Industry News

Interview with an Engineer: Vic Amoroso


March 26_Muscatine County Courthouse ImageWater in the basement, leaky pipes and loud units were some of the more obvious signs that the 30-year-old cooling and heating system in the historic Muscatine County Courthouse needed to be replaced. The nagging effects of the outdated system and the design challenges presented by the 105-year-old building coupled with the county’s goal to decrease energy usage led to the installation of our VRF zoning system. In addition to providing optimal air quality and energy savings, our system contributed to the building becoming one of only a handful of courthouses in the U.S. to earn ENERGY STAR® certification.

We sat down with Vic Amoroso, founder and principal of A & J Associates, to discuss why our VRF zoning system was the ideal choice for the job.

ME: What factors in any given situation lead you to specify VRF zoning systems? Are there typical situations where VRF is the right solution?

Vic Amoroso (VA): Yes. Because VRF systems heat and cool via a change of state, from liquid to gas and back again, you transfer more BTUs per pound of fluid — very much like a steam system. One result is that VRF systems don’t require as much ductwork as air transport systems. That means VRF systems are friendly to projects where space is limited — such as historic rehabilitation projects in buildings that didn’t originally have air conditioning.

The other big advantage with VRF is that it provides better individual control at a lower cost. A central air system would use central terminal air boxes and tie them to variable flow diffusers to get individual zone control. That costs more than VRF but doesn’t allow the level of control you get with VRF. Another alternative would be individual heat pumps or fan coil units in rooms. But that’s more expensive than VRF because of the larger components. In buildings with limited space — typical in older buildings — VRF has the lowest first cost because it requires about 20 percent less ductwork than air transport systems.

Another HVAC system that’s competitive with VRF cost and energy-wise is radiant heating and cooling. However we don’t usually use radiant heating and cooling because it requires drop ceilings and “clouds” that are not historically appropriate in older buildings.

ME: Does Mitsubishi Electric’s CITY MULTI VRF zoning system have advantages over other VRF systems?

VA: Yes. First, Mitsubishi Electric’s VRF system is the only two-pipe simultaneous cooling and heating VRF system available. So it costs about 10 to 30 percent less than comparable VRF systems. Second, Mitsubishi does a better job of interfacing with a geothermal system. Third, Mitsubishi’s outside air-cooled units can handle lower temperatures better than other VRF systems. So in most comparisons, Mitsubishi’s VRF system gets the job.

To read the full interview, check out the article in our Fall 2013 Engineer newsletter. For more information on this installation, click here for the Muscatine County Courthouse Case Study. To subscribe to our newsletters, click here.