Home
water heating proves to be a much more expensive process
as compared to using a solar hot water (SHW) system. In
fact, investing in a SHW system is considered as a
second choice by many once you have invested in a
home.
There
are several types of SHW systems including Batch Water
Heating System, Thermo-siphon system, Open-loop direct
system, Pressurized Glycol system and Closed-loop Drain
back system that are currently available in the market.
They are briefly described here.
·
Solar
Batch Water Heaters,
also called Integrated Collector Storage type, are a
‘One Unit’ system where collector and the storage tank
form a single unit. Cold water in well insulated glass
or porcelain cover is placed in the sun facing the
south. While cold water is piped to the bottom of the
tank, hot water is collected from the top. As the water
in this process is heated directly, this is an example
of open-loop system and as no pump is used to conduct
the water from the collector to the end use, this may be
termed as passive. Solar Batch Heaters are comparatively
cheaper and so are widely used in ‘non-freeze’
areas.
·
Solar
Thermosiphon Water Heaters
are based on the principle that hot water always rises
to the surface while cold water always goes down. One of
the advantages of the Termosiphon system over the Batch
Heaters is that, the solar heat is well contained in
thoroughly insulated water tanks and so hot water
becomes available at night when the sun is no more
there. Here the tank is located directly over the
collector.
·
Open-Loop
Direct System Water Heaters
are the simplest form of active systems ever built.
These are called active since small 10 watts circulatory
pumps powered by 10-watt PV modules are involved here.
Otherwise, these consist of standards electric water
tanks and 40- square-feet solar thermal collectors.
Under normal conditions, the tank merely works as a
storage tank for pre-heated water that feeds the back-up
water heater.
·
Pressurized
Glycol System
is a closed-loop system where the incoming water is
conducted to the solar storage tank and not into the
collectors. Water mixed with antifreeze (Glycol) is
allowed to circulate from the collectors through a coil
of pipe in the solar tank which is then piped back
through the collectors. The water in this case is heated
by heat transfer process, coming in contact with the
pipe.
·
Closed-Loop
Drainback Systems
are effective and reliable and they work for years
without needing any maintenance. The heat transfer fluid
is distilled water which is stored in a 10-gallon
reservoir tank. When the system is turned on, it
automatically turns a pump on that circulates the
distilled water back through the collector and the heat
exchanger, conducting heat to the water in the solar
tank. As the system is turned off, it turns off the
pump, too, causing the distilled water to drain back
into the reservoir.
Getting
a solar system for water heating makes a lot of sense
because it is sure to save you a lot of money on your
power bills. An alternative energy, solar power is
eco-friendly too. You can install a solar power system
but you need to get informed on the best place to set it
up, learn about installing and wiring the system, and
also know about the sources of cheap parts and
batteries. You will also need to know about the safety
precautions.
