COOLNOMIX

AVERAGE 40% ENERGY SAVINGS ON AIR CONDITIONING

HOW IS THIS POSSIBLE?

Internationally patented COOLNOMIX Optimized Refrigerant Supply (ORS) encompasses two key processes:

• Delivery of the required room temperature
• Optimization of the running-time of the compressor to reduce energy wastage

Since the compressor consumes about 95% of all the energy used by an air-conditioner, ORS’s optimization of its running-time delivers world-beating energy savings at an average 40% worldwide.

COOLNOMIX APPLICATIONS

COOLNOMIX delivers these awesome savings through being retro-fitted to existing air-conditioners of any-size and any kind in which the refrigerant is used to cool the air directly. Retrofitting takes about one hour to complete and there are zero maintenance requirements. COOLNOMIX is already delivering energy savings around the world on:

• Split-type air conditioners (e.g. wall-mounted and cassette based)
• Package based and double expansion (DX) units up to the largest sizes available
• Ducted air-conditioners with AHU’s
• Inverter based (VRV and VRF) air-conditioners

Even inverter based (VRV and VRF) air-conditioners are enjoying an average 40% savings!

HOW IT WORKS

The first point to note is that there is nothing magical about it; COOLNOMIX only extracts energy savings from excess capacity in the cooling systems:

• Well-designed cooling systems always have a cold supply capacity that exceeds peak demand
• Maintenance of this excess capacity requires professional regular servicing of the cooling system
• The excess capacity will, of course, vary according to the outside climate changes and changing heat loads – this is why we only ever talk about average savings – 40% average on AC’s and 30% average on Refrigerators

The fundamental cooling system operation that COOLNOMIX targets is that the useful work of a compressor is fully converting the refrigerant gas to a liquid – the liquid is then pumped through the evaporator so that its decompression can be used to generate cold supply – continuing to run the compressor once the refrigerant is fully liquefied is a waste of compressor energy which typically represents ~95% of the total cooling system energy consumption.

Cooling systems typically operate “blind” to what is happening with the compression of the refrigerant gas and therefore “blind” to when the useful work of the compressor has been completed because they only have one temperature sensor – the space thermostat – and will keep the compressor running, even when it cannot do any useful work, until the space temperature is at the desired set point.

COOLNOMIX overrides the existing space thermostat and employs two temperature sensors; a space temperature sensor and the cold supply temperature sensor:

• The space temperature sensor is used to ensure we deliver the desired space temperature
• The cold supply temperature sensor is used as a proxy to determine when the compressor completes its useful work – once the minimum cold supply temperature is reached, COOLNOMIX determines that the compressor cannot do any more useful work and sends the a “thermostat signal” to the cooling system equivalent to the original thermostat to stop the compressor

Until the compressed refrigerant becomes fully decompressed there is still a reservoir of cooling capacity in the system and this continues to provide cold supply into the space (this is why it is essential never to run AC’s, for example, in auto mode – it is essential that we keep the fan blowing the cold supply into the space). Once the cold supply temperature nears the space temperature COOLNOMIX determines that more cold supply is needed and sends its “thermostat signal” to restart the compressor.

Note that in the case of inverter drive AC’s, on which we still deliver an average 40% saving, where I talk earlier about starting and stopping, what the inverter system is doing in response to COOLNOMIX “thermostat signals” is speeding up and slowing down.

COOLNOMIX AND COMPRESSOR LIFETIME

Doesn’t the more frequent stopping and starting of the compressor reduce its lifetime?

This is a common question/objection and there are a number of aspects to responding:

• There are two things that can damage a compressor in its stop/start sequences:
  • Stopping the compressor after its start too soon results in the motor coils retaining heat within them which, over time, will degrade the coils. Modern cooling systems incorporate a minimum run-time of 3 minutes to mitigate against this risk.
  • Re-starting the compressor when there is residual pressure differential between the suction and discharge across the compressor means the compressor starts under load and this can, over time, degrade its performance.
• Optimized Refrigerant Supply (ORS), the internationally patented technology embedded in COOLNOMIX units, incorporates protection against the foregoing risks:
  • ORS ensures a minimum run-time of the compressors of 4 minutes.
  • Due to the way ORS works, every re-start of the compressor only happens when the suction and discharge pressures are in equilibrium. In any event, the minimum time before a re-start occurs is 3 minutes
• When the ORS routines outlined in item 2 are taken into account, the maximum number of stops/starts in one hour is ~6. Remember it is the length of the compressor off-time that delivers the energy savings, not the frequency of stop/start.

Bearing in mind that the way compressor operational life-times are specified is numbers of hours of run-time and that COOLNOMIX delivers energy savings by reducing the compressor run-time, if COOLNOMIX has any impact on the compressor it will be to increase its life-time!

MORE ABOUT OPTIMIZED REFRIGERANT SUPPLY (ORS)

Air-conditioner manufacturers make use of room temperature measurement to determine the run-time of the compressor. Even with modern inverter drives this approach wastes energy by over-running the compressor. COOLNOMIX ORS employs data from two temperature sensors for determining when work is needed from the air-conditioner’s compressor.

• The first sensor replicates the function of the room temperature measurement and is employed by COOLNOMIX ORS to deliver the required room temperature as a priority
• The second sensor measures the temperature of the cold-supply air from the air-conditioner and this is used to determine when the compressor has completed its hydraulic work of fully compressing the refrigerant gas

Of course, once the refrigerant gas is fully compressed, continuing to run the compressor is a waste of energy and yet this is what use of the room temperature measurement persists in doing.

With the additional information derived from its second sensor, COOLNOMIX ORS is able to stop (non-inverter) or slow down (inverter) the compressor whilst the air-conditioner uses the reservoir of cooling capacity that has been created to cool the room. Once COOLNOMIX ORS determines that further cooling capacity is needed, the compressor is started (non-inverter) or speeded up (inverter) again until its hydraulic work has been completed once more.

COOLNOMIX vs SMARTCOOL

COOLNOMIX vs AIRCOSAVER