密闭式蛋鸡舍外围护结构冬季保温性能分析与试验

蛋鸡舍围护结构的保温隔热性能是影响鸡舍温度的稳定性,进而影响蛋鸡健康和生产性能的关键因素。由于蛋鸡舍一般不采暖,依靠蛋鸡的自身显热产热量来维持冬季蛋鸡舍内温度,因此如果蛋鸡舍冬季饲养密度较低、通风过度或围护结构保温性能不足,都难以满足蛋鸡舍温度环境的要求。如何确定不同气候区鸡舍围护结构必要的保温性能和饲养密度要求是解决蛋鸡舍冬季通风和保温矛盾问题的关键。该文通过建立蛋鸡舍动态热平衡理论模型,系统分析了不同气候区鸡舍围护结构的最低热阻需求,得出不同气候区鸡舍围护结构的保温性能要求与蛋鸡饲养方式(密度)的关系。结果表明:冬季舍外计算温度分别为-25℃(东北、内蒙古)、-15℃(华北、西北)、0℃(长江以南)的地区,蛋鸡舍墙体、屋面的最小热阻应分别不小于0.778、0.972;0.573、0.716;0.266、0.333(m~2·℃)/W;对应3层全阶梯笼养、4层半阶梯笼养和4层叠层、6层叠层、8层叠层笼养等饲养模式最大饲养密度下,所能够适应的围护结构冬季室外计算温度应分别不低于-14、-17、-19、-22、-23℃。研究结果为不同气候地区选择适宜饲养模式以及密闭式蛋鸡舍围护结构保温系统的设计提供了理论依据。

Analysis and experiment on thermal insulation performance of outer building envelope for closed layer house in winter

The main considered environmental factors affecting performance of poultry is temperature. Thermal insulation performance of building component is the key factor that affects temperature stability, which is essential to ensure the bird's well-being, maximum productivity and efficient feed utilization. Generally, laying hen houses are not equipped with heating system in winter, the temperature meets the requirements of layer hen rely on sensible heat production of layers. Bird's sensible heat production and good insulation of building component are generally sufficient to maintain the houses temperature. If the stocking density is low or poorly insulated buildings, it's difficult to meet the layer house environment requirements, including temperature, humidity and air quality. Improving thermal insulation performance of the building component would reduce heat loss and increasing stocking density could raise sensible heat production. However, ideal ventilation control system is required to ensure that aerial pollution emissions levels are within the acceptable limits and not to result in unnecessary ventilation heat losses. As such, minimum ventilation rate is particularly important. It is crucial for indoor temperature level and uniformity. Layer house minimum ventilation and air flow are crucial not only for indoor temperature and humidity, but also for temperature control uniformity. But there was a lack of information about the design theories. No information could be found in the literature that optimum relationship between thermal insulation performance of the layer house component and stocking density in laying-hen housing systems with different climatic regions in China. It was required to settle the urgent issue on how to determine the layer houses component thermal insulation performance under different climate zones, especially in the layer house building construction and environmental control fields. The objectives of this article was to analyze on minimum thermal resistance of building component in different climatic regions of China, and according the law of energy and quality conservation, to build dynamic heat balance model for layer house. A model was developed to determine the thermal insulation performance. It was important to build dynamic heat balance model in layer house, in order to maintain the temperature of the house of laying hen and to keep the healthy environment of layer hen. Those can reduce the energy consumption and construction cost, providing a guidance for laying house thermal insulation system design. In this paper, we conducted theoretical analysis and numerical calculation the building component minimum thermal resistance under the different climate regions and built steady-state heat balance theory model for layer house. Results showed that: 1) When calculated temperatures were -25℃ (Northeastern China), -15℃ (Northern and Northwestern China), -0℃ (South of the Yangtze River China), the minimum thermal resistance of the layer hen houses walls should not be less than 0.778, 0.972, and 0.573 m2·℃/W, and the minimum thermal resistance for the ceiling should not be less than, 0.716, 0.266, and 0.333 m2·℃/W respectively for the above mentioned three regions. 2) A-frame cage of three tiers, semi-A-frame cage of four tiers, four overlap tiers cages, six overlap tiers cages, and eight overlap tiers cages, with maximum stocking density and outdoor design temperature should not be lower than -14, -17, -19, -22, -23℃. As such, dynamic thermal balance of layer house can be achieved. The results of this study provided theoretical foundation for the design of insulation system for closed layer hen house. Those research results can reduce the energy consumption and construction cost and providing a theoretical basis for layer house thermal insulation design system.