A curtain regulating strategy for high energy performance in office buildings

Internal shading technologies, as an essential strategy for improving the indoor optic-heat environment and reducing building energy consumption, still lack effective energy-saving regulating methods. In this study, a heat gain, daylight illuminance, and energy consumption model for office buildings was established based on the energy balance principle. Using the model, a curtain regulating strategy with high energy performance was developed. In this strategy, an energy-saving curtain regulating method (ECRM) was proposed, distinct from the traditional curtain adjustment method (TCAM), to improve the energy performance of buildings. Furthermore, a simplified internal shading optic-heat ratio (η) was utilized to evaluate the shading performance and support curtain optical-property selection under the studied conditions. The energy consumption characteristics of office buildings were analyzed under various electric lighting power and curtain surface reflectivity (ρc) conditions. The energy-saving potential of the ECRM was also explored. The results show that the energy-saving potential in offices with curtains is greater than that in offices without curtains, and that the surface reflectivity significantly affects the internal shading optic-heat ratio (η). In buildings with higher electric lighting power, the optimal optical reflectivity of the curtains was between 60% and 80%. On a typical summer design day, the ECRM in the office was consistently more energy-saving than the TCAM. Simulation results predict that, on a typical summer design day, ECRM can reduce the office energy consumption by up to 26.6% compared with TCAM when the curtain reflectivity is 80%. Even for office buildings with lower electric lighting power, ECRM was predicted to have greater energy-saving potential than TCAM.