Question:  What is a BTU?
Answer:  A British Thermal Unit is the amount of energy (heat) required to raise the temperature of one pound of water by one degree Fahrenheit.    (1 BTU = 1 lb. x 1°F)

Question:  Why is refrigeration capacity measured in terms of "Tons"?
Answer:  Many thousands of BTUs are needed to achieve a change in temperature in homes and other buildings, or to freeze water or melt ice. The term "Ton" is used to abbreviate the large number of BTUs required to melt 1 ton of ice at 32°F (into 1 ton of water at 32°F).

Question:  How can I calculate how many BTUs are needed to heat water?
Answer:  The calculation begins with the starting temperature and the desired temperature of the water (T1 and T2 measured in degrees Fahrenheit). The differences in the two temperatures is TD (temperature difference) (TD = T2 - T1). Next, the weight of the water is determined by multiplying the number of gallons by 8.34 (1 gal. = 8.34 lbs.).

BTU = TD x #lbs.     BTU = TD  x  #gal. x  8.34

Question: How are the power consumption and the power factor of a 3-phase motor calculated?
Answer:  Most 3-phase compressor motors are wired as "Y-Connected Load." To determine power factor and power consumption, nine different values must be measured while the compressor is running:

We will need to measure  nine (9) different values of the compressor while running :

EL = The average line voltages between phases 1-2, 1-3, and 2-3

Vp1 = Voltage between Phase 1 and neutral

Vp2 = Voltage between Phase 2 and neutral

Vp3 = Voltage between Phase 3 and neutral 

Ap1 = Amperage through Phase 1

Ap2 = Amperage through Phase 2

Ap3 = Amperage through Phase 3

The True Power (Pt) can be calculated several ways.  Two of which follows.

1)   Pt =  0.6 x [(Vp1 x Ap1) + (Vp2 x Ap2) + (Vp3 x Ap3)] 

2)   Pt =  1.039 x EL x (Ap1 + Ap2 + Ap3) / 3

The power factor is always 0.6 (lagging) for a Y-Connected Balanced Load.  Therefore, the Volt Amps (Volts x Amps) will always be 1.67 times greater than the true power.

Question:  I have water flowing through a heat exchanger at 10 gallons per minute (GPM).  It enters at 50 F and exits at 60 F.  How many BTU/hr are being added to the water?
Answer:  BTU = GPM x TD x 500.4     TD = 10   So, 10 GPM x10 F x 500.4 = 50,040 BTU/hr

Question:  If I have a heating system that produces 48,000 BTU/hr, how long will it take to heat my 40 gallon water tank from 50 F to 120 F?
Answer:  Minutes = (gallons  x  TD  x  500.4) ÷ BTU/hr

So,     (40 gal  x  70 F  x  500.4) ÷ 48,000 BTU/hr  =  29.19 minutes

Question:  In a humid climate, how can you assure proper dehumidification in the cooling mode?
Answer:  Optimum comfort can be assured by the selection of the appropriate capacity unit to match the heating and cooling load. It is essential to accurately determine the effect of the building's construction, materials, window sizes, insulation values, orientation to the sun, the effect of use and occupancy, air infiltration and ventilation. The Air Conditioning Contractors of America (ACCA) developed a procedure to quantify these factors and calculate their effect. The "Manual J" procedure is routinely used by competent heating and cooling contractors in the U.S. Computer programs such as those created by Elite Software are available to simplify the process.

ECR requires that a Manual J calculation be performed before a system is specified. Correctly matching the system to the load avoids discomfort as well as spending too much money to install a unit that is oversized. A unit that is too large for the load will cool too quickly, then turn off before it has operated long enough to remove sufficient humidity. A unit that is too small for the load will run longer as it unsuccessfully attempts to lower the temperature, resulting in good dehumidification but inadequate cooling. It lowers the latent heat load (humidity), but does not sufficiently lower the sensible load (temperature).

Question:  If an EarthLinked system is sized to serve a large heating load and a small cooling load, will it quickly satisfy the sensible cooling load, then short cycle and not remove adequate moisture?
Answer: Although air source heat pumps must struggle inefficiently to extract heat from cold ambient air in winter, and frequently rely upon supplemental heat, then discharge heat into hot air in summer, EarthLinked systems rely upon the more favourable, stable temperature of the earth. Heat from the earth provides the Earthlinked unit greater heating capacity in winter, and reduces or eliminates the need for supplemental heat. Therefore, the ECR system can serve a greater heating demand in winter and still be matched to a lighter cooling demand in summer. The longer run cycles designed into the system add further assurance of adequate dehumidification.

Question:  Can I use HD poly pipe as the ground loop for an EarthLinked system?
Answer:  All polymer pipes have some permeability for refrigerants, and therefore are not appropriate. They also do not exchange heat as efficiently as standard refrigeration copper tubing.

Question:   Is it possible to use earth loops that are longer than 100 feet?
Answer: Except for horizontal loop systems, the maximum is 100 feet of earth loop length. Refrigerant flowing through the system must maintain a certain minimum velocity in order to entrain and return the compressor lubricating oil to the compressor. A loop length greater than 100 feet results in an excessive pressure drop and reduction in flow velocity. In the cooling mode, the hot refrigerant gas condenses into a liquid as it gives up its heat to the earth. To return that vertical column of liquid to the heat pump would require an auxiliary pump.

Question:   For the Vertical loop (1.5 per ton), the specification is 1.5 x 100'. Does this mean the loop is 150' long? Or does it mean that 1.5 times as many loops are required?
Answer:  The latter is correct. Two tons of capacity require 3 earth loops totalling 300 feet; 2.5 and 3 tons require 400 feet; 3.5 tons require 500 feet; 4 tons require 600 feet; 5 tons require 700 feet; and 6 tons require 9 loops totalling 900 feet.

Question:  Will burying the loops in subsurface water allow for a better heat exchange and require fewer loops?
Answer: If the earth loops are in subsurface water, heat exchange will be improved during air conditioning operation, creating higher system efficiency. However, the number of earth loops specified for a system should not be reduced.

Question:  Should I have a concern about corrosion of the copper pipe?
Answer:  Copper is a noble metal that exists in its natural state in the earth. It was used to convey water and for tools and weapons by ancient Egyptian and Roman civilizations. It resists corrosion by forming a thin patina on its surface. For hostile subsurface environments and for customers who want absolute assurance, ECR offers the Cathodic Protection System (CPS). An anode is buried in the ground and a very small amount (milliamps) of self-adjusting electrical current is applied (a "trickle charge"). This establishes a protective electrical field that surrounds the earth loop cluster and precludes the galvanic action that is corrosion. The CPS is quite affordable and is easy to install with the earth loops.

Question:  Are the tubes used for the EarthLinked system bare copper or is there any sort of protective coating applied?
Answer:  Many years of research and consultation by ECR with metallurgy experts clearly established that 1) coating the earth loops was not appropriate because any small breach in the coating would focus all galvanic action at that location, and 2) the only scientific method of precluding corrosion is to establish a protective electrical field that surrounds the earth loop cluster (as does the ECR Cathodic Protection System).

Question:  What if I have very low pH shallow water? Will this corrode the refrigerant lines?
Answer:  A pH as low as four (4) and as high as eleven (11) can be accommodated. The ECR Cathodic Protection System (CPS) has been designed for these extremes.

Question:  How do you keep the copper from reacting in the soil?
Answer:  The copper begins reacting as soon as it is installed. Some locations react more than others. Over 90% of installed EarthLinked systems do not have a CPS and there have been no corrosion-related leaks in the loop fields.

Question: Please explain ECR's copper protection system.
Answer: ECR offers a proprietary Cathodic Protection System (CPS) which can be used to protect copper earth loops in locations where there is a concern that corrosion of the copper might occur. Protection of the copper tubing in the earth is accomplished by an “impressed” electrical current, which flows from an “anode” buried adjacent the earth loop field, through the earth and into the surface of all of the copper in the earth loop system.

The voltage that is applied is sufficient to establish and maintain an electrical current inflow to all of the surfaces of the copper and thereby preclude corrosion, but the voltage, and resulting current, is not of sufficient magnitude to have any effect upon humans, other animals, or plant life

A step-down transformer in the CPS reduces the 120 volts from a standard wall outlet, to a nominal 28 volts, and isolates this secondary voltage from its 120 volt source. Then the isolated 28 volts is rectified with a full-wave rectifier and filtered with a capacitor to produce a smooth direct current (DC) voltage. The resulting smooth DC current then passes through an electronic current regulator which is designed to hold the current output at a fixed pre-determined value. The output voltage ranges from a maximum of about 32 volts, down to minimum of about 15 volts, and the pre-determined impressed current, flowing though the anode, earth, and protected copper, ranges from about 50 milliamperes to 200 milliamperes, depending on the size of the earth loop system.

The design of the Cathodic Protection System is such that no AC voltages or currents and no radio frequency voltages or currents are produced or emitted. Only a low DC voltage and minimal DC current are produced. A person or animal can touch the output terminals and not be able to feel the voltage. The output terminals present the highest voltage that is accessible in the entire CPS system, and this voltage is totally harmless to humans and animals. The positive (red) terminal of the CPS is connected by specially insulated wire to the anode, which consists of a specially coated titanium rod or a high-silicon steel rod. The anode is buried in the earth which makes accessibility to the output voltage virtually impossible. The negative (black) terminal is connected by insulated wire to the earth loops, thereby completing the path for the current to flow from the control module to the anode, to the loops, and back to the control module.

If a metallic object is on the ground within the vicinity of the protected copper system, no significant amount of current can flow from the anode to that object unless the object is electrically connected to the negative terminal of the CPS. Objects such as tanks, troughs, and metal posts could be subjected to the insignificant voltage gradient described below, and no harm would result. If such objects were connected to the negative terminal of the control module, then a portion of the impressed current intended to flow to the copper would flow to such objects. The current flow to such connected objects would be protective in nature for the objects, but since it would rob some of the current intended for the copper, connecting such objects is not advised.

Theoretically, since the earth provides an almost infinite number of current pathways from the anode to the copper, a minuscule current could flow from the anode to the earth surface and along the surface and back into the earth and down to the copper. This flow at the surface would establish a voltage gradient along the surface. The magnitude of this voltage is on the order of micro-volts or nano-volts and could be detected only with very sensitive and sophisticated instrumentation. Even a wet human or animal would not be able to detect the presence of such a small voltage. Since this voltage gradient is several orders of magnitude below the level detectible by humans or animals, it is inconceivable that ECR's Cathodic Protection System could have any effect on humans or animals.

Question:  What kind of soil requires the Cathodic Protection System (CPS)?
Answer: CPS protection is required if:

• soil test results indicate the pH is lower than 6.0 (acidic soil) or higher than 11.0 (alkaline soil);
• the soil has concentrations of acids, chlorides, sulphides, sulphates or ammonia; or
• the soil is in coastal areas influenced by brackish water marshes, saltwater intrusion or acidic peat bogs. 

Question:  Is maintenance required for the CPS?
Answer: There is a green indicator light on the CPS Control Module to indicate the CPS is operating. If the light is on, no maintenance is required. If the light is off, the electrical circuit of the CPS should be checked.

Question:   Should the manifold pit be excavated before the bore holes are drilled?
Answer:  If you are drilling diagonally, dig first. This allows you to drill diagonally from the bottom wall of the manifold pit.   If you are drilling vertically, drill first, then proceed to trench from one vertical bore hole to the next and manifold them together.

Question:  If I only need air-conditioning, what kind of model would you suggest?  Will I still require the heat pump? 
Answer: If A/C is its only function, an HC model (heat only) will perform perfectly, but it must be ordered as an A/C only unit.  Otherwise it will be labelled as a "Heat Only" unit.  The plumbing is the same in the cabinet, but the labels will be wrong if it is not specified. A Manual J heat gain calculation is still required on the building to determine which size unit will perform properly.

Question:  What is the COP for the EarthLinked system at various outside temperatures and for various applications?
Answer: Our Geothermal system boasts verified coefficients of performance (COPs) from 3.5 to greater than 5 in space heating and cooling. For a complete overview of the system's performance under various conditions, have a look at our complete performance table.

Question:  Can you describe the Active Charge Control (ACC) and its function?
Answer: The ACC is a patented EarthLinked system component that has three functions:

• allows only saturated refrigerant vapour and entrained oil to be returned to the compressor, which maximizes compressor and system performance and extends compressor life;
• is a reservoir for holding liquid refrigerant and oil that is not needed in circulation at any given time, thereby modulates to allow the system to operate at maximum efficiency throughout the full range of operating conditions; and
• is equipped with sight glasses (windows) to enable quick and accurate refrigerant charging of the system.

Click here for a detailed description of the ACC.

Question:  The diagram for the EarthLinked water heater application seems to require both your system and a separate water heater. Why do you need both a storage tank and water heater? Please explain the radiant floor and house supply hot water. Is the supplemental water heater needed because the recovery time of your geothermal system is too slow?
Answer:  Heating hydronic water or domestic water are two processes. First, domestic: typically domestic hot water (DHW) is heated to about 140°F for dishwashing and to assure hot water. The hot water is tempered with cold water at its outlet to make it bearable for bathing. The EarthLinked system can very efficiently heat DHW to 120° F, then supplemental heat is used to "top off" the remaining 20°F.

Consider the following example: people are familiar with their shower control handle. For years, they knew that the 12 o'clock position will yield water at the desired temperature (hot and cold mixing), and they have always had enough hot water to finish showering. After installing the EarthLinked geothermal water heating system, their water is heated three times faster for 1/3 the cost. The first night in the shower, they notice that the shower control must now be set for 10 o'clock position to deliver the usual water temperature. No problem--new set point. Later, the water begins to get cold before the shower is over. Why? Because the water in the tank is not 140°F anymore. It is 120°F. So, more of it is required (and less cold water) to maintain the same outlet temperature. So, the heated water is used faster--and drained completely. The heat pump is attempting to replace the water, but even a 4-ton unit can heat only two gallons 50 F per minute. 1 BTU = 1 lb water x 1 degree F. One gallon of water weighs 8.34 lbs.

Yes, the EarthLinked heats water faster and cheaper, but even the largest system would struggle to keep up with a normal shower's usage rate. Why not make the tank bigger so you do not run out? Because an EarthLinked system prioritizes DHW. If it diverts to heat DHW, its main load (heated air or hydronic heating) must pause and wait while the DHW tank is satisfied. Discomfort may be felt in the main house while you wait for the DHW to finish. The system heats only one thing at a time. This is why we recommend two 40 gallon tanks. It is the best of both worlds.

The pre-heat tank is serviced by the EarthLinked and heated to 120°F. The main tank, plumbed and wired normally draws the pre-heated water into itself and tops it off to 140°F. EarthLinked heated water from 50°F to 120°F, then electrically heated water from 120°F to 140°F. You get the benefit of the EarthLinked heating the water up to 120°F and the hotter water from the main tank (140°F) to which you are accustomed. Next, two smaller 40 gallon tanks can be used which are cheap and readily available. Lastly, if the EarthLinked has minor trouble, you have the back-up of the main tank which can heat from 50°F to 140°F by itself.

Hydronic Water Heating (HWH) It is best to design the in-floor heat exchanger to operate at about 115°F. The water is hot enough and little stress is placed on the compressor or other parts. One single 40 gallon water tank is adequate per system. The water tank serves only as a small buffer between heat pump and flooring. The system will satisfy the tank thermostat fairly quickly (no load). When the floor loads come on, the tank will be drained of its heat rapidly. The heat pump will likely not be able to keep up with the drainage rate, but it will then begin to supply heat at its own rate adequate to change the temperature of the floor and eventually satisfy the load and the thermostat settings. Once the in-floor pumps stop, the heat pump need only finish heating the water in the tank to the set-point.

Question:  How do you get the refrigerant gas into a liquid state before entering the earth loops?
Answer:   In the air conditioning mode, the hot gas enters the ground loop directly after it leaves the compressor.  Then it condenses into a liquid before it leaves the earth loops.

Question:  Are auxiliary pumps used to circulate refrigerant?
Answer:   The only "pump" that circulates the refrigerant is the compressor itself.  There are no other refrigerant pumps involved. One circulates water to/from the water tank in the water heating mode.

Question:  What is the highest sustained room temperature in the heating mode and lowest cooling temperature in the cooling mode?
Answer: Sustaining temperatures far outside the comfort range is a unique situation but is possible within reason. The limiting factor is the pressures of the refrigerant at those extremes, because the pressures of the refrigerant are directly proportional to the temperatures of the refrigerant, and the temperature of the air over the indoor coil dictates the temperature of the refrigerant.

I can hypothetically determine the temperature extremes, though these air temperatures have not been tested or proven as far as their limits go. Expect the highest indoor temperature to be sustained between 100°F and 110°F. Expect the lowest indoor temperature to be sustained between 50°F and 60°F. Temperatures below this begin to drift into the Medium Temperature Range. These temperatures are used for refrigeration, and, while the EarthLinked could continue to drop the temperature lower, it would require a method of defrosting the indoor coil, because it would be operating below freezing (32°F).

ECR's controls are currently operating refrigeration equipment used for chilling milk and commercial refrigerators, but these applications are design-sensitive, and the installers are aware of the operating criteria when they purchase the controls. If air temperatures are required above or below these indicated, ECR may be able to assist in designing such equipment utilizing our patented refrigerant controls.

Question:  Why does ECR specify the use of the Danfoss HP8000 thermostat with its heat pumps?  Other than it being programmable, does it work differently than typical heat pump thermostats?  What will happen if I use a different make and model?
Answer:   The Danfoss thermostat line was chosen because of a relatively unique function it performs.  It is able to identify the "Balance Point" automatically with no external sensors or human input. The Balance Point is the temperature outside where a building's heating system, such as a furnace or heat pump, can no longer provide the heat at the same rate at which the building is losing heat. So, for every degree below the Balance Point, the indoor temperature will drop an equal number of degrees even though the heating system is operating continuously.  Obviously, supplemental heat (back up) is required below the Balance Point--enough heat to provide for the building's heat loss down to the lowest outdoor temperature expected.

All heat pumps are designed to provide heat for the building, but none are expected to provide all of the heat down to the lowest outdoor temperatures.  All heat pumps require supplemental heat sources. Typical heat pump thermostats have two heat stages.  The first bulb operates the heat pump.  If the heat pump can no longer supply all of the heat, the indoor temperature drops two degrees activating the second stage (supplemental heat source).  As the second stage switch toggles the supplemental heat, the heat pump operates continuously via the first stage switch.  This method of operation is adequate for air-source heat pumps because the outdoor air temperature (heat source) is relatively constant. 

Ground source heat pumps should not operate continuously.  Doing so causes the earth temperature (heat source) to be reduced over time.  The recovery time for the earth requires more time than that of the outdoor air, and, as the heat source is reduced, the system's capacity is also reduced.  Prolonged periods of operation in this fashion can "strip" the heat from the earth rendering the ground source heat pump inadequate if not disabled.  Once this occurs, the heat pump can not supply enough heat to satisfy the thermostat even if the outdoor temperature is greater than the Balance Point.

The Danfoss HP8000 thermostat utilizes an internal microprocessor which contains an algorithm that recognizes the Balance Point.  When the thermostat calls for heating, the heat pump always responds first.  While the heat pump operates, the thermostat constantly monitors the rate at which the indoor air temperature is rising in an attempt to reach the set-point.  If the indoor air temperature is not rising at a rate of seven degrees F. per hour, the thermostat turns on the supplemental heat to operate with the heat pump.  Thereafter, the supplemental heat remains on with the heat pump until the set-point is achieved.  Then, the thermostat turns off both the heat pump and the supplemental heat.  The heat pump is allowed to rest momentarily, the ground is not stripped of its heat, and the earth temperature remains high enough to control indoor temperature when the outdoor temperature is greater than the balance point.

If an alternative to the HP8000 thermostat is used instead, an additional outdoor thermostat must be used in order to recognize the balance point.  A heat loss/gain calculation will yield a numerical value for the balance point.  The outdoor thermostat must be manually adjusted to equal this value, then installed, and wired.  ECR will provide wiring instructions to make the "other" thermostats operate the EarthLinked system correctly.  This control method will yield a virtual replication of the HP8000's method saving the earth from having its temperature stripped, but reduced levels of comfort and controllability will be noticeable.   All alternative thermostats require the outdoor thermostat to operate the EarthLinked system properly.

Question:  Why is it economic to use supplemental heat to "top off" the water temperature?
Answer: The EarthLinked system is capable of heating the water from its supply inlet temperatures (typically 50°F to 75°F up to 120°F) three times faster and at one quarter the cost of standard electric heating. When a compressor is called upon to deliver heat to water that is hotter than 120°F, there is greater resistance to heat transfer, so the compressor must work harder and use more electric energy. Although it may still be twice as efficient as standard resistance heating elements, it is necessary to avoid overloading the compressor. The remaining temperature rise is accomplished with supplemental heat, usually electric heating elements. Thus the EarthLinked system does most of the heating (69-77%) with high efficiency and the remainder is done with supplemental heat.

Question:  Is a two-speed compressor feasible with an EarthLinked system?
Answer: The velocity of the refrigerant that circulates for heat exchange in the earth loops is crucial because it must maintain a sufficient rate of circulation to continuously transport the compressor lubricating oil. A two-speed compressor would reduce the velocity to the extent that oil would not be returned to the compressor, which would be detrimental to the unit.

Question:  Is direct-exchange better than water-based geothermal system in hot or cold climates?
Answer:   Direct-Exchange is better than water-source anywhere it is used.  Two exceptions where water-source has a better application is (1) in large commercial jobs where many tons of heating or cooling are required.  The heat can be captured from very far away and then transported back to the building while the direct-exchange in-ground heat exchanger must remain close to the building. (2) is where many smaller heat pumps utilize one large circulating header that shares cooling and heating loads throughout a large building.  Heat rejected from one zone is absorbed into another zone via the header circulating water.  If the header becomes too cold or too hot, the water is sent into the earth for heat rejection/absorption.  Sometimes a boiler and cooling tower is used for non-geothermal systems.