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