| A | B |
|---|
| heat pump | a refrigeration system used to supply heat or cooling using valves to reserve the refrigerant gas flow |
| balance point | the temperature in a structure where the heat pump will run full-time and maintain the temperature in the structure; auxiliary heat must be used to accompany the heat pump when the temperature is below the balance point |
| check valve | a device that permits fluid flow in one direction only |
| coefficient of performance (COP) | the ratio of usable output energy divided by input energy |
| four-way valve | the valve in a heat pump system that changes the direction of the refrigerant flow between the heating and cooling cycles |
| filter-drier | a type of refrigerant filter that includes a desiccant material that an attraction for moisture; it will remove particles and moisture from refrigerant and oil |
| liquid line | a term applied in the industry to refer to the tubing or piping from the condenser to the expansion device; it contains liquid during both heating and cooling cycles |
| thermostat | a device that senses temperature change and changes some dimension or condition within to control an operating device |
| air-to-air heat pump | removes heat from the outside air in the winter and rejects it into the conditioned space of the house; resembles the central air-conditioning system |
| indoor coil | is a condenser in the heating mode and an evaporator in the cooling mode |
| gas line | the large diameter pipe of the interconnecting piping is called the gas line because it always contains gas |
| outdoor unit | the unit outside the house |
| water-to-air heat pump | may not need auxiliary heat because the heat source (the water) can be a constant temperature all winter |
