热回收通风系统结合锅炉房预热改善严寒地区兔舍室内环境

Heat recovery ventilation system combined with boiler room preheating to improve the indoor environment of rabbit house in severe cold areas

热回收通风在寒冷地区畜舍中应用越来越广泛,但严寒地区热回收通风的热交换器的结冰问题限制其应用。为找到经济的办法解决热回收通风在严寒地区冬季运行的问题,探索严寒地区冬季兔舍通风与供暖合理搭配的模式,缓解通风与保温之间的矛盾,本研究在中国东北阿荣旗冬季兔舍开展了热回收通风结合锅炉供暖的试验。试验中利用锅炉散发的余热对寒冷空气预热后,再进入热交换器中进行排风热回收,防止热交换器结冰导致其无法运行。结果显示,当该系统运行时,兔舍内氨气和二氧化碳浓度分别降低了46%和64%。室外温度为-15.8~-11.8℃时,通风带来的兔舍温度下降仅为1.8℃;家兔呼吸道和皮肤病冬季的发病率相比上一年分别降低了16%和4%。室外冷空气通过锅炉房预热,温度提高了8.1℃,再通过空气热交换器时,温度从提高了6.4℃,运行过程中未观察到热交换器结冰的现象。锅炉房预热和热回收通风对冷风的加热能量负荷分别为6.8和5.6 kW。热回收通风系统的显热回收效率为75.6%,能效比为6.2,设备投资回收期为3年。将热回收通风系统结合锅炉房预热可以在不额外增加耗能的情况下,大幅改善冬季兔舍的环境,为改进严寒地区兔舍冬季通风与供暖模式提供了参考。

Heat recovery ventilation(HRV)is type of energy saving ventilation.It has been widely used in animal house to alleviate contradiction between thermal comfort and ventilation in recent years.However,air heat exchanger freeze of HRV caused by severe cold weather limited HRV application in northeast China.It is necessary to find an economic way to ensure HRV being operated without freezing.Establish a more reasonable integration of heating and ventilation system in severely cold area.An experiment was conducted in rabbit house during winter in Arun Banner,northeast China.The rabbit house was heated by a coal boiler in the next room.Hot water produced by boiler was supplied to heating radiator inside the rabbit house.The boiler room was warm because of some extra heat release by boiler.To prevent freezing,the boiler room was used to preheat cold fresh air before it entered the heat exchanger.The HRV was installed on the ground of the rabbit house.It was an integration of HRV and boiler heating system.Temperature,relative humidity and concentration of noxious was measured with automatic recording sensor instrument.Data was collected to evaluate the decrease in air pollutants and air temperature of the rabbit house.Preheating effect of the boiler room and the HRV were tested when the system was in operation.The performance of the HRV and prevention of freezing in heat exchanger was evaluated in typical cold weather in northeast China.The economic benefit of the system was analyzed.The results showed that when the HRV and boiler system began to operate,concentrations of ammonia(NH_(3))and carbon dioxide(CO_(2))in rabbit house dropped by 46%and 64%,respectively.Moreover,indoor air temperature only dropped by an average of 1.8℃when the outdoor air temperature varied from-15.8 to-11.8℃.It means that the system can significantly improve indoor air quality with barely a slight decline of indoor air temperature.Respiratory and skin disease decreased by 16%and 4%,respectively.It is great potential for better health and production of rabbits.The boiler room heated fresh air by 8.1℃,and the HRV heated fresh air by 6.4℃on average.No frozen of the heat exchanger was observed.Heated load of the boiler room and the heat recovery load of the HRV were 6.8 and 5.6 kW,respectively.Sensible heat recovery efficiency of the HRV was 75.6%.Coefficient of performance of the HRV was 6.2.The system was operated efficiently.The method of freezing prevention ensure HRV in good condition among the whole cold season in northeast China.It is an economic option because the system can operated without extra energy consumption.The return of investment is 3 years in this work condition.The integration of HRV and boiler allowed HRV and boiler heating to operate with high efficiency and solve the contradiction between heating and ventilation in severely cold weather in the rabbit house.This finding can provide a sound reference for the design of animal house heating and ventilation system in severely cold climate northeast China.