Dynamic Simulation And Optimization Design Of Ground-couple Heat Pump System

As energy supplies become increasingly tense, building energy consumptioncontinues to grow, air conditioning energy consumption as the main source ofbuilding energy consumption, in order to make the air conditioning industry towardssustainable development, renewable energy used in air-conditioning system is thegeneral trend. In recent years, along with actively promoting renewable energyresearch and application, ground-couple heat pump as an highly efficient、environmentally friendly、 energy-saving air-conditioning system, an applicationexample of the theoretical research and demonstration projects continue to increase.However, due to this research and application of technology started relatively late, thetechnical standards and specifications is not perfect, as well as technical designdifficulties, the design and the actual running of ground-couple heat pump systemrevealed some problems, in order to improve the performance of ground-couple heatpump system, study on heat transfer characteristics of ground heat exchanger and thedynamic optimization design of ground-couple heat pump system.First， study on heat transfer of underground hear exchanger. ground heatexchanger is the key equipment for ground-couple heat pump system, it is veryimportant to reasonably determine heat transfer model of ground heat exchanger andreliably compute. Based on the quasi-3-dimensional heat transfer model inside theborehole and the finite line heat source theory outside the borehole of ground heatexchangers, by using superposition principle of temperatures, writing heat transferprogram of ground heat exchangers. underground geotechnical thermal responseradius was simulated under the action of alternating pulse heat flux. By introducingconcept of hydraulic radius of pipe-groups cross section, under the action ofalternative pulse heat flux, heat transfer performance of ground heat exchangers wasanalyzed under different layout forms of pipe-groups.Secondly, because the air conditioning system operating conditions change in realtime, in order to achieve the optimal running of the whole life cycle of theair-conditioning systems, required system dynamics simulation method to achievevariable parameter operation optimization. In this paper, use the energy consumptionanalysis software to calculate the dynamic cooling and heating load of building,thenestablish the underground coupling dynamic simulation model of ground-couple heatpump system in Trnsys transient simulation software platform, to achieve operation optimization of ground-couple heat pump system under variable working conditions.Based on this model, explored the best design heat flux intensity of heat exchangerper unit length and ground source heat pump system undertake the optimal proportionof heating and cooling load, order to achieve the optimal operation of ground sourceheat pump system in the whole life cycle and the highest energy efficiency of unitsand systems.Finally, according to the specific project designed three kinds of commonly usedair conditioning system, the case1: Ground source heat pump and cooling towerair-conditioning systems; case2: Air source heat pump system; case3: Chillers andgas-fired boiler system. On transient simulation software platform, builded theprograms air conditioning system dynamics simulation model to calculate the primaryenergy consumption of different programs throughout the year, obtained the energyefficiency of different systems, and using the dynamic annual expense value and thestatic investment recovery period method, carried on the economic analysis of thedifferent air conditioning system. Then analyzed different air conditioning systemsimpact on the environment, the conclusion is used to guide the engineering design.