about freecooling

[COLD WANG]

I have heared a new tech about freecooling ,in winter industry plant need refregeration ,we can stop the compressor and the plant can provide refregeration through a refregerant liquid pump transport liquid from condensor to evaporator or thermosiphon technical can do so without pump
who has some sharing experience with this project ,who can reconstruct extant chiller by this freecooling tech ,so we can provide a very high cop value .its wonderful for us!

[LRAC]

Do you mean an air blast cooler as part of a chilled water system, that can cool the process water without it being refrigerated by the main chill plant.

Please advise

[Andy]

I have heared a new tech about freecooling ,in winter industry plant need refregeration ,we can stop the compressor and the plant can provide refregeration through a refregerant liquid pump transport liquid from condensor to evaporator or thermosiphon technical can do so without pump
who has some sharing experience with this project ,who can reconstruct extant chiller by this freecooling tech ,so we can provide a very high cop value .its wonderful for us!

Hi COLD WANG

used on water chiller with a flooded evaportor (without pump) or DX with a pump. the vapour boing off in the evaporator is bypassed around the compressor, straight to the condenser and condensed before being fed directly to the evaporator, bypassing the expansion device.

Kind Regards Andy

[NoNickName]

It's the answer of Carrier against our european manufacturer who free-cool with brine. Refrigerant does not freeze, so they claim it is a better choice. They seem to forget that in the evaporator,flooded or not, water is circulating, and if refrigerant cools very much, the evaporator may be in danger. Also, in case of leakage, the amound of refrigerant lost would be huge.
In countries were the taxes are payed based on refrigerant content, this carrier thing can't be used.

[TSK]

I have seen this free cooling system in place but not worked on it, refrigerant vapour from the evaporator (+10C water chiller) is allowed to by-pass the compressor using a valve, the vapour travels up to the condenser on the roof and condenses into liquid, the liquid being heaver than gas and affected by gravity stacks up in the liquid line and creates a PD across the expansion valve, saw it for myself, cooling the water by a few degrees but that was all, not sure the result was worth the effort but maybe in the right conditions, V-cold outside by the condenser?

[Andy]

not sure the result was worth the effort but maybe in the right conditions, V-cold outside by the condenser?

Hi TSK

AndyP's company use large versions os this with SMC 108 sabroes.

The water is cooling in strings, all the chillers in a string (usually 4) are piped on the water side in series, one after the other. The effect is in the autumn, spring and especially winter the free cooling meets quite a lot of the load before any of the chillers have to start the compressors (water at 10 or 12 deg c).

COP in the region of 10 to 12.

This system would mainly be used in large data centers, such as banks.

Kind Regards Andy

[LRAC]

I have seen this free cooling system in place but not worked on it, refrigerant vapour from the evaporator (+10C water chiller) is allowed to by-pass the compressor using a valve, the vapour travels up to the condenser on the roof and condenses into liquid, the liquid being heaver than gas and affected by gravity stacks up in the liquid line and creates a PD across the expansion valve, saw it for myself, cooling the water by a few degrees but that was all, not sure the result was worth the effort but maybe in the right conditions, V-cold outside by the condenser?

Why bother mucking about with the fridge system when you can install a blast air chiller on the water side of things, we install these and in the winter the fridge plant only runs the water pumps.

Lrac

[Andy]

Why bother mucking about with the fridge system when you can install a blast air chiller on the water side of things, we install these and in the winter the fridge plant only runs the water pumps.

Lrac

Hi LRAC
Because no air blast cooler is required the water can be cooled lower making it more effective and the system COP would be higher

Kind Regards Andy

[LRAC]

Ok i'll listen better next time cheers.

[Andy]

Hi LRAC
having said thermosyphon is better we use blast air cooler as it suits our systems better

Kind Regards Andy

[Brian_UK]

Sorry it posted twice, how do i delete posts

As it is your post you should have an "Edit" icon available.

Click on that and you will find a "Delete" option within the editing section.

[404cab]

hello,

I have been working with free cooling, made some test, and started some plant equipped with free cooling. But our applications was a little bit special, it is York Centri Chillers for marine applications, (Cruise Ships) and I must admit it is working pretty good on Alaska conditions, we just need to have required sea water conditions (below 11 deg C) and it is really working perfect when we had 7 deg C sea water, of course these units are equipped with sea water condenser, and the fact that they are working so good is that in this centri units, it is a "open" system, there is no check valve or long pipe or valve between high and low pressure side, so the pressure drop is minimum.

[Shakey]

I have worked on quite a few of these free cooling systems, and what Andy said is correct. The one factor for these systems to work efficiently is a very low OAT. -10 to -15 is perfect.

[NoNickName]

I still think and air cooled water chiller with drycooler is more efficient when it comes to winter time.
We have FC application with air to water coils capable of partial savings with air temperature at +5°C

[momo]

Have I missed a point (Carnival burnt brain) ? : you by-pass the compressor "low pressure gas to high pressure gas" and replace it with a liquid refrigerant pump on the outlet of the condenser (to insure pressure on the TXVs) since the condenser is running at negative temperatures it will have a low inlet pressure and condense evaporator gas easily...

The issues that arise oil return and seperation, intelligent control system: outdoor temperature setpoints, load temperature in the freezer/cooler, fan control on evap/condenser, by-pass valves , refrigerant pump control...
Definitely a final year college project.

Why not pump glycol/etc based coolant through a parallel system?

[NoNickName]

Why not pump glycol/etc based coolant through a parallel system?

Because otherwise there would have been nothing unusual to market