In hot and humid climates, the application of conventional radiant cooling systems is often limited by condensation risk and insufficient cooling capacity. To address these limitations, a decoupled radiant cooling (DRC) technology has been developed, in which a new type of radiant cooling panel is adopted. The new panel, titled as DRC panel, uses an air layer that is sealed by an infrared-transparent membrane to separate its radiant cooling surface from the air-contact surface. This design enables high radiant cooling capacity while minimizing the risk of condensation. However, existing research mainly focuses on the thermal performance analysis of DRC systems using steady-state models. There is a lack of research on their dynamic behavior under varying external boundary conditions and internal load disturbances. This study addresses the research gap in the dynamic thermal performance analysis of DRC systems by developing a quasi-2D dynamic model using a resistance-capacitance (RC) thermal network, calibrated through a non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ). The model was validated against experimental data, achieving mean absolute errors (MAE) and root mean square errors (RMSE) not exceeding 0.28 ℃ and 0.34 ℃ for both the membrane surface temperature and the radiant cooling surface temperature. The model also showed reasonable agreement in predicting the indoor air temperature and outlet water temperature. A simulation platform based on the developed model was constructed for a typical office conditioned by a DRC system, demonstrating its effectiveness as a tool for analyzing the dynamic thermal environment. The results highlight the model’s ability to provide accurate predictions, laying a solid foundation for future studies on energy consumption forecasting and operation control method development for DRC systems.

In many chiller plants, high coefficient of performance (COP) is only achieved at a few favorable part load ratios (PLRs), while the COP is low at many other non-favorable PLRs. To address this issue, this study proposes a generic load regulation strategy that aims to maintain chiller plants operating at high COP, particularly under non-favorable PLRs. This is achieved by incorporating thermal energy storage (TES) units and timely optimizing the charging and discharging power of the integrated TES units. The optimal charging and discharging power is determined by solving a dynamic optimization problem, taking into account the performance constraints of the TES units and the chiller plants. To provide an overview of the energy-saving potential of the proposed strategy, a comprehensive analysis was conducted, considering factors such as building load profiles, COP/PLR curves of chillers, and attributes of the TES units. The analysis revealed that the proposed load regulation strategy has the potential to achieve energy savings ranging from 5.7% to 10.8% for chiller plants with poor COPs under unfavorable PLRs, particularly in buildings with significant load variations.

Decoupled radiant cooling units (DRCUs) are capable of increasing the cooling capacity without increasing condensation risks even using a much lower cooling temperature than conventional radiant cooling units (CRCUs). However, it is unclear whether DRCUs using low radiant cooling temperature will increase the cooling load of the conditioned indoor spaces. In this study, the cooling load characteristics of a thermal chamber conditioned by a DRCU was investigated through developing a steady-state analysis model suitable for both DRCUs and CRCUs. The total/radiative heat flux, as well as the heat exchange with a thermal manikin and walls were analysed under different surface temperatures of DRCUs. The effect of the emissivity of the thermal chamber' external wall on the cooling load was also investigated. Results indicated that the cooling load under the DRCU was slightly smaller than that under the CRCU when the same operative environment was created. Decreasing the infrared emissivity of the exterior wall's inner surface could lead to a significant decrease in the cooling load for both the DRCU and CRCU. By decreasing the wall emissivity from 0.9 to 0.1, the total cooling load of the DRCU can be decreased by 8.4% and the heat gain of the exterior wall decreased by 21.6%. This study serves as a reference for developing the analysis model and understanding the load characteristics when DRCUs are used to create the thermal environment for indoor spaces.