Experimental Investigations on Photovoltaic-Thermal Arrays Designed for the Use as Heat Pump Source
Abstract
Uncovered, liquid-based photovoltaic-thermal (PV-T) collectors are usually integrated in brine-water heat pump systems as additional heat source to increase the inlet temperature of the heat pump, to regenerate the ground or to directly supply low temperature heat distribution systems, like floor heating. The paper analyzes the behavior of a novel PV-T collector specially designed for the use as single source in this kind of heat pump systems. After presenting the results of the module efficiency measurements, which attest the unusual parameters of the collector (b1= 22 W/m²K, b2 = 15 J/m³K, bu = 0.2 m/s), we report about the long-term tests carried out on large PV-T fields at two different locations, focusing on the impact of real environmental, installation and operational conditions on the system performance. The results confirm the high overall heat transfer coefficient of the module (up to 40 W/m²K) as well as its high sensitivity.