2. Experimental setup
The new SWHS consists of three main parts, as shown in
Fig. 1:
1. A solar collector (four panels) having a total area of
1.58m2 and 141 inclination. It initially contains 4.1 l of
water and 1.3 l of air.
2. An overhead tank (OT), made of a 0.5mm stainless-steel
sheet and has 0.4m0.4m0.3m dimension. It is
installed at an upper level above the solar collector and
has an air vent at atmospheric pressure.
3. A hot water ST, which is similar to the OT except that
there is a heat exchanger installed within it. It is placed
at a lower level under the solar collector and contains
30 l of water at atmospheric pressure.
4. A control valve (CV) which is a one-way valve and has
no moving part. Based on Bernoulli equation it can be
automatically closed by a very high-pressure drop across
the valve. It is much easier for water to flow from the
collector to the OT through the lower ST, than through
the valve.