Q: How are the buried pipe section of the loop joined?
A: The only acceptable method to connect pipe sections is by thermal fusion. Pipe connections are heated and fused together to form a joint stronger then the original pipe. Mechanical joining of pipe for an earth loop is never an accepted practice. The use of barbed fittings, clamps, and glued joints is certain to result in loop failure due to leaks.
Q: Will an earth loop affect my lawn or landscape?
A: No. Research has proven that loops have no adverse effect on grass, trees, or shrubs. This, of course, will leave temporany bare areas that you can restore with grass or sod.
Q: Can I reclaim heat from my septic system disposal field?
A: No. Such usage is banned in many areas.
Q: If the loop falls below freezing, will it hurt the system?
A: No. The antifreeze solution used in loops that operate at low temperatures will keep it from freezing down to about 15F (-9C) fluid temperate. In the US and Canada, three types of antifreeze solution are acceptable; propylene glycol, methyl alcohol, and ethyl alcohol. Some states/provinces may require one type over another.
Q: Can I install an earth loop myself?
A: It's not recommended. In addition to thermal fusion of the pipe, good pipe-to-soil contact is very important for successful loop operation. Nonprofessional installations may result in less than optimum heat pump performance.
Q: I have a pond near my home. Can I put a loop in it?
A: Yes, if its deep enough and large enough. A minimum of 8-10 feet in depth at its lowest level during the year is needed for a pond to be considered. Generally, a minimum of 1/2 acre pond is required to provide adequate surface area for heat transfer.
Q: What is an open-loop system?
A: The term "open-loop" is commonly used to describe a geothermal heat pump system that uses groundwater from a coventional well as a heat source in winter and a heat sink in summer. The groundwater is pumped through the heat pump where heat is extracted (in winter) or rejected (in summer), then the water is disposed of in an appropriate manner. Since groundwater is a relatively costant temperature year-round, it is an excellent heat source/heat sink.
Q: What do I do with the discharge water?
A: There are a number of ways to dispose of water after it has passed through the heat pump. The open discharge method is the easiest and least expensive. Open discharge simply involves releasing the water into a stream, river, lake, pond, ditch or drainage tile. Obviously, one of these alternatives must be readily available and must prossess the capacity to accept the amount of water used by the heat pump before open discharge is feasible.
The second means of discharge is the return well. A return well is a second well bore that returns the water to the ground aquifer. A return well must have enough capacity to dispose of the water passed through the heat pump. A new return well should be intalled by a qualified well driller. Likewise, a professional should test the capacity of an existing well before it is used as a return.
Q: How much groundwater does an open-loop system need?
A: Geothermal heat pumps used in open-loops systems need differing amounts of water depending on the size of the unit. The water requirement of a specific model is usually expressed in gallons per minute and is listed in the specifications for that unit. Your heating and cooling contractor should be able to provide this information. Generally, the average system will use 6-10 gpm while operating. An extremely cold day might result in a usage of 6,000-10,000 gallons of water.
Your well and pump combination should be large enough to supply the water needed by the heat pump in addition to your domestic water requirements. You will problably need to enlarge your pressure tank or modify your plumbing to supply adequate water to the heat pump.
Q: What problems can be caused by poor water quality?
A: Poor water quality can cause serious problems in open-loop systems. Your water should be tested for hardness, acidity, and iron content before a heat pump is installed. Your contractor can tell you what level of water quality is acceptable.
Mineral deposits can bulid up inside the heat pump's heat exchanger. Sometimes a periodic cleaning with a mild acid solution is all that's needed to remove the build-up.
Impurities, particularly iron, can eventually clog a return well. If your water has a high iron content you should be sure that the discharge water is not aerated before it's injected into a return well.