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Getting More Accurate Sensible Cooling Load Calculations

From eSociety, March 2018

One of the articles in the March edition of Science and Technology for the Built Environment looks at five peak cooling load methods covered by ASHRAE during a 46–year period beginning in 1967.

The study, “Literature Review of Building Peak Cooling Load Methods in the United States,” summarizes the method differences that can lead to inaccurate sensible cooling load calculations, according to the authors, Chunliu Mao; Juan-Carlos Baltazar, Member ASHRAE; and Jeff S. Haberl, Fellow ASHRAE.

The authors address how the research can help engineers in the field better choose a proper calculation in addition to providing information on the methodologies, which was sometimes a challenge to find.

1. What is the significance of this research? Why is it important to explore this topic now?

This research is significant because it provides a comprehensive review of ASHRAE’s five peak cooling load calculation methods (i.e., the total equivalent temperature difference/time averaging method, the transfer function method, the cooling load temperature difference/solar cooling load/cooling load factor method, heat balance method and the radiant time series method).

The review covered previous literature not only on the early building load calculation methods but also on the peak cooling methods published by ASHRAE between 1967 and 2013. The authors feel this review is important to explore because, since 2001, the ASHRAE Handbook–Fundamentals only contains detailed information about the heat balance method and the radiant time series method. However, a recent survey revealed that many ASHRAE users are still using the older methods, and several of the most popular textbooks for engineers and architects still contain the older methods.

Hence, ASHRAE members who wish to learn more about the procedures used in the other ASHRAE methods must consult a number of different references; some of which can be difficult for ASHRAE members to obtain. Therefore, this study can be a handy reference for those readers who are interested in the building peak cooling load methods.

2. What lessons, facts, and/or guidance can an engineer working in the field take away from this research?

This article provides the reader with a historical review of how the peak cooling load calculation methods evolved, and includes a description of the procedures used in each method. For some practitioners it will be a first opportunity to get guidance on the limitations and advantages of each methodology. The article also provides a comprehensive list of references where the reader can go to find additional details about all the methods.

3. Were there any surprises or unforeseen challenges for you when preparing this research?

In the research performed for this article, it was discovered that very few of the previously published articles contained a sufficient description of the procedures used in each method. In addition, some of these articles were more than 80 years old, which required access to an archival library to locate an original copy of each article. The authors feel that the article’s uniform review across the five methods provides a valuable reference for ASHRAE members, as well as a comprehensive list of references for the reader to consult and to learn more.

4. How can this research further the industry's knowledge on peak cooling load methods?

The research published in this article provides a unique reference point regarding a comparison of all five methods from a procedural perspective, which can better guide ASHRAE field engineers to choose a proper calculation. The paper also lays out enough information on the methodologies that will allow properly addressing issues that each procedure has.

To see what other topics are included in the March 2018 edition, visit.