Glossary of heat pump and HVAC terms

B

BTU – British thermal unit

A British thermal unit is a unit measurement of heat. It is the amount of heat needed to raise a single pound of water by a single degree Fahrenheit. A high BTU rating indicates a higher heating capacity.

C

Collector

It is device used to collect heat from the source in geothermal heat pump systems. This could take many forms such as a horizontal loop field for example.

Compressor

The heat pump component that pressurizes the vaporized refrigerant increasing it’s temperature.

Condenser

The heat pump component that turns the hot vapours into fluid which is then distributed through the building’s heating system (radiators, underfloor units,
fan coils etc.).

COP, CoP, CP – Coefficient of Performance

A measure of heating efficiency. It is the ratio of useful heating provided to energy required. A COP of 4 means that a system can provide 4kWs of heating for
1kW of energy. The higher the COP, the more efficient the heat pump.

D

DHW Domestic hot water heat pump (or HPWH)

A domestic hot water heater (for faucets, showers etc.) that uses a heat pump to heat water instead of an electric heater. They are superior in efficiency than traditional water heating systems and can be found integrated in certain systems (i.e. the Hydrotank).

E

EER (Energy Efficiency Ratio)

A measure of cooling efficiency. It is the ratio of useful cooling provided to energy required. An EER of 4 means that a system can provide 4kWs of cooling for 1kW of energy. The higher the EER, the more efficient the heat pump.

Evaporator

The heat pump component where the vaporized refrigerant captures the ambient warmth from the heat source.

Expansion valve

The heat pump component that decompresses the fluid refrigerant allowing it to vaporize in the evaporator.

H

Heat distribution system

The systems in place for circulating heating or cooling within a building. This could include radiators, underfloor heating, wall units, etc.

Heat Exchanger

A device that transfers heat from one system or medium to another. Heat pumps use the evaporator as a heat exchanger when heating. A radiator system linked to the system would also operate as a heat exchanger as it transfers heat from water to air.

Heat Source

Where the heat pump captures heat from – it could be the air, the ground, water or a heat process where heat is stored.

Hydrobox

In TermoPlus air-to-Water system the Hydrobox is the interior unit that enables the heat pump to circulate hot water into the building’s existing radiators or underfloor heating.

Hydrotank

The TermoPlus Hydrotank is essentially a Hydrobox with an integrated domestic hot water and storage tank.

K

kW (Kilowatt)

It is a unit of power that can be used to measure heating power output and / or electrical power required. When used for heating output it is referred to as a thermal kW.

kWh (Kilowatt hour)

It is a unit of energy that can be used to measure energy used. kWhs are what the electrical provider measures and charges for.

TonsBTUs/hkWh
1120003.52
2240007.03
33600010.55
44800014.07
56000017.58
67200021.10
78400024.62
89600028.13
910800031.65
1012000035.17

R

Refrigerant

It is the chemical used as a heat transfer fluid within a heat pump system.

Reversible heat pump

Heat pumps that can reverse the heating cycle in order to provide cooling. This means they can offer heating during winter and cooling during summer. Not all heat pumps are reversible.

S

SCOP (Seasonal Coefficient of
Performance)

A measure of heating efficiency over a season. SCOP is the ratio of useful heating provided to energy required over a season. A SCOP of 4 means that a system can provide 4kWs of heating for 1kW of energy during a specific season. SCOP is mostly used to compare performance during variations in the seasonal temperature of the source.

SEER (Seasonal Energy Efficiency
Ratio)

Heat pumps that can reverse the heating cycle in order to provide cooling. This means they can offer heating during winter and cooling during summer. Not all heat pumps are reversible.

T

Ton (TR, Ton of refrigeration)

It is a measurement unit of power for refrigeration and air conditioning typically used in North America.

V

Vertical probe

It is device used to collect heat from the source in vertical geothermal heat pump installations. Vertical probes are placed within the drilled boreholes to collect heat from the heat source.