Study On Dynamic Heat Transfer Law Of The Wall Implanted With Heat Pipes

As a new type of passive solar energy utilization technology, the wall implanted with heat pipes(WIHP), using the one-way thermal conductivity and high efficient heat transfer performance of the gravity heat pipes, transfers the solar radiation on the outside surface of the external wall quickly into the indoor environment, driven by the temperature difference between the outside and inside surface temperature of the south wall. The WIHP solves the contradiction between the use of the solar energy and the high heat resistance of the external wall of buildings in north area, and improves the indoor thermal environment.Based on the dynamic heat transfer theory of the conventional wall and the simplification of the heat transfer process of the WIHP, the dynamic heat transfer model of the WIHP is built:The heat transfer capacity of the WIHP inside surface is divided into the heat transfer capacity of the conventional wall and the heat transfer capacity of the condensing and heating section. In this way, the combination is the hourly heat transfer capacity of the WIHP inside surface.The internal disturbance temperature of heating section is the main factor of influencing the heat transfer capacity of condenser the condensing and heating section. In order to obtain the relationship between the outdoor air synthetic temperature and the internal disturbance temperature of the condensing and heating section, the attenuation coefficient and the working-hours-weighted mean temperature are introduced. The local attenuation coefficient in Tianjin is set to be 0.30 experimentally. On the basis of the local attenuation coefficient, the hourly internal disturbance temperature is obtained, and the heat transfer capacity and the inside surface temperature of the WIHP are calculated to compare with those of the conventional wall. The results of the comparative analysis indicate that:1、The main factor of determining working condition of the WIHP is the outdoor air synthetic temperature, which is affected by the outdoor air temperature and the solar radiation intensity.2、The heat transfer capacity of condenser the condensing and heating section is divided into the instant heat transfer capacity and the heat release. The instant heat transfer capacity is the value of the heat transfer from the condensing and heating section to the inside surface of the wall when the heat pipes are working. The heat release is the value of the heat transfer the inside surface from the thermal storage of wall when the heat pipes stop working. In the whole heating season, the ratio of the instant heat transfer capacity and the heat release is 4:1.3、In ideal working state, the WIHP can significantly reduce the heat load(even gain heat) and enhance the inside surface temperature. When heat pipes are working, the temperature of inside surface temperature of the condensing and heating section upgrade average about 2.4 ℃. In the whole heating season, the energy-saving rate of the WIHP is 21.61%.