Research On Operation Performance Of Ground Source Heat Pump System At The Air Conditioning Terminal Of Chilled Beam

The air conditioning system that combines active chilled beams and ground source heat pumps has great advantages in terms of building energy saving and thermal comfort.The combination of the two can fully reflect the energy saving,environmental protection and comfort of the air conditioning system.This paper takes an office building in a science and technology park in Beijing as the research object,adopts the methods of field testing and simulation research,evaluates the performance of the ground source heat pump system combined with active chilled beams,and uses TRNSYS for system optimization and simulation analysis.The main research results are as follows:(1)Field test and performance evaluation.The cold and heat source system of this project is divided into two strategies that are part load operation and full load operation.The ground source heat pump system of the two operation strategies is tested in the cooling and heating conditions respectively.The heat pump units and systems are tested according to the standards.The annual operating performance of the company was comprehensively evaluated.The results show that under the partial load operation strategy,ACOP of a single heat pump unit is 6.6,COP of the system in winter is 4.2,and EER of the system in summer is 4.5,which meets the national standards(ACOP ? 4.0,system COP ? 3.0,system EER ? 3.4);Under the full-load operation strategy,ACOP of the two heat pump units are 5.9 and 5.3,COP of the system in winter is 3.9,and EER of the system in summer is 3.9,which also meets the national standards.Comparing the two operating strategies,it can be seen that when the air conditioning system is at a lower load rate,the operating performance parameters of the heat pump unit and the system under the partial load operation strategy are better than the full load operation strategy.(2)TRNSYS software simulation.First,the TRNSYS is used to simulate the annual load of the building.Then the simulation model of the soil source heat pump system is built.And the simulation results of the summer operation energy consumption of the ground source heat pump unit,the water cooled refrigeration unit and the air cooled heat pump are compared and analyzed.According to the results,the average EER of soil source heat pump unit,water-cooled unit and air-cooled heatpump are 5.76,5.49 and 3.40.The average EER of a typical daily unit of ground source heat pump unit is the highest,which is higher than that of water-cooled unit by5.09%,higher than air-cooled heat pumps by 69.55%;In terms of average EER of the system,the three schemes of ground source heat pump,water-cooled unit,and air-cooled heat pump are 3.81,3.44,and 2.77.Among them,the average daily EER of the typical ground source heat pump unit is the highest,higher than the water-cooled unit solution by 10.66% and than the air-cooled heat pump solution 37.44%;In terms of total energy consumption in summer,the ground source heat pump system consumes the lowest energy,which saves more energy than the water-cooled unit by10.69% and air-cooled heat pump by 33.73%.Therefore,in summer conditions,the ground source heat pump has higher operating efficiency and better energy saving effect than water-cooled refrigeration units and air-cooled heat pumps.(3)System plan optimization.According to the characteristics of the chilled beam,the high-temperature chilled water heat pump scheme,the heat pump water supply and the chilled beam backwater mixing scheme were proposed.The TRNSYS software was used to simulate and analyze the two schemes to explore the advantages and disadvantages of the different schemes.The results showed: the high-temperature chilled water heat pump scheme Compared with the pre-optimization scheme,the typical daily system EER is increased by 9.80%,the total energy consumption is reduced by 9.31%,and the total cost is reduced by 8.72%.At the same time,the average energy efficiency ratio of the high temperature chilled water heat pump unit is higher than that of the ordinary heat pump unit by 38.66%;Heat pump water supply and cooling beam Compared with the pre-optimization scheme,the backwater mixing scheme has a typical daily system EER increased by 1.80%,total energy consumption reduced by 3.96%,and total cost reduced by 3.02%.Therefore,both optimization schemes can achieve the effect of saving system energy consumption and operating costs.And the high-temperature chilled water heat pump can greatly improve the energy efficiency ratio of the heat pump unit.(4)Energy saving suggestions.Since Beijing implements a tiered electricity price,the use of an optimized ice storage transformation scheme can save operating costs;The addition of load forecasting and control modules in summer can avoid condensation on chilled beams to a certain extent and save system energy consumption;Increase solar backup auxiliary heat source heating in winter to prevent the problem of low water temperature on the buried pipe side of the source heat pump system in winter;Use a new magnetic suspension centrifugal variable frequency chiller to optimize the operating efficiency of the unit.This subject has positive significance for the optimization and energy saving of central air conditioning and cold and heat source projects,especially chilled beam terminal with high requirements for anti-condensation,dry fan coil with independent temperature and humidity control,and capillary radiant cooling ceiling.And it is also of reference value for cold and heat source projects for process air conditioning systems such as IDC computer room,electronic equipment room,medical andpharmaceutical rooms that require high temperature and humidity control accuracy.