Research On The Air-injection Heat Pump Air-conditioning System Of Low Temperature

For poor heating capacity of the system when the ambient temperature of electric vehicles is low,gas-injected compression(GIC)heat pump air conditioning system for heating is a feasible solution.The greater heat production is achieved by increasing the refrigerant mass flow in the compressor by equipping a gas-injected loop.Even though,the gas-injected loop makes the whole heat pump system more complex and more difficult to control,the GIC heat pump air conditioning system with an economizer is preferred due to its relatively higher stability.In this paper,a parametric modeling on a GIC heat pump air conditioning system with economizer is presented,focusing on the performance of the GIC heat pump air conditioning system under low ambient temperature operating conditions.A onedimensional simulation performance analysis platform for GIC heat pump air conditioning is designed and established to analyze the effects of different operating conditions and parameters on the system performance.Firstly,a one-dimensional simulation model of the main components in the GIC heat pump air conditioning system with economizer is established,including the gas-injected scroll compressor model,micro-channel parallel flow condenser model,economizer model,etc.The accuracy of the micro-channel parallel flow condenser and evaporator models is verified,and the error is less than 10%.Secondly,the economizer is modeled in full scale using 3D software and multiphysical field analysis is carried out accordingly.Based on the geometric characteristics of the original structure,the influence of the corrugation width,corrugation height and punching angle on the heat transfer performance and flow resistance characteristics of the economizer are investigated.Orthogonal tests are established for different structural factors and the results of the orthogonal experiments show that the corrugation height has the highest degree of influence and the punching angle has the lowest degree of influence.The best economizer single plate structure parameters are 1mm for corrugation height,2.48 mm for corrugation width and 48° for punching angle.The optimized economizer single plate structure reduces the flow resistance of the heat exchange medium by 39.2%while ensuring the heat flow.Finally,a one-dimensional simulation and analysis platform for the performance of the GIC heat pump air conditioning system with economizer is established based on the models of the main components,and the maximum error is verified to be less than 12%.The platform is used to perform a multi-case performance analysis of the GIC heat pump air conditioning system,and the effects of gas-injected pressure and economizer heat exchange on the system performance are investigated.