Abstract:
Cooling load calculation is the first step in designing the air-conditioning system of a building. The calculated
cooling capacity with appropriate buffer is then used to select the number and size of chillers in the
system. Nþ 1 is a common formula used by designers to size the chiller plants in Hong Kong buildings,
where N is the actual number of chillers required and 1 is a redundant chiller provided to ensure reliability.
This paper reviews the problem of excess capacity and discusses the risk exposure of chiller systems
without redundant chillers. The cooling load profiles of the chiller plants of four medium-sized commercial
buildings inHong Kongare reviewed. The risk exposure of chiller systemswithout redundant chillers can be
minimized byapplying risk-based preventive maintenance. The just-in-demand design reduces capital cost
of the building and frees up funds for continuous energy measurement and improving the energy efficiency
of chiller plant systems. This paper presents a model for designing chiller plants that improves the energy
efficiency of the plant in a cost effective and thoughtful manner. It is designed with consideration of the life
cycle of the plant and real-time continuous commissioning, monitoring, measurement, comparison and
execution for better energy managemen
