Extended Hottel-Whillier Models for uncovered PVT-Collectors
Abstract
Photovoltaic thermal (PVT) collectors are getting more and more attention for their simultaneous production of electricity and low temperature heat. Established mathematical models for the thermal efficiency of thermal collectors as well as the electrical efficiency of PV modules don’t include the interactions between the thermal and electrical energy balance. In order to predict efficiencies, we extend the standard Hottel-Whillier collector model to collectors with an additional PV-layer and distinguishable temperature levels for the front side and the back side of the collector. The model is then included in a discrete model of a collector field mounted with a ventilated back side. Based on the field model, we analyze the effect of different sizes of the air gap.