The HoegTemp® heat pump uses a Stirling system where the helium working fluid, or gas, is repeatedly compressed and expanded by double-acting pistons in a dry gas-phase system undergoing isothermal compression. This is a process of moving heat between objects or substances so slowly that the thermal equilibrium is maintained. A dry process is not limited by the compatibility of lubricants like conventional heat pumps.

The Stirling system is deal for high-temperature applications largely because it operates in a closed-loop system that moves the same gas back and forth rather than relying on a phase change material or conventional refrigerants. Because of this, the HoegTemp is able to achieve its impressive single step lift process between greatly varying source and sink temperatures. The Stirling machine is compact and cost-efficient.

Helium (R704) is an inert natural, safe refrigerant, which means that it is non-flammable, non-explosive and non-toxic, with zero Ozone Depletion Potential and Global Warming Potential. There is no lengthy health and safety approval process that adds to total cost.

Helium is an ideal, noble gas – stable and unreactive to other elements. It has the lowest boiling and melting points. This makes HoegTemp® invulnerable to changing conditions and equally good at all temperatures. It does not lose its heating capacity when it is cold, like other heat pump systems.

The HoegTemp® is as flexible and as easy to control as a boiler. It can be adjusted by a factor of two, in seconds, and from zero to full capacity in minutes. There is no internal process that needs time to adapt to changes in demand, just heat exchangers that react instantly.

• The heat pump can supply steam, hot water or thermal oil up to 250°C (482°F).

• The heat pump can be stopped immediately.

• 40% — 100% in seconds.

• 0% — 100 % in two minutes.

It is able to achieve a one step temperature lift process for steam, hot water and thermal oil up to 250°C (482°F), from sources as low as -30°C (-22°F).

It wins in efficiency for temperature lifts over 176-212°F (80-100°C), achieving a 50 to 70% energy saving which makes it versatile for many settings.

Because the HoegTemp® operates at lower temperatures with less loss of efficiency and heat output, the frequency of vital defrosting cycles is reduced. Using multiple outdoor fan coil units with separate glycol loops and available steam heat makes defrosting fast and efficient, without interrupting the heat pump’s operation. This results in less down-time and energy losses compared to other heat pumps.