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
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
running fine, yet another technician can say there is a performance issue. This is a problem since all HVAC contractors rely on the technical expertise of each of their technicians to guarantee that maintenance is being done correctly and effectively. Most HVAC units are critically charged and technicians adjusting the charge without the correct procedures or tools can significantly reduce a unit’s efficiency. Adding charge is one of the simplest repairs. This makes it easy to overcharge units, making them less efficient. Indoor airflow problems are caused by dirty filters, dirty indoor coils and restricted ductwork. When an air conditioner has difficulty absorbing heat from the indoor air stream, it compensates by making the indoor coil colder, which lowers the unit’s efficiency. Dirty condenser coils have a similar effect on the outdoor coils, also reducing efficiency. As a result, HVAC units, although running, may not be doing so at their peak energy efficiency. So, what is the answer? As the HVAC industry continues to develop new technology for maintaining and servicing
units, there are now tools on the market that help technicians maintain units and create some level of consistency. Some of these tools, such as the Digi-Cool System Analyzer and the Testo 523 Refrigeration System Analyzer, replace a technician’s standard set of manifold gauges with a data acquisition tool that collects and processes unit operating data and provides the technician with more definition of the problem. There is also the Honeywell HVAC Service Assistant that not only does what the other tools do, but also provides automated fault detection and diagnostic features that assist the technician in determining exactly what the problem is within the unit, and what is needed to correct it. This tool goes one step further and can actually provide a detailed analysis as to how energy-efficiently the unit is running and the approximate gains in energy efficiency from correcting the fault that it has detected. In the end, retailers have to look closely at how energy usage plays an important role in their HVAC maintenance program. With the continued rise
in energy prices, retailers and HVAC contractors must get creative and find ways to validate that the PM program not only provides consistently performing units but, just as importantly, units that are running at their most proper energy-efficient levels. Keep in mind that a 10% increase in HVAC unit efficiency could reduce or eliminate your overall HVAC maintenance budget for that unit. In coming articles, I hope to provide more details around this issue and further illustrate the importance of bringing these two budget line items closer, to provide retailers with potential energy savings that have not yet been realized. PRSM
MARK BARRACLOUGH IS PRESIDENT OF ALPINE MECHANICAL SERVICES, A NEW BRITAIN, PENNSYLVANIA-BASED SELF-PERFORMING HVAC CONTRACTOR.
Reprinted From Professional Retail Store Maintenance, April 2006 © 2006 France Publications, Inc. Atlanta, GA (404) 832-8262. www.FrancePublications.com
Published on Sep 6, 2012