A transfer function model of lighting heat dissipation for detecting time-delay effect and dynamic cooling demand during the real-time operation of buildings

Abstract

Monitoring real-time heat dissipation of lighting, a major indoor heat source, is essential for determining the dynamic cooling demand of buildings, and it provides a reliable basis for sizing air-conditioning systems and saving energy. Contemporary models cannot be used to obtain the accurate real-time heat dissipation of lighting or the time-delay effect, because of which these models have critical limitations in precisely detecting dynamic cooling demand of buildings. To address this problem, a transfer function model is proposed for calculating the real-time heat dissipation of lighting in this paper. First, the model structure is determined according to the energy conservation law, heat transfer principles, and so on. Second, an experiment is conducted using a nearly adiabatic test chamber. Third, parameter identification and order reduction analyses are performed, and the real-time heat dissipation model of lighting is determined as a third-order transfer function. Experimental data of the same and different types of lighting are employed to verify the proposed model, and the maximum mean absolute percentage error (MAPE) is 7.83%. Comparing with the fixed ratio method, the proposed transfer function model not only reduces MAPE by 66.05% within 1 h after lighting is turned on but also describes a time-delay effect in the stability of lighting heat dissipation. The results of this study exhibit the promising applicability for accurately determining the cooling demand of a building during real-time operation, thus improving the indoor thermal environment and reducing energy consumption.