Studies on the Temperature Control System of the Geothermal-Source Heat Pump under Different Modes

抄録

Geothermal-source heat pump technology can increase the production efficiency and reduce the energy consumption. However, the application performance of the control system for the geothermal-source heat pump is always poor; such as a larger system operation energy consumption, low efficiency, poor stability and time effectiveness. In order to solve this issue, two advanced control strategies based on the research object of the geothermal-source heat pump temperature control system with different modes are developed: one is a feedforward-feedback control based on the variable speed integral PID control algorithm ("FFC-VSIPC"), the other is a feedforward-feedback control based on the fuzzy control algorithm ("FFC-FC"). The simulation and experimental studies of the effects of temperature control system in a geothermal-source heat pump by different models are carried out. The results shows that: (1) The overshoot of FFC-VSIPC is slightly larger than the FFC-FC when the set value is abruptly changed, but the adjustment time of FFC-VSIPC is shorter and there is no static error after the stabilization; (2) Changing the rate of flow interference suddenly, both FFC-VSIPC and FFC-FC can effectively eliminate the effects of interference with adding a feedforward control, also the adjustment time of FFC-VSIPC is greatly shortened than FFC-FC, but the stability of the adjustment is worse; (3) When the frequency amplification factor is suddenly changed, FFC-FC shows a non-stable control state of divergence gradually, FFC-VSIPC shows good robustness. The further comparisons between simulations and experiments reveal that FFC-VSIPC is better than FFC-FC in terms of the energy regulation and controlling of the geothermal-source heat pump. Therefore, FFC-VSIPC is an advanced control strategy, which is worthy of research and application promotion.