Center for the Built Environment

The current standard procedure for design sizing of cooling systems is not well suited for design of buildings with radiant cooling. There are several reasons that the standard design procedure for radiant cooling systems (ASHRAE Systems & Equipment 2016 Chapter 6: Radiant Heating and Cooling) is flawed, including that the current standard definition of space cooling load (ASHRAE Fundamentals 2017 Chapter 18: Nonresidential Cooling and Heating Load Calculations) omits fundamental principles that are essential to the operation of radiant cooling. This report identifies several specific shortcomings with the current standard cooling load definition and with the standard cooling system design sizing procedure. We explain the fundamental flaws with each, discuss why addressing these shortcomings is especially important to the optimal design and operation of radiant cooling systems, and provide general recommendations for how the procedures ought to be improved. The issues and recommendations presented in this report have been informed by several research projects conducted as part of the CEC EPIC research program Optimizing Radiant Systems for Energy and Comfort (EPC-14-009). In addition to identifying specific flaws with standard cooling load and design sizing procedures, we also discuss how each aspect of our research has provided evidence about or potential solutions to each issue.