Abstract :
A new photovoltaic–thermal (PVT) system has been developed to produce electricity and cooling energy. Experimental studies of
uncovered PVT collectors were carried out in Stuttgart to validate a simulation model, which calculates the night radiative heat exchange
with the sky. Larger PVT frameless modules with 2.8 m2 surface area were then implemented in a residential zero energy building and
tested under climatic conditions of Madrid. Measured cooling power levels were between 60 and 65W m 2, when the PVT collector was
used to cool a warm storage tank and 40–45 W m 2, when the energy was directly used to cool a ceiling. The ratio of cooling energy to
electrical energy required for pumping water through the PVT collector at night was excellent with values between 17 and 30. The simulated
summer cooling energy production per square meter of PVT collector in the Madrid/Spain climatic conditions is 51 kWh m 2 a 1.
In addition to the thermal cooling gain, 205 kWh m 2 a 1 of AC electricity is produced under Spanish conditions. A comparative analysis
for the hot humid climate of Shanghai gave comparable results with 55 kWh m 2 a 1 total cooling energy production, mainly usable
for heat rejection of a compression chiller and a lower electricity production of 142 kWh m 2 a 1.
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