absorption cooling units mostly are operated on LPG or natural gas. Some freestanding refrigerators also use kerosene as energy sources.

The noiseless hotel minibars are equipped for electric operation only.

The special ENTEX heat transfer system in the boiler allows the additional use of many more energy sources for the operation of the units:

• engine waste heat (exhaust)

• solar heat from collectors

• coal gas

• biogas

• wate heat from chemical processes

• steam

• kerosene, diesel, heating oil

• wax, stearine

• heat transfer liquids

• geothermal heat (thermal)