| With the problems of microbial contamination caused by conventional air-conditioning becoming serious, indoor air quality becomes more and more people’s attention. The air-conditioning system control method of considering indoor air quality has been put forward. In this paper, the reproduction of microorganisms in conventional air-conditioning with fan coil system is studied, including the growth details of microorganisms, detection of microbial species and the analysis of microbial reproduction conditions. It was found that the number of bacteria colonies on the fin were the least, condensate tray were the second, and the bacteria in the drainage channel were the most in fan coil system.Dedicated outdoor air dehumidification system has different control forms, which has its own characteristics. Combined with the characteristics of hospital operation room air-conditioning system, a model of dedicated outdoor air system was built in this study. Then, a program was written by VBA to simulation, researching the operating performance, energy consumption characteristics and the stability of the system under different operating conditions. Moreover, the effective control strategy of the energy saving and stable operation of the system are also presented. The results show that, the design temperature and humidity of indoor air can not only affect the energy consumption of the system, but also the dew point temperature of fresh air, which affect the stability of the system. Increasing the quantity of fresh air appropriately can improve the apparatus dew point temperature of it and conducive to the safe operation of the system, but the energy consumption of the system will increase. Such as design conditions, when the fresh air ratio increased from 0.2 to 0.25, the cooling capacity of the surface cooler change from 38.24 kW to 46.59 kW, increased by about 21.8%. The system can be stable operation if the design temperature and humidity of indoor air and the quantity of fresh air matching reasonably.When the quantity of fresh air is too small to make the dew point temperature of fresh air lower, dedicated outdoor air dehumidification system is hard to keep stable operation. So a model of dedicated outdoor air system with the return air undertaking part of indoor wet load was built in the article, researching the effect of operation control of the system under different conditions, just like indoor wet load ratio undertaking for return air, the quantity of return air and so on. What more, the effective optimization control strategy of the system were presented. The study found that the system undertaking part of indoor wet load by return air will increase the dew point temperature of the fresh air processing unit, but greatly improving the heat of the system. Reducing return air rate will reduce the heat of the system.According to characteristics of transition season climate in hot summer and cold winter zone, the calculation model of dedicated outdoor air dehumidification system in transition season was built, researching the effect of outdoor conditions, interior temperature and relative humidity and the quantity of fresh air on the system. And the partition control strategy in transition season was put forward, making the system energy saving and stable operation, ensuring good indoor air quality. The study found that, the system energy consumption will reduce with the decrease of indoor relative humidity in the heating and humidification zone. Under cooling and dehumidifying zone, the energy consumption of the system will reduce with the increase of indoor relative humidity. |
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