Archive for the ‘geothermal’ Category

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Geothermal Loopfield Flush Cart

Wednesday, April 14th, 2010
Dan Frawley

Dan Frawley

The use of a geothermal flush cart is the last and most important part of any geothermal loopfield installation.  The geothermal flush cart allows you to purge the loopfield of debris and to  fill the loopfield with a glycol/water solution.

Improper purging and filling of a loopfield could result in poor performance or significant damage to your geothermal heat pump.  It’s important that you have the proper equipment.

Purchase or rent your flush cart?

We recommend that you purchase your own flush cart.  As a contractor or certified geothermal installer, it makes good business sense to own a geothermal flush cart.  Renting a flush cart for each project would cost you more in the long term than purchasing a flush cart outright.

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Install Geothermal Heat Pump in the Attic

Monday, March 29th, 2010
Dan Frawley

Dan Frawley

Where do you put your geothermal heat pump if you are building a home with a crawl space, or it is slab on grade and you do not have a large enough mechanical room?  Where do you put your geothermal heat pump if you are retrofitting your home for geothermal HVAC and have no room in your basement or existing mechanical room?

These, among others, are very important questions to ask before you begin your geothermal installation.  The location of the heat pump is crucial to know before you even put your project in the hands of the engineers and designers here at Eagle Mountain. Placement affects pump pack size, supply and return size, etc.  Where can you locate the heat pump?  An option is in a space that is normally used for storage, the attic.

The problem with this answer lies in whether or not your attic is a conditioned space or not.  The general rule of thumb for a geothermal heat pump is that it must be placed in a conditioned space.  The solution to the problem of placing a heat pump in an unconditioned attic is, what we call here at Eagle Mountain, a hot box.

Hot Box

Hot Box

The “Hot Box” can be essentially a 2×4 framed container that is sheathed in plywood with a removable top to create easy access for service. Once the container is built around the heat pump, you lay insulation across the attic floor and around the outside of the box.  This creates a conditioned space for the heat pump to sit in, essentially making that space part of the house, or heated space.

This “Hot Box” solution allows for two things.  First, it allows the heat pump to be placed in a conditioned space for optimal performance and efficiency.  Secondly, it allows the attic to remain unconditioned to conform to the outdoor temperature.  This is important, especially in winter, if ice damage is a concern.  Also, the attic will not be comfortable in the winter and then uncomfortably warm in the summer.  It is also important to note that piping from your geothermal loopfield to the heat pump must be insulated and contain the correct propylene glycol mixture for geothermal systems.

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Propylene Glycol Mixture: Geothermal Freeze Protection

Monday, March 29th, 2010

Our installers often ask why we recommend a 25% mixture of propylene glycol to water for geothermal loopfields.

Propylene glycol at a 25% mixture by mass yields a freezing point of about 12.5 degrees F. Since propylene glycol is slightly more dense, 1.036 g/cm3 to 1.0 g/cm3 for water, this equates to a mixture by volume of 25% freezing at 12.95 degrees F. 20% by mass freezes at 18 degrees F. This is sufficient for interior hydronic lines.

Our pump sizing is based on the viscosity of a 25% glycol mixture by volume. We use this mixture because it uses the minimum amount of glycol for pumping viscosity losses while providing freeze protection.

The reynolds number also plays a part in the ratio. The greater the volume of the thicker glycol, the faster you have to pump to reach turbulent flow. Use 25% glycol to 75% water with our product in a correctly designed geothermal loop field for optimum performance.

Since our product is inhibited, it has a glycol ratio of 96%.  Four percent is the additives for corrosion resistance and the anti-foaming agent. This is the highest ratio available in this type of glycol. Some products labeled -100 can be as low as 65%. If you mix that at 25% you would actually be only 16.25%.

Download the Freeze Safe 100 PDF Spec Sheet for more information.

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Water treatment for a geothermal system

Thursday, March 25th, 2010
Dan Frawley

Dan Frawley

You may not be considering a geothermal heating and cooling system for the plain and simple fact that someone has told you that your hard, high mineral content, low or high PH water is not conducive to an efficient geothermal system.

What if you have an aquifer that can support an open loop geothermal system but your quality of water is not the best?  You may know or can find out that Eagle Mountain carries cupro-nickel heat exchangers for our open loop units.  These heat exchangers are more resilient to what we in the industry call scaling.

Scaling is the process where minerals, and organics accumulate on the heat exchanger.  While cupro-nickel coils are resilient to this phenomenon, they are not immune so it becomes a question of time.  How long until I have to replace the heat exchanger?

Source Snap: Click for Link

Source Snap: Click for Link

You can extend the life of your heat exchanger by having a certified installer install a water treatment system in your home.  This would work to filter and clean the water before it entered your heat pump, effectively extending the working life of your cupro-nickel coil heat exchanger.

The goal of the water treatment center is first and foremost to lower the mineral and organic content from the incoming water.  This will reduce the mineral scaling that will occur.  Secondly, the water treatment system will need to bring the PH of the water to neutral, as a neutral PH will not eat away the heat-exchanging surface.

Ultimately, the goal of any water treatment system is to improve the quality of the incoming water.  This improvement is beneficial for both the heat exchanger in your geothermal heat pump as well as for other aspects of your home plumbing system.  The better quality water you have flowing through your heating, cooling and plumbing systems the longer those systems will last and ultimately will keep money in your wallet.

You can avoid water quality issues with a closed system that uses geothermal loops in the ground.

If you have any questions give us a call at 1-800-572-7831.

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