Research On Heat And Mass Transfer Process Of Closed-type Heat Source Tower Under Summer Conditions

As a new type of cold and heat source equipment, closed-type heat source towerhas a wide application prospect, which effectively overcomes the defects inherent inthe traditional cold and heat source technology. Closed-type heat source tower canextract the low-grade heat from the air for using of heating during the winter, while inthe summer, the working principle of the closed-type heat source tower is similar tothe closed cooling tower, with a more efficient heat transfer performance because ofthe finned tube heat exchanger. What,s more, it will improve the equipment utilizationrate because of no equipment idles.At first, the assumptions of heat transfer model of the closed-type heat sourcetower in the summer was put forward, and according to the principle of heat and masstransfer, the heat transfer model was established in the paper. The heat and masstransfer coefficient and other parameters involved in the heat transfer equation wasintroduced, and based on the numerical calculation process given in the paper, thenumerical solution was presented for the heat transfer equation. Secondly, anexperiment platform was set up to test the heat transfer performance of theclosed-type heat source tower in summer. The various parameters of the measurementprocess and the matters need attentions were introduced in the paper, and the heattransfer model was validated by the experimental measurements. Finally, theparameters influence of the heat transfer performance of closed-type heat sourcetower, such as the air wet bulb temperature, water spray flow rate, air flow rate andcooling water flow rate were analyzed in the summer condition.Results showed that the heat transfer model of closed-type heat source tower inthe summer working condition was in good agreement with the experimentalmeasurements, so it can be used in the design and simulation calculation of theclosed-type heat source tower with important theory significance and use value.Keeping other parameters constant, the studies indicated that the cooling water outlettemperature increased with the increasing of the inlet air wet-bulb temperature, whilethe cooling efficiency decreased correspondingly. Increasing the spray water volume,we could find that the cooling water outlet temperature reduced, while the coolingefficiency increased accordingly, and the cooling water outlet temperature and thecooling efficiency was stable when the spray water volume increased to a certain degree. The increasing of the air flow rate could lead to the reducing of cooling wateroutlet temperature, while the trend of cooling efficiency did the reverse. Changing thecooling water flow rate, the cooling water outlet temperature increased with theincreasing of it, while the change of cooling efficiency was, which can be adjusted bychanging the other parameters.