HYDRONICS FROM THE FIELD
Air-to-water heat pump technology
BY DAN FOLEY CONTRIBUTING WRITER
out well while others … not so well. Do the names GlowCore or HTM ring a bell? These were products that fell into the latter category, and I have the scars to prove it. Let’s just say they were ahead of their time —good in concept but poorly executed. Believe it or not, I still have one GlowCore in a dedicated snowmelt application still chugging away. It still stands, as if to mock me for cursing its existence and the midnight no-heat calls, failed ignitors, screaming pumps, leaking heat exchangers and all the other failure modes I have long purged from my brain. We recently tried a new system that falls into the former
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category, the Daikin Altherma. This is an air-to-water heat pump designed for the hydronic market with COPs that approach ground source heat pumps. Think of it as a geo system but with an outdoor condenser in place of the ground loops. This system was designed for the European hydronic market, to replace fossil-fuel burning appliances. It is my understanding that other manufacturers, such as Mitsubishi, have similar systems on the way. What differentiates the Altherma from currently
available unitary equipment and even from geo units is the
ver the years, I have not been afraid to try cutting edge products and to apply these new technologies to our projects. Some have worked
One thing I learned from my two trips to ISH-Frankfurt is that the Europeans are working much harder than we are at weaning themselves off of Middle Eastern oil and Russian natural gas.
boilers and tie into low temperature hydronic systems. Lance Dyer, Daikin product manager says that over 200,000 Altherma units have been installed in Europe and, since its release in the U.S. a little over a year ago, close to 500 units have been installed here. This product was designed to work in cold climates. One of the first large U.S. projects was a condo complex in New Hampshire, where 140 systems have been operational for over a year. We did our first Altherma project about a year ago and
installed a second last summer. We have a third system lined up to replace a traditional cast iron boiler and DHW tank. The outside unit looks similar to any other
Horbaly Residence located in Montross, Va. overlooks the Potomac River. Two Viessmann Vitosol flat panel solar collectors are mounted on the upper left portion of the roof.
inverter drive compressor. This allows the compressor to vary its output to match the load, similar to the way in which a modulating condensing boiler can vary its output. This allows for very efficient operation with long run times minimizing cycling losses. One thing I learned from my two trips to ISH-
Frankfurt is that the Europeans are working much harder than we are at weaning themselves off of Middle Eastern oil and Russian natural gas. They have done this with a combination of solar thermal, solar PV, bio fuel, wind turbines and heat pump technologies. They understand well the political costs of being addicted to fossil fuels and are doing all they can to divorce themselves from these fuels. The Altherma was designed to replace fossil fuel burning
An Altherma outdoor unit is mounted on concrete base pad.
refrigerant-based heat pump. The refrigerant is piped to an indoor hydrobox that looks just like any modern wall hung boiler. Inside the hydrobox is the refrigerant to water heat exchanger, expansion tank, circulator pump and control panels. This part of the system is piped just as a boiler system would be piped. (Note: Daikin also has a Monobloc unit that combines the heat pump and hydrobox into one outdoor chassis). The Altherma system can also incorporate DHW
production through an indirect tank. Both of my installed systems have Viessmann solar panels connected to the DHW tank. This solar input is important for two reasons: 1. The Altherma cannot simultaneously heat and cool. 2. The solar component will qualify for the 30%
uncapped federal tax credit for renewable energy sources e Turn to FOLEY on p 26
phc may 2011
www.phcnews.com
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