24 June 2014

Variable Capacity Air Source Heat Pump Coupled with a Building Integrated Photovoltaic/Thermal (BIPV/T) System


TRNSYS simulation software was used to evaluate the performance of a variable capacity air-to-air air source heat pump (VC-ASHP) coupled with a building integrated photovoltaic/thermal
(BIPV/T) system. A known heat pump performance curve of an ASHP at a characterized test house was used in the simulation. The TRNSYS model was validated with the data collected
from monitoring the VC-ASHP. From the results of the data collection, a curve was developed illustrating the daily heating output of the VC-ASHP with respect to the daily average outdoor temperature. This curve was used to validate the TRNSYS house model by matching the TRNSYS daily heating demand of the house at various daily average outdoor temperatures with the developed curve from the data. The BIPV/T system was integrated into the roof and the wall.
Air was circulated behind the photovoltaic arrays to recover the thermal energy. The recovered
warm air was supplied to the VC-ASHP. The thermal performance of the VC-ASHP was evaluated for three scenarios when the heat pump is running in heating mode. The Three scenarios are: (A) by directly feeding ambient air to the ASHP; (B) by coupling the ASHP to a wall integrated BIPV/T only; and (C) by coupling the ASHP to a roof integrated BIPV/T only. The coefficient of performance (COP) of the VC-ASHP was evaluated for these three separate
scenarios and compared. The COP was evaluated for three typical winter days: January 12, February 5 and March 5. Results suggest that the COP of the ASHP can be improved by coupling the VC-ASHP to either of the BIPV/T systems, i.e., either to the roof integrated BIPV/T system or to the wall integrated BIPV/T system.