Who is REACT?
Since 1999 REACT has been dedicated to introducing “green” building technologies to the development and construction industry.
What is the definition of a “green” building technology? Green building technologies are defined as those building components that dramatically reduce or eliminate greenhouse gases.
Which building technologies are specified as green? There are numerous products available that can eliminate or reduce greenhouse gases. Wind farms, photovoltaic panels that create electricity from the sun, micro-turbines, and fuel cells that create electricity from a variety of fuels and geothermal heat pumps are all “green” technologies.
Why are geothermal heat pumps considered a green technology? Geothermal is considered to be a green heating technology because 70% of the energy required to heat or cool buildings comes from the renewable energy of the sun warming the earth.
What do geothermal heat pumps look like? Geothermal heat pumps are located inside a metal box the size of a conventional furnace.
Are they noisy? No. Heat pumps are located in a central mechanical room in the basement of your building and will make a noise that is equivalent to your household refrigerator or the fan noise from your furnace.
Are there smokestacks or anything else visible outside? No. Geothermal heat pumps operate on electricity and as a result there are no greenhouse gases or other by-products that need to be vented to the outside.
Are geothermal heat pumps a new technology? The first geothermal heat pumps were installed in Europe in 1912 and there are presently more than 1 million units installed worldwide.
What is the principle behind a heat pump? A heat pump uses the basic principles of refrigeration. Just like your refrigerator at home, a geothermal heat pump removes and transfers heat from one location and expels the energy to another location. A refrigerator's heat pump removes heat from inside the refrigerator box and transfers this energy out of the back of your refrigerator and into your home using a series of black coils mounted on the back. The refrigerant in the system is the transfer agent. A geothermal heat pump air conditions the building by removing the heat from inside the building and expelling it into the ground.
But I want to heat my building too, not just air conditioning! When we reverse the flow of the refrigerant in the heat pump we are heating the building instead. In heating mode, we are removing heat from the earth, amplifying the temperature we get from the ground by using the refrigeration process and then pumping the heat into the building.
How do I get the heat or air conditioned air to various parts of my building? The process of moving heat or air conditioning around to various parts of the building can be identical to those of a conventional system. Ground source heat pumps can provide forced air heating of cooling through conventional sheet metal ducting, can manufacture hot water for use in hydronic space conditioning systems such as in-floor heating or can produce both heated and chilled fluids for use in a fan coil. We can also produce hot water for domestic use such as drinking water or for washing. Some machines can do all three functions at the same time.
Do I need a supplemental system or back-up? If the system has been designed and installed correctly, you should not need a back up or second system. We often add an auxiliary heating to the system as a secondary heat source just in case there is a mechanical failure with the primary system. We do this for the benefit of our clients and homeowners. This is not something you will ever see being done in a conventional system.
How much heat can I get from a ground source heat pump? Geothermal heat pumps typically produce 100 degrees F (37 C) hot air and up to 115 degrees F (46C) of heated fluids or can be used to chill your building as cold as your refrigerator.
How much pipe do you put in the ground? It all depends! The quantity of pipe is entirely dependent on the size of the building, the quality of construction and what kind of soil the pipes will be in., This is a critical component and the proper sizing is important to the success of the system.
How is the pipe put in the ground and where does it go? There are 2 methods of installing pipe in the ground. Vertical boreholes or horizontal trenches can be placed under parking lots, lawns or even in some instances, right underneath the building.
What kind of pipe is it? The pipes being installed in the ground are made of high density polyethylene. It is the same material used by the natural gas industry to feed your home except that the natural gas pipe is called medium density where as geothermal piping is high density. High density pipe is used because it can withstand the installation process better than medium density and once it has been installed it should never need replacing again. The manufacturer warranties the piping for 55 years.
How much pressure can these pipes withstand? The high density polyethylene has been designed to withstand internal pressures of up to 180 pounds per square inch (psi). When these pipes have been installed but prior to final hook-up to the geothermal heat pumps, REACT will pressure test the piping to make sure that they do not leak. We will test piping up to 100 psi even thought the operating pressures is only at approximately 20 to 25 psi.
What happens if the pipes should break? Our experience with broken pipes has been limited to errors made by a backhoe operator or some other trenching device working in the area that the geothermal pipes are situated in and piercing the pipes with their machinery. In the event that this happens, we can repair the piping using the same fusion process which was used to initially install the system.
What does a vertical loop field look like? Vertical loop fields are used when the amount of land available to us is limited for the amount of pipe going into the ground. A series of 4 inch holes are drilled and each hole is from 100 to 300 feet deep (30M to 90M). Each hole has a 3/4 inch or 1 inch (2-2.5 cm) pipe going down to the bottom of the hole and then back to the top. A special grout is used to fill the hole so that the pipes are in constant contact with the soil and not insulated from the soil by air. The pipes in the holes are then joined together in a horizontal trench about 5 feet below the surface using another high density pipe so that the fluids circulating through the ground can be brought back into the building.
What is a horizontal trench? Instead of installing pipe in a vertical hole, it is laid into a horizontal trench. More pipe is needed in this method than a vertical borehole but trenching is less expensive than drilling. This method is only used when there is an adequate surface area to work with.
Are there other types of heat exchangers instead of pipes in the ground? Other methods of transferring heat include putting pipes in a large body of water instead of the ground or an open loop system where water from one source is pumped into the heat pump before being discharging back to its source.
What kind of fluid is circulated through the pipes? The solution being sent through the pipes is water with an anti-freeze mixture. Methanol, ethanol and glycol are all equally effective at maintaining freeze protection.
What circulates the fluid through the pipes? A circulating pump designed for this application maintains the flow of fluids through the system.
If the heat pump runs on electricity and the power is interrupted in the building, how will I get heat? If the power goes out in a building with a traditional system, there is no way of circulating the heat from the furnace or boiler into the distribution system. If power goes out in a building with our heating/cooling system, there is no method of circulating the heat either.
What if there is a mechanical breakdown, how do I get it fixed? The technology inside the machine is made from off-the-shelf parts. If something goes wrong and the original supplier or installer is not around to fix it, any competent refrigeration mechanic should be able to fix it. The equipment inside the box is just like the parts they would work with at the local grocery store freezer section.
Is there a lot of maintenance with this system? Maintenance with this equipment is identical to the work you should be doing with the refrigerator in your home. Keep the coils clean and replace dirty filters.
How do I control the heat in my building? These units operate with a thermostat just like ordinary furnaces.
What is the estimated capital cost of a geothermal system? Pricing of geothermal systems are based on the size of your home and how well insulated it is, how many windows and doors there are and if you are replacing a furnace, air conditioner, and boiler or if you are only replacing one of these. Do you want it to supply your domestic hot water as well? All of these variables can change pricing.
Down to Earth Renewable Technologies
