Thermal model for cooling load calculation and its applicability of coincident design weather data generation for intermittent air-conditioning systems

The intermittent air-conditioning systems are widely used in practical buildings due to its short operating cycles and low energy consumption. However, there is currently no design cooling load calculation model specifically suited for intermittent air-conditioning systems, and traditional design weather data (TDWD) also lacks sufficient accuracy for design cooling load calculation. In this study, a thermal model based on state space method has been proposed to calculate the hourly cooling load of intermittent air-conditioning systems. The thermal model was also validated by the simulation results of EnergyPlus. The results indicated that the relative deviation of the annual cooling load calculated by the thermal model to that by EnergyPlus was 8.04%, while the relative deviation of peak cooling load to that by EnergyPlus was 6.21%. These relative deviations fall well within the requirements of ASHRAE Guideline I4. In addition, the thermal model was applied to generate coincident design weather data (CDWD). The relative deviation of design cooling load was utilized to evaluate the applicability of the thermal model in generating CDWD. The results for Shanghai revealed that the average relative deviation of the design cooling load by CDWD was 2.47%, significantly lower than 12.29% by TDWD. The relative deviation for 90% room samples for CDWD ranges from −5.8% to 6.74%, while for TDWD, it ranges from −11.46% to 46.95%. Thus, the thermal model can not only accurately calculate hourly cooling load but also be suitable to generate coincident design weather data for intermittent air-conditioning systems.