Effect of the energy-saving retrofit on the existing residential buildings in the typical city in northern China

Abstract

Since the last ten years, non-energy-saving residential buildings have been retrofitted in China. However, theoretical and practical effects did not match. Due to the lack of actual measurement, the effect of energy-saving retrofit is affected. This study emphasizes on heating energy consumption of the existing non-energy-saving residential buildings in typical cities in northern China and intends to measure them through a heat exchange station, a secondary network, and building during the heating season from 2015 to 2016 and from 2016 to 2017 (before and after retrofit). Comparing the actual measured energy consumption and the energy consumption boundary index of each nod, the energy consumption levels before and after retrofit of different links are analyzed. Comparing the measured energy consumption data of the typical projects at each node before and after the retrofit and using the data standardization method, the buildings before and after the retrofits are at the same boundary conditions. And the actual energy consumption levels and energy savings before and after the transformation of different nodes are analyzed. The main influence factors are determined in the retrofit process. The effect of heat exchange station's control strategies on heating energy consumption is studied. The change of heating radius before and after retrofit is explored. Moreover, the influence of energy-saving retrofit on the indoor temperature and excess heating were analyzed. Results show that the energy-saving rates of the heat supply for heat exchange stations and the heat consumption of buildings were 12.5% and 15.6%, respectively. The intermittent regulation of the heat exchange station, after the energy saving retrofit, saved 18.5% compared with before retrofit, when the heating was stopped. The range of heating radius was expanded by 25.5% after retrofit. There was an increase of 2° centigrade in the indoor temperature of the buildings. And the pass rate of indoor temperature increased by about 20%. Energy loss cannot be ignored and it was caused by 32.8% increase in the excess heating rate.