History & Origin of Geothermal Heat Pumps
Geothermal Heat Pump Heating and Cooling systems have come along way in the last 100 years. Even from early inception these systems have shown great promise. While only in the last three or four decades has geothermal systems really started showing promise. Installed primarily by farmers with the land and resources to trench ground loops in. Also, by engineers dedicated to developing the technology through trial and error usage in an attempt to reap the rewards the technology had to offer.
Only in the last 20 years has the technology started to become more widely used in residential and commercial applications. With the recent wide spread demand, more companies have invested resources into the market, thus bring down the cost and making geothermal more affordable for everyone. Coupled with tax incentives and utility company rebates, there is really no reason not to consider utilizing geothermal technology.
With these developments many people are wanting to know more and more about what geothermal is, how it works and the different types of systems that are available. The following paragraphs are dedicated to explaining the different types of systems and the pro's and con's inherent to their installations and long term use.
Loop Types & Requirements
First lets discuss the two types of loops used, open and closed. Open loops can either be located in a body of water or a water well. The first aspect of deciding if an open loop will work for you is knowing about the restrictions. These restrictions can be legal, water quality and amount of water.
Geothermal heat pumps need to have a constant flow of water around a maximum of three gallons per minute, per ton of unit capacity. So ultimately, capacity dictates everything. If your water sources cant support it, it can't be done.
The second aspect is the legal aspect needs to be factored. Are there restrictions that have to be met or is the use of the water supply even allowed. Many shared or Core of Engineers controlled lakes and ponds have restrictions, many do not allow open loops. Check with your local water authorities to find out more details.
Then functionality comes into play, is the water source large enough and deep enough? Typically a water sources needs to be at least an 1/2 acre in size per ton to ensure proper rates of rejection and extraction, which we will get into a little later. As far as depth, many manufactures recommend that the loop be covered by no less then 8 feet of water, due to thermal transference properties. Water quality must also be given attention with the consideration of how Ph levels can effect the life span of the coax coils and loop.
While opens loops work great there are obviously a lot of factors that must be considered.
Now that we have covered the simpler open loops, lets get into closed loops. Closed loops, are simply that, loops that recirculate a water and anti-freeze solution. We will cover the solutions later on. The important factor for the moment is that the loop is recirculating the same fluid and is not dependent on a constant water source. Which offers three immediate benefits, one operational costs, and two, no dependence on a constant water supply.
There are there typical methods of utilizing closed loops. Vertically drilled, horizontally trenched and in a body of water. Lets start with the characteristics of a vertically drilled loop system first.
Planning, Design & Implementation of a Geo System
While Geothermal heating and cooling systems have so much to offer. Without the proper attention on the front end of design and follow thru with a quality installation and correct procedural start-up. All the expense could very well be for nothing! That is why it is very important that when a geo system is commissioned that every effort is spent to ensure that all factors are taken into consideration. With any heating and cooling system, a heating load must be performed.
Thankfully ACCA's approved Manual J standards have been established so as to guarantee that a heating and cooling load is accurate. After a proper heating load has been determined, the process of a Manual D comes into play. An ACCA approved Manual D is used to determine the air flow requirements to handle Btu rejection and extraction. Meaning each material used in construction has an formulated rate of Btu transfer. We use air flow to move desired Btu's through out the building.
Now that the system has been properly designed, it is imperative to make sure what is needed in the building will work in conjunction with the land features present on site. Whether use of a body of water, water well or area of land. Generally home owners have a preconceived notion of what they would like o do and need scientific verification that what they think can be done is actually ok to do. Thanks to all the information on the internet, homeowners generally are on the right track and many times are right! This kind of research is always recommended and appreciated. There are many sources of information available, just make sure they are accredited and experienced. But more importantly that the manufacture of the equipment shares the same thoughts. Since they carry the warranty on their products. If they aren't installed correctly there is no warranty! With that said, checking on the ground conditions, optimally performing a conductivity test, can be as easy as talking to local land owners and getting feed back from their experience as well as local water well drillers. Many with a history in the area can tell you what to expect for ground conditions and with enough information you can definitely get a sense of a pattern. However, there is no guaranty what will be found or how the ground will conduct heat. Make sure you have everything laid out as too what extra charges and fees may apply if unknown conditions become a problem. Our policy is too make sure that our homeowners understand the normal per foot drilling charge and the likelihood of finding unfavorable conditions and the per foot charge of potential solutions matching potential problems.
Benefits - Energy & Environmental
With geothermal heating and cooling become more affordable more and more people are getting interested in the benefits geothermal has to offer. With in the last 5 years alone the demand has sky rocketed. Not only can owners claim tax credits that have a huge impact on the ROI. But also have the long term benefit of lower utility costs. Not to mention the reduction of environmental impacts. Less energy consumption means lower utility bills, less energy needed on a production level. Thus reducing not just the end users carbon foot print but our national dependence on foreign oil and the consumption of our national resources such as natural gas and coal. While these power producing technologies are getting cleaner and safer everyday. An over all reduction is the best solution for all, not just in America but globally.
Financial & Performance Expectations
The short and simple answer is that there is no way to put a dollar amount on the expense to operating any heating and cooling equipment after in has been installed in a building. While the equipment can be quantified in a laboratory for output vs. consumption. Once it is installed, there is no way to know for sure unless we define the building as thoroughly as we would a factored testing lab. While that sounds extremely complicated, and it is, with the right equipment it is very doable! Now that is only the case in an existing building, but what about new construction. Well that almost easier, with the right modeling and usage information we can get right back to what we should see when comparing to a RESNET Model home. Of course, garbage in garbage out... Without the right information we still can't properly design a model.
Now, what we can tell you is the averages and expectations. While these are not to the dollar either, they are surprisingly accurate, there is value in history and experience! Not that you can take it too the bank, but you will be able to make decisions based upon the experience of others. But keep in mind, science is the only accurate method for determining energy consumption and associated costs. Don't discount the value in taking the time and spending the resources needed to accurately determine the building science. Once you look at the ice berg from under the surface, there is a monumental cost in the future for operating any equipment.
While we are not the biggest company out there or the only company working with geothermal technology. We are one of only a very few competent companies in the Northwest Arkansas region. So why choose our company? Simply, we bring the best advantages... professionalism, expertise, experience and dedication to our customers. Taken even a step further...reasonable price, makes 1st Choice Home Comfort the best value!
One system at a time. Or the only company working with geothermal technology, we are one of only a few.
Contact us or give us a call at 479.633.7586 if you have questions about a geothermal system or if you need to schedule service.