©2013 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 55, no. 2, February 2013.
Long-Term Commercial GSHP Performance: Part 7: Achieving Quality
About the Authors
Steve Kavanaugh, Ph.D., is a professor emeritus of mechanical engineering at the University of Alabama, Tuscaloosa, Ala., and Lisa Meline, P.E., is a principal at Meline Engineering, Sacramento, Calif.
This is the final installment in a series that summarizes a data collection and analysis project to identify common characteristics of successful ground source heat pump (GSHP) systems.
The goals of GSHP systems are common to conventional HVAC systems and include the following:
- Low building energy consumption and costs;
- Installation costs that are economically viable in relatively short time periods;
- Room conditions that are satisfactory to occupants; and
- Minimal maintenance requirements and costs.
Finding good data for this project was challenging because typical measures of success identified in the list of goals were either not accessible or made unavailable for GSHPs (and traditional HVAC systems) that did not perform as expected. A larger study of LEED buildings was able to obtain actual energy data for only 121 out of 585 buildings requested. The authors posed the question, “Why is it so hard…to get this information for the buildings being profiled?”
Every electric utility encountered in this survey had the necessary information. The hitch was the building owner needed to approve access, and in some cases, the owner chose not to do so. The information on installation costs was even more restricted than the utility data.
From the survey, it may be surmised that:
A reason it is so hard to obtain energy data (and costs) is that in some cases “…the buildings are using significantly more energy than predicted,”1 so designers, contractors, and owners are unwilling to share results.
Designers, contractors, and owners willing to share energy and costs data are likely to have completed successful GSHP projects with good energy performance (i.e., high ENERGY STAR rating) and reasonable first costs.
The average ENERGY STAR ratings for the GSHP buildings surveyed in this study may be higher than the average of GSHP systems (because of the first two items).
However, the average could potentially be much higher if owners (and architects) were able to choose engineers based on quantifiable information. Publication of energy data, installation costs, and satisfaction levels will allow engineers to demonstrate GSHP quality and provide owners (and possibly architects) an effective metric for selecting outstanding designers.
A magazine article published during the low point of the recent financial crises suggested that when economists are speaking on television, statistics should be shown for the accuracy of their predictions in a manner similar to the screen display of baseball player’s statistics. This may be something to think about for design engineers.
However, architectural portfolios are probably a more professional format to follow than ball player statistics. An “engineering portfolio” would likely contain fewer pictures and more numbers than typically provided by the architectural community. Table 1
and Figure 1
suggest a framework for possible formats to be included in an engineering portfolio, although they undoubtedly could be enhanced by graphic artists and marketing consultants. Table 1
presents a summary for the energy rating, mechanical system cost, and occupant satisfaction for recent projects completed by an imaginary firm. Figure 1
provides much greater detail with text to highlight the building characteristics and energy conservation features and a succinct listing of results to show how well primary goals have been achieved.
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