Evaluation methods of intermittent heating at the individual scale: From theory to terminal application

Accelerating energy conservation and carbon reduction in the building sector is crucial for achieving carbon neutrality. The energy consumption of a building is primarily influenced by room load, service time, service space, and the energy efficiency of equipment. While previous studies have concentrated on reducing room load and enhancing equipment efficiency, research on service time and service space dimensions remains limited. Notably, the evaluation of equipment used for intermittent heating remains incomplete. In this study, the terminals and evaluation methods for intermittent heating were investigated. A temperature response matching coefficient focused on the human scale was proposed. The temperature response matching coefficient indicates the proportion of the actual temperature-rise area to the temperature demand curve area. Experiments were conducted on the intermittent effects of conventional convective and radiant terminals using fan coils and floor heating as examples. The suitability of conventional terminals for intermittent heating was quantitatively assessed, leading to the development of a novel radiant-convective terminal that integrates convection and radiation. Utilizing the phase change of flat heat pipes as a radiant surface, a radiant-convective terminal with low thermal inertia was proposed. Experimental results indicated that the temperature response matching coefficients for convection and radiation modes per 10 min in the first half-hour were 0.24, 0.42, 0.55 and 0.12, 0.21, 0.29, respectively. These results were consistent with those of fan coil and floor heating methods. The new radiant-convective terminal combined the effects of two conventional terminals, thereby simplifying the system. This study provides a reference for the evaluation methods of and terminals used for intermittent heating.