Exploration On Operational Optimization Of Ground Source Heat Pump System Coupling With Radiant Ceiling Cooling Panel

In recent years,the energy consumption of HVAC(Heating,Ventilation and Air Conditioning)in large public buildings has increased.Ground source heat pump(GSHP)technology and radiation air conditioning system have been widely used in HVAC because of their energy saving and environmental protection.The development prospect of GSHP technology is very broad,but there are still some problems in its practical application process,which often can not achieve the desired results.At the same time,there is a risk of condensation at the end of radiant ceiling in summer.Therefore,it is necessary to make a profound study on its operation strategy,so that the composite system technology can be promoted and applied in China in the further.The GSHP coupling with radiant ceiling cooling panel of an office building with a building area of 2440m~2 in Xi’an(total cooling load is 150.15kW,total heat load is145.25kW)is selected as research object.A set of mathematical model for buried heat exchanger,heat pump and radiant terminal devices is developed based on exergy analysis method.Firstly,genetic algorithm is implemented to search for the lowest exergy losses of three heat pumps by optimizing the hourly load distribution rate.And then,Multi-objective optimization genetic algorithm(MOGA)method is implemented to search for the lowest exergy losses of three subsystems by optimizing the hourly load distribution rates of the three heat pumps.Results show that,compared with the original load distribution method,taking the minimum total loss of heat pump as the optimization objective,optimized load distribution strategy can obviously reduce the exergy loss and energy consumption of the heat pump.Heat pumps full-day total exergy loss and energy consumption are reduced by 27.75 kW·h and 28.17 kW·h respectively,energy saving rate up to 10.53%;Taking the minimum loss of three subsystems as the optimization objective,the optimized load distribution strategy can obviously reduce the exergy losses of some subsystems and the entire system.And the total exergy losses and energy consumption of HVAC system during the topical day reduced by 44.84 kW·h and 26.5 kW·h,respectively,the energy saving ratio reached9.9%.The HVAC system operating efficiency improved significantly.And then,the variable flow PID control at the radiant terminal devices is realized,and the indoor temperature,PMV,radiation ceiling condensation,unit and pump energy consumption are simulated in TRNSYS17 software.Results show that variable flow PID control has excellent control accuracy,stability and sensitivity for indoor temperature,and the radiant terminal devices does not produce condensation after control.Indoor PMV can meet the thermal comfort requirements of most people.Finally,a constant static pressure-variable flow PID control method for radiant terminal devices is proposed to solve the problem of the interaction between the terminal water volume after the end variable flow PID control in practical engineering.