Employing heat pumps to utilize ambient warmth is a technology which has so far been used mainly for single and multiple-unit residential buildings. For large-volume buildings heat pumps as an economical and environmentally friendly alternative to conventional heating and cooling systems are still a fringe phenomenon. Industrial-scale heat pumps (> 100 kW) and high-temperature heat pumps (up to 98 °C) can bring about a considerable reduction of energy consumption and emissions in industry by utilizing not only groundwater or ambient air but also heat emitted from server rooms, airing and air-conditioning systems, cooling grids and drains.
Pioneering air-source heat-pump technology
As part of the TOPPUMP project Ochsner GmbH has developed a new technology for efficient air-source heat pumps with which large-volume buildings can be heated and cooled at very reasonable cost. The new range of industrial-scale split-layout air-source heat pump models delivers up to 300 kW and thus achieves a new dimension in air-source heat-pump technology. The advantage of the split layout is that the heat pump is located inside the building, where it is protected, while the evaporator is outdoors, where it taps the heat source there without any losses. Building expense and space requirements are therefore comparatively limited.
Indoors the Ochsner Toppump measures 1400 mm in height, 2750 mm in width and 1280 mm in depth, and is equipped with a shell-and-tube condenser. Each heat pump has two outdoor evaporators, each equipped with a copper/aluminium fin package and four axial ventilators; for compression ultra-efficient rotary screw compressors are used. This technology has leapt ahead in recent years, with efficiency increases of about 10 %.
The minimum outdoor temperature for a Toppump with 300 kW rated output is -15 °C; it delivers inflow temperatures up to 50 °C. During service at air temperatures below 0 °C, if the evaporators need to be defrosted, this is done thermodynamically: the cooling circuit is reversed. Defrosting is managed very economically by an electronic control unit.
Within the framework of the IEA Research Cooperation, Austrian researchers and companies participate, inter alia, in the International Energy Agency‘s Implementing Agreement “Heat Pump Program”. This international program launches research projects, holds workshops and conferences, and provides the information service “IEA Heat Pump Center”. The aim of Annex 35 (“Application of industrial heat pumps”) is to promote more widespread use of heat pumps in industry by presenting the current state of the art and by documenting facilities already implemented.
