DON'T EXHAUST YOUR ENERGY SAVING OPTIONS

With the ever increasing cost of electricity, Williams Notaro & Associates, Inc. is often asked by Facility Managers to evaluate options to reduce the operating costs of their facility. We were recently asked to determine if operating cost savings could be realized if the existing ventilation system in the parking garage could be better controlled. As we examined the system and how it operated, we were confident that significant savings could be achieved with relatively minor modifications to the control and operation of the system.

The facility evaluated was constructed in 1988 and was designed to provide continuous 24-hour ventilation to reduce the buildup of carbon monoxide in the garage. At that time, the 1984 BOCA National Mechanical Code required a ventilation rate of 1.5 cubic feet per minute (cfm) per square foot in garages. This resulted in over 400,000 cfm of continuous ventilation provided by 13 fans. At an electric rate of $0.076 per kilowatt-hour (kWh) this system consumed approximately $57,000 of electricity annually.

Continuous improvements to engine design have resulted in a significant reduction of carbon monoxide emissions from modern vehicles. As a result, the buildup of carbon monoxide in garages is reduced and the 1.5 cfm per square foot of continuous ventilation is often not required except during peak traffic times.

Current code allows the ventilation system to be automatically controlled to limit the concentration of carbon monoxide to 25 parts per million. If a carbon monoxide control system were installed, the operation of the existing exhaust fans could be reduced when low levels of carbon monoxide are present reducing both energy consumption and operating costs.

The current International Mechanical Code requires that automatic operation of the mechanical ventilation system for parking garages "shall not reduce the ventilation rate below 0.05 cfm per square foot of floor area and the system shall be capable of producing a ventilation rate of 1.5 cfm per square foot of floor area." By providing a continuousventilation rate of 0.05 cfm per square foot of floor area and only energizing the large fans as required to limit the carbon monoxide concentration, we estimated that the operating costs could be reduced by 85%. This would result in an annual savings of approximately $48,000 yielding approximately a 2½ year payback period for the system modifications.

This is one example of the many opportunities available to reduce energy consumption within a facility. WNA specializes in performing these types of facility evaluations and would be happy to speak to you specifically, regarding any concerns or options you may have to reduce your energy consumption.

Mr. Tekampe is a project manager with Williams Notaro & Associates, Inc. and holds a Bachelor of Science in Mechanical Engineering from Virginia Polytechnic Institute and State University. He specializes in managing and designing projects supporting the high-tech industry that typically requires extensive coordination and detailed HVAC solutions to meet the changing needs of that industry.  He has worked for clients such as Raytheon, the British Broadcasting Corporation (BBC), Lockheed Martin, Acterna, and Northrop Grumman.