Solar Water Heating systems

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

Min number of operating days in Andhra Pradesh 340 days per year.

Solar thermal collectors capture and retain heat from the sun and use it to heat a liquid.

Two important types of technologies of solar thermal collectors:

  • Flat Plate Collector Based Systems
  • Evacuated-tube solar collectors
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Evacuated tube collector

Main characteristics of the evacuated tube collector should be :

  • Capability to endure environmental conditions (rain, dust, etc. and in some cases marine environment)
  • Capable of enduring large variations in temperature
  • Resistance to leakage from any part of the system
  • Stable and durable
  • Easy to install
  • Efficient in energy conversion

Flat Plate Collector based Solar water heating Systems

Flat plate collector collects solar radiation and converts solar energy intoheat energy for heating water. Flat plate collector should be reliable, durable with a useful lifeof 15 years or more.

Main characteristics of this collector should be

  • Resistance to environmental conditions (marine environment, rain, dust, hail etc.)
  • Resistance to large variations in temperature
  • Resistance to leakage from any part of the system
  • Stable and durable
  • Easy to install
  • Efficient in energy conversion
Selection of Right technology
Application Technology
Low temperature application from 40ºCup to 80ºC FPC / ETC
Low temperature commercial application (swimming pool) FPC / ETC
Medium temperature application from 80ºCto 120ºC Heat pipe ETC
High temperature application from 120ºC to 250ºC    Solar concentrator
Who can use these systems? - applciation areas

Household/domestic sector

  • In the residential sector, there are 0.7 million SWH user households;.
  • The use of SWH-water is mainly for bathing.
  • The customers perceive it as a product suited for independent houses and not so much for apartment buildings.

In Hotel Sector

  • In the hotel sector, SWH provisioning recognizes year-round demand for hot water.
  • The use of expensive petroleum fuels and electricity support the case for SWH.
  • Roof availability, for 15 room upward capacity hotels, is not a significant barrier.

In Industries

  • The SWH experience among industries is limited and scattered.
  • Heating of boiler feed water is the major application.
  • Some of the candidate industries –rice-mills, pulp and paper, tea-gardens, leather, textile processing-utilize biomass and coal;
  • Other Industries utilizing oil-fired boilers-mainly dairy, fertilizer and sub-set of textile
  • In addition, industrial canteens.

In Rural Sector

  • Households, Dhabas, Primary Health-Centers, Hostels
  • Village-industries (Silk-Reeling, Textile-Dyeing, Puffed Rice-Making)
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