| Condensing dehumidifier can be highly efficient dehumidification work,so that the relative humidity in the high humidity environment in a short period of time,and no restrictions on the heat source,no cooling water,so the equipment structure is simple,convenient operation,easy maintenance.However,the condensing dehumidifier in the lowtemperature environment when the operation of the heat exchanger finned tube surface will occur frost phenomenon,resulting in the dehumidifier can not work properly.In this paper,the condensing dehumidifier heat exchanger fin tube surface frost phenomenon of a large number of theoretical and experimental research,the use of frost suppression technology to inhibit and delay frost,and through a variety of frost melting methods on the surface of the heat exchanger fin tube after frost melting treatment to achieve the normal operation of the condensing dehumidifier in low-temperature operating conditions,expanding the working temperature range of the dehumidifier to meet the different needs of people’s production and life.First,the dehumidifier heat exchanger finned tube surface frost experiments.The experiment includes two elements:First,the dehumidifier heat exchanger finned tube surface frost state division experiment.Control the ambient temperature of 22℃,the inlet air speed of 1.5m/s,the ambient relative humidity of 80%,record the average temperature value of the heat exchanger rib tube surface in different frost states.And through a combination of theory and experiments on the frosting process in different stages of the state of the division,to determine the state of the heat exchanger fin tube surface frost layer uniform coverage,for the subsequent frosting experiments to prepare for the work.Second,on the basis of the frost state division experiment,the dehumidifier heat exchanger finned tube surface frost experiments undermultiple conditions to determine the melting conditions.Control the ambient air temperature of 20℃,22℃,24℃,the inlet air speed of 0.5m/s,1m/s,1.5m/s,2m/s,2.5m/s,ambient relative humidity of 65%,70%,75%,80%,85%,90%,the experiment a total of 90 groups.Through the experiment to determine the dehumidifier heat exchanger finned tube surface frost process and the conditions of melting frost,to obtain the operating conditions of the heat exchanger finned tube surface frost to frost uniform coverage stage required time for the subsequent melting experiments to determine the starting time.Secondly,the best frost inhibiting effect of propanetriol solution was selected through the experiment to determine the frost inhibiting conditions,and the frost inhibiting treatment was carried out on the basis of the frost inhibiting treatment after the frost experiment.Control the ambient temperature of 20℃,22℃,24℃,equipped with four kinds of concentration of 30%,50%,66.7%,80%of the solution of propylene glycol,the heat exchanger surface for a spray,continuous second spray,continuous third spray,the experiment a total of 36 groups,the best frost suppression effect experiments to determine the number of sprays of propylene glycol solution and solution concentration,to achieve the best frost suppression effect.The best working conditions of the solution of propylene glycol sprayed uniformly on the surface of the heat exchanger fin tube for frost inhibition conditions of frost experiments,the ambient temperature of 20℃,22℃,24℃,the inlet wind speed of 0.5m/s,1m/s,1.5m/s,2m/s,2.5m/s and air relative humidity of 65%,70%,75%,80%,85%,90%,respectively,the experiment A total of 90 groups were used to determine the frosting time under different working conditions.Through the experiment to obtain the heat exchanger finned tube surface in the frost suppression conditions frost to frost uniform coverage stage required for the subsequent heat exchanger in the frost suppression conditions to determine the starting time of the melting experiment.Again,the frosting process of the heat exchanger rib tube wall is simulated numerically.Through the heat exchanger rib tube around the air component distribution cloud map can be obtained from the frosting process of the various stages of change;through the heat exchanger rib tube,rib and surrounding air temperature field simulation,the heat exchanger fin tube surface temperature distribution and heat exchanger rib tube and surrounding air temperature change over time cloud map,the heat exchanger fin tube surface frosting mechanism and process,and frosting experiments with the comparison,to verify the simulation of The correctness of the simulation was verified by comparing with the frosting experiment.Then,frost melting experiments and numerical simulations were conducted on the heat exchanger finned tube surface.First,the melting experiments were conducted on the heat exchanger finned tube surface under different melting methods to determine the best melting method.Using the hot air method and electric heating method for heat exchanger finned tube surface melting frost experiments,in the ambient temperature of 22℃,control the inlet air speed of 0.5m/s,lm/s,1.5m/s,2m/s,2.5m/s,air relative humidity of 65%,70%,75%,80%,85%,90%,a total of 60 sets of experiments,through the experiment to obtain two melting methods of frost Dehumidification capacity and unit power dehumidification capacity of the two melting methods,compare the experimental results to select the best melting method.Then the numerical simulation of the change of parameters before and after the melting of the heat exchanger rib tube and the surrounding air,to obtain the volume fraction field of liquid water,water vapor volume fraction field,air volume fraction field and relative humidity field in the simulated area,as well as the condensation and dehumidification of the heat exchanger rib tube wall before and after the melting treatment and comparative analysis.Finally,the dehumidifier’s dehumidification performance under multiple working conditions is compared and tested.The dehumidifier without improvement,after the frost suppression treatment,after the frost suppression-melting frost treatment of three different situations,in the entrance air temperature of 20℃,22℃,24℃,26℃,28℃,30℃,the relative humidity of the environment were 65%,70%,75%,80%,85%,90%of the conditions,a total of 108 groups of dehumidification performance experiments.The experimental results of dehumidification performance comparison analysis,to obtain the dehumidification capacity of three different cases of dehumidifier under each working condition,and the normal operation of the dehumidifier temperature range,to determine the widest temperature range of the dehumidifier after the frost suppression-melting frost treatment. |
