:: Solar Water Heating System

The solar water heating system consists of a solar collector, toughened glass, insulated storage tank, cold water supply tank and insulated piping. The sun rays penetrate through the glass and fall on the absorber. The heat of the sunrays is absorbed by the cold water inside the absorber thereby increasing its temperature. The heated water gets collected inside the insulated

storage tank either through the thermosyphon or the forced flow system. In the Thermosyphon system up to 3000 liters per day can be installed, however, for higher capacities it is necessary to use the forced flow system. The water temperature can be raised up to 85C. The solar water heating system can be used for bathing, washing, boiler feed water and similar other purposes where hot water is required in domestic, commercial and industrial sectors. The cost of the solar water heating system range from Rs.140/- to Rs.220/- per litre, depending upon the capacity of the system and the investment made can be recovered in 4 to 6 years time. The life of the system is around 10-15 years if maintained properly. The operation and maintenance cost is negligible. In Maharashtra, solar water heating systems of total around 35.00 lakhs liters per day have been installed.

No subsidy is available for purchasing solar water heating system. However, loans up to 85 % of cost of the system having ISI mark is available at 2% (for individual), 3% (for non profit making organization) and 5% (for profit making organization) interest from some nationalized & co-operative banks. This has been arranged by MNES with a few nationalized banks. The MNES has plans to include more nationalized banks for such loan facilities in the future. The loan repayment period is 5 years. In addition, Indian Renewable Energy Development Agency (IREDA), New Delhi, is also extending soft loans to end users under certain terms and conditions. In Maharashtra there are eight manufacturers who have got ISI mark for solar flat plate collectors from BIS authorities.

If loan is not availed central subsidy is of Rs 2200/- per collector for non profit making institute and Rs.1650/- per collector for profit making institute is available.

Basic Requirements for installation of Solar Water Heating System :

Plenty of sunshine during most part of the year.
Availability of space either on ground or on terrace, free of shadow for at least 0800 hrs to 1600 hrs a day.
Reasonably soft water.
Electricity for operation of the pump in the forced flow system.
A 100 Liters per day (LPD) system needs around 3-4 sq.mt. area.
If the system is to be installed on terrace it is necessary to check the load bearing capacity of the slab.
The space selected should be very close to all use points in order to save on piping.
The solar collectors are installed facing due south with a tilt equal to the latitude of that place plus 15 deg.
The hot water insulated tank shall be at least 50 cm above collector top and cold water tank shall be at least 50 cm above hot water tank in the case of the thermosyphon system.

MEDA offers consultancy services that include feasibility studies, tender preparations, evaluation of tenders, report preparations, inspections and monitoring at a reasonable price.

List of BIS & MNRE Approved Manufacturers/Installers is available on www.mnes.nic.in