Heat Transfer Performance And Optimization Of Evaporative Condenser

The heat and mass transfer theory analysis and data programming calculation of evaporative condenser are studied in this article.And evaporative condenser performance test bench is built.With the test bench,we can study the laboratory test of heat and mass transfer performance of evaporative condenser,and contrast experiment research of evaporative condenser and air-cooled condenser.In this paper,through the experimental study on heat and mass transfer performance of evaporative condenser,to provide some guidance for future design of evaporative condenser.The evaporative condenser is the use of evaporation of water film to achieve the principle of cooling.The amount of wind and the spray of water,if appropriate,can make better film of water distribution.And water film thermal resistance can be reduced to improve the heat transfer performance of the evaporative condenser overall,otherwise it will affect the overall system heat exchanger performance.The influence of evaporative condenser's water temperature,head-wind and spray density to evaporative condenser performance is studied in this issue through experiment.Through the analysis of experimental data,research the following conclusions:?1?In dry condition,the evaporative condenser overall heat transfer coefficient K is in the range of 39.79 46.57 W.m^-2.K^-1.The outside air convection thermal resistance plays a dominant role,directly determines the size of the overall heat transfer coefficient.?2?When the refrigeration system is running stable,circulating water temperature may be less than,equal to,or greater than the supply water temperature of the circulating water;When the circulating water quantity is constant,the circulating water temperature is lowered with the increase in the amount of wind,The beginning of the decreased rapidly,with the air volume increases gradually slowed down,and finally leveled off.?3?The best face velocity of evaporative condenser is 3.28 m / s,although the face velocity has little effect on the water film heat transfer coefficient ?w,?w changes very little in the experimental range of face velocity.But the face velocity has greater impacted on K,q,Q_o,?_wa,?_m,?_i and EER.So in order to optimize the evaporative condenser heat and mass transfer,face velocity must be controlled so that it comes close to the best face velocity.?4?The evaporative condensers' best spray density is 0.057 kg.m^-1.s^-1.For any given evaporative condenser has the best spray density.Although the spray density has little effect on air convection heat and mass transfer,but it has large effect on the cooling efficiency,K,Q_o,q,?_i and ?_w.?_w has been on the rise with the increase of the spray density,and the rest of the amount are at the peak when the spray density is 0.057 kg.m^-1.s^-1.Above these show that the spray density is a very important factor affecting the evaporativecondenser.So in order to optimize the heat transfer performance of the evaporative condenser,it is necessary to make the evaporative condenser to achieve the best spraying effect.?5?The overall heat transfer coefficient in dry condition is approximately 1/10 of normal working condition,using the latent heat of evaporation cooling with high heat transfer efficiency.Comparing the effect of face velocity and spray density on evaporative condenser performance,we can be seen that face velocity mainly affect air convective heat and mass transfer efficiency in the film of water-air interface.Spray density is relatively large effect on the heat transfer performance of the water film.And both of which are the main factors to affect the evaporative condenser heat and mass transfer performance.This issue through theoretical analysis and experimental study of evaporative condenser,has optimized the evaporative condenser theory,and obtained the best face velocity and best spray density of evaporative condenser.This article provides a useful reference for further study on the performance of the evaporative condenser.