How a heat pump works You Tube video

This You Tube video refers to an air source heat pump (air conditioner).It is useful because it will explain how a heat pumps works. It is short and runs very quickly. Watch and listen to it a second and third time if needed.

In the video, the heat from the building is discharged to the air outside of the home. Usually when an air conditioner is running, it has to discharge the heat to an already warm place. It would be easier and less expensive for the heat pump to transfer the heat to a cooler place.

With a geothermal system, the heat is discharged into a cool place below the surface of your yard. The earth is typically 58 degrees at a depth of 6'-'8' below the earths surface near St Paul, Minnesota. The temperature will vary according to your location -colder to the north and warmer to the south.

In the winter months, the heat pump is reversed to move heat from the earth, and place it inside of your home. Here is the link to the video.

http://www.youtube.com/watch?v=B-cnkjjJUaQ

Thank you,

Builder Bob
http://www.bmichels-const.com/

Picture of my "Parade of Homes -Dream Home" mechanical room.

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This is a picture of the mechanical room of the home in post #1, located in Stillwater, Minnesota. The room looks like the inside of a submarine- compact and organized. All mechanical rooms should be neat and organized. The components are identified below.

Water to air heat pump

The water to air Heat pump is the white cabinet on the left of the photo. You can see the two insulated lines coming down from the ceiling that circulate the antifreeze solution from the loop field outside through the heat pump's heat exchanger plate. The lines going down are the refrigerant lines that are exchanging heat with the anti freeze solution, and are connected directly to the heat pump on the inside of the cabinet. The heated refrigerant is circulated through a "radiator" in the upper section of the cabinet. Air from the return registers in the home is pulled through the "radiator and heated. The heated air is then forced through the supply registers through out the house. The heat pump has a two stage compressor for efficiency. The blower motor is a variable
speed motor to conserve electricity . The copper lines on the left connect the de-superheater to the water heater pre- heat tank.

Steam Humidifier

The small box mounted on the duct-work near the ceiling is the steam humidifier. Geothermal heating is done at a lower temperature than fossil fuel combustion heating. The air returning from the house passes though a large surface coil that is heated by hot refrigerant from the heat pump. The air moves slower and at a greater volume through a geothermal air handler than through a fossil fuel combustion furnace. Traditional humidifiers spray a mist of water, steam is absorbed more easily by the lower temperature air of the geothermal heat system.


Back up natural gas furnace and "switchable electrical service"

The grey cabinet to the right of the water to air heat pump is a 96% efficient natural gas furnace. The heat pumps and the water heater is connected to Xcel Energy's "switchable electric meter socket" Excel Energy can switch off the electricity to the heat pumps and the water heater during times of peak demand in the summer and the winter. In the winter, it can be off for up to 6 hours. During this time, the natural gas furnace is given the job to heat the home by a panel on the Water to air heat pump. It is a seamless transition.

The water heater is large enough to handle being off for 6 hours as there are 110 gallons of 130 degree water in the tank.

In the summer, Excel Energy can "toggle" the power during times of peak demand causing the cooling function to turn on and off in 15 minute intervals. The house is very tight and well insulated, so the occupants do not feel this happening.


Domestic hot water indirect preheat tank

The 50 gallon domestic hot water pre -heat tank is the first tank to the right of the back up furnace. Cold well water is pre -heated in the tank to 110 degrees by the circulation of the water in the tank through the de-superheater. Preheated water then passes to the 110 hot water heater down line.

In floor heat buffer tank and water to water heat pump

The in floor heat buffer tank is where antifreeze solution returning from the in floor hydronic heat tubes (in floor heat) is stored; and indirectly heated by the water-to-water heat pump (low white cabinet to the right). A series of pumps circulate the antifreeze solution to the 5 zones (basement floor, garage floor, mud room floor, master bath floor and pub floor).


The water to water geothermal heat pump is the low white cabinet to the right of the two tanks described above. This heat pump is taking heat from the loop field and transferring it to the buffer tank. It will heat the antifreeze in the buffer tank to 110 degrees and maintain that temperature for the in floor heating system.


"Marathon" 110 gallon electric hot water heater


The "Marathon" 110 gallon water heater is filled with 110 degree pre heated water from the pre-heat tank. The "Marathon” electric hot water heater is connected to the switchable electric service and uses .053 cent electricity (off peak) to heat the domestic hot water to 130 degrees for use in the home. It is the most efficient hot water heater on the market (EnergyStar Rating).

In a future post I will cover a geothermal retro-fit of a home in North Oaks. Two natural gas furnaces were replaced with water to air geothermal heat pumps using a vertical loop system.

Thanks,
Builder Bob
www.bmichels-const.com

30% tax credit for the installation of geothermal HVAC systems

Long Term Value

Quality, value and environmentally sensitive minded homeowners and builders increasingly are choosing geothermal HVAC systems. These systems provide heating, cooling as well as domestic hot water for their homes.
By adding a geothermal system, builders will enhance the appeal of any new home or remodeling project. Homeowners benefit from receiving heating, cooling and hot water heating in one compact, indoor unit - with savings of up to 70 percent.


Proven Technology

Geothermal is a proven technology - more than ever, homeowners nation wide are using geothermal systems. Many new subdivisions are being built entirely with geothermal energy by pre-installing earth loop systems before the homes are built. This is a very cost-effective installation method for geothermal systems.Because of the inherent benefits of geothermal, builders easily can increase the overall energy efficiency of their homes These systems also help builders gain an advantage in today's energy-conscious, environmentally sensitive market.



30% Tax Credit for New Homes or Retro Fit Installations
The Energy Star program endorses and recognizes geothermal HVAC systems as the most efficient, environmentally friendly available. The "2009 Stimulus Bill" is giving the homeowner a 30% tax credit for the installation of geothermal systems (with out a cap on the credit). This tax credit applies to the entire costs to install the geothermal HVAC system, as well as the costs associated with the installation of the loop field and powering the equipment! A typical payback period for the system is reduced by years and will depend on the fossil fuel it is replacing. Geothermal systems offer increased energy efficiency because they move heat, rather than create it. For each unit of energy used, a geothermal systems generates three or four units.



For more on the tax credit issue, click here http://www.energystar.gov/index.cfm?c=products.pr_tax_credits

Thanks,
Builder Bob http://www.bmichels-const.com/

Geothermal - geoexchange loop systems and a video

One of the many important parts of a good geothermal heat pump systems is the method used to gather and disperse heat. This heat transfer is called geoexchange. In the summer months when we want to cool our homes, we use the heat pump to attract the heat from the house and transfer it to the geoexchange system and place the heat in the earth. In the winter months, we gather heat from the earth using the heat pump and transfer it to the interior of the home.

There are two types of geoexchange that are typically used in Minnesota. Open loop geoexchange and closed loop geoexchange. An open loop exchange system is when water from a well, lake or river is pumped through a geothermal heat pump. The heat pump adds heat to or removes heat from the water. The water is then pumped and lost into a lake or river . This is commonly referred to as a "pump and dump" geo-exchange system. If you want to consider this application, you will need permission from government agencies to do so. This option is simple and may be the least expensive way to gather and lose heat. However, permission (permits) are hard to obtain and will consume a lot of your time, making it a less desirable option.

In a closed loop system, a series of high quality plastic loops are installed,filled with water and food grade anti-freeze . The solution is then circulated to gather or lose heat in the earth through the geothermal heat pump. There are three types of closed loop systems

1. Using a private lake or pond of sufficient depth and size, a series of loops are filled with antifreeze solution and sunk to the bottom. The loops are connected to a manifold and connected to the geothermal heat pump inside the home.This is a very good option if you own the lake and do not need permission from government agencies to install this loop system. Permits from the DNR or U S Army Corp of Engineers, if needed, are very hard to obtain and in most cases you will want to use option #2 or option #3.

2. Horizontal loop fields consist of excavating an 8' deep a trench and installing a loop field. The width and length of the trench and loop field will vary with the size of the geothermal heat pump.The sizing of the Geothermal heat pump is a function of house size and the thermal efficiency of the home. The loops are connected to a manifold that enters the house and connects to the geothermal heat pump inside. This is a good option if you have new construction on an open acreage lot with wet sand.

3. Vertical loop field consist of a series of 4" holes that are drilled with well drilling equipment to a depth of 180-200'. The 4-3/4" holes containing the vertical loops are installed 10'-12' apart and are sealed with bentonite to prevent contamination of the ground water. The number of vertical loops is a function of the size of the Geothermal heat pump and the thermal efficiency of the home. A back hoe then connects the vertical loops to a manifold. This loop field is used most often for retro fits and remodeling, or where there is a lack of soil moisture. In most remodeling situations, this the only choice for the loop field since there is a minimal disruption of the landscape and will work on a city lot.

Here is a good video on geoexchange systems.

click here http://www.youtube.com/watch?v=nWCNEoUTte4

Thanks,

Builder Bob http://www.bmichels-const.com/

Installed geothermal system, energy usage, cost and payback after 17 months

The link below contains the total energy costs and KWH to operate a 10 ton geothermal system (geo-exchange) in Stillwater Minnesota.

The house:

5000 square foot of the story and one half home is finished (above grade). It is heated to 70 degrees in the heating season and cooled to 76 degrees in the summer.

1200 square foot three car garage that is heated to 62 degrees in the heating season.

2400 square foot unfinished basement using in-floor heating. It is heated to 70 degrees in the winter and cooled to 76 degrees in the summer.

1700 square feet of floor warming. The floors of the master bath, mud room, laundry room and bonus space over the garage (recreation room /pub). these spaces are included in the5000 square foot finished area.

The geothermal system consists of :

1- 5 Ton water to air "Geocomfort" geothermal heat pump with a desuperheater. It has an average coefficient of performance (COP) rating of 4.45. For example a toaster has a COP rating of 1. You put $1 worth of electricity into a toaster you will get $1 of heat out. So ,with the COP of a 92% efficient furnace, you will get 92 cents worth of heat out of it. With a heat pump with an average COP of 4.45, you will get $4.45 worth of heat for that same $1.00. This heat pump /air handler combination heats and cools the air in the home through a sheet metal duct work system. All duct work is sealed.

1- 50 gallon indirect water heating tank. The indirect water heating tank is used to preheat 58 degree well water to 110 degrees by using the desuperheater that is installed on the water to air heat pump.The domestic well water fills the 50 gallon indirect water heating tank as domestic hot water is taken from the water heater down line. Thus, the water heater is filled with the preheated 110 degree water and is bumped up to 130 degrees by the water heater.

1- "Marathon 110 gallon water heater. This water heater has the highest "Energy star" rating for all water heaters of it's size. It is a plastic lined tank that is very well insulated with foam insulation.

1- 5 Ton water to water "Geo comfort" geothermal heat pump that has an average COP rating of 3.3. The heated water produced is used to provide in- floor heat the floors of the garage, master bath, mud room and the recreation room/pub that is built in the "bonus" space over the garage.

1-50 gallon buffer tank heat and store the anti-freeze and water solution that is used by the in-floor heat system.

1- 10 ton vertical loop field. A vertical loop system was used for this house since the soil 8' below the finished grade is a mix of sand and gravel.


click on link www.bmichels-const.com/geothermalblog.pdf

I hope you find this information useful!
Thank,

Builderbob

http://www.bmichels-const.com/