How pumps work


An Affordable Heat-Pump Water-Heater Retrofit

An Affordable Heat-Pump Water-HeaterEBN that he also intends to use the
Retrofitproduct(from: in a 100-unit subdivision
The engineers at AirGenerate (previouslythat is in the works.
Beyond Pollution) appear to have doneSkyland Falls is installing the AirTap
something remarkable: create anunits on new, 40- and 50-gallon (150 and
affordable, effective, heat-pump water190 l) electric water heaters, set up so
heater that can be retrofit onto athat the standard electric element
conventional gas or electric waterprovides a backup. The controls on the
heater, more than doubling the energywater heater are set so that the
performance compared with a standardstandard element will come on at 100°F
electric water heater. The AirTap A7(38°C), while the AirTap is set to heat
water heater has a rated output of 7,000water to 130°F (54°C). If the
Btu/hour (7.4 MJ/hour), a first-hourheat-pump module stops working for some
rating of 42.5 gallons (160 l), areason, the conventional
maximum water temperature of 135°Felectric-resistance element will still
(57°C), an efficiency of 240%keep the water warm, but homeowners will
(coefficient of performance of 2.4), andnotice the problem and contact Skyland
an energy factor of 2.11. (Energy factorFalls. The company(from: will go out
is a standardized measure of performanceand troubleshoot the problem-but it
of water heaters; the higher the number,probably won't be an emergency call,
the better.) All this is in a unit thatsince the water will remain at least
measures only 18" wide by 14" deep bywarm. "Since this is a new system, we
14" high (460 x 360 x 360 mm), weighswanted a backup," Alexander told EBN.
only 48 pounds (22 kg), and sits on topWith some units in place for four
of a standard water heater. The listmonths, Skyland Falls has yet to receive
price is $499. The energy factor anda call.
first-hour rating of the AirTap areInstallation is fairly easy-even
certified by GAMA (previously the Gasfeasible for skilled do-it-yourselfers.
Appliance Manufacturers Association andAccording to Alexander, one of his
now a broader association of applianceemployees can install three AirTap units
and equipment manufacturers).in a day. Skyland Falls installs the
Heat-pump(from: water heaters havewater heaters in utility closets with
always been a good idea, but mostthe outflow air from the AirTap heat
efforts to design, build, and marketpump vented into the adjacent garage;
them have failed. With today's highthis setup provides some cooling to the
energy prices, however, consumers shouldgarage, which is beneficial in the
be more receptive to heat-pump watersummer. Of the 30 units so far
heaters, according to Harvey Sachs,installed, only one unit has had a
Ph.D., the buildings program director atproblem-a loose bolt that Skyland Falls
the American Council for aneasily fixed. In late spring 2008, the
Energy-Efficient Economy. "The economicall-electric homes were using less than
savings potential is so much greater$2 per day for energy, according to
than before, with the run-up of energyAlexander, though how much of this is
prices," Sachs told EBN.for water heating is not known.
AirGenerate initially produced itsOther heat-pump water heaters will be
AirTap A7 water-heater(from: kit incoming along soon. General Electric
Houston, Texas. After selling a fewexpects to introduce its Hybrid Electric
hundred units in late 2007, the companyWater Heater in late 2009. The model
began sourcing the product from anwill sell for about $400 more than a
offshore supplier. The outsourcing ofstandard, 50-gallon (190-l) electric
production will allow the company towater heater but save an average family
significantly ramp up production. The$250 per yearwith electricity(from: at
first of the new (offshore-manufactured)10 cents per kWh, the company claims.
AirTap units were received in JanuaryAccording to Sachs, a second major
2008, and about 200 had been soldplayer is likely to soon announce
through May 2008. Of 400 units scheduledanother heat-pump water heater. Having
to arrive in June, almost all weremajor manufacturers enter the heat-pump
pre-sold by the end of May, according towater-heater market, according to Sachs,
Sunil Sinha, chief scientist atwill give this sort of product
AirGenerate.legitimacy. "[AirTap] may be able to
Skyland Falls, a Tennessee developer,ride the wake instead of having to break
has installed 30 AirTap units sincethrough the ocean waves," he said.
January 2008 in a 70-unit subdivisionIn addition to the AirTap A7 model,
currently under construction. Houses inAirGenerate is introducing a larger
the subdivision are 2,000 ft2 (190 m2)12,000 Btu/hour model in August 2008,
each and sell for an average ofaccording to Sinha. This model will
$230,000. "The AirTap is doing aoffer the same energy factor of 2.11 but
fantastic job," according to Skylandwill have a first-hour rating of 60
Falls president Gary Alexander, who toldgallons (230 l).



1 A B C D E F 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138