Congratulations to the Stevens Institute of Technology  Its SURE House was designed to resist a storm the size of Hurricane Sandy that devastated New Jersey coastal areas in 2012Photo taken from Solar Decathalon website

Congratulations to the Stevens Institute of Technology! Its SU-RE House was designed to resist a storm the size of Hurricane Sandy that devastated New Jersey coastal areas in 2012.
Photo taken from Solar Decathalon website.

Loads are Getting Lower

The "lower loads" trend is another incentive for HVAC contractors to get into the home performance market.

A couple events that I attended recently brought home to me that HVAC contractors will need to get comfortable with selecting and installing low-capacity heating and cooling equipment.

The first was the Solar Decathlon, the biennial event where teams of college students compete to design, build and operate the most cost-effective, energy-efficient and attractive solar-powered houses.

The overall winner was Stevens Institute of Technology with its SU-RE House, which was designed to resist a storm the size of Hurricane Sandy that devastated New Jersey coastal areas in 2012.

Contractors will have to get used to designing systems for low-load houses. The trend is another incentive for HVAC contractors to get into the home performance market.
The NexusHaus, by the team from the University of Texas at Austin.
The Alf House, by the State University of New York at Alfred College of Technology and Alfred University.

The house, like many of the others entered, was built like a refrigerator. With dense insulation, air sealing and high-performance windows, the Stevens Institute of Technology SU-RE House actually exceeds Passive House construction standards. The house uses a Daikin ductless mini-split but you don’t need a whole lot of heating and cooling capacity for a structure like that.

My Decathalon favorites were the ones that contained more mechanical equipment than just a ductless mini-split. More on those later.

The second event was the recent Greenbuild Show in Washington. Both Whirlpool and Kohler were talking about a joint venture they started about six months ago, called the ReNEWW House near the Purdue University campus. ReNEWW stands for, "Retrofitted Net-Zero Energy, Water and Waste." More than a dozen other partners are involved, including Nest Labs and Honeywell. The house, now occupied by Purdue grad students, is being used as a living lab to see what can be attained in energy and water conservation. The first thing they did was retrofit the house to Net Zero standards. This is a 1927 house that’s now Net Zero. The implications are that you may have to size equipment for a heat gain or loss of 10 Btuh/square foot even in an older existing house.

Back to the Solar Decathlon. The University at Buffalo, The State University of New York, took second place with its GRoW House that’s designed as part greenhouse, part solarium. I guess that’s the “sunny” way of looking at winters in Buffalo. This was one of my favorites because it contains a Trane 20 SEER four-zone variable-air-volume air-to-air heat pump system that ensures maximum energy savings by only conditioning and distributing air on an as-needed basis to individual spaces. The house also features a smart monitoring system that oversees temperature, humidity, and electricity use and allows the resident to access the data via an online portal.

I particularly like the NexusHaus from the University of Texas at Austin that was explained to me by Charles Upshaw, the mechanical engineer who designed the system. Because of drought in Texas, the house makes the most of rainwater recovery and reuse. But, because he had this big tank of water, Upshaw designed it to double as stratified chilled water storage that could be charged off-peak by the heat pump for air conditioning. UT, which partnered with Technische Universitaet Muenchen, took third place in the engineering competition of the Decathlon.

The Alf House — by State University of New York at Alfred College of Technology and Alfred University — had a 21 SEER Carrier heat pump in the attic along with an ERV. Heating was supplied with a 5 kW electric boiler (which sounds odd, until you consider the offset from PV solar) that fed into Watts Radiant Onyx tubing in the floor.

All of these houses, regardless of the mechanical systems, were super insulated. Structural insulated panels abounded. Many of them relied solely on ductless splits, most of which were  Mitsubishi or Daikin.

Contractors will have to get used to designing systems for low-load houses. The trend is another incentive for HVAC contractors to get into the home performance market.

When it comes to insulation and air sealing, why let somebody else get that money?   

 

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