Heat Pump Systems and Controls

A heat pump is a home heating and cooling system. They can pull heat from cold outside air and transfer it indoors during cooler months. During warmer months, it pulls heat out of indoor air to cool the house.

Heat pumps do not burn fossil fuel like furnaces do, making them more environmentally friendly.

Common types of heat pumps:

1. Air Source:

These transfer heat between indoor air and outdoor air and are more popular for residential heating and cooling.

2. Ground Source:

Sometimes called geothermal heat pumps, these transfer heat between the air inside your home and the ground outside. They are expensive to install but are generally more efficient and have a lower operating cost.

Note:

A heat pump is different from a furnace. A furnace creates heat that is distributed throughout a home, but a heat pump absorbs heat energy from the outside air (even in cold temperatures) and transfers it to the indoor air.

In cooling mode, a heat pump operation is essentially the same as an air conditioner (absorbing heat from the inside and releasing it to the outside)

Generally, heat pumps are common in milder climates where the temperature does not typically drop below freezing. See below sample diagram illustration of a heat pump.

Diagram illustrating heat pump components.

Heat Pump Components

Outdoor unit: Looks like that of a split-system. Contains a coil (operates as a condenser or an evaporator) and a fan (blows outside air over the coil to facilitate the heat exchange).

Indoor unit: Usually referred to as air handling unit. Also contains coil and fan but coil operates the opposite that of the outdoor unit.

The indoor units can either be:

Ducted heat pumps:

See below an image illustration of Hitachi heat pump system showing the outdoor unit, indoor ducted unit, zone controller, and zone damper.

Hitachi image illustration of a ducted heat pump system

An example of a controller that can be used with a ducted indoor unit is:

PC-ARFZ (Compatible ducted indoor units include: RPI-4.0FSN2SQ, RPI-5.0FSN2SQ, RPI-6.0FSN2SQ, RPI-7.0FSN2SQ),
SPX-WKT3 (compatible models include RADRAD-E50, 60, and 70)

Ductless heat pumps:

They can be the cassette type. See below illustration:

Outdoor unit connect to indoor cassette units.

They can also be the ductless heat pump type. An example of this type is the Hitachi's RAS-E25YHAB and RAS-E50YHA. These units can be controlled with a remote wireless controller or a wired wall controller PAC-ARF1.

Outdoor unit connect to indoor heat pump wall mount units.

Optionally, it is possible to connect your indoor air-handler to the internet using a Wi-Fi controller module. Hitachi's SPX-WFG02 can connect most Hitachi's indoor units to the air cloud home (compatible units include: RAS-S25YHAB, RAS-S35YHAB, RAS-S50YHAB. RAD-E50YHA, RAD-E60YHA, and RAS-SH18CKM).

Sample heat pump system connection to the internet/cloud through a Wi-Fi module

For help on HVAC system integration contact an RFWEL HVAC control specialist.