Solar Water Heater

Solar water heating (SWH) is the conversion of sunlight into heat for water heating using a solar thermal collector. ... A sun-facing collector heats a working fluid that passes into a storage system for later use.

A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. The solar energy incident on the absorber panel coated with selected coating transfers the hat to the riser pipes underneath the absorber panel. The water passing through the risers get heated up and is delivered the storage tank. The re-circulation of the same water through absorber panel in the collector raises the temperature to 80 C (Maximum) in a good sunny day. The total system with solar collector, storage tank and pipelines is called solar hot water system.

1- Flat Plate Collectors (FPC) based Solar Water Heaters

2- Evacuated Tube Collectors (ETC) based Solar Water Heaters

Solar Hot Water System turns cold water into hot water with the help of sun’s rays.

1. Around 60 deg. – 80 deg. C temperature can be attained depending on solar radiation, weather conditions and solar collector system efficiency

2. Hot water for homes, hostels, hotels, hospitals, restaurants, dairies, industries etc.

3. Can be installed on roof-tops, building terrace and open ground where there is no shading, south orientation of collectors and over-head tank above SWH system

4. SWH system generates hot water on clear sunny days (maximum), partially clouded (moderate) but not in rainy or heavy overcast day ¾ Only soft and potable water can be used

5. Stainless Steel is used for small tanks whereas Mild Steel tanks with anticorrosion coating inside are used for large tanks ¾ Solar water. heaters (SWHs) of 100-300 litres capacity are suited for domestic application.

6. Larger systems can be used in restaurants, guest houses, hotels, hospitals,

Fuel Savings

A 100 litres capacity SWH can replace an electric geyser for residential use and saves 1500 units of electricity annually

Environmental benefits

A SWH of 100 litres capacity can prevent emission of 1.5 tonnes of carbondioxide per year.

Life : 15-20 years Approximate cost : Rs.15000- 20,000 for a 100 litres capacity system and Rs.110-150 per installed litre for higher capacity systems

Payback period : 3-4 years when electricity is replaced 4-5 years when furnace oil is replaced 5-6 years when coal is replaced