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

Abstract: 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.