing time controls, and setting them to correctly reflect the hours of hot water

requirement

Setting sanitary hot water thermostats to the appropriate temperature no more than 60C

for normal requirements (but ensure the water does not drop below 56C)

Switching off electric heating elements (immersion) when hot water from the boiler is

available

Switching off any associated pumps when hot water is not required

Replacing any damaged or missing insulation from all hot water pipe work and cylinders,

except where the pipes are providing useful heat into the space

Identifying a suitable hot water system.

The most significant reduction in energy use for hot water can be achieved by providing

solar water heating.

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RENEWABLE ENERGYSYSTEMS INBUILDINGS1.3.6 REDUCING CONSUMPTION OF OFFICE EQUIPMENT AND APPLIANCES

Most businesses rely on a range of office equipment in order to function. From the basic

essentials such as computers, monitors, printers, fax machines and photocopiers to projectors,

scanners and teleconference facilities, it is widely recognized that these items have become

integral to daily activity. Office equipment is the fastest growing energy user in the business

world, consuming 15 per cent of the total electricity is used in offices. This is expected to rise to

30 per cent by 2020. There are also associated costs that are often overlooked, specifically those

of increasing cooling requirements to overcome the additional heat this equipment produces. As

ventilation and air conditioning are major energy consumers themselves, it makes good business

sense to ensure they are only used when absolutely necessary. Typical measures to reduce

consumption which also apply to household appliances

are:

Switching off switching off or enabling power down mode reduces the energy

consumption and heat produced by equipment, which in turn lowers cooling costs

Upgrading existing equipment some energy efficient appliances may cost more to buy

but will recoup savings over the lifetime of the equipment

Matching the equipment to the task bearing in mind current and predicted requirements

and purchase equipment that meet these

Taking advantage of energy labeling schemes some well know energy labeling

schemes are Energy Star, European Ecolabel Scheme, Energy Saving Recommended and

the Market Transformation Program.

1.3.7 GOOD HOUSEKEEPING AND PEOPLE SOLUTIONS

The level of achievable energy savings from office equipment is down to the everyday

management by staff. A simple energy conservation program for an organization

would consider:

Setting up an energy policy for the organization

Appointing an energy champion

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RENEWABLE ENERGYSYSTEMS INBUILDINGS Involving staff

Setting targets

Using notices and reminders

Conducting walk-rounds

Taking meter readings

CHAPTER 2

BUILDING AUTOMATION SYSTEM

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RENEWABLE ENERGYSYSTEMS INBUILDINGSBuilding automation describes the advanced functionality provided by the control system

of a building. A building automation system (BAS) is an example of a distributed control system.

The control system is a computerized, intelligent network of electronic devices designed to

monitor and control the mechanical, electronics, and lighting systems in a building.

BAS core functionality keeps the building climate within a specified range, provides lighting

based on an occupancy schedule, and monitors system performance and device failures and

provides email and/or text notifications to building engineering/maintenance staff. The BAS

functionality reduces building energy and maintenance costs when compared to a non-controlled

building. A building controlled by a BAS is often referred to as an intelligent building or a smart

home.

Most building automation networks consist of a primary and secondary bus which

connect high-level controllers with lower-level controllers, input/output devices and a user

interface. The primary and secondary bus can be BAC net, optical fiber, ethernet, ARCNET, RS-

232, RS-485 or a wireless network. Most controllers are proprietary. Each company has its own

controllers for specific applications. Some are designed with limited controls. Inputs and outputs

are either analog or digital. Analog inputs are used to read a variable measurement. Examples are

temperature, humidity and pressure sensor which could be thermistor, 4-20 mA, 0-10 volt or

platinum resistance thermometer (resistance temperature detector), or wireless sensors. A digital

input indicates if a device is turned on or not. Some examples of a digital input would be a

24VDC/AC signal, an air flow switch, or a Volta-free relay contact (Dry Contact).Analog

outputs control the speed or position of a device, such as a variable frequency drive, a I-P

(current to pneumatics) transducer, or a valve or damper actuator. An example is a hot water

valve opening up 25% to maintain a set point. Digital outputs are used to open and close relays

and switches. An example would be to turn on the parking lot lights when a photocell indicates it

is dark outside. The Fig 3.1 shows a BMS system.

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RENEWABLE ENERGYSYSTEMS INBUILDINGS

Fig 2.1: Building Automation System

2.1 CONTROLLER

Controllers are essentially small, purpose-built computers with input and output

capabilities. These controllers come in a range of sizes and capabilities to control devices

commonly found in buildings, and to control sub-networks of controllers. Inputs allow a

controller to read temperatures, humidity, pressure, current flow, air flow, and other essential

factors. The outputs allow the controller to send command and control signals to slave devices,

and to other parts of the system. Inputs and outputs can be either digital or analog. Digital

outputs are also sometimes called discrete depending on manufacturer. Controllers used forbuilding automation can be grouped in 3 categories. Programmable Logic Controllers (PLCs),

System/Network controllers, and Terminal Unit controllers. However an additional device can

also exist in order to integrate 3rd party systems (i.e. a stand-alone AC system) into a central

Building automation system).PLC's provide the most responsiveness and processing power, but

at a unit cost typically 2 to 3 times that of a System/Network controller intended for BAS

applications. Terminal Unit controllers are usually the least expensive and least powerful. PLC's

may be used to automate high-end applications such as clean rooms or hospitals where the cost

of the controllers is less of a concern. In office buildings, supermarkets, malls, and other

common automated buildings the systems will use System/Network controllers rather than

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RENEWABLE ENERGYSYSTEMS INBUILDINGSPLC's. Most System controllers provide general purpose feedback loops, as well as digital

circuits, but lack the millisecond response time that PLC's provide. System/Network controllers

may be applied to control one or more mechanical systems such as an Air Handler Unit (AHU),

boiler, chiller, etc., or they may supervise a sub-network of controllers. In the diagram above,

System/Network controllers are often used in place of PLCs. Terminal Unit controllers usually

are suited for control of lighting and/or simpler devices such as a package rooftop unit, heat

pump, VAV box, or fan coil, etc. The installer typically selects 1 of the available pre-

programmed personalities best suited to the device to be controlled, and does not have to create

new controllogic.

2.2 OCCUPANCY

Occupancy is one of two or more operating modes for a building automation system.

Unoccupied, Morning Warm-up, and Night-time Setback are other common modes. Occupancy

is usually based on time of day schedules. In Occupancy mode, the BAS aims to provides a

comfortable climate and adequate lighting, often with zone-based control so that users on one

side of a building have a different thermostat (or a different system, or sub system) than users on

the opposite side. A temperature sensor in the zone provides feedback to the controller, so it can

deliver heating or cooling as needed. If enabled, Morning Warm-up (MWU) mode occurs prior

to Occupancy. During Morning Warm-up the BAS tries to bring the building to set point just in

time for Occupancy. The BAS often factors in outdoor conditions and historical experience to

optimize MWU. This is also referred to as Optimized Start. An override is a manually initiated

command to the BAS. For example, many wall-mounted temperature sensors will have a push-

button that forces the system into Occupancy mode for a set number of minutes. Where present,

web interfaces allow users to remotely initiate an override on the BAS. Some buildings rely on

occupancy sensors to activate lighting and/or climate conditioning. Given the potential for long

lead times before a space becomes sufficiently cool or warm, climate conditioning is not often

initiated directly by an occupancy sensor.

2.3 LIGHTING

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RENEWABLE ENERGYSYSTEMS INBUILDINGSLighting can be turned on, off, or dimmed with a building automation or lighting control

system based on time of day, or on occupancy sensor, photo sensors and timers. One typical

example is to turn the lights in a space on for a half hour since the last motion was sensed. A

photocell placed outside a building can sense darkness, and the time of day, and modulate lights

in outer offices and the parking lot. Lighting is also a good candidate for Demand response, with

many control systems providing the ability to dim (or turn off) lights to take advantage of DR

incentives and savings.

2.4 AIR HANDLERS

Most air handlers mix return and outside air so less temperature change is needed. This

can save money by using less chilled or heated water (not all AHUs use chilled/hot water

circuits). Some external air is needed to keep the building's air healthy. Analog or digital

temperature sensors may be placed in the space or room, the return and supply air ducts, and

sometimes the external air. Actuators are placed on the hot and chilled water valves, the outside

air and return air dampers. The supply fan (and return if applicable) is started and stopped based

on either time of day, temperatures, building pressures or a combination.

2.5 CENTRAL PLANT

A central plant is needed to supply the air-handling units with water. It may supply a

chilled water system, hot water system and acondenser water system, as well as transformers

and auxiliary power unit for emergency power. If well managed, these can often help each other.

2.5.1 CHILLED WATER SYSTEM

Chilled water is often used to cool a building's air and equipment. The chilled water

system will have chiller and pumps. Analog temperature sensors measure the chilled water

supply and return lines. The chiller are sequenced on and off to chill the chilled water supply. A

chiller is a refrigeration unit designed to produce cool (chilled) water for space cooling purposes.

The chilled water is then circulated to one or more cooling coils located in air handling units,

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RENEWABLE ENERGYSYSTEMS INBUILDINGSfan-coils, or induction units. Chilled water distribution is not constrained by the 100 foot

separation limit that applies to DX systems, thus chilled water-based cooling systems are

typically used in larger buildings. Capacity control in a chilled water system is usually achieved

through modulation of water flow through the coils thus, multiple coils may be served from a

single chiller without compromising control of any individual unit. Chillers may operate on

either the vapor compression principle or the absorption principle. Vapor compression chillers

may utilize reciprocating, centrifugal, screw, or rotary compressor configurations. Reciprocating

chillers are commonly used for capacities below 200 tons centrifugal chillers are normally used

to provide higher capacities rotary and screw chillers are less commonly used, but are not rare.

Heat rejection from a chiller may be by way of an air-cooled condenser or a cooling tower (both

discussed below). Vapor compression chillers may be bundled with an air-cooled condenser to

provide a packaged chiller, which would be installed outside of the building envelope. Vapor

compression chillers may also be designed to be installed separate from the condensing unit

normally such a chiller would be installed in an enclosed central plant space. Absorption chillers

are designed to be installed separate from the condensing unit.

2.5.2 CONDENSER WATER SYSTEM

Cooling towers and pumps are used to supply cool condenser water to the chillers.

Because the condenser water supply to the chillers has to be constant, variable speed drives arecommonly used on the cooling tower fans to control temperature. Proper cooling tower

temperature assures the proper refrigerant head pressure in the chiller. The cooling tower set

point used depends upon the refrigerant being used. Analog temperature sensors measure the

condenser water supply and return lines.

2.5.3 HOT WATER SYSTEM

The hot water system supplies heat to the building's air-handling unit or VAV box

heating coils, along with the domestic hot water heating coils (Calorifier). The hot water system

will have aboiler(s) and pumps. Analog temperature sensors are placed in the hot water supply

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RENEWABLE ENERGYSYSTEMS INBUILDINGSand return lines. Some type of mixing valve is usually used to control the heating water loop

temperature. The boiler(s) and pumps are sequenced on and off to maintain supply.

2.6 ALARMS AND SECURITY

Many building automation systems have alarm capabilities. If an alarm is detected, it can

be programmed to notify someone. Notification can be through a computer,pager, cellular phone

or audible alarm.

CHAPTER 3

RENEWABLE TECHNOLOGIES AND ENERGY EFFICIENCY IN BUILDINGS

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RENEWABLE ENERGYSYSTEMS INBUILDINGSThere is an extremely important connect between renewable energy technologies and

energy efficiency. Technologies like solar PVs are extremely expensive to install, especially

when used along with a battery bank. If a conventional building is to be run using solar PVs the

cost of installation and size of the entire system increases substantially.

This is so because the energy demands of a conventional building are high as compared

to an energy efficient building. Once a building and its systems are optimized for high energy

efficiency its overall energy requirements reduce by up to 50 %. This helps in downsizing the

solar PV system there by reducing the installation costs of the panels as well as the size of the

battery banks. In case of grid connection, excess electricity generated from the solar panels in a

building can be sold to the grid. Excess electricity production can be achieved only once the

building is designed to be energy efficient.

Utilizing low flow fixtures in the building reduces the amount of water required by the

building occupants by almost 40 %. Thus the sizes of solar water heater panels and storage tanks,

required for meeting the hot water requirements of the building, can be effectively reduced as

water consumption levels are brought down. This brings down the capital investment required

for solar water heater as well.

3.1. PASSIVE INTERVENTIONS

Passive interventions refer to measures in building design which respond to sun path,

Solar access and local wind movement. Solar and Wind energy can be harnessed by adopting

various passive features which determine the design of the building. These can further be

supplemented by various active systems. There are various ways in which a building can be

designed to harness the solar energy available at a given location. Building orientation plays an

important role in reducing the energy consumption. Since almost 90 % of the regions in India

face extensive heat, buildings should be designed keeping the longer facades facing north and

south. It is extremely simple to cut off direct solar radiation on the northern and southern

facades. The area of glazing on the facades also determines the heat gain in a building. The

greater the glass surface area on the facades ,the higher is the heat gain. This principle can be

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RENEWABLE ENERGYSYSTEMS INBUILDINGSused in cold climates in order to capitalize on solar radiation to reduce artificial heating demands.

In colder regions, glazing are should be increased to allow for natural heat gain. In warm areas,

the glass area need to be reduced and shaded to avoid excessive heat gains. Buildings can be

designed to allow for maximum penetration of daylight while simultaneously cutting off direct

solar radiation and glare. Natural light can prevent use of artificial lights during the day in

buildings. Different spaces in a building can be designed to benefit from suns energy. In cold

regions, additional spaces called Solariums are added next to main living/ working areas of a

building. Solariums capture the suns heat and heat up the air is then circulated in the living /

working areas to avoid the use of electric heaters,

Building envelopes can be constructed using material compositions which have high

thermal mass. All building surfaces absorb the heat of the sun during the day which permeates

inside the building thereby heating the indoor spaces during the day which leads to

uncomfortable ambient conditions. Buildings where building surfaces are constructed using

materials with high thermal mass have much more comfortable indoor conditions as these

materials prevent the heat absorbed from reaching the interior spaces during the day. During

night when the outdoor temperatures drop, this stored heat in such materials is released into the

living areas making them comfortable.

Natural wind movement can also be harnessed in building design. Natural ventilation

provides fresh air to building occupants removes internal heat gains and makes the spaces

comfortable. Opening on facades can be designed keeping in mind the natural wind flow patterns

for the given area. Besides these, natural wind movement can be harnessed by the use of wind

towers which can be used to channel wind inside the building into various areas. Commonly in

such wind towers, the air is passed over/ mixed with water droplet which reduces the

temperatures of the air and cools it there by eliminating the need of air-conditioning systems.

These are called Passive Down-draft Evaporative Cooling Systems.

3.2. SOLAR PHOTO VOLTAIC SYSTEMS

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RENEWABLE ENERGYSYSTEMS INBUILDINGSSolar PVs systems allow for building users to generate a certain portion of their daily

electricity requirements which can be stored for later use as well. Solar PV systems can be grid

interactive in which case they supply the excess electricity generated back to the grid. Solar PVs

can be used to generate electricity for day-use only or for night-use as well in which case the

excess electricity generated during the day is stored in battery banks for use at night. Solar PV

systems can be of two types:

Building Mounted

Building Integrated

Building mounted solar PV refers to solar panels which are mounted on different building

components like roof, porches etc. Mounting the solar panels on rooftops is the most commonstrategy adopted as it allows for maximum solar access, efficiency and output. In India, Solar

panels should be mounted facing south at an angle which is equal to the latitude of the place for

maximum efficiency and solar access. Grid interactive systems consist of the solar panels, DC-

AC converter, various structural and electrical components and meters. Systems with battery

backup include an additional battery storage system, charge controllers and sub panel besides the

other components. The Fig 3.1 shows a Building mounted solar PV

Fig 3.1 :Building mounted solar PV

Building Integrated PV systems refer to use of glazing systems with solar PVs

incorporated in them. Building Integrated PV can be used in roof skylights as well as faade

glazing systems. In India Building Integrated PV can be used on southern facades and skylights

facing south for maximum output and efficiency. If you are doing new construction or a

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RENEWABLE ENERGYSYSTEMS INBUILDINGSreroofing job, it is possible to make the roof itself a solar PV collector. This saves the cost of the

roof itself, and offers a more aesthetic design. The new roof can be shingled or look like metal

roofing. An example is shown below in Fig 3.2

Fig 3.2 Building Integrated solar PV

3.3. SOLAR WATER HEATERS

There is a huge potential for Solar Water Heaters in India. They should be placed on

rooftops in a completely shadow free area. There are two types of SWH available:

1. Flate Plate Collector.

2. Evacuated Tube Collector

Flat Plate SWH systems comprise of a metallic box which contains the absorber sheet

with in laid water channels carrying water which gets hot by absorbing the heat from the

absorber sheet.Evacuated Tube SWH consists of dual-layered glass tubes with vacuum in

between them. The outer layer of the tubes is covered with an absorbent material which absorbs

the heat from sun rays and transfer it to the water.

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RENEWABLE ENERGYSYSTEMS INBUILDINGSEvacuated Tube Collector systems have a shorter life than Flat Plate Collector and are

relatively cheaper than Flat Plate Collector systems as well. Average life of a Flat Plate

Collector systems is usually 15-20 years. Evacuated Tube Collector systems are more reliable

for colder regions. The Fig 3.3 shows a Solar Water Heater

Fig 3.3: Solar Water Heater

3.4. PRECAUTIONS FOR SOLAR PV AND THERMAL SYSTEMS

While mounting the PVs or water heaters on rooftops, care should be taken to re-seal the

waterproofing layers of the roof.

The materials being used for the systems should be able to withstand the high

temperatures and sunlight resistant.

The PV panels should be installed in a shadow free area which has abundant direct

sunlight from 9:00 am to 4:00 pm.

Water pipes in case of Solar Water Heater should be properly insulated.

3.5. WIND MILLS

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RENEWABLE ENERGYSYSTEMS INBUILDINGSUtility of windmills exists only in places which have substantial, unobstructed wind flow

round the year. Urban areas offer a lot of disruption and resistance to wind flow. Hence, there

are very few urban areas where small scale windmills can be used for electricity generation.

There are few manufacturers which have begun to manufacture small-scale windmills for the

purpose of generation of electricity in areas which have unobstructed and plentiful wind flow all

year round. However, due to reasons mentioned above, their use in individual building units has

not been extremely beneficial yet.

CHAPTER 4

NATIONAL RATING SYSTEM

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RENEWABLE ENERGYSYSTEMS INBUILDINGSGreen Rating For Integrated Habitat Assessment (GRIHA) has been adopted by Ministry of

New and Renewable Energy (MNRE), Government of India as the National Green Rating

System for Green Buildings in India. GRIHA has been developed by TERI (The Energy and

Resources Institute) as a rating tools, which evaluates a building on 34 different criteria and

rates the greenness of a building on a scale of 1-100 points. A building has to achieve a

minimum of 50 points for it to be certified Green. The buildings are given star rating from 1-5

with 5 stars being the highest rating. GRIHA has various criteria dedicated to incorporation of

renewable energy systems in the buildings. The criteria on outdoor lightning lays stress on use

of renewable sources of energy for powering the outdoor lights on site. GRIHA has also made

mandatory that 1 % of the total connected load of internal lighting and HVAC systems should

be met by renewable sources of energy. Beyond that a building scores more points if it meets

more of its internal lighting loads through the use of renewable energy systems. In case of hot

water supply, the criterion has allotted points to a building for meeting its supply of hot water

through renewable energy systems. A minimum of 20% of annual hot water demand has to be

met through renewable energy systems to qualify for a point under this criterion.

In order to support and promote renewable technology systems in buildings, MNRE, Gol

has launched various schemes for promotion of solar PVs and Solar Water Heaters. The

Ministry has offered various incentives and financial benefits towards incorporation of Solar

PVs and Solar Water Heaters in buildings. This is expected to provide impetus and create more

awareness and acceptance of these systems within the buildings sector.

CHAPTER 5

EXAMPLES OF RENEWABLE ENERGY UTILISATION IN BUILDINGS IN INDIA

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RENEWABLE ENERGYSYSTEMS INBUILDINGSTorrent research centre Ahmadabad shown in Fig 5.1 is a complex consisting of

research laboratories which require cleanest possible indoor air conditions. The buildings uses

PDEC systems (Passive Down-draft Evaporative Cooling) to provide treated fresh air to the

indoors. In PDEC systems wind towers capture outside wind and guides it through a spray of

water which cools the air naturally through evaporation and then channels this cool air indoors

eliminating the need for mechanical air-conditioning. Filters are used to purify air. The indoor

conditions have been monitored for a couple years and result show that they are quite

comfortable for building users.

Fig 5.1 :Torrent research centre Ahmadabad

Rabirashmi Abasam shown in Fig 5.2 is Indias First Solar Housing complex which has

come up in the New Town area of Kolkatta, West Bengal. The project is supported by the West

Bengal Renewable Energy Development Agency (WBREDA) with support from Ministry Of

New and Renewable Energy (MNRE), Government of India. Besides the various features like

sustainable site planning, energy and water efficiency etc. Renewable energy system has been

incorporated in a big way. All outdoor lights are powered by solar PVs. Each house has been

provided with Evacuated tube type Solar Water Heaters of 130 lpd (Liters per day) capacity.

The rooftop of each house has been fitted with solar PV panels which generates about 2 KW of

power. Each house has been provided with battery backup of 3 KW of power for use during the

evening. When the demand of electricity rises, the power will automatically switch over to a

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RENEWABLE ENERGYSYSTEMS INBUILDINGSconventional grid. In order to reduce loads and to run maximum appliances and fixtures on solar

PVs ,the houses have been asked to opt for LED and CFL lamps along with high efficiency

appliances. The complex uses net metering which means that excess electricity generated by the

solar PVs will be supplied back to the main power grid.

Fig 5.2 :Rabirashmi Abasam

Mangarpatta city shown in Fig 5.3 is a development coming up on the outskirts of pune.

It comprises of almost 10,000 dwelling units spread over 550 acres. Each residential dwelling in

the city has an Evacuated Tube Solar Water Heater installed for its use. This is expected to help

save almost 1.45 crore units in a year as well as 13483 tones of carbon dioxide and Rs.3.9

crores every year in savings from power .This city has won a place in the LIMCA Book of

Records for the biggest residential solar water heating system in India. Besides the SWH

systems, the city also incorporates features like rainwater harvesting systems, garbage

segregation, a Biogas plant, Vermiculture and utilization of fly ash.

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Fig 5.3: Mangarpatta city

The CESE building at IIT KANPURshown in Fig 5.4 is the first 5 star TERI-GRIHA

rated building in India. It has various features like sustainable site planning incorporation of

energy efficient and waste efficient measures, waste management and health and well-being of

building users. The building has also incorporated solar PV panels in the building generated

power equivalent to the over 30% of the total internal lighting load. Outdoor lighting systems

have been powered by solar PVs as well. The SWH systems cater to more than 70% of the

buildings annual hot water requirements.

Fig 5.4 :CESE building at IIT KANPUR

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RENEWABLE ENERGYSYSTEMS INBUILDINGSCONCLUSION

Building sector in the country is in the middle of tremendous growth due to massive

urban population influx into the metropolitan cities. In order to meet the requirements of these

cities while simultaneously reducing the dependence on conventional fuels, renewable sources

of energy need to be adopted at a large scale. The renewable energy systems offer clean energy,

free of GHG emissions and can be adopted at various scales in buildings. There are passive

features which can be incorporated in building design as well as active systems like Solar Photo

Voltaic panels to generate electricity. There are various examples of buildings in India where

such systems have been effectively adopted. A higher promotion of such systems by creating

more awareness about their benefits and advantages will help in increasing their adoption. This

will eventually help in contributing towards establishing a cleaner, more sustainable and

environmentally friendly habitat.

REFERENCES

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[1] Apoorva. Vij, Renewable Energy Systems in Buildings in India, Electrical India journal,

Page 76 , January 2010.

[2] Pranjal Dutta, Building Efficiency, Electrical India journal, Page78, November 2011.

[3] Shruthi Goel & Prem C Jain, Innovations in Building Design For Energy Conservation,

Electrical India journal , Page 52,December 2009.

[4]www.wikkipedia.com

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http://www.wikkipedia.com/http://www.wikkipedia.com/

renewable energy systems in buildings pdf.doc

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