Building energy-saving mechanism for indoor cooling temperature set-point with different envelope: A case study in Guangzhou

Abstract

The temperature set-point of air conditioning system is a crucial parameter for behavior adjustment. Nevertheless, the thermal characteristics of building envelopes are different at varied construction ages. In this context, there are already several systematic studies demonstrating the differences in energy savings as a result of raising the same temperature set-point for air conditioning. In this study, an office building was used under four assumed envelopes representing different construction ages, and the characteristic temperature method was applied to simulate the hourly dynamic air-conditioning load before and after the set temperature rise of 1°C presenting monthly and annual cooling consumption. We then explored the energy-saving effect and difference in the mechanism of air conditioning with increasing indoor temperature set-point. The results showed that, provided that the temperature set-point is increased by 1°C under the same climatic conditions, the worse the thermal performance of the envelope, the higher the annual air-conditioning energy and the higher the annual energy-saving rate of air conditioning, which indicates that the behavioral energy-saving guidance for the groups with the poor performance of the older envelope has more immediate effects. The hourly load reduction of different envelopes at the outdoor temperature between 26°C and 27°C constitutes the behavioral energy-saving effect, which is the main contribution of air-conditioning energy saving (58 – 79%), while the energy-saving effect contribution of temperature difference reduction is secondary. The newer the construction age, the better the performance of the envelope, the smaller the hourly load reduction amount of the building, and the smaller the relative energy-saving rate, but its energy-saving behavior in the total energy saving ratio is greater, and the contribution of the energy-saving behavior is greater. The results of this study can provide a reference for guiding occupant energy-saving behavior and standard formulation.