| The development of Chinese highway industry is very rapid in recent years.The construction facilities along the highway provide a range of functions for the normal operation of the highway.Whether the air conditioning system is reasonable or not directly affects the function of the building construction facilities along the highway.The use of VRV system along highway is worth of further study due to its wide range of use,flexible design and use,high coefficient of performance.The energy efficiency ratio of heat pump units has got a lot of attention all along.How to evaluate the energy efficiency ratio is very important when VRV system is widely used today,and IPLV to is used to evaluate the energy efficiency of VRV in China.The part load rate of 100%,(75 ± 10)%,(50 ± 10)%,(25 ± 10)% should be obtained by controlling the indoor unit’s operating rate under 35℃,31.5 ℃,28 ℃,24.5 ℃ outdoor temperature respectively,and the result of EER should be used to calculate IPLC(C).In this paper,a VRV model in the Energy Plus software is used to simulate VRV system.The result under varying temperature is compared with the average EER of the system during the whole cooling season.The difference between IPLV(C)and average EER is 10.6%.Compared with the result under constant temperature,the result under varying temperature is closer to the true value.In addition,The simulation results show that the average COP of the whole heating season is 3.41,and the reason is that frost on the outdoor heat exchanger affects the heating performance of the unitAlthough VRV system has outstanding advantages,there is frost technicalobstacles when it is used in heating mode.The traditional temperature-time defrost control method will cause the unit to produce "mal-defrost" accident and affect the use of the unit effect.A VRV system in the office building of Nanzheng toll station which belongs to Baohan highway is tested in this paper,and the change regulation of the parameters in frosting and defrosting process is analyzed.The refinement of frost cycle is done based on the evaporation temperature of outdoor heat exchange,and the variation of each parameter in each refinement period is pointed out.Set the minimum frost time for the setting of the defrost start point.According to the experimental data,the heating capacity is taken as the control target.When the temperature of the atmospheric dry bulb and the surface temperature of the bottom coil meet T_e = KT_a-α,the unit starts to remove the defrosting time. |
