A study on thermal characteristic and sleeping comfort of a hybrid solar heating system applied in cold rural areas

A hybrid solar heating system combining a solar kang subsystem and a solar air heating subsystem for keeping indoor space within thermal comfort level is investigated in this article for the climatic conditions of Qinghai Province (35 degrees N 96 degrees E)- China. The main aim of the current research is to study the hybrid heating system's thermal characteristic and the sleeping comfort of occupants in rural buildings. A mathematical model to study the hybrid heating system has been developed and the results have been validated by conducting an experimental study at a building located in Qinghai province. The influence of the different solar thermal collector areas, insulation levels of wall, thermal sensation of the system and different operation strategies have been investigated. It has been observed that the indoor temperature can be improved by up to 6 degrees C when the ambient temperature is -7.8 degrees C (average). By changing the solar collector area from 4 m(2) to 8 m(2), the kang surface average temperature can be improved from 22 degrees C to 31 degrees C. Thermal load of sleeping can also remain within acceptable levels when the beddings insulation value is maintained at 4.0clo during night time. It has been observed that without auxiliary power, making the kang system work only at night would be more suitable in the experimental condition. (C) 2018 Elsevier B.V. All rights reserved.