Validation of a Single Tank, Multi-mode Solar-assisted Heat Pump TRNSYS Model

This work explores the operation and performance of a solar-assisted heat pump (SAHP) system which employs a single domestic hot water (DHW) tank. The solar heat source is connected to the storage tank via a heat pump and heat exchanger, which operate in parallel paths, providing multiple modes of operation. A TRNSYS (TRaNsient SYstem Simulations Tool) model of this SAHP system is validated using a purpose-built experimental test apparatus. The main goals of the validation are to: benchmark accuracy, identify strengths and weaknesses, and build confidence in the model. The model will be used to conduct more advanced studies supporting the development of similar SAHP system configurations. Both the system and model are operated and monitored for representative days from typical meteorological year (TMY) data for Ottawa, Ontario, Canada. The agreement between simulation and experiment was found to be very strong, with typical differences in average DHW tank temperatures of less than 1 C°. The DHW tank model does bring forth some issues, as simulated stratification can often differ appreciably from experimental stratification.