Consulting-Specifying Engineer - October 2008 - (Page 47)

A strange thing occurred: The circulation pumps and heat exchangers associated with the lake rarely operated in the winter. When the system did operate, heat was rejected during the heating season because of rising loop temperatures. This was a result of heat pumps serving interior spaces, continuously cooling them and rejecting the heat to the loop. Further analysis indicated that there were large enough cooling loads in the interior spaces to sustain the loop water temperatures to meet the heating requirements at the exterior of the complex during the heating season. With a little more insight and possibly a dose of skepticism, the additional costs might have been avoided. The final justification was that the lake avoided unsightly cooling towers and exposed mechanical equipment on the property. Bottom line, the system worked but the additional costs to be “geothermal” were not necessary. Another consideration regarding geothermal systems: heat pumps traditionally consume more than 1 kW per ton of cooling. The overall efficiency is a factor of the amount of recoverable heat used in the process of producing that one ton of cooling. The net operating costs are a factor of dollars per BTU for electricity versus that of some other fuel, such as natural gas. From a totally holistic environmental view, the consumer sees 3,413 BTU/kW. The actual energy expended by the utility is approximately 11,300 BTU/kW. Heat pumps require electrical energy to operate. Most areas in the country have moratoriums on developing any type of new power plant. One could argue that wind or solar could provide the necessary power; however, the costs and long-term reliability of these technologies are factors. This is not an attack on geothermal systems, heat pumps, or other green or sustainable technologies. The point is to substantiate the use of any new technology to the end user. Because it is sleek, shiny, or slick does not always mean it is appropriate. The outcome will be beneficial for all of us and future generations. We, as design We, as design professionals, have a duty to be analytical, to challenge, and to differentiate between sound judgment and emotionally driven perceptions. professionals, have a duty to be analytical, to challenge, and to differentiate between sound judgment and emotionally driven perceptions. It is refreshing to observe the next generation of engineers—enthusiastic, bright, innocent, and filled with new ideas. However, the real world is filled with consequences, and that youthful enthusiasm has to be balanced by the practicality of the experienced cynic. Our industry is headed in the right direction. The environment and energy efficiency seem to be less of a fad and are accepted as practical realities. As professionals, we need to ensure this momentum with sound design concepts and not just fashionable perceptions. Remember, it is failures that are highlighted and remembered, even if they are a small percentage, and it is those failed projects that will inhibit any positive progress. Zak is principal with Graef Anhalt Schloemer and Assocs. Inc. and is a dedicated environmental curmudgeon. He is a member of Consulting-Specifying Engineer’s editorial advisory board. Find a World of HVAC&R Technology for a More Sustainable Future INTERNATIONAL AIR-CONDITIONING • HEATING • REFRIGERATING EXPOSITION McCormick Place North & South Halls January 26-28 2009 January 26-28, 2009 Chicago, Illinois Co-sponsored by: Honorary sponsor: Free Registration and Information: www.ahrexpo.com Input #230 at csemag.com/quickResponse http://www.ahrexpo.com http://www.ahrexpo.com http://www.csemag.com/quickResponse

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - October 2008

Consulting-Specifying Engineer - October 2008 Contents Viewpoint Letters News M/E Roundtable Cities Under One Roof Eight Design Tips for Integration Is 'Green' Really New? Down the Drain Product of the Year Awards Codes & Standards Case Study New Products Equipment Lifecycles Advertiser Index Green Space

Consulting-Specifying Engineer - October 2008

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