Heating & Cooling With the Horizontal Geothermal Loop
Video Transcript
Hey we’re back here at the Ultimate House. The geo-loops been put in we’re gonna take a look at it here. This is Tim and Teresa’s house and Grayson Home Builders built it for them okay. The place was kinda tight. So we did a unique loop design, Chicken-foot loop, we got an inch and a quarter line coming in, inch and a quarter line going back. I tell you somethin’ – when you’re doing a geo loop you got one shot to get it right. You mess this up, you got problems.
And I’m always having people that don’t know about geo come to me and go, “Dean how’s this work?” Well I’m gonna show you how it works. We’ve got some one inch pipe here this is geo pipe it’s good for 200 pounds of pressure okay. So it takes a lot destroy this pipe. But how this basically works is this is a supply pipe and this is a return pipe going back to the manifold. Water pumps through this pipe goes to the end of the loop comes back goes back to the geo unit. Now it works through conductivity. So this water is gonna take the same temperature as the ground. So right now, I measure temperature while ago, 60 to 58 degrees in here about six foot down. This ground is nice and cold. It’s nice and damp so it’s gonna make a great conductor. In the air condition mode this 60 degree water is gonna go back to my condenser and it’s gonna be able to get that heat off of that unit very efficiently.
All right, we’re gonna talk about what not to do. This is why it’s bad to short your loop. This pipe right here transfers water through it as we went through before and extracts the heat out of the ground, okay. Now if this pipe gets too hot because you don’t have enough fluid enough transfer, what happens is is the dirt around the pipe is called “Baked” and it will basically get hot freeze up around it and it will expand off the pipe, ever so lightly, you won’t get your transfer. But if you oversize your loop, and you’ve got plenty of loop and we’re putting in a soaker hose. Tim and Theresa will never have a problem in their loop.
Let’s talk briefly about the soaker hose. Basically what we gonna do is we gonna cover about two foot of dirt over this trench right here. And we’ll take some schedule 80 pipe and it goes right up on the house and all they had to do is hook a water hose to it. If they ever had a problem with the loop getting hot, which they won’t, but if they ever did, it’s just a matter of hooking up the water, letting the water soak into this loop and the water will get to the pipe which it will stop the baking bond the pipe and it’ll go back and working just like it always did. But if you oversize you loop, you don’t have to worry about it. But just in case it ever did happen, it’s a matter of flipping a switch and putting some water in the loop.
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TLDR
Incorporating geothermal heating and cooling in your energy efficient home is a great way to save energy and maximize efficiency. When building your system, geothermal horizontal loops are commonly used. These loops are installed horizontally in the ground and designed to fit the environment. Using geothermal energy provides benefits like decreased energy costs, increased comfort and saving, improves home value, and is an environmentally friendly solution.
As a part of our Energy Efficient Home series, we’re introducing the concept of heating and cooling your home with a horizontal geothermal loop, and discussing one we installed here in Raleigh, NC. Along with the benefits – like lowering energy consumption and bills, home comfort, and being environmentally friendly – we’ll explain how geothermal loops work and what common mistakes you need to avoid when installing and using one in your new home construction.
How Does Geothermal Heating and Cooling Work?
The simple explanation of how a geothermal works is heat exchange. In warm climates like North Carolina, explaining how the system cools your home often makes the most sense.
Water in your system absorbs heat from the air inside your house the same as a typical conditioner. It then circulates that water through the geothermal loop – a series of pipes buried underground in your yard – and back to the unit in your house. The heat exchange happens through the process of conductivity. As the warmer water runs through the underground loop, it conducts the heat out to the cooler soil, which in NC is usually 60 degrees F or lower. Once the water has been cooled, it returns to the home to begin the process over again.
Horizontal Geothermal Loop Design
A horizontal geothermal loop design is one of several options when installing a ground source heat pump (GSHP) system in your new construction. Others include vertical loops and pond/lake loops. For a horizontal loop, the pipes are buried horizontally in the ground, typically at a depth of 4 to 6 feet (1.2 to 1.8 meters). When determining the geothermal horizontal ground loop design and size, there are a few considerations:
- Sufficient Land Area: Horizontal geothermal loop systems require ample land area for installation. This makes it a suitable choice for larger properties with sufficient land area.
- Lower Installation Costs: In many cases, the installation cost of a geothermal system tends to be lower compared to vertical systems. The excavation required for horizontal loops is generally less extensive, which can result in lower labor and equipment costs.
- Soil Composition: Horizontal loops work well in areas with adequate soil conductivity and thermal characteristics. Soil with good heat transfer properties, such as moist and compacted soils or sandy soils, allows for efficient heat exchange between the loop and the ground.
- Permitting and Regulations: Depending on local regulations and permit requirements, a horizontal geothermal loop design may be more readily approved compared to vertical designs. Some jurisdictions may have specific guidelines or restrictions due to concerns about drilling and potential impacts on underground water sources.
Benefits of Geothermal Heating and Cooling
Like most ENERGY STAR® home features, the upfront cost for a geothermal loop to heat and cool your new home is higher than traditional methods. But with some research on short term incentives, and an eye towards long term savings and comfort, you may decide that the geothermal loop is the right choice for you.
Energy Efficiency and Economic Value
To help offset the initial purchase and installation cost of a geothermal loop, there is a 30% tax credit available under the 2022-2023 Inflation Reduction Act. This means that if you are eligible, you could claim up to 30% of the cost of your geothermal loop as a credit on your taxes. With initial costs of a geothermal loop ranging from $15,000 – $34,000, that translates into a tax credit of $4,500 to $10,200.
While some of the initial costs are covered by tax incentives (short term), the long-term ongoing savings are what provide the most value. A geothermal loop – connected in your home to a geothermal heat pump (GHP) – typically uses 25% to 50% less electricity than conventional HVAC systems. The GHP system has another money saving benefit – free hot water! Read our blog on the American Standard Geothermal Unit to learn how.
Another benefit of a GHP system is their longevity. Conventional heat pumps have a lifespan of 10-20 years, with about 15 years being the average. Geothermal piping typically carries a 25-50 year warranty, and geothermal heat pumps often last 20 years or more.
Comfort and Convenience
Along with cost savings, geothermal systems deliver comfort and convenience for those building an energy efficient home. Geothermal systems are very effective in areas like Raleigh with high humidity as they maintain about 50% relative indoor humidity. These systems also allow for “zone” space conditioning, enabling different parts of your home to be heated or cooled to different temperatures. Unlike a traditional outdoor HVAC unit, the system components are within the living space (attic or crawl space) and are easily accessible for ongoing maintenance. As a result of not having an outside condensing unit, there is no noise outside the home and the system runs very quietly, often going unnoticed by those inside the home.
Geothermal Is Environmentally Friendly
Geothermal systems are more environmentally friendly, producing far less carbon dioxide emissions than oil, gas, or electricity-driven systems; in some cases reducing emissions by 75-85%!
How to Avoid Mistakes in Your Geothermal Loop
Don’t Short Your [Geothermal] Loop!
It’s crucial to make sure your loops – the place where water cools as it runs through the underground piping – are large enough to enable heat dispersion. Larger loops allow for the space needed to transfer the heat out of the water and into the soil.
If the loops are too small, it could result in soil “baking” around your pipes and disrupting the cooling process. What this means is that the hot water from the pipes heats up the dirt around the house, baking it hard and preventing the proper transfer of heat out of the hose.
Add a Soaker Hose
Along with proper over-sizing of the loops, the addition of a soaker hose helps handle “baking” if it does occur. By setting up the structure to easily attach a soaker system to run over the top of the loops, you can make it easy to solve baking issues should they ever occur. The water dripping over the underground loop will break up the baking allowing the geothermal loop to operate as it should.
Proper Ductwork
You need to make sure that you have proper air distribution. This means that the duct work that distributes the cool air through your home is designed to match your GHP system. A mismatch hinders the ability of the system to circulate air in your home, hurting its overall performance.
Don’t Oversize Your Geothermal Heat Pump
A common problem is oversizing the heat pump and its components. This can happen when an inexperienced contractor sizes the unit to specification, and then makes it a little bit larger “just in case”. An oversized pump will use more energy and have shorter cycle times, which leads to more wear and tear on your equipment and can lead to wider temperature variations in your home.
Especially when building a new home, changes can take place during the build which makes the coordination of contractors extremely important. Be sure your builder and HVAC company are in sync so that changes to the new build don’t negatively affect the GHP and HVAC system installation and performance.
Summary
A geothermal loop for heating and cooling your home provides a number of benefits, ranging from energy cost savings and comfort to environmental friendliness. Because the loop is buried six feet underground, getting the installation done correctly is critical. Starting with the outdoor portion of the system, be sure that your loops are sized correctly to allow for heat transfer. And consider a soaker line in case your system develops an issue with baking. Moving into your house, coordinate with your contractors to make sure that the ductwork has proper distribution and your GHP unit is sized correctly. You can avoid the pitfalls we’ve mentioned here, and more, by working with professionals that have the expert know-how to properly install your geothermal loop. Look no further than the pros at Casey Services.
Previous – Air Circulation in Your House and Why It Matters
If you are building your home and looking to manage the humidity levels, a whole house dehumidifier can greatly improve your comfort at home and save you money on your energy bills.
Next – American Standard Geothermal Unit
The American Standard Geothermal Unit combined with a proper geothermal loop provides many benefits including you may not have expected – free hot water!
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