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What is a Hallowell heat pump?

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2007-06-25 02:06:19

Excerpt from: = Will Utilities Warm Up to Low-Temperature

Heat Pumps? = 2.3.06 Jay Stein, Managing Director, E Source



What Is a Low-Temperature Heat Pump? We have defined the

low-temperature heat pump (LTHP) as an air-source unit, capable of

providing both heating and cooling, that:

  • Operates down to an outdoor temperature below –10°F. It’s rare

    for a conventional air-source unit to operate below this


  • Meets or exceeds its rated capacity at 0°F. Conventional heat

    pumps typically put out roughly half of their rated capacity at

    this temperature.

  • Exhibits a coefficient of performance (COP) of at least 2 at

    0°F. Conventional heat pumps typically exhibit COPs of 1.7 or less

    under these conditions.

LTHPs incorporate several recent technological innovations in order

to achieve this performance. The most significant one is a

sophisticated microprocessor control system that until recently

would have been far too expensive to include in a mass-produced

residential air-conditioning product. These control systems,

working in concert with other features, enable LTHPs to solve some

persistent problems for northern electric utilities by:

  • Improving on the efficiency of electric-resistance and

    conventional heat pump space heaters,

  • Reducing the peak loads imposed on transmission and

    distribution systems when large stocks of conventional heat pumps

    simultaneously call for backup electric-resistance heating,

  • Competing more-effectively with natural gas and other fossil

    fuel–burning furnaces for space-heating load, and

  • Providing a less costly and less complex alternative to


Low-temperature heat pump technology clearly has much to offer to

the electric utility industry. The Playing Field David Shaw,

who used to work for Carrier Corp., started conceptualizing the

first LTHP in 1995. He set up his own research laboratory—Shaw

Engineering—to create an air-source heat pump for cold climates

that would eliminate the need for electric-resistance backup

heating in very cold weather. After a few years, he received strong

interest from Northeast Utilities, which was working with Nyle

Special Products (a small specialist heat pump company based in

Bangor, Maine) to develop a heat pump water heater. Shaw then

licensed the technology to Nyle, allowing it to develop a product

based on his work. Nyle built four prototypes that were tested over

the winter of 2002–2003. Nyle dubbed its product the Cold Climate

Heat Pump, and we estimate that somewhere between 150 and 200 units

have been delivered to customers to date—with around 20 of the

installations located in Canada and the rest in the U.S. The

performance of these units was decidedly mixed, with some operating

demonstrably well and others experiencing problems due to

inadequate installation, poor quality control, and flawed control

strategies. In early 2005, Shaw decided not to renew Nyle’s license

to the technology, and he began negotiating with other

manufacturing partners. Nyle, however, retains the trademark to the

Cold Climate Heat Pump name and claims that it will develop a

similar product that can be manufactured without violating any of

Shaw’s patents. In July 2005, Duane Hallowell, a former Nyle

employee who led that company’s efforts to commercialize the Cold

Climate Heat Pump, acquired the rights to the patent for David

Shaw’s LTHP technology. Hallowell says that his company, Hallowell

International, will spend the rest of 2005 perfecting the product

and begin releasing 2,000 beta units for a pilot study in the third

quarter of 2006. A hallowell heat pump (or All Climate Heat Pump)

is a heat pump designed specifically for heating while still

providing high efficiency cooling. This product was invented in

1995 by a former carrier corp engineer. Now commercially available

( see ). It has been studied though several

organizations to show much greater comfort, significantly reduced

defrosts compared to traditional systems, and can maintain high

heating capacities in northern climates at temperatures as low as

30 below zero while keeping efficiencies above 200%. There are

three new studies coming out in the coming months showing the

results of an 8 state cooperative research study by the national

rural electric cooperative association. The system is only released

as air to air for about $6500.00 and installs like a central air

conditioner. My wife and I were considering a geothermal but the

price to install ran about 30k for a 3.5 ton system for our 2500sf

home. We called Hallowell and asked for references and spoke with a

customer of theirs on Cape Cod. They heated 3000sf home for about

$700.00 for 2006 / 2007, with an electric rate of 17 cents per kwh.

This could be a very disruptive technology finally offering an

alternative to fossil fuel

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