The prototype was installed onto a test rig, as shown in Fig. 3.
Solar energy was absorbed by the CLOHP/CV through the solar
collector, and then transferred to the condenser. The temperatures
were measured using type-K thermocouples with a Yokogawa
MX100 data acquisition system. The temperatures were recorded at
five points on the collecting plate surface, TC1–TC5, and represented
the plate surface profile. Their average value was taken as the
average plate temperature (Tp). The thermocouples were attached
to the glass tube, Tg1–Tg3 as (Tg). The water temperature of the
water tankwas measured using four thermocouples, 2 points at the
inlet and 2 points at the outlet. Ambient temperature was
measured using two thermocouples as (Ta). Thewall temperature of
CLOHP/CV was measured by attaching eight thermocouples,
5 points at the evaporator section and 3 points at the condenser
section. The thermopile based pyrheliometer integrated to
a computer based data-logger, mounted on a surface parallel to the
plane of the collector was used to measure the intensity of the
global solar irradiation on the collector surface. It was recorded as
instantaneous values, taken as (I). the radiation shield covering the
solar collector panel was removed at 08:30 and data collection commenced at 09:00. Day-long experiments were carried out from
09:00 to 16:00, and data were recorded at half-hour intervals. The
experiments were performed throughout March and April 2007. On
each day, the hot water storage tanks were completely drained in
the morning and refilled with cold water. The controlled parameter
was the water flow rate at 0.6 liters/min. The tests were performed
on March 30, 2007 and April 4, 2007.