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PrePrePrePre Heaters for Heaters for Heaters for Heaters for Boiler Boiler Boiler Boiler ,,,, Thermic Fluid Heater orThermic Fluid Heater orThermic Fluid Heater orThermic Fluid Heater or Hot Air Hot Air Hot Air Hot Air GeneratorsGeneratorsGeneratorsGenerators

SSSSave ave ave ave upupupup to 20to 20to 20to 20----25 % of 25 % of 25 % of 25 % of Fuel Fuel Fuel Fuel Energy Cost Energy Cost Energy Cost Energy Cost . . . .

InstallInstallInstallInstall Solar Solar Solar Solar Water HeatWater HeatWater HeatWater Heateeeersrsrsrs to preheat , Wato preheat , Wato preheat , Wato preheat , Water or Air or ter or Air or ter or Air or ter or Air or Thermic Fluid OilThermic Fluid OilThermic Fluid OilThermic Fluid Oil ....

Solar water heatingSolar water heatingSolar water heatingSolar water heating (SWH) or solar hot watersolar hot watersolar hot watersolar hot water (SHW) systems comprise several innovations and many mature renewable energy technologies that have been well established for many years. SWH has been widely used in Australia, Austria, China, Cyprus, Greece, India, Israel, Japan, Spain and Turkey.

In a "close-coupled" SWH system the storage tank is horizontally mounted immediately above the solar collectors on the roof. No pumping is required as the hot water naturally rises into the tank through thermo siphon flow. In a "pump-circulated" system the storage tank is ground- or floor-mounted and is below the level of the collectors; a circulating pump moves water or heat transfer fluid between the tank and the collectors.

SWH systems are designed to deliver hot water for most of the year. However, in winter there sometimes may not be sufficient solar heat gain to deliver sufficient hot water. In this case a gas or electric booster is used to heat the water.

Overview

Water heated by the sun is used in many ways. While perhaps best known in a residential setting to provide domestic hot water, solar hot water also has industrial applications, e.g. to generate electricity.[1] Designs suitable for hot climates can be much simpler and cheaper, and can be considered an appropriate technology for these places. The global solar thermal market is dominated by China, Europe, Japan and India.

India is densely populated and has high solar insulation, an ideal combination for using solar power in Indiasolar power in Indiasolar power in Indiasolar power in India.. In the solar energy sector, some large projects have

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been proposed, and a 35,000 km2 (14,000 sq mi) area of the Thar Desert has been set aside for solar power projects, sufficient to generate 700 to 2,100 GW. Also India's Ministry of New and Renewable Energy has released the JNNSM Phase 2 Draft Policy, by which the Government aims to install 10 GW of Solar Power and of this 10 GW target, 4 GW would fall under the central scheme and the remaining 6 GW under various State specific schemes.

In July 2009, India unveiled a US$19 billion plan to produce 20 GW of solar power by 2020.[2] Under the plan, the use of solar-powered equipment and applications would be made compulsory in all government buildings, as well as hospitals and hotels. On 18 November 2009, it was reported that India was ready to launch its National Solar Mission under the National Action Plan on Climate Change, with plans to generate 1,000 MW of power by 2013.[4] From August 2011 to July 2012, India went from 2.5 MW of grid connected photovoltaic’s to over 1,000 MW.

According to a 2011 report by BRIDGE TO INDIA and GTM Research, India is facing a perfect storm of factors that will drive solar photovoltaic (PV) adoption at a "furious pace over the next five years and beyond". The falling prices of PV panels, mostly from China but also from the U.S., has coincided with the growing cost of grid power in India. Government support and ample solar resources have also helped to increase solar adoption, but perhaps the biggest factor has been need. India, "as a growing economy with a surging middle class, is now facing a severe electricity deficit that often runs between 10% and 13% of daily need".[5] India is planning to install the World's largest Solar Power Plant with 4,000 MW Capacity near Sambhar Lake in Rajasthan.

On 16 May 2011, India’s first 5 MW of installed capacity solar power project was registered under the Clean Development Mechanism. The project is in Sivagangai Village, Sivaganga district, Tamil Nadu.

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Installed capacitInstalled capacitInstalled capacitInstalled capacityyyy

The amount of solar energy produced in India in 2007 was less than 1% of the total energy demand. The grid-connected solar power as of December 2010 was merely 10 MW.[13] Government-funded solar energy in India only accounted for approximately 6.4 MW-yr of power as of 2005. However, India is ranked number one in terms of solar energy production per watt installed, with an insolation of 1,700 to 1,900 kilowatt hours per kilowatt peak (kWh/KWp). 25.1 MW was added in 2010 and 468.3 MW in 2011. By January 2014 the installed grid connected solar power had increased to 2,208.36 MW, and India expects to install an additional 10,000 MW by 2017, and a total of 20,000 MW by 2022.

State MWp % Ref

Andhra Pradesh 41.75 3.18 [54]

Chhattisgarh 4.0 0.30 Delhi 2.5 0.19

Gujarat 654.8 49.90

Haryana 7.8 0.59

Jharkhand 4.0 0.30 Karnataka 9.0 0.69

Madhya Pradesh 2.0 0.15

Maharashtra 20.0 1.52

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State MWp % Ref

Orissa 13.0 0.99

Punjab 9.0 0.69

Rajasthan 510.25 38.89 [55]

Tamil Nadu 15.0 1.14

Uttar Pradesh 12.0 0.91

Uttarakhand 5.0 0.38

West Bengal 2.0 0.15 Total 1312.10 100 [17][56

Challenges and opportunities

Land is a scarce resource in India and per capita land availability is low. Dedication of land area for exclusive installation of solar arrays might have to compete with other necessities that require land. The amount of land required for utility-scale solar power plants — currently approximately 1 km2 (250 acres) for every 20–60 MW generated— could pose a strain on India's available land resource. The architecture more suitable for most of India would be a highly distributed set of individual rooftop power generation systems, all connected via a local grid.[12] However, erecting such an infrastructure, which does not enjoy the economies of scale possible in mass, utility-scale, solar panel deployment, needs the market price of solar technology deployment to substantially decline, so that it attracts the individual and average family size household consumer. That might be possible in the future, because PV is projected to continue its current cost reductions for the next decades and be able to compete with fossil fuel.[8] Government can provide subsidies for the production of PV panels, in which there will be reduction in the market price and this can lead to more usage of solar power in India. In the past three years, solar-generation costs here have dropped from around ₹18 (31¢ US) a kWh to about ₹7 (12¢ US) a kWh, whereas power from imported coal and domestically-produced natural gas currently costs around ₹4.5 (7.7¢ US) a kWh and it is increasing with time. Experts believe that ultra mega solar power plants like the

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upcoming world’s largest 4,000 MW UMPP in Rajasthan, would be able to produce power for around ₹5 (8.5¢ US) a kWh.

Some noted think-tanks recommend that India should adopt a policy of developing solar power as a dominant component of the renewable energy mix, since being a ensely populated region in the sunny tropical belt, the subcontinent has the ideal combination of both high solar insolation and therefore a big potential consumer base density. In one of the analysed scenarios, India can make renewable resources such as solar the backbone of its economy by 2050, reining in its long-term carbon emissions without compromising its economic growth potential.

Types of solar water heating systemsTypes of solar water heating systemsTypes of solar water heating systemsTypes of solar water heating systems

Direct and indirect systems

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Passive and active systemsPassive and active systemsPassive and active systemsPassive and active systems

PassivePassivePassivePassive systems rely on heat-driven convection or heat pipes to circulate water or heating fluid in the system. Passive solar water heating systems cost less and have extremely low or no maintenance, but the efficiency of a passive system is significantly lower than that of an active system. Overheating and freezing are major concerns.

ActiveActiveActiveActive systems use one or more pumps to circulate water and/or heating fluid in the system.

Though slightly more expensive, active systems offer several advantages:

• The storage tank can be situated lower than the collectors, allowing increased freedom in system design and allowing pre-existing storage tanks to be used.

• The storage tank can always be hidden from view.

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• The storage tank can be placed in conditioned or semi-conditioned space, reducing heat loss.

• Drain back tanks can be used.

• Superior efficiency.

• Increased control over the system.

Modern active solar water systems have electronic controllers that offer a wide range of functionality, such as the modification of settings that control the system, interaction with a backup electric or gas-driven water heater, calculation and logging of the energy saved by a SWH system, safety functions, remote access, and informative displays, such as temperature readings.

Passive direct systemsPassive direct systemsPassive direct systemsPassive direct systems

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An integrated collector storageintegrated collector storageintegrated collector storageintegrated collector storage (ICS or Batch Heater) system uses a tank that acts as both storage and solar collector. Batch heaters are basically thin rectilinear tanks with a glass side facing the position of the sun at noon. They are simple and less costly than plate and tube collectors, but they sometimes require extra bracing if installed on a roof (since they are heavy when filled with water [400–700 lbs],) suffer from significant heat loss at night since the side facing the sun is largely uninsulated, and are only suitable in moderate climates.

A convection heat storage unitconvection heat storage unitconvection heat storage unitconvection heat storage unit (CHS) system is similar to an ICS system, except the storage tank and collector are physically separated and transfer between the two is driven by convection. CHS systems typically use standard flat-plate type or evacuated tube collectors, and the storage tank must be located above the collectors for convection to work properly. The main benefit of a CHS systems over an ICS system is that heat loss is largely avoided since (1) the storage tank can be better insulated, and (2) since the panels are located below the storage tank, heat loss in the panels will not cause convection, as the cold water will prefer to stay at the lowest part of the system.

A rough comparison of solar hot water systems Comparison of SWH systemsComparison of SWH systemsComparison of SWH systemsComparison of SWH systems[21]

CharacteristicCharacteristicCharacteristicCharacteristic ICS ICS ICS ICS (Batch)(Batch)(Batch)(Batch)

ThermosiphonThermosiphonThermosiphonThermosiphon Active Active Active Active directdirectdirectdirect

Active Active Active Active indirectindirectindirectindirect

DrainbackDrainbackDrainbackDrainback Bubble Bubble Bubble Bubble PumpPumpPumpPump

Low profileLow profileLow profileLow profile----unobtrusiveunobtrusiveunobtrusiveunobtrusive

Lightweight Lightweight Lightweight Lightweight collectorcollectorcollectorcollector

Survives freezing Survives freezing Survives freezing Survives freezing weatherweatherweatherweather

Low maintenanLow maintenanLow maintenanLow maintenancececece

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Simple: no Simple: no Simple: no Simple: no ancillary controlancillary controlancillary controlancillary control

Retrofit potential to Retrofit potential to Retrofit potential to Retrofit potential to existing storeexisting storeexisting storeexisting store

Space saving: no Space saving: no Space saving: no Space saving: no extra storage tankextra storage tankextra storage tankextra storage tank

Applications

Broad Spectrum of Industrial SectorsBroad Spectrum of Industrial SectorsBroad Spectrum of Industrial SectorsBroad Spectrum of Industrial Sectors Industrial SectorIndustrial SectorIndustrial SectorIndustrial Sector ProcessProcessProcessProcess Temperature ( deg C )Temperature ( deg C )Temperature ( deg C )Temperature ( deg C )

Adhesive Tape IndustryAdhesive Tape IndustryAdhesive Tape IndustryAdhesive Tape Industry

Drying and Curing

80-180

Flexible PackagingFlexible PackagingFlexible PackagingFlexible Packaging

Drying 70-150

Rubber IndustryRubber IndustryRubber IndustryRubber Industry

Curing/ vulcanising

70-150

Paper IndustryPaper IndustryPaper IndustryPaper Industry

Drying / Bleaching

70-180

Plastic IndustryPlastic IndustryPlastic IndustryPlastic Industry

Extrusion and drying

150-180

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0

Invest OnceInvest OnceInvest OnceInvest Once And And And And get Heat energy for free life timeget Heat energy for free life timeget Heat energy for free life timeget Heat energy for free life time With in a Maximum period of 4.5 years For life time .

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Solar Energy Solar Energy Solar Energy Solar Energy for for for for IndiaIndiaIndiaIndia A Gift by the almightyA Gift by the almightyA Gift by the almightyA Gift by the almighty

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The calculation of long term cost and payback period for a household SWH system depends on a number of factors. Some of these are:

• Price of purchasing solar water heater (more complex systems are more expensive)

• Efficiency of SWH system purchased

• Installation cost

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• Price of electricity use for mains pumping (if this is used)

• Price of water heating fuel (e.g. gas or electricity) saved per kW.h

• Amount of water heating fuel used per month by a household

• Upfront state or government subsidy for installation of a solar water heater

• Recurrent or annual tax rebates or subsidy for operating renewable energy

• Annual maintenance cost of SWH system (e.g. antifreeze or pump replacements)

• Savings in annual maintenance of conventional (electric/gas/oil) water heating system

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The following table gives some idea of the cost and payback period to recover the costs. It does not take into account annual maintenance costs, annual tax rebates and installation costs. However, the table does give an indication of the total cost and the order of magnitude of the payback period. The table assumes an energy savings of 200 kW.h per month (about 6.57 kW.h/day) due to SWH. Unfortunately payback times can vary greatly due to regional sun, extra cost due to frost protection needs of collectors, household hot water use etc. so more information may be needed to get accurate estimates for individual households and regions. For instance in central and southern Florida the payback period could easily be 7 years or less rather than the 12.6 years indicated on the chart for the US

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