Thermal comfort and energy performance of chilled ceiling systems

Abstract

Chilled ceiling systems are a relatively new approach to cooling and they have been applied in Europe and other countries for many years. The technology is based on ceiling-based radiant cooling panels coupled with chilled water pipes or coils. By combing convection and radiation, these systems have the potential to enhance thermal comfort and reduce energy use in air-conditioned buildings. This research studied the basic principles and key characteristics of chilled ceiling systems in order to assess their potential benefits on thermal comfort and energy performance. Field studies in two pilot projects in Hong Kong were carried out to investigate the system performance and practical considerations. Building energy simulation was applied to assess the potential benefits of the system on building energy performance. It is found from the field studies that the thermal comfort can be maintained in most of the time but some occupants feel that the air movement is sometimes too low. As compared with the conventional all-air systems, the chilled ceiling systems can reduce energy requirements by increasing chilled water temperature, decreasing supply air flow, downsizing air handling equipment and promoting higher room temperature. The results of building energy simulation show that the fan energy saving is the most important component and the percentages of energy saving for the HVAC system (19.8%) and the whole building (12.1%) are significant.

冷却吊顶系统是一个相对较新的冷却方法，在欧洲和其他国家已应用多年。该技术是基于冷冻水管道或盘管联结的天花板辐射冷却面板。这些系统通过结合对流和辐射，有潜力以提高热舒适度，并减少空调建筑物的能源使用。本研究探讨冷却吊顶系统的基本原理和主要特点，以评估其对热舒适性和节能性能潜在的好处。在香港的两个试点项目，进行了系统性能的调查和实际的考虑。并且应用建筑能耗模拟，来评估系统性能的潜在建筑节能好处。从研究试点项目发现，系统可以在大部分时间保持热舒适性，但也一些用户感到空气的流动有时过低。冷却吊顶系统与传统的全空气系统相比，可降低冷冻水温度增加的能源需求，减少空调供应送风量，削减空气处理设备，并促进更高的室温。建筑节能模拟分析结果表明，风机节能是最重要的组成部分，对空调系统(19.8%)和整个建筑(12.1%)的节能百分比结果是显著的。