Research On Winter Environment Of Beef House And Ventalation Modified In Cold Regions

The main parameters of thermal environment and air quality were measured for six types of beef house in three beef farms in Heilongjiang province in order to realize the environmental situation and to explore the reasons of environmental problem, and to provide theoretical basis for the design of beef house and improvement of husbandry and management. Results showed that average air temperature for type A Ⅰ and type AⅡ beef house were2.3℃and1.0℃respectively, and average internal surface temperature were-4.7℃and-4.9℃, average relative humidity were94.3%and99.4%, and CO2concentration were7399mg/m3and6063mg/m3respectively. Average air temperature for type B Ⅰ and type BⅡ beef house were-0.6℃and-11.2℃respectively, and average internal surface temperature were-6.7℃and-16.7℃, average relative humidity were99.9%and78.8%, and CO2concentration were3207mg/m3and1414mg/m3respectively. Average air temperature for type C Ⅰ and type CⅡ beef house were-2.5℃and-3.5℃respectively, and average internal surface temperature were-9.8℃and-7.2℃, both average relative humidity were99.9%, and CO2concentration were5660mg/m3and5253mg/m3respectively. These results indicated that lower air temperature, higher relative humidity and foul air quality were common problem in these six types of beef houses in winter. The main reasons for these problems were lower heat insulating capability of building envelope, imperfect ventilation system design and poor environmental management measures.Ventilation system of type A Ⅰ beef house were transformed in order to improve these problems. Type A Ⅰ beef house was named type A Ⅰ-G beef house after it was transformed. Transformation for type A Ⅰ included that wall was covered with two layers of plastic film instead of one layer of plastic film and the space between films was8cm, and34air inlets, which were1.0m×0.2m in size, were installed under eaves of beef house, and exhaust pipe was stretched for1.0m. The main parameters of thermal environment and air quality were measured for type A Ⅰ-G beef house and type A Ⅰ-D beef house (control). Results showed that average air temperature for type A Ⅰ and type AⅡ beef house were-6.0℃and-2.2℃respectively, and average internal surface temperature were-9.2℃and-5.8℃, average relative humidity were96.7%and99.9%, and CO2concentration were3316mg/m3and4341mg/m3respectively. The CO2concentration of type A I-G beef house decreased by707mg/m3and2467mg/m3respectively when14and28air inlets had been opened for150min. These results indicated that two layers of plastic film played a role in increasing the thermal insulation of beef house to some extent and air inlets which were installed under eaves of beef house increased ventilation volume of beef house significantly.