Spokane, WA
Mann-Grandstaff VAMC
AHU Feasibility
This was a feasibility study to examine the practicableness of replacing nine AHUs in areas where customer complaints, age of units, duct leaks and other factors have illuminated the need to perform some type of capital upgrade. This study entailed the evaluation of air handling units for capacity and performance, creating as-built drawings for existing duct work, and the recommendation of upgrades and improvements that would improve efficiency. We had to examine hydronic loop (pumps, pipes, cooling tower, chiller), steam and condensate loop, electrical, DDC, seismic, epoxy flooring, OSHA, Joint Commission, and CFM guidelines to establish the SCIP Funding for replacement of these units.
We worked with Controls Solutions NW to develop required logic to extract as much energy savings as possible the hydronic loop while meeting all cooling and humidity requirements. This study identified several AHUs that had exceeded their expected life cycle and many others that had less than 5 years remaining before estimated failure. The energy efficiency of each aged unit was deemed to be far below the current standards. Many units were lacking variable speed drives and run continually at full load while only just meeting the required temperature and humidity ranges for their service locations. These units had no redundancy and because of their age, reliability was the chief risk for Veterans being served by the equipment. Several AHUs were undersized for their servicing areas; however, they were limited in deliverable volume by the restricted size of ducting used throughout the building. Most of the ceiling mechanical area was overcrowded by unused services and hardware thereby limiting the available space for increasing ducting size. This study determined what actions a future designer could take to alleviate the symptoms being expressed by the shortcomings of the HVAC System in these nine areas. Project was completed on time and ahead of schedule.