| Recently,with the improvement of people’s life quality and higher requirement for comfortable living environment,the energy consumption of air conditioning system in our country is significantly increasing.It is urgent to save more energy and enhance the energy efficiency of the existing air conditioning devices.Heat dissipation of air-cooled air conditioning condenser is getting worse with the rising of outdoor environment temperature.However,the evaporative condenser has been increasingly concentrated in HVAC industry on the advantages of energy saving,water saving as well as compact structure.Based on the design of finned tube air-cooled condenser,a dual-purpose condenser of air cooling or evaporative cooling was developed in this paper,and a test platform which contains an independent air treatment system for testing the performance of evaporative condenser was also established.The power consumptions of evaporative condenser and air cooled condenser have been comparatively studied under different parameters by combining orthogonal experiments as well as single factor experiments.Effects of air inlet velocity,air inlet temperature and water volume on the energy-saving efficiency of evaporative condenser were obtained,and experimental correlations for heat and mass transfer coefficients were fitted,which will provide a reference for further studies of later scholars.Main conclusions of this paper are as follows:(1)In this paper,the height and length of condenser on the windward side are 480 mm and 410 mm,respectively,and the width of fins along the air flow direction is 86.6mm.When the distance between the nozzles of the water spraying device is 102.5mm and the distance between the nozzles and the condenser is 80 mm,the covering effect of spraying water film on the condenser is optimum.(2)Without water spray system,for same air inlet velocity,the higher air inlet temperature,the more compressor power consumption in air-conditioning system,and for same air inlet temperature,the compressor power consumption decreases with the increase of air inlet velocity.(3)For same parameters conditions,energy consumption of compressor is less by using the water spray system to achieve the same cooling effect,and the compressor power consumption decreases at first and then remains unchanged with the increase of water volume,while increases with the increase of air inlet temperature and the decrease of air inlet velocity.At air inlet temperature of 28℃,air inlet velocity of 2.5m/s and water volume of 22L/h,the compressor power consumption reaches the minimum of 418 W.(4)Energy saving efficiency of the evaporative condenser reaches to a numerical value at first and then remains the same with the increase of water volume.With the increase of air inlet temperature and inlet air velocity,the energy saving efficiency increases to a certain value at first and then slowly decreases.The maximum of energy saving efficiency is 36.92% for the same cooling capacity with opening spray device,when air inlet temperature is of 33℃,air inlet velocity is of 2.5m/s and water volume is of 20L/h.Considering the primary and secondary relations of various factors affecting compressor power consumption and energy saving efficiency,air inlet temperature is the uppermost,later for water volume,last for air inlet velocity.(5)Experimental correlations of the convective heat transfer coefficient between water films and condenser wall,and the mass transfer coefficient between water films and air,are 762.0(47Γ)/ow=dh,193.1093.0ad=Gh,respectively. |
