Geothermal Furnace
A geothermal furnace is a heat pump that uses water instead of air as a source of heat gain or loss. Water is pumped through a closed loop of pipes buried in the ground, or pumped from a well and discharged into another well or into a pond. The condenser and evaporator coil are enclosed in one cabinet. A backup electric heating element may be installed in the supply ductwork
In heating mode, heat is extracted from water as it passes through the condenser, and released through the evaporator coil.
In air conditioning mode, heat is extracted from the evaporator coil and released into water through the condenser.
Accessories can include; an air filter, electronic air cleaner, high performance media filter, and a humidifier. The humidifier can be of the steam generating type, which will be line voltage powered, so caution must be taken to shut off power before servicing. Sometimes a condensate pump will be used to dispose of the water produce in the dehumidifying action of the air conditioning.
If the system is zoned, a zone control panel and motor actuated dampers will be installed on the unit or in the ductwork.
A filter or strainer may be installed in the supply side of the water feed to keep sediment out of the pump and condenser if drawn from a well.
Routine maintenance includes replacing the air filter or washing the electronic air cleaner grids, cleaning the humidifier, and servicing the water filter or strainer. All maintenance should be done with the system shut down.
Heat Gain
Cold is another word for empty. It isn't really anything. It is, as a vacuum is, the lack of something. Cold is the lack of heat. The earth we live on is almost empty. We live on the edge of a delicate temperature balance only some 500° F above empty. The coldest it can ever get is about -460° F, but "hot-wise" temperatures can reach into the billions. We live at the bottom of a thermometer that stretches to the moon. Our planet is a cool puddle in a desert of heat, but water works only at these narrow temperature ranges, and life depends on this water.
Our planet must remain empty in order to support life. Refrigerants that leak into the atmosphere cause damage which allows extra heat to alter and fill our emptiness. Federal and international regulations have been devised and enacted to curb the release of certain refrigerants into the atmosphere to prevent our emptiness from being disrupted. A federal license is required for handling these refrigerants. If you’re going to use refrigerants, use them conscientiously. Much depends on it.
It is the function of a cooling system to remove unwanted heat from a structure and relocate it to the out of doors. This heat exchange is accomplished by the use of the refrigeration cycle as performed by your air-conditioning system. The refrigeration cycle takes advantage of the relationships between pressure, temperature and volume; in such a way that heat is collected inside and released outside. It uses a condenser, a compressor, and an evaporator to accomplish this task.
The condenser and compressor are located outside of the house, while the evaporator is located inside the air distribution system. The quantity of heat that needs to be removed to maintain indoor comfort, on a specific warm day for your region, is known as the heat gain for your structure*. A building gains heat from the actual outdoor temperature and humidity levels. It gains heat from the people inside of it, from the lights, computers, copiers, dishwashers and ovens. But mostly it gains heat from its exposure to sunlight, from solar radiation. The hot sun beating down on the walls and the roof, the sunlight pouring through the windows and warming the floors it lands on.
The sum of all of this heat accumulation is known as the heat gain of the building.
* Many contractors distribute an extra 1500 BTU of cooling to the kitchen to offset the heat given off by the appliances, and an extra 400 BTU to various rooms for occupants.
Condensers
The coil is usually made of copper tubing with aluminum fins, but some manufactures use aluminum tubing. Its purpose is to transfer heat as rapidly as possible. Pressure inside the coil can exceed 400 psi, during extremely warm weather conditions. The cleaner it is kept, the better it transfers heat. Rinsing with a garden hose occasionally when the unit is not running will help keep it operating efficiently. After many years of use it may be necessary to put special chemicals on to clean it.
The condenser fan moves air across the coil to increase the transfer of heat. It is critical to the system. Obstructing the flow of air will not only reduce efficiency but can lead to compressor failure. Keep debris and objects away from the coil and fan to allow maximum air flow. Some condenser fan motors have sealed bearings, others need lubrication. Damage to the fan can occur if removed improperly. Have a qualified serviceman handle the lubricating if needed. |