Appliance Design - May 2008 - (Page 32)

QUALITY & STANDARDS The Efficiency Table 1. Table 2. A new measure of refrigeration efficiency promises to improve system design. by rajan rajendran Rajan Rajendran is director of application engineering for Emerson Climate Technologies, Refrigeration Division, Sidney, Ohio 32 applianceDESIGN May 2008 he refrigeration industry currently has a number of standards and methods of measurement in place to provide a helpful guide for determining the energy efficiency of equipment. These methods, such as the Energy Efficiency Ratio (EER), allow engineers to compare different compressors and operating conditions, ultimately finding a combination that fits the application at hand. However, a new approach takes these useful measurement tools a step further. The Annual Energy Efficiency Ratio (AEER) allows for a better representation of how refrigeration systems actually operate, taking into account factors that don’t always figure into other simple measurements. The level of accuracy brought about by this new AEER measurement will help system design and application engineers provide the best suitable products for their end-users’ refrigeration equipment needs. Over the years, the Air-Conditioning, Heating and Refrigeration Institute (AHRI) has set various standards for the industry. Standard 540-2004 spells out the conditions T at which commercial refrigeration and airconditioning compressors must be tested for measuring and reporting important compressor performance data, such as capacity and energy efficiency. These AHRI test conditions are different for high-, medium-, and low-temperature applications, as seen in Table 1. The table also shows the appropriate pressure and temperature settings for different operating conditions. EER and SEER The current Energy Efficiency Ratio (EER) method of measurement is calculated according to these AHRI standards and is a single point efficiency measurement for an air-conditioning or refrigeration compressor at high-, medium-, and low-temperature operating conditions. It is based on one rating point, at one evaporating temperature, and one condensing temperature. For lowtemperature applications, this is –25 DegF evaporating temperature and 105 DegF condensing temperature to calculate the capacity, power and EER of the compressors. For medium temperature applications, www.applianceDESIGN.com http://www.appliancedesign.com

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Appliance Design - May 2008 Contents Editorial Shipments/Forecasts News Watch New and Notable Displays & Indicators Elastomers Quality & Standards Indoor Air Quality IHHS Highlights New Products Classifieds Design Marts Advertiser’s Index Association Report: PSMA

Appliance Design - May 2008

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