Green Design

Published on July 25th, 2008 | by Low Impact Living

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Low Impact Living: Are Geothermal Heat Pumps For You?

Popular Mechanics Geothermal (courtesy of Popular Mechanics)Over the past few months we’ve noticed quite a bit of interest in geothermal heating and cooling amongst our site visitors, and in particular in geothermal heat pumps. We’ve also had many questions from people about exactly what they are and how/if they should consider them as an eco-friendly heating/cooling option. If this describes you, then read on – these systems ARE incredibly promising technologies to heat and cool your home, but they’re also more complicated than your typical AC or furnace unit. We’ll try to help clear the air!

We get into quite a bit of detail below, but before you get into that here’s a very quick summary of geothermal heat pumps:

  • Geothermal (or ground source) heat pumps can be incredibly efficient, delivering 3-6x as much energy for heating and cooling as you use to power the equipment;
  • They are in some ways a renewable energy system, since they use the heat contained in the earth to provide heating / cooling;
  • They do require extensive installation work, including excavation or drilling to install subsurface pipes; and
  • They are more expensive than traditional heating/cooling equipment, but the payback period is less than five years almost everywhere in the country due to their greater efficiency.

What is a Heat Pump?

First things first, though: what exactly is a heat pump? Well, just like it sounds, a heat pump moves heat from one place to another rather than creating heat or cooling by burning a fuel (like a furnace or boiler). They do this by taking advantage of the fact that liquid refrigerants absorb huge amounts of heat when they turn into gas via evaporation, and release that same heat when they are condensed back into liquids.

US DOE Energy Efficiency & Renewable EnergyThe most common kind of heat pump, called an air-source heat pump, uses the energy in outdoor air to heat and cool. To cool a warm space, a heat pump evaporates the liquid refrigerant in copper coils indoors and condenses it (via a compressor) in similar coils outdoors. To heat a cold room, a valve is activated that reverses the process: the gaseous refrigerant is condensed indoors where it gives off heat, and it evaporates in the outdoor coils, picking up heat from outdoors in the process. Air conditioners and refrigerators use the same exact process to deliver their cooling performance.

Why are they such great heating and cooling options? For one, heat pumps can be incredibly efficient: because they move rather than create heat, they can often deliver 3-4x more energy into your home than you use to power the heat pump (high efficiency air conditioners have the same benefit). Unlike air conditioners, heat pumps also provide both heating and cooling, meaning you don’t need two separate systems that only get used for half the year.

With all of these benefits, you might expect to see air source heat pumps everywhere, so what’s the catch? Well, because they are more complicated than typical air conditioners and furnaces, they’re a bit more expensive up front. And, they work best in relatively moderate and humid climates: the greater the difference between the indoor and outdoor temperatures, the harder they have to work. Once outdoor temperatures drop below 40 degrees or so, heat pumps are no longer efficient as heaters and you need some kind of auxiliary heating. In very hot climates with low heating needs, air source heat pumps are no more efficient than air conditioners but are more expensive.

The Joys of Geothermal

Fortunately, there’s a great way around these limitations on traditional air source heat pumps. In even the most extreme climate regions, the temperature several feet underground is between 45 and 75 degrees Fahrenheit. Enter the geothermal heat pump (also called GeoExchange heat pumps and ground source heat pumps). These heat pumps circulate a fluid through piping buried in the ground, discharging heat to the ground in summer and pulling it from the ground in winter. The heat pump coils are in contact with this fluid rather than the outside air as in a standard heat pump, thereby avoiding the huge temperature swings of our atmosphere. Geothermal heat pumps can be incredibly efficient, delivering from 3-6x the amount of energy used to power the pump’s compressor and fans/pumps.

There are several options for installing a ground source heat pump. The choice of which one makes sense in your area involves many factors, such as how much land you have available, what the underground conditions are like, and the skill / experience of installers in your area. As you scan these options you might think “wow, these must be expensive!”, but due to the incredible energy efficiency of these systems payback periods can often be less than five years.

Installation Options

Closed Loop Horizontal (courtesy of waterfurnace.com)The most cost-effective option for residential applications is called closed loop horizontal installation. In this type of installation, plastic pipe is laid in horizontal trenches at least four feet deep. The pipes can be installed straight or in loops resembling a big Slinkly – this requires deeper but shorter trenches, which can help in smaller yards. For a typical home, you might have to install 1,000 – 2,000 feet of tubing/piping, so this isn’t a small project!

Closed Loop Vertical (courtesy of waterfurnace.com)A second option is called the closed loop vertical system, in which u-shaped sections of pipe are installed in borings drilled 150+ feet deep. These systems are more expensive because of the drilling costs, but they can be used in tighter places or where the soil is very rocky or difficult to dig in. Vertical systems have been employed in areas as densely populated as New York City.

Open Loop (courtesy of waterfurnace.com)A final common option is referred to as an open loop system. Here the heat exchange is done via groundwater withdrawn from a well rather than through a closed loop of piping. Heat is transferred from the water to the building via the heat pump, and then the water is reinjected into the groundwater aquifer via a second well some distance away. This can be the easiest approach from a technical standpoint (and can work in dense urban areas as well), but it can introduce some permitting hassles in areas where groundwater is used for drinking or is tightly regulated.

There are some other options (such as using a lake or pond as your heat source), but the three above are the most common options in most residential situations. There are also some interesting innovations in the technology of the heat pump equipment itself (such as using the waste heat for hot water, hooking the heat pump up to in-floor radiant heating systems, and other higher-tech approaches), but we’ll cover those in a separate posting.

Geothermal Heat Pumps Near You

Clearly, finding a contractor skilled in this type of system is critical! We have a directory of geothermal heat pump installers around the country here. If you don’t find any in your area, then check out the installer lists provided by some of the top heat pump manufacturers:

Oh, one more thing to note. A geothermal heat pump is NOT the same as geothermal heating, where you heat your house directly using hot water pulled from deep underground. There aren’t that many parts of the country with the necessary underground geothermal energy to do this (primarily in the West), and even in these places almost all systems are commercial-scale operations. So if you’re thinking of harnessing the earth’s energy for your heating / cooling needs, most likely a geothermal heat pump is the way to go!

New photos released of missing boy’s mother; Different look, piled brown hair; Hope to jog memories of those who saw her.(NWSaturday)

The Seattle Times (Seattle, WA) November 19, 2011 Byline: Christine Clarridge; Seattle Times staff reporter Bellevue police investigating the disappearance of a 2-year-old Sky Metalwala have released new photographs of the boy’s mother unlike the snapshots of the smiling, glamorous blond from her social-media sites.

Maj. Mike Johnson said investigators were struck by the difference between the photos of Julia Biryukova from her Facebook page and other social-media sites and the way she actually looked “in the days and hours” before her son’s Nov. 6 disappearance. The newly released photos include some of Sky looking older than the pictures previously handed out by police.

Johnson said he hoped the new images would spark the memories of people who may have seen her or Sky.

“She does look considerably different from she did on the social-media sites,” said Johnson. “And that’s why we feel it’s so important to get these photos out, so people can see this is the woman who was out there on Sunday morning with her child.” Pictures and video stills taken from surveillance shots in a retail store that Johnson would not identify showed Biryukova in a sweatsuit. Her hair was piled on top of her head and it appeared brown rather than blond. website highlights for brown hair

The sweatsuit, according to Johnson, appears to be the same one she was wearing the day her son reportedly vanished.

Biryukova, a 30-year-old mother of two, told police she was driving Sky to Overlake Hospital Medical Center on the morning of Nov. 6 because the boy was sick. She said the car ran out of gas in the 2600 block of 112th Avenue Northeast in Bellevue, so she left the sleeping toddler in the unlocked car and walked with her 4-year-old daughter to a gas station.

When she returned, Sky was gone, she said.

An examination of the Acura Integra revealed there was still enough gas in the car “to run a significant distance,” according to Johnson. The car, which belongs to Biryukova’s brother, also had no obvious mechanical defects, he said.

“We believe there’s something suspicious afoot here,” Johnson declared after the car was tested. “The story doesn’t add up.” Police have questioned why Biryukova would leave Sky in the car, especially after she was cited along with her husband for leaving the boy in a car for nearly an hour in a store parking lot in 2009. see here highlights for brown hair

Johnson said Friday that police have continued to seek additional information from Biryukova, through her attorney, to no avail.

He said she has not been named a suspect or person of interest.

Johnson said the investigation has literally led them “around the globe to try and find answers about this disappearance, and so far we don’t have any reason to believe that the answer lies any further away than our own backyard.” One of Biryukova’s lawyers, Veronica Freitas, challenged the police assertions that Biryukova has not cooperated.

“She gave them her home, car, computer, cellphone. She talked to them for hours. What else is she supposed to do?” Freitas said last week.

Freitas said she advised Biryukova not to take a polygraph test because Biryukova is emotionally overwhelmed and the tests are notoriously unreliable.

Information from Seattle Times archives is included in this report.

Christine Clarridge: 206-464-8983 or cclarridge@seattletimes.com Tips CAPTION(S):

Bellevue Police Department: Bellevue Police released this photo of Julia Biryukova, which was taken in the days before Sky’s disappearance. (0419256983) Sky Metalwala (0419257007)




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  • http://www.geo-exchange.ca Ted K

    Great article.

    Great other resource:
    Check out the Canadian GeoExchange Coalition for a US-and-Canada list of qualified installers and designers. The group is the Canadian industry association for heat pumps and some of the most forward thinking and professional American contractors have taken the much more up-to-date Canadian training and then applied for their accreditation program. The four manufacturers named in the article are members of the Canadian association and believe in the Canadian quality approach, though FHP Manufacturing is not at this writing (July 2008). There is no equivalent accreditation or training or association in the US at this time. See http://www.geo-exchange.ca.

  • http://www.geo-exchange.ca Ted K

    Great article.

    Great other resource:
    Check out the Canadian GeoExchange Coalition for a US-and-Canada list of qualified installers and designers. The group is the Canadian industry association for heat pumps and some of the most forward thinking and professional American contractors have taken the much more up-to-date Canadian training and then applied for their accreditation program. The four manufacturers named in the article are members of the Canadian association and believe in the Canadian quality approach, though FHP Manufacturing is not at this writing (July 2008). There is no equivalent accreditation or training or association in the US at this time. See http://www.geo-exchange.ca.

  • Jerry Ansong

    Hay! I think A geothermal heat pump is what the world needs in the near future. I know of places that this technology will work extremly well now, will pay anything for it. also, if giving the oppotunity to promote the technology, I will not only sell this product well, but also help train new associate on the instulation part. this will be a cheap labor associates. so if you are intrested and want to know the extent of my ideas. call me @ (773) 414-9484. I will not let you down. (Jerry)

  • Jerry Ansong

    Hay! I think A geothermal heat pump is what the world needs in the near future. I know of places that this technology will work extremly well now, will pay anything for it. also, if giving the oppotunity to promote the technology, I will not only sell this product well, but also help train new associate on the instulation part. this will be a cheap labor associates. so if you are intrested and want to know the extent of my ideas. call me @ (773) 414-9484. I will not let you down. (Jerry)

  • Miles M

    I’m geothermal all the way! Its an awesome technology.
    I just wanted to add another geothermal heat pump manufacturer. TETCO Geothermal Heat Pumps

    Turns out they have been doing business since the 1970s, so I think they know what they are doing.

  • Miles M

    I’m geothermal all the way! Its an awesome technology.
    I just wanted to add another geothermal heat pump manufacturer. TETCO Geothermal Heat Pumps

    Turns out they have been doing business since the 1970s, so I think they know what they are doing.

  • michelle ajamian

    I have an air heat pump system. Can it be converted to geothermal? Can a geothermal heat pump (the unit) reside inside a greehouse?

  • michelle ajamian

    I have an air heat pump system. Can it be converted to geothermal? Can a geothermal heat pump (the unit) reside inside a greehouse?

  • http://www.geopros.org JP

    GEOTHERMAL with all Hotr Water heating is thoughorly expalined simply as this:
    WANT the heat of your refrigerator at home, or water cooler in the office to not be wasted?
    While the compressor heats on one side and cools onthe other, you can bnefit from both sides
    BUT with 100% ON Demand HW as well as a desuperheating little HW generator. These Systems by TETCO and HYDRO-TEMP of AR (contractors magazine 2004) are from parents from 1981 – and growing in handling the need for HW but not having to buy a high-cost instant HW !

    see http://www.GEOPROS.org for details NOW HVAC-GT-HW-Reclaimed Heat Energy Recovery ! (restaurants do not need a loop for QUICK paybacks , a/c while 100% preheating water to 118 degrees ! (great in nursing care facilities and other high water heating consumption needing cooling and dehumidification!)

    • http://www.GEOPros.org JP Jon Pierce GEOTHERMAL PROS

      Have you seen the top 4 in variable Drive Compressors for GreenBuildingTalk and GreenBuildingAdvisors and GEOconsortium news:

      Please find what I tried to relate to all there are only a few GREENEST GeoThermal Full HW 100% and one 1981 patented heat reclaim in INSTANT HW On-Demand.
      http://www.energystar.gov/index.cfm?c=most_efficient.me_geothermal_heat_pumps

      There are plenty of “Joe’s” out there with little or no knowledge of the realitites of 3-Staging GeoThermal which with DUAL COMPRESSORS runs withing 4% of some Variable Drive GeoThermal Heat Pumps TODAY STILL!

      GEOTHERMAL can be a 20day installation by the right folks, drilling or excavating in one day and the tie-in in a second. That is the difference with experience.

      Oversizing the ground loop has many long term benefits.
      Guaranteed minimum loop temperatures to the system such as 34* or more in Northern Ohio, MI, NY, PA, IA SHOULD BE IN WRITING at for average coldest winters analaysis/testings. have written what they will do if it drops to the very minimal Energy Star(TM) 32f-degrees!

      Pipes with holes for adding water a bit as Soakers in long ditches have worked since 1979 well-designed for dryer ground conditions.

      Going to 1″ pipe in residential has little to offer over 3/4″, and if space is an issue fro trenches, a 3 layer installation in a trench can be more expensive than just a horizontal driller coming in grouting lines at 8ft to 12 feet deep. 6 feet is much better than 5 and 7 or 8 ft depths are premo!

      geopros.org

      • http://www.GEOPros.org JP Jon Pierce GEOTHERMAL PROS

        That is a 2-DAY installation (rarely over 3 days to complete retrofits.
        And retrofits work VERY well in old farmhouses and residences on oil. propane, etc. !

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