Technical Info - iCooler

by Hamburg Vacuum
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Our basis: 25 years of dry vacuum pump technology
(variable frequency drive)
Water lubricated bearings
Displacement machine
9 000m³/h machine
weighs less than 180
Highly efficient due to wet steam compression
Ethanol suitable
for sub-zero
Wide operating range
up to 100°C
Comparison of different Compressor Principles
Impeller of a "Turbo" compressor
Impeller of a turbo
  • dry running
  • very high rpm
  • huge transport volume
  • low pressure ratio
Rotors of a "Screw" compressor
Screws of a compressor
  • oil lubricated
  • low rpm
  • small transport volume
  • high pressure ratio
"Spindle" rotors as with a SIHIdry vacuum pump
Spindle rotors as with a SIHIdry vacuum pump
  • dry running
  • multi stage
  • high rpm
  • medium transport volume
  • huge pressure ratio
  • medium volume ratio
iCooler rotors (like a "Spindle")
iCooler rotors
  • dry running
  • multi stage
  • high rpm
  • high transport volume
  • high pressure ratio
  • high volume ratio
Due to the huge gas volume of water, only a compressor with a high transport volume is useful. This eliminates the screw compressor. In addition, oil and steam should not mix.
This leaves the turbo and the spindle compressors.
For Water, the pressure ratio quickly exceeds values of 6. For example, the pressure ratio between the corresponding pressures of 2°C and 30°C is already 6.
This is only achievable with a two stage turbo compressor.
For heat pumps temperatures like 60°C are needed for hot water and starting at 2°C the pressure ratio is near 28.
Characteristics of the iCooler
The iCooler is an advanced R718 optimized spindle. It is capable of pressure ratios well above 20. A standard vacuum pump reaches values over 1000.
To achieve high efficiencies the iCooler spindle rotors reduce the enclosed volume over several turns of the rotor to get as close as possible to an isentropic process.
For that reason the iCooler has a high internal volume ratio that can be reduced via pre-outlets to get a wide and efficient operating range.
Common Technology for R718 is a Turbo Compressor
The turbo is paving the way for the breakthrough of R718.
Solutions with a turbo are available for applications like IT, industrial process and building cooling.
These applications have in common the low temperature difference they require.
  • Chilled water output preferably above 16°C
  • Cooling water input preferably below 45°C
The next step: A new compressor to achieve higher temperature differences.
A higher temperature difference is equal to higher pressure ratios. This is needed to open up markets like heat pumps and several segments in the HVACR sector.
To attain this a displacement compressors is the optimal choice.
But compared to classical displacement (screw) compressors the transport volume has to be increased significantly.
High Transport Volume and Pressure Ratio with the iCooler
The way to a high transport volume screw.
A common screw is oil lubricated and this results in a low rotational speed.
Otherwise the hydraulic losses would increase noticeably.

This is not the case for dry running screw or spindle compressors. In fact they need the higher rotational speed to reduce back flow. This also increases the volume flow.
A spindle compressor has also a significantly higher transport volume at suction pressures below atmospheric pressure.
Due to its inclined axis, the iCooler has a further increased transport volume in relation to its size. This also results in a high volume ratio to meet the the volume ratio of water.
Comparison COP_heating
Higher COP thanks to Injection and R718
Water and Water + Ethanol have due to thier properties higher COP values especially at higher temperature differences. These values are further increased when compressing wet steam (injection).
These facts make the iCooler in addition to HVACR applications a perfect solution for heat pumps, even for industrial high temperature heat pumps.
Comparison COP_heating
The iCooler Model Series
The first available size of the iCooler will be 9 000 m³/h.
With this size, the cooling capacity varies between 30 kW and 95 kW depending on the evaporation temperature.
A high rotational speed results in a relatively compact and light weight compressor. The 9 000 m³/h version weights less than 180 kg.
iCooler model series
The compressor for the world's most environmentally friendly refrigerant, R718 (water).
© 2019
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