Small household pumps have internal motors, while larger spaces need an external motor. The internal motor is weak but keeps the pump watertight, because the pump does not need to interact with anything outside itself. External motors are needed for large applications; otherwise the water cannot circulate through the circuit, but these systems are more difficult to maintain.

For a two-phase flow, only two of these phases are considered, usually a liquid and a gas. For example, a typical refrigerant liquid usually will change into a gas from a liquid when compressed and from a liquid back into a gas when expanded. The primary method of energy transfer during this two-phase flow is usually with heat energy.

Refrigerant lines that are incorrectly sized can cause significant damage to the cooling system components. Pipes that are too large will reduce the pressure within the system, leading to poor performance. Without the proper level of pressure, the refrigerant will change states at the wrong time, making it incapable of transporting heat energy as intended. Pipes that are too small may lead to excess pressure, which could flood the cooling system.

 

There are various types of ventilation systems, which are typically classified as natural or mechanical systems. A natural ventilation system relies on atmospheric conditions, while a mechanical system is a man-made device that assists in the filtration and circulation of the air. The most common form of a natural system consists of an outlet on the roof and openings throughout the lower part of a building. This allows air to rise and exit through the roof, and new air to enter from below, providing constant circulation.

Mechanical ventilation systems actively pull fresh air in and push old air out. They may have other capabilities, including heating and cooling, and require some form of energy to operate. One common form of mechanical ventilation system is the heating, ventilating, and air conditioning (HVAC) units which are used in homes and other buildings.

All types of residential geothermal systems must be professionally installed. Accredited installers, trainers, and certified designers can be located through professional associations such as the International Ground Source Heat Pump Association (IGSHPA). These associations should be able to provide local contractors listed by area.

The best residential geothermal system for a home depends on the site's climate, available land space, and soil conditions. With thoughtful professional design and installation, residential geothermal systems can provide long-term energy savings.

 

Geothermal heating harnesses natural thermal energy from within the Earth’s crust for water and space heating. This method of heating is hailed for its energy efficiency, lack of pollution, and financial benefits. Areas such as Iceland with abundant geothermal sources, called hot spots, can freely use the energy for heating. Regions lacking hot spots can also achieve geothermal heating, however, using a geothermal heat pump.

A series of pipes are set up in a loop beneath the house and cooled water is pumped through. As the water passes through the ground, it conducts heat, which is then re-extracted in a heat exchanger below the house. The heat that the exchanger pulls from the water and the heat created as a byproduct of the exchanger’s work are used to heat the house. When the loop is reversed and warmed water is pumped through the ground to lose heat in the relatively cooler soil, the system can be used to cool the house. Geothermal heating uses far less energy than electric heating and cooling or an air source heat pump.

Geothermal heating is celebrated for several environmental and financial reasons. This method of heating draws energy from a renewable source and creates less of the pollution common to burning fossil fuels. From a financial perspective, geothermal heating systems require less maintenance, last for decades, raise the value of a building, and cut costs normally accrued in monthly oil or electric bills.