Evaluation of energy-saving retrofits for sunspace of rural residential buildings based on orthogonal experiment and entropy weight method

Abstract

The retrofit of building envelopes in rural areas is a necessary measure to reduce building energy consumption. However, the traditional retrofit strategy is mostly a subjective decision, therefore, a scientific and objective evaluation method is proposed, which is a multi-factor and multi-objective preferred method based on orthogonal tests and entropy weights. The construction strategy for an additional sunspace of a typical rural residence in severe cold areas is studied. The results show that the glass type and the window-to-wall ratio have a remarkable influence on the optimization of the sunspace, accounting for 64.03 % and 17.42 %, respectively. Compared with the original rural building, the heating energy consumption of building with retrofit sunspace reduces by 12.82 %. Considering comprehensive energy saving, incremental cost, cost-benefit ratio and carbon emission reduction, the optimal construction strategy is the scheme 13, which has three layers of insulating glass with a window-to-wall ratio of 0.9, a depth of 0.9 m, 60 mm foamed concrete insulation board on the roof, 20 mm extruded polystyrene thermal insulation board on the ground and 120 mm foamed concrete insulation board on the adjacent south wall. The weights of the aforementioned parameters are 0.2967, 0.1916, 0.2021, and 0.3095, respectively, which are calculated by the entropy weight method.