Does climate change significantly impact the benefits of existing building energy-saving retrofit? evidence from a parametric study

A key strategy for lowering emissions and reducing the effects of climate change is to execute energy-saving retrofits in residential buildings. Despite extensive research on different retrofit pathways for building energy efficiency, the current retrofitting of the aged housing stock in China is still constrained by several factors, including occupant willingness, government financial situation, and low energy prices, so retrofitting projects are almost entirely government-led and most of the solutions of existing studies are not applicable. Therefore, a comprehensive optimization framework for low-budget compliance retrofit strategies in the Chinese context is urgently needed. In order to fill this gap, this study established a set of procedures for developing an optimal energy-saving retrofit scheme in old residential buildings in Nanjing city. The results showed that the optimal scheme can reduce 18.52% of residential building energy consumption in five central districts of Nanjing City, and the total energy saving is about 260.43 GW h. The study also showed that improving wall insulation and heating, ventilation, and air conditioning systems were the most efficient retrofit measures but came at a high cost. Setting a reasonable air conditioning target temperature was further identified as the most cost-effective retrofit measure. This study provided a mechanism for district-level retrofit planners to formulate a strategy that may take the performance of retrofitting on the environment and the economy into account while still adhering to code requirements.

Many cities are striving to develop urban transformation strategies, in order to transit from traditional city to a sustainable city. Improving the energy efficiency of the existing buildings is the key to address climate change mitigation and adaptation. This paper considers different climate scenarios using different series of future climate in four different European cities, namely, Kiruna, Stockholm, Valencia and Madrid. The study adopts the TABULA database to get access to basic construction information. Energy simulation and data analysis using IDA ICE and MATLAB are performed. Based on climate change, an overall retrofitting plan was developed by combining energy-saving retrofit solutions. The results show that in Madrid and Valencia, future heating demand will decrease and cooling demand will increase. In Kiruna and Stockholm, with the increase of the insulation material, the heating demand of the house has decreased, but the cooling demand has shown a downward trend compared with the cases of Madrid and Valencia. The first reason is the introduction of hybrid cooling, and the second is that the average indoor temperature has been maintained at 21 degrees Celsius due to the low outdoor temperature in summer. The findings indicate that in Kiruna, Stockholm, and Madrid it is better to insulate façades to lower the heating demand in winter. In Valencia, it is possible to have relatively low heating and cooling demand without façades insulation as insulated façades require more cooling demand during summer.