VRF System Ratings and Qualifying for Demand Side Incentives

The American Heating and Refrigeration Institute (AHRI) has finally developed a new certification program for variable refrigerant flow multi-zone split air conditioners and heat pumps. In years past, systems manufactured by Mitsubishi, Daikin, LG and the like were unable to qualify for utility rebates and Federal tax incentives because there was no way to rate their efficiency performance. This was primarily because multi-zone ductless and ducted VRF systems had so many potential variations of installed indoor components that it made it nearly impossible to accurately rate SEER (Seasonal Energy Efficiency Rating), EER (Energy Efficiency Ratio) and HSPF (Heating Season Performance Factor). To solve this problem, AHRI came up with this new 2012 certification program. “This certification program covers matched variable refrigerant flow multi-split air-conditioner and multi-split heat pump systems, that comply with either the National Appliance Energy Conservation Act (NAECA) or the Energy Policy Act (EPACT) and use distributed refrigerant technology with cooling and heating capacities for outdoor units from 12,000 Btu/h [3508 W] to 300,000 Btu/h [87,692 W] and indoor units from 5,000 Btu/h [1,462 W] to 60,000 Btu/h [17,538 W]. Each indoor unit is designed to condition a single zone.”

As a result, we can now submit certain combinations of VRF systems to LIPA (utility) for residential and commercial rebate programs. This is great news because VRF systems provide their greatest savings because of their ability to operate at part load capacity. Very rarely will an air conditioning or heating system be required to operate at peak load (outdoor temps at or above 95 degrees F or below 15 degrees F). This is where the variable speed compressors in VRF systems and their ability to shift load from one area to the next comes into play. Although some VRF systems may not be able to achieve the top peak load efficiency ratings that a single or dual speed DX system can, they are considerably more efficient in partial load situations because of their DC inverter driven ability to ramp up and down from 10% to 100%+ of required capacity. Also, because most of these systems utilize electronic expansion valves that allow for an increase or decrease in refrigerant volume flow depending upon load, they have the ability to shift capacity requirements as the cooling or heating load shifts in a space due to environmental factors like solar gain variance (sun movement), occupancy levels and infiltration. This ability also allows for the use of up to 150% of indoor coil versus outdoor coil capacity.  This is something that cannot be done with standard ducted systems unless they have VAV (variable air volume) terminals or are part of a chilled water system.

Ultimately, this is a great win for the VRF industry, energy conscious consumers and VRF system installers.

As always, to keep up to date with what’s new in HVAC technology, visit our website at airideal.com and follow us on Twitter @airideal and at our Facebook page!


The Benefits of Combining VRF and Geothermal Technologies

Two of my favorite (and most efficient) technologies can actually be combined to form an uber-efficient HVAC system. Both Mitsubishi and Daikin have provided water-cooled condensing units as part of their US line-up for several years. However, only recently has this technology been refined through plate and frame heat exchangers and control logic to perform optimally with geothermal ground loop heat exchangers. Mitubishi’s WR2 series (heat recovery) and WY series (heat pump) along with Daikin’s VRV-WIII series can combine the benefits of variable speed inverter compressor technology and geothermal heat pump efficiency. Add to this the additional benefit of being able to install multiple types of ductless, ducted and concealed indoor evaporators and you have one of the most flexible and highly efficient solutions for a green building project. Because of the system’s flexibility, it can be designed into new building and retrofit mechanical schemes (see Mitsubishi schematic).

Unfortunately, as these systems are only available in larger sizes of 6 tons and up and only available in 3 phase, they are not yet a viable option for single family homes. However, we are seeing these systems specified on multiple dwelling residential projects like apartment buildings and condominiums. For the most part, this is really primarily a commercial option that can deliver added points for LEED buildings and deliver the ultimate in sustainable design. Existing ground source heat pumps on the market provide dual speed for their premium models (like the WaterFurnace Envision line), but there has not been a variable speed inverter compressor option available to the market. In redeveloping their water-cooled condensing unit lines to accommodate the geothermal market, these VRF/VRV manufacturer’s have provided a significant boost in efficiency. Based upon an energy modeling study for assisted living facilities in various cities across the country, it was proven that this type of hybrid VRF-Geothermal installation provides on average a 37% efficiency increase over VRF air-cooled heat pumps. Although VRF/Geothermal is still a costly initial installation versus established fossil fuel and air-cooled systems, emerging energy efficiency technology experts are now touting ground-source variable refrigerant flow heat pumps as an affordable energy option.

As always, to keep up to date with what’s new in HVAC technology, visit our website at airideal.com and follow us on Twitter @airideal and at our Facebook page!

VR Technology Becomes Mainstream Solution in Urban Environments

Variable Refrigerant technologies have become a mainstream HVAC application in urban environments over the past decade. The flexibility of unit design and layout configurations has made this a market niche for Air Ideal and other mechanical design/build firms in the New York metropolitan area. With a variety of indoor evaporators for floors, ceilings, walls and concealed spaces, they provide a simple solution for city projects with minimal space considerations for mechanical equipment. For many years SCAV (self contained air-cooled vertical) package units were the dominant city specified systems for individual tenant spaces, but they were notoriously inefficient and provided poor climate control and distribution across spaces with high diversity and multiple loads. Mitsubishi, Daikin and now LG and Fujitsu have all brought commercial products to the US city markets that provide solutions for office, retail, industrial and multi-dwelling residential projects.

These Asian manufacturers have also had the savvy to provide the necessary marketing expertise and design and application software to design/build contractors and engineers so that they can be properly specified, installed and commissioned. Each manufacturer and their individual distributors have been intelligent enough to provide direct training and certification for their equipment through local training and education centers located close to the metropolitan areas being served to further enhance their products diffusion to the marketplace. This also prevents poor installations as the result of lack of product knowledge and technical application inexperience.

The only barrier towards gaining major market share in urban HVAC applications has been the relative cost of these products. Equipment cost, import tariffs and three step distribution have been competitive disadvantages, but as more systems have been specified and installed, the economies of scale are ramping up and making these systems a viable alternative to standard unitary products. The partial load efficiencies of inverter technology from these products has also served as an ROI tool for convincing more owners and developers to include Variable Refrigerant equipment as a green alternative to standard unitary HVAC systems.

As always, to keep up to date with what’s new in HVAC technology, visit our website at airideal.com and follow us on Twitter @airideal and at our Facebook page!