Technical FAQ’s

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)

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.

Answer: BTU = GPM x TD x 500.4 TD = 10 So, 10 GPM x10 F x 500.4 = 50,040 BTU/hr

Answer: Minutes = (gallons x TD x 500.4) ÷ BTU/hr

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.
Direct Energy 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).

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, Direct Energy systems rely upon the more favourable, stable temperature of the earth. Heat from the earth provides the Direct Energy unit greater heating capacity in winter, and reduces or eliminates the need for supplemental heat. Therefore, the Direct Energy 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.

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.

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.

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.

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.

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.

Answer: The ACC system component 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.
Is equipped with sight glasses (windows) to enable quick and accurate refrigerant charging of the system.

Answer: Heating hydronic water or domestic water are two processes. First, domestic: typically domestic hot water (DHW) is heated to about 60°C 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 Direct Energy system can very efficiently heat DHW to 50°C, then supplemental heat is used to “>
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 Direct Energy 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 60°C anymore. It is 50°C. 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 Direct Energy 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 Direct Energy 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 Direct Energy and heated to 50°C. The main tank, plumbed and wired normally draws the pre-heated water into itself and tops it off to 60°C. Direct Energy heated water from 10°C to 50°C, then electrically heated water from 50°C to 60°C. You get the benefit of the Direct Energy heating the water up to 50°C and the hotter water from the main tank (60°C) to which you are accustomed. Next, two smaller 160L tanks can be used which are cheap and readily available. Lastly, if the Direct Energy has minor trouble, you have the back-up of the main tank which can heat from 10°C to 60°C 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.

Answer: Sustaining temperatures far outside the comfort range is a unique situation but is possible within reason. 

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 38°C and 45°C. Expect the lowest indoor temperature to be sustained between 10°C and 15°C. Temperatures below this begin to drift into the Medium Temperature Range. These temperatures are used for refrigeration, and, while the Direct Energy 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).

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. Direct Energy will provide wiring instructions to make the “other” thermostats operate the Direct Energy 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 Direct Energy system properly.

Answer: The Direct Energy system is capable of heating the water from its supply inlet temperatures (typically 10°C to 25°C up to 50°C) 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 50°C, 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 Direct Energy system does most of the heating (69-77%) with high efficiency and the remainder is done with supplemental heat.