HVAC
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ENERGIZING HVAC PROGRAMS Is your HVAC maintenance program costing you energy dollars? | Mark Barraclough
he rising cost of fuel and energy is no surprise to anyone. When you take your car to the gas station, I’m sure you’ve noticed that you’re spending as much as 25% more per gallon over the last couple years. Likewise, the Department of Energy is reporting a 19% increase in energy costs over the last year, and these rising costs are starting to chip away at many retailers’ bottom line. Historically, retailers have had separate line items in their budget for HVAC maintenance and energy/utilities expenses. In most cases, facility managers have the HVAC maintenance line item in their budget, and the energy and utilities budget is usually someone else’s responsibility. Some retailers report that HVAC energy usage within their stores is second only to lighting and in some cases can represent more than 35% of their total energy bill spent. Why, then, is energy usage not considered when an HVAC maintenance program is developed, implemented and reviewed? Why is energy usage not a criteria for determining if proper HVAC maintenance is being performed? Proper maintenance is critical to continued operation of a store’s HVAC equipment — thereby ensuring customer and employee comfort. Let’s face it: customers will not spend time in a store that is too hot or too cold. Most HVAC maintenance programs are structured around this theory but are driven mostly by price. Contractors with the lowest maintenance pricing, in most
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Keep in mind that a 10% increase in HVAC unit efficiency could reduce or eliminate your overall HVAC maintenance budget for that unit.
cases, are awarded the contract to provide maintenance. Maintenance quality considerations are usually overlooked as they relate to wasted energy dollars. A recent study performed for Purdue University’s International Refrigeration and Air Conditioning Conference showed some shocking results. The Public Interest Energy Research (PIER) project investigated inefficient design and maintenance practices in small HVAC systems. The study found that: • 63% of unit economizers were malfunctioning. • 46% of units had incorrect refrigerant charges. • 39% of units had air flow issues. • There were numerous control related problems causing fans, heating and cooling to operate incorrectly.
(A total of 75 buildings and 215 rooftop units were studied as part of this project.)
The reason the result was so shocking was that economizers are designed to allow for free outside air to be used when store conditions require cooling and the ambient temperatures are below 55 degrees. Disconnected or malfunctioning economizers force the unit to run mechanical cooling to keep the store comfortable and use energy to run the compressors. Also, when the compressors are running, the common charge and indoor air problems cited in the study significantly reduced the energy efficiency of units. Even small problems can reduce efficiency by 10% to 20%, and large problems (e.g. most charge issues) can bring the efficiency to zero. How does this happen? The HVAC industry is a fragmented industry and one where most technicians work on roofs, out of site and devoid of effective technical management. It is also an industry with few defined standards from which technicians work. Within the same company, one technician can review the operating data of a unit and confirm it is