Optimization of solar-assisted GWHP system based on the Trnsys model in cold regions

In this study, a Trnsys simulation prediction model for multistage utilization solar-assisted groundwater source heat pump system and a new year-round operation control strategy are proposed. A new dual-interface solar and groundwater heat storage module Type299 was created, which was imported into Trnsys transient simulation model for simulation. A one-year experiment was conducted to test the accuracy of the new model Type299 and Trnsys transient simulation prediction model, taking a case system in the Shenyang area as an example. When the proposed new system and control strategy was applied to the case system, the results showed that the maximum comprehensive performance coefficient of the new system is approximately 4.54, which is 23.8% higher than that of the original system. The annual solar energy utilization of the new system increased by approximately 4.68 × 105 MJ compared with the original system. After 10 years of simulation operation, it was found that the groundwater temperature under the action of the new system was approximately 3.1 °C higher than that of the original system. This effectively alleviates the underground water temperature decrease year by year caused by the operation of the original system.