In-Situ Monitoring of a Photovoltaic-Thermal (PVT) Collector-Heat Pump System With Ground Sources Used for Heating and Cooling Applications
Abstract
Photovoltaic-thermal (PVT) collectors are regarded as a potential key technology for climate-neutral energy supply in buildings due to their feature of cogenerating thermal and electrical energy. This paper analyses the performance of a demo plant consisting of uncovered (WISC) PVT collectors in a system configuration, with a brine-to-water heat pump and ground sources i.e., borehole and horizontal ground heat exchangers, used for heating and cooling purposes in a non-residential building. The seasonal performance factor of the system before storage (𝑆𝑃𝐹𝑏𝑆𝑡) for the monitored year 2022 was 3.3 in the heating mode and 4.1 in the cooling mode. PVT collectors proved to be an essential source in the system, covering around a quarter of the heating demands and around 35 % of the cooling demands through nocturnal cooling. In addition, 56 % of the solar heat produced by PVT collectors was used for the regeneration of the ground sources. In this demo site, the solar regeneration enabled the sizing of relatively smaller ground sources during the design phase. Furthermore, the thermal parameters of the PVT collectors are identified with the monitoring data according to the quasi- dynamic test (QDT) mathematical model based on ISO 9806. On average, the typical heat loss coefficient defined specifically for nocturnal cooling per m2 PVT estimated from the monitoring data was 21 W/K.
Keywords
Pvt collectors, Heat pump, Monitoring, Heating, Cooling, Quasi-dynamic test method, Thermal parameters