Study On Indoor Thermal Environment Radiated By Solar Low-temperature Floor In Gannan

Gannan Tibetan Autonomous Prefecture is located in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau.It has abundant solar energy resources and the thermal construction area belongs to a severe cold area.In winter,the main heating materials are coal,and cow manure.The indoor thermal environment is poor and polluted environment.How to use abundant solar resources to improve indoor thermal environment and reduce buildings energy consumption is an issue that we need to solve urgently.In this paper,a residential house in Shanglangkanmu Village,Zogai manma Township,Hezuo city,Gannan Tibetan Autonomous prefecture,was selected as the research’s object,and its traditional heating method was transformed to solar low-temperature floor radiation.Mean while,another nearby building with similar structure and orientation was taken as the control building.By analyzing the operating characteristics of solar low-temperature floor radiation,using indoor thermal environment evaluation system,and conducting simulations,it is found that solar low-temperature floor radiation has a significant effect on improving the indoor thermal environment.The main research results of this article are as follows:(1)The energy input of the heating system in the coldest month is less than the energy output,and it needs to be supplemented by auxiliary heat sources.In the typical daily heat storage stage,the temperature of the water tank reaches a maximum of 53.9℃,and solar radiation plays a major role in the temperature of the water tank;in the heat release stage after 18:00,the temperature of the water tank continues to drop from 51.6℃ to about 36℃,and the indoor temperature can be increased by 2℃,the temperature difference between the heating inlet and the return water continued to shrink,and the indoor surface temperature increase trend slowed down;After 24:00,because of the heat storage water tank under the influence of environment temperature and wind speed,water tank temperature drop is accelerated,indoor temperature is keeping falling until the end of heating.(2)Except for the coldest month in the heating season,the indoor thermal environment basically meets the requirements,but the indoor thermal environment of the test building in the coldest month is better than that of the control building,and the PMV index is used to evaluate the indoor thermal comfort of the test building,the thermal comfort index is low,and the coldest month requires supplementary heat source.The indoor temperature in the coldest month in January fluctuates around 12℃,which cannot meet the 14℃stipulated in the Design Standard for Energy Efficiency of Rural Residential Buildings(GBT50824-2013).However,compared with the control building,the indoor temperature of the test building can be increased by up to 4℃.good.The indoor humidity in the coldest month in January is 30%to 60%,which meets the requirements of ISO7730 between 30%and 70%.Compared with the control buildings,the indoor humidity is basically similar.The thermal comfort of the test building is low,and an auxiliary heat source needs to be added to the low-temperature floor radiant heating system,and the indoor PMV value is roughly the same as the subjective questionnaire.(3)The simulation of low temperature floor radiation confirms that the system can effectively improve the indoor thermal environment.In the lowtemperature floor radiation simulation model,the temperature difference between the heating inlet and return water,the temperature of the water tank,and the surface temperature curve conform to the law of the measured data.The low temperature floor radiation can increase the living room by 1.8℃ and the study room by 1.1℃ respectively;reduce the humidity in the living room and study by 1.8%and 2.1%,and the humidity range meets the ideal state of 30%to 60%.The TRNSYS simulation results show that the solar low temperature floor radiation can effectively change the indoor temperature and temperature stability,thereby improving the indoor thermal environment and indoor thermal comfort.To sum up,the solar low-temperature floor radiant heating system can meet the heating demand in winter in Gannan area,and can effectively improve the utilization rate of energy and indoor thermal comfort.This topic can guide the design,popularization and application of clean heating systems in winter in severe cold regions.