iCooler, a Compressor for R718 (Water)

The iCooler is a newly developed Compressor for R718 (Water)

HVACR sector, mobile and stationary, incl. heat pumps

F-Gas discussion
is at its end

No oil or grease due to water lubricated bearings

Sub-zero with
water + ethanol

It is the first displacement machine capable of handling the unique challenges of R718

Our Basis: 25 Years of dry Vacuum Pump Technology

A fundamental difference of water compared to classic refrigerants is that it operates at pressures below atmospheric pressure.

That's why the iCooler is based on a dry running spindle vacuum pump.

These vacuum pumps have proven their worth in chemical and process engineering for more than 25 years.

Even before that the robustness of the spindle rotors used in these vacuum pumps has been shown many times in the offshore-industry.

Thanks to electronic synchronization the rotors run dry, without oil. This enables compression in the liquid vapour region for a higher efficiency by means of injection, also known as wet steam compression.

Liquid-Vapour-Equilibrium pressures at 25°C

Refrigerant		Pressure
	R718	0.03 bar
	R134a	6.7 bar
	R290	9.3 bar
	R717	10 bar
	R407C	12 bar
	R32	17 bar
	R410A	17 bar
	R744	64 bar

R718 / The Refrigerant with Future

R718 and a more than 10% higher energy efficiency make the iCooler a huge step up when it comes to environment protection.

It complies with the F-Gas Directive and other regulations like the "Kigali Amendment on HFCs" and the "Paris Agreement", a result of the UNFCCC. A GWP of Zero makes R718 a future-proof refrigerant.

R718 also reduces operating and inspection costs as the environmental and safety regulations for the refrigerant simply do not apply. This eliminates costly inspection and leak testing.

The iCooler can cover evaporation temperatures down to just above 0°C and condensation temperatures over 90°C.

-25°C can be achieved either in combination with ethanol e.g. or in cascade with CO₂. In cascade with CO₂ -50°C is also possible. Ethanol also acts as an anti-freeze but for higher concentrations the flammability increases.

Compared to classic refrigerants

R718 has a better performance than other refrigerants, especially at high condensation temperatures.

Common refrigerants are gaseous at atmospheric pressure, R718 and ethanol are liquid. Because of this, the system is under vacuum. In case of a leak, air enters the system instead of the refrigerant escaping.

Market Situation and Climate Protection

Water as refrigerant R718 is already used successfully for several years.

Turbo compressors are used for R718 in applications like IT or industrial process cooling. The covered applications have in common that the needed cold water temperature is not very low, e.g. 16°C.

The need for heat pumps to reduce the use of fossil fuels.

To use R718 instead of refrigerants with a high GWP or a low efficiency, a different compressor is needed.

The iCooler can easily achieve temperatures above 60°C to provide hot water without Legionella.

R718 has a beneficial physical characteristic. With the high temperature differences required for hot water, the efficiency is significantly better than with any other refrigerant. This makes the use of heat pumps with R718 also more economical when replacing an old oil heater.

The iCooler, a new Development for R718

The main characteristics of a refrigerant and the required cooling capacity determine the compressor principle.

For a medium transport volume and a high pressure difference a screw is used, but for a small transport volume and a medium pressure difference a scroll is best.

For very high transport volumes a turbo is commonly used. R718 requires a huge transport volume per kW cooling, but despite a low pressure difference the pressure ratio is in comparison to other refrigerants very high.

The pressure ratio of a single stage turbo is limited.

Principle of the iCooler

The iCooler as a displacement machine is

capable of high pressure ratios
robust (principle is proven over 20 years in harsh vacuum industries)

and as a dry-running spindle compressor with a high rotation speed it is also capable of

a high transport volume
compressing gas liquid mixtures

Compression of R718 with a displacement machine has been proven with an off-the-shelf vacuum pump (SIHIdry from Flowserve)

Two SIHIdry vacuum pumps are up and running at HAMBURG VACUUM for demonstration purposes.
Soon also with a refrigeration cycle.