Influence of air-conditioning intermittent operation on the cooling load from opaque envelopes in residences

Abstract

Air-conditioning (AC) intermittent operation is extensively employed owing to occupancy regulations and residents' habits. This conditioning operation type significantly affects the indoor air temperature as a result of the on-off cycles of AC, leading to potential high temperature differences between adjacent rooms due to varying operation rules. Based on this, numerical simulations were done to deal with the overall thermal behavior of typical bedrooms under intermittent operation, and the individual contributions from different envelope components were discussed considering four models of AC operation in adjacent rooms. The results demonstrate that optimizing these four envelope components can lower average transient heat flows by 16.6 %–65.03 % with the consideration of the operation model. Among these components, the ceiling exhibited the highest energy efficiency potential with a reduction ratio of up to 42.8 %. Furthermore, the AC operation model in adjacent rooms had a significant impact on cooling load, and optimizing these four envelope components greatly reduced thermal disturbances from neighboring rooms. The fluctuation percentage of daily heat transfer capacities decreased from 33.89%-37.16 % to 20.64%–23.76 %. Specifically, optimizing opaque envelopes resulted in reductions in heat transfer capacities by 32.06 % and 30.48 % respectively, with ceilings contributing most significantly at 15.1 % and 14.2 %.