Operational energy-saving rate prediction of one office building renovated to comply with GB 55015-2021 under three different China climate zones

The building sector takes up nearly half of the total energy consumption and CO2 emission of China in the year of 2020. During the lifecycle of one building, improving the operation energy efficiency plays a vital role to achieve China’s “Dual Carbon” Goals (Carbon Peak by 2030 and Carbon Neutral by 2060). To promote the energy saving and carbon reduction of China buildings, the “General code for energy efficiency and renewable energy application in buildings” (GB 55015-2021) has put in force since April of 2022.

The code sets a general goal of 20% operation energy reduction for public buildings compared with relevant standards around 2016. 20% is an average number because China is known for various climates across the country and energy-saving rate may be different among climate zones. This study aims to use EnergyPlus to numerically investigate the operation energy-saving rates of one office building renovated to comply with GB 55015-2021 under three different China climate zones, which are Cold, Hot Summer & Cold Winter (HSCW) and Hot Summer & Warm Winter (HSWW).

The performance limits of envelopes, lighting, and HVAC equipment were set according to GB 55015-2021 for the renovated office buildings under the three climate zones. The parameters of original office buildings under different climate zones for energy-saving rate comparison were set according to China standards around 2016. The cooling and heating load were firstly predicted and compared.

The office building of HSWW climate zone has the largest cooling load, while that of Cold climate zone has the largest heating load. Office buildings complied with GB 55015-2021 have cooling load reduction by about 10% thanks to the improved envelope performance. Further, the operation energy was predicted and discussed. Although the cooling load of the office building of Cold climate zone is the smallest, much more heating energy was consumed, which makes it consume the largest annual energy.

On the other hand, the office building of HSWW climate zone complied with GB 55015-2021 has the lowest annual energy and the energy-saving rate compared with that complied with China standards around 2016 is also the largest among the three climate zones. Such result is mostly owing to the significant improvement of envelope thermal resistance and chiller performance of GB 55015-2021. In the future, more detailed simulation using EnergyPlus is helpful for further enhancing energy-saving rate of China public buildings targeting zero energy buildings.