Simulation of a solar-ice system for heating applications. System validation with one-year of monitoring data

• A model for a complete solar-ice system is presented and validated with monitored data of a pilot plant for one complete year.
• Most of the simulated results are within the uncertainty range of the experiments.
• An annual system performance factor of 4.6 is achieved in the pilot plant.
• A sensitivity analyses for storage heat losses, heat exchanger efficiencies and ground properties is provided.
• The use of Meteonorm data compared to real climatic data during 13 years results in 24% decrease in SPFSHP+.

In the present paper a dynamic system simulation for a combined solar thermal and heat pump system including an ice storage is presented. The simulated system was validated with one-year measurements from a pilot plant situated in Rapperswil-Jona, Switzerland. The system is installed in an old kindergarten with a yearly heating demand of around 35 MWh and a high temperature hydronic heat distribution system (radiators). The pilot plant is composed of 50 m2 of covered and 14 m2 of uncovered collectors, both with selective coating; a heat pump of 17 kW, a sensible storage of 3.5 m3 and an ice storage of 75 m3. The monitored yearly system performance factor was 4.6.The system simulation was compared to measurements at monthly and yearly bases for global variables of interest such as system performance factor, energy flows between the collectors, ice storage, heat pump and combi-storage. The yearly difference in system performance (SPFSHP+) was found to be within the uncertainty range. After the system was validated, a sensitivity analysis was conducted. The most sensitive parameter was found to be the variation of ground properties between two extremes, i.e. from wet clay to dry sand where differences up to 4% were found in the yearly SPFSHP+.Results from annual simulations with Meteonorm weather data were compared with results from simulations using measured weather data for the climate of Zurich. The average of the results of 13 years with real data showed an increase of SPFSHP+ of 24% compared to the results obtained with Meteonorm data.