| Energy conversation and water-saving have become the long-term aim and significant demand in the planning of the energy development of our country. Energy conversation is a long-term strategic policy in the national economic development and the primary approach to solve energy problem. The principal means of saving water is to improve the efficiency in recycling water. Evaporative condenser is a kind of new highly effective heat exchange equipment, which has the advantages of saving energy and water. At present, we face a serious situation concerning energy and water resousces in China. And such equipments have being greatly improved and widely applied under such a circumstance.Evaporative condenser is one of new highly effective heat exchangers developed by combining the non-sature evaporation and the condensation. Its working process coupling the mass and heat transfer between air and liquid flows. The flow fild inside the evaporative condenser is very complex. Therefore, in-depth theoretical research and experimental study on the characteristics of air-water two-phase flow and its heat and mass transfer are necessary.First, the characteristics of heat transfer between working fluid in tube and water out of plate have been analyzed. Then, a three-dimensional computed model of flow field inside the condenser was established and studied by using commercial computational fluid dynamics (CFD) software. Effects of number, size of the air inlets were investigated and the influence mechanics concerning heat transfer was analyzed. The results show that pressure field and temperature field inside the evaporative condenser with four or two air inlets are more evenly than that with single inlet; appropriate a+ can reduce the turbulence of air flow inside the condenser, hence can reduce the thermal resistance of the evaporative condenser;A air conditioning system with evaporative condenser was established. Effects of the different wind operations (foou air inlets, two air inlets and single air inlet), and wet-bulb temperature of the inle air were studied. The results show that: (1) Wet-bulb play a key role in the performance of the system, the capacity and EER decreased 20% and 27%,with the wet-bulb temperature increasing from 18.4℃to 26.5℃, respectively. The load of compressor and EER grow 1.24% and 3.42% with every one increment of wet-bulb temperature, respectively. The study on the effects of air inlets number indicate that the best number is 2 and the best air flow rate is 4900m3/h When wet-bulb temperature is 19.4℃,the maxium capacity of the thriller and EER is 32.3 kw and 4.63, respectively. When wet-bulb temperature 19.8℃,he maxium capacity of the thriller and EER is 32 kw and 4.6 respectively. The investigation of the effects of the size of air inlets show that the best ration between area of air inlet and area of heat transfer is 0.14, when the EER of the system is 4.1~4.5。This dissertation present study on the performance of air conditioning system with water cooling tower or evaporative condensers in different loads. COP of both system in different loads were testing and the results indicate that the IPLV of system with evaporative condensers is 21.1% higher than those with water cooling tower and 36.8% higher than those with air cooling tower.The analsys on the energy efficiency of this project reveal that the air conditioning system with evaporative condenser has a good energy conservation ability. The index of year average energy consumption is 16.01% lower than those with water cooling tower,while SEER is 27.3% higher.The study on flow characteristic of evaporative condenser and energy analysis of air conditioning system with it in this subject enriched both theoretical research and application development of the both the evaporative condenser and evaporative air conditioning system. Therefore make a good basis for further study of the performance and optimal design of the evaporative condenser and air conditioning system. |
