Research On Optimal Temperature Difference Combination Of Variable Air Volume And Variable Flow Air Conditioning System

Ground-source heat pump air-conditioning system,as a form of utilization of geothermal energy,has been vigorously developed in recent years.More and more buildings use ground-source heat pump air-conditioning systems,but most of the public buildings use air-conditioning systems.Excessive energy consumption is not conducive to energy conservation.Taking the ground source heat pump air conditioning system of a public building in Wuhan as an example,the simulation model of the system is established by using dynamic simulation software TRNSYS The energy consumption,exergy efficiency and equivalent carbon dioxide emission of vav and VAV systems are analyzed and simulated,and the optimum temperature combination of air system and water system is studied.It is found that under the design condition,the efficiency ratio of constant air volume and constant flow air conditioning system used in the building in cooling season and heating season is 2.32 and 1.27,and the efficiency ratio is 8.52% and 1.65%,and the variable air volume and variable flow air conditioning system is used instead After the design temperature was taken as the actual operating temperature parameter,the energy efficiency ratio(er)of the system was changed to 3.22 and 3.17,and the Er and er of the system were improved to 10.87% and 17% respectively.Based on the TRNSYS model,the reference temperature of wind system and water system of the office building is analyzed and studied.It is found that the combination of water system temperature difference of 5? is not necessarily the most energy-saving operation mode within 10? of the traditional design air supply temperature difference.By changing the supply air temperature,the supply and return water temperature of the water system on the load side and the supply and return water temperature of the ground source water measuring system,the temperature combination of the air conditioning system under the most energy-saving operating condition can be found.In this paper,the temperature variation range of wind system and water system is firstly determined,and some samples are sampled by Latin hypercube sampling method Secondly,the relationship between the temperature combination parameters and the energy efficiency ratio of the air-conditioning system is established by using the BP neural network principle The temperature combination corresponding to the optimal energy efficiency ratio of the global system is found.The simulation results show that the optimal combined operating temperature of the building's air conditioning system is 11.7? in cooling season,5.9? in the load side,7.0? in the load side and 23.4? in the return water temperature of ground source heat pump The temperature difference of ground source is 6.6?,the temperature difference of air supply is 10.8? in heating season,the temperature difference of heat pump outlet water on the load side is 43.4?,the temperature difference of heat pump return water on the load side is 6.4?,the temperature difference of heat pump return water is 13.5?,and the temperature difference of ground source is 7.4?.In summary,this paper studies the ground-source heat pump air conditioning system from the point of view of energy analysis and analysis,and analyzes the optimal temperature combination of variable air volume and variable air volume system It provides a reference for setting the operating temperature difference of air conditioning system in the future.