| Rotary wheel heat recovery device for indirect evaporative cooling is another newtypical thermal recovery plant, can be used to recover the cold (hot) energy of the indoorexhaust to enhance the efficiency of energy utilization and reduce the fresh air cooling(heating) capacity to deal with in the air-conditioning system, is an energy-savingair-conditioning.Rotary wheel heat recovery device for indirect evaporative cooling is:the primaryair(that is outside supply air) and the secondary air(that is the exhaust air ofair-conditioning systems)are flowing counterly, and the indoor exhaust air after packingdirect evaporative cooling in the secondary air passage of the counterflow rotary heatrecovery for indirect evaporative cooling. The heat of the primary air is transferred to thesecondary air passage through the core. In summer, the cold of the exhaust released to theaccumulator core, the exhaust temperature rises, the core body temperature is reduced, thehot fresh air come into contact with the cold accumulator core, due to the temperaturedifference, the core and the release of cold to the fresh air, the fresh air temperaturedecreases; In winter, using the heat of exhaust to preheat the fresh air.In order to improve the effectiveness of the overall unit, rotary wheel indirect coolingis often coupled with a second direct evaporative cooling section to get the lower air outlettemperature, making the air temperature is more close to the wet-bulb temperature of theoutdoor air, even the dew point temperature of the outdoor air outdoor, proposed rotarywheel thermal recovery air-conditioning unit of indirect-direct evaporative cooling.Firstly, we analysed structural features, working principle of the unit and rotary wheelin theory, according to different outdoor state point, on the psychrometric chart makingfive partitions, analysis the application forms for the various functions of the unit in thedifferent regions, theoretical analysis the using evaporative cooling proportion of totalrunning time of March to October Urumqi, Xi’an, Nantong were93.6%,79.7%,75%; Design and equipment selection of rotary wheel indirect evaporative cooling stage anddirect evaporative cooling stage for the design air volume3000m3/h air-conditioning unit.In order to analyze the performance of the unit in depth, we respectively did the testof the areas of moderate humidity and the high humidity in summer, but also we did rotarywheel heat exchanger running in winter testing, the results show that:(1) The running tests of experimental prototype in the moderate humidity area outdoorweather conditions,the following conclusions:a) In this experimental range, when we just open rotary wheel indirect evaporativecooling section, secondary to primary air ratio up to1.1, the highest value of the efficiencyreaching0.785.b) When the best secondary to primary air ratio of the rotary wheel indirectevaporative cooling section is1.1. Open the unit, we find that the total temperature drop is14.66℃.(2) The running tests of experimental prototype in high humidity areas (Nantong)outdoor weather conditions, the following conclusions:When the best secondary to primary air ratio of the rotary wheel indirect evaporativecooling section is1.1, the unit’s total temperature drop is largest, up to5.98℃; the rotarywheel indirect section efficiency up to0.74, the final temperature of the unit may beapproaching the dew point temperature of the outdoor air.(3)The running tests of rotary wheel heat exchanger in the winter, the followingconclusions:When the best secondary to primary air ratio of the rotary wheel indirect evaporativecooling section is1.0, the outdoor air temperature is8.3℃, indoor exhaust air temperatureis26℃, the heat exchange efficiency up to0.753.(4) In accordance with the actual test results predicted roatry wheel two stageevaporative cooling air conditioning units can save50%of the running costs than thetraditional mechanical refrigeration in a large supermarket in Urumqi(3to10months). |
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