AIR-TO-WATER (A2W) HEAT PUMPS DETAILS

Components of an Arctic heat pump system

There are three main components:

  • Heat pump

  • Buffer tank

  • Emitters (radiant heat etc)

Even though we talk a lot about heat pumps, the place this discussion starts is at the BUFFER TANK.

Buffer Tank

The buffer tank is the center of the system; a thermal battery, as it stores either warm energy or cool energy (liquid).

  • A buffer tank is filled with freeze-protected non-toxic glycol and has at least four ports

  • Two ports (left in this case) are connected to the heat source which is the outdoor-mounted heat pump, and usually a back-up heat source (for temps below -15F)

  • The other two ports (right side of tank) are connected to the house distribution (e.g. radiant floor) to warm (or cool) the house

  • Buffer tank size typically ranges from 40 to 80 gallons

Illustration of a buffer tank with a gradient from red to blue, labeled "Buffer Tank" at the top and "40g" at the bottom, indicating capacity or volume.

Heat Pump

HEAT MODE
The buffer tank is heated by a heat pump (but it could also be a boiler or solar heating panel). In this case the target temperature of the buffer tank is 120 F.

COOL MODE
Or, a heat pump can operate in cooling mode The buffer tank target temperature is shown at 48 F:

Diagram showing a heating system with an A2W HP or other heat source connected to a buffer tank. An arrow indicates flow in heating mode aiming for a target temperature of 120 F in the buffer tank.

Hydronic Emitters to Distribute Heat

Diagram illustrating a heating and cooling system with a heat pump, buffer tank, and distribution emitters like a radiant floor or radiator. Arrows show the flow of heat or cool air between the components.

Then we add the emitters, such as a radiant floor to heat or cool the house.