All-in-One Systems for Heating, Cooling and Ventilation
By Sheri Koones, a
friend of modular and prefab housing
Most people understand the advantage of building a very energy-efficient house -- lower energy costs and
reduction of fossil fuel use. Another advantage in building tight,
energy-efficient homes is they need smaller heating and cooling systems than
houses with air seeping in because the structure isn't tightly sealed.
However, when a house is built with minimal air leakage, it is essential to have an excellent ventilation system to maintain a healthy environment inside.
"Magic Boxes" combine all the functions of an HVAC
and ventilation system in one unit, saving energy and space.Most people
understand the advantage of building a very energy-efficient house -- lower energy costs and
reduction of fossil fuel use. Another advantage in building tight,
energy-efficient homes is they need smaller heating and cooling systems than
houses with air seeping in because the structure isn't tightly sealed.
However, when a house is built with minimal air leakage, it is essential to have an excellent ventilation system to maintain a healthy environment inside.
However, when a house is built with minimal air leakage, it is essential to have an excellent ventilation system to maintain a healthy environment inside.
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BuildEquinox CERV model |
All-in-one systems are often called "Magic Boxes"
because they combine all the functions of an HVAC system in one unit. One of
the truly revolutionary systems is the Compact P Heat Pump from Nilan, certified by the Passivhaus Institut in Germany . The
Compact P Heat Pump, which functions as a ventilation system with heat
recovery, also includes space heating and cooling and provides the household's
hot water supply. (Heat recovery means that the heat -- or cooling -- already
created for the stale air in the home is not lost. The temperature
"magically" is transferred to the incoming fresh air.) This type of
system is compact, provides healthy indoor air, and reduces energy costs.
While heat recovery can recapture a portion of space heating energy before stale air is exhausted and replaced with fresh air, the additional heat pump in this system also can warm the fresh air on the coldest days. Separately, the same heat pump also provides 47.5 gallons of hot water for domestic use. This unit has additional options to incorporate a geo-thermal heat pump or outdoor air-to-water heat pump, which can supplement air heating with radiant floor heating. Most of the Compact P units produced are being used in Europe, but some are being tested in recentU.S.
projects, including in Vermont , which has some
of the more challenging weather conditions in the United States . So far these
"boxes" are functioning very well.
While heat recovery can recapture a portion of space heating energy before stale air is exhausted and replaced with fresh air, the additional heat pump in this system also can warm the fresh air on the coldest days. Separately, the same heat pump also provides 47.5 gallons of hot water for domestic use. This unit has additional options to incorporate a geo-thermal heat pump or outdoor air-to-water heat pump, which can supplement air heating with radiant floor heating. Most of the Compact P units produced are being used in Europe, but some are being tested in recent
Though European countries have led the way, an example of an
all-in-one system manufactured by a U.S. company is the CERV
(conditioning energy recovery ventilator), developed by Build Equinox. CERV
systems, which are UL Listed, incorporate heating, cooling, dehumidification
and ventilation. The systems have been incorporated into a 25-unit, moderately
priced prefabricated housing complex that HVAC engineer Peter Schneider is
working on in Vermont .
Schneider, a leader in his field, called the CERV system a "brilliant
device," adding that so far he is very pleased with the systems' efficiency,
comfort and usage in a location that is high-demand because of the climate.
Other companies around the world making similar systems include Drexel & Weiss inAustria and Daikin in Japan , which
produces an all-in-one system that doesn't include a ventilation system.
Another company with a strong ventilation business in the United States , Zehnder, produces an all-in-one system called the ComfoBox which
is not available in the U.S.
market.
Magic Boxes are becoming more popular in Europe, but are still in limited use inNorth America . The demand has been small,
probably because of a lack of awareness of the systems and because of the small
number of extremely energy efficient homes being built here. All-in-one units
tend to be more expensive than unbundled systems -- although according to
Schneider, that additional cost seems small when all HVAC factors are taken
into consideration, including energy efficiency, comfort and health. However,
one potential disadvantage is that if one of the systems breaks down, all
systems are lost -- including heat, cooling, ventilation and water heating.
Also, there are not yet enough professionals in this country who are able to
fix these systems, but that is likely to change as building codes become
stricter and people become more familiar with the optimal building materials
available.
Other companies around the world making similar systems include Drexel & Weiss in
Magic Boxes are becoming more popular in Europe, but are still in limited use in
Sheri Koones' latest book, "Prefabulous
World: Energy-Efficient and Sustainable Homes Around the Globe," includes
homes that use magic box systems. She won the prestigious Robert Bruss
Real Estate Book Award from NAREE in 2008, 2011, and 2013, and is a columnist,
freelance writer and speaker.
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