The Impact of Traditional Raw Earth Dwellings’ Envelope Retrofitting on Energy Saving: A Case Study from Zhushan Village, in West of Hunan, China

Abstract

This study presents the CO2 emissions and energy performance of traditional raw earth dwellings’ envelope retrofitting located in the Zhushan Village, western Hunan Province, China. The numerical simulations of heating energy consumption on the building models were performed using DesignBuilder, an energy simulation program. The energy performance was evaluated using the indexes (including energy consumption, CO2 emissions, heat balance analysis, and air temperature profiles). The detailed evaluation process of the energy performance is presented as follows. First, the current situation was analyzed through the field research, and two typical building models were built. Second, all schemes were simulated using the DesignBuilder software. Subsequently, the four main retrofit measures (replacing the external insulation windows, setting the external wall insulation layer, setting the roof insulation layer, and setting the ceiling insulation layer) were analyzed, respectively. The optimal parameters of the respective retrofit measure were calculated. Lastly, a multi-objective optimization analysis was conducted on all retrofit plans using the coupling method. In the winter, the results indicated that the “I-shape” dwelling heat consumption of the enclosure structure was reduced by 12.8 kW·h/m2, and the CO2 emissions were reduced by 882.8 kg. While in the benchmark building, the results showed that the “L-shape” dwelling heat consumption of the enclosure structure was decreased by 13.27 kW·h/m2, and the CO2 emissions were reduced by 894.4 kg. As the renewal scheme has been progressively implemented, the whole Zhushan Village will save energy by 11.2 × 104 kW·h after the insulation renewal of the envelope structure is completed.