In this post I’ll be describing the HVAC system installed at the Byrne residence. One of the key HVAC design considerations described to me by both Bill Byrne and Will Bruder was the need to deal with the significant thermal load presented by the south-facing and west-facing “Solex” glass walls and to end up with an aesthetically-pleasing – and economical – installation. Additionally, the lack of conventional soffits in some rooms would make routing the duct work a real challenge, so a creative solution was in order!
Their idea was to match four (4) Lennox heat pumps with four air handlers from The UNICO System®. This approach meant the different zones of the house could be managed on separate thermostats, offering a degree of independent operation – per zone – which would have been difficult to achieve with fewer units. Additionally, a benefit of using The UNICO System® duct work, (due to its smaller dimensions), meant the ducts could be routed in the tight confines between both the ceiling and floor joists.
The original system was installed in 1998, which meant it used R22-based refrigerant vs. R410A-based refrigerant required by law for systems being installed today, (though I did happen to run across an interesting paper describing how well both refrigerants work in hot climates authored by NIST). I mention this because in the summer of 2010, we replaced the 5 ton Lennox unit with another 5 ton Lennox unit and this past spring, the three remaining Lennox units were replaced with three equivalent units from their sister brand, Aire-Flo, (3, 2 and 1.5 tons respectively), and we stuck with R22-based replacement units to avoid having to open up ceilings and replace the air handlers too. In other words, had we been forced to replace the heat pumps with units using R410-based refrigerant, we would have had to replace the four (4) air handlers as well.
February 2013 Update: The Lennox/Aire Flow heat pumps have proven to be fundamentally incompatible with The UNICO System® air handlers they were paired with and, as a consequence, all four (4) of the Lennox/Aire Flow heat pumps were replaced – again – in February 2013 with American Standard heat pumps.
I’ve inserted several images of The UNICO System® below. The first is a simple diagram of the basic elements in a system:
The second is an image of an air handler – the three units serving the Living Room/Kitchen/Dining room, the Master Bedroom/Bathroom and the entire lower-level, (Office, Living Room, Library, Laundry Room), look quite a bit like this one. The unit serving the Guest Bedroom/Bathroom on the main level is vertically-oriented, but made up of the same three elements, located in a utility closet in the Garage.
This third image is a close-up photograph of the 2 inch duct and the typical white outlet which fits into the end of the duct to finish off the appearance. These tiny portholes are what you’ll find projecting through the floors, walls and ceilings throughout the Byrne residence to supply cold, (summer), or warm, (winter), air in each zone/room.
A quick look at where the four heat pumps are located on the north side of the house in a specially-designed A/C enclosure, (below).
…and a close-up, (below), of the connections to one of the units, (electricity, high pressure, low pressure and thermostat). You can also see an example of the new pads we requested for each unit. The original pads were concrete, while these new ones are made out of plastic! We used the original pads to establish a level foundation on top of the decomposed granite we spread around inside the enclosure, then we placed the new pads on top of the concrete pads to elevate each heat pump about 2 inches above grade. I thought the plastic would isolate the vibrations coming from the heat pump units themselves, (slightly), and also keep rain water from pooling beneath each unit.
I thought a small sample of images highlighting the locations in several rooms where the outlets are located might be of interest, so I’ve included several, along with brief descriptions of where they were taken.
This first image, (below), is of the lower-level Living Room right after we purchased the home – we hadn’t moved any furniture into the house yet. You can see the outlets in a row there in the upper left-hand corner of the photograph, in the soffit running the length of the room, (the soffit defines the “hall” while the higher portion of the ceiling defines the “room” itself). The small, round fixtures in the ceiling are all lighting-related – there are two sizes of fixtures used throughout the Byrne residence – 2″ diameter fixtures with low-voltage 50 watt halogen lamps in them and 6″ recessed lighting “cans” with 6″ halogen floodlights in them. The two in the foreground are of the 6″ variety, and the 3 in the background are of the 2″ variety.
The next image, (below), is of the lower-level Living Room taken earlier this spring. Martha was standing in the southeast corner of the room, looking back to the northwest corner, when she took the photograph. Again the outlets are visible toward the top of the image. The sculpture on the table over against the wall is by Steve Kestrel and the mixed media piece hung on the wall immediately above it is by Mayme Kratz.
The third image is of the lower-level Guest Bedroom – the room we’ve started referring to as the “Library”, since installing a bookcase along the north wall of the room, just below the soffit you see in the upper right-hand corner of the image where the outlets are installed. This is a similar location to that depicted in the previous two images of the lower-level Living Room.
The fourth image is of the upper-level Guest Bedroom. You can glimpse the outlets in the ceiling along the top edge of the image – those five round outlets above the center of the west-facing window are what I’m referring to. This is the only area of the Byrne residence where all of the outlets are mounted in the ceiling, (the same holds true for the Guest Bathroom and the hallway leading to this wing, which is just off the Garage). The outlets in this wing are the only outlets which are “chrome” in color, while the rest of the outlets in the house are painted to match the color of the surrounding walls, (the one exception being the outlets mounted in the floor of the Living Room and Dining Room – more on this in a moment).
I mentioned the outlets mounted in the floor in the Living Room and Kitchen… I’ve inserted two photographs, (below), the first was taken with a slight perspective so you can see how the outlets are placed along the perimeter of the room, while the second is a close-up showing how the outlets are attached to the concrete floor.
This last image, (below), is of the Master Bedroom, again from the southeast corner, looking toward the northwest corner. These outlets emerge directly from the wall on either side of the doorway leading to the Master Bedroom Closet and Master Bathroom, (the outlets are visible in the upper left-hand corner working their way back toward the center of the image along the white wall).
…so why “Goldilocks”?
One of the advantages touted by the makers of The UNICO System® is the ability to keep an entire room at a consistent temperature due to the velocity of the air emerging from the outlets, their specific location and the sheer number of outlets used, (all of which are part of the detailed design captured in an extensive worksheet created prior to installation). What we’ve observed is as you move through the various spaces at the Byrne residence, you rarely, if ever, experience big differences in temperature at various places in the room. In other words, there is a consistency in the ambient air temperature which would have been harder to achieve if a more conventional duct system and air handler had been used.
When I first read the description of this effect in The UNICO System® literature, the notion of Goldilocks immediately came to mind – not too hot, not too cold, but rather just right!