CO2 compression systems

[GCAP CoolCast]

40%??!! We all have to change to CO2 now. Com'on be serious, this isn't true and it can't be, even not pure thermodynamical, so certainly not in a real life situation. Give us precise and real numbers and then we can talk again.
40% savings is peptalk for salesman.
I was at Atmosphere 2010, a very big congress about CO2 and there was another story heard.

I'm suprised that you will buy into the global warming with little or no tangible evidence but doubt energy savings of using CO2. I'll attempt to provide you with the necessary data to back up that claim.

I did make a mistake, -40 degree rooms see a 30% energy savings, you dont reach 40% untill you get below -50 degrees C

Compared with conventional two-stage or economized single-stage systems,
a CO₂ /NH₃ System uses significantly less power.

you can see some of this information at
http://mmrefrigeration.com/co2compressor.html

Also here is the PDF file M&M Refrigeration sent us containing actual data from a US Cold Storage plant they installed a CO2 system in.

http://www.gcapcoolcast.com/20101001101734532.pdf

I have spoken with the engineer of this facility before and he assures me that the savings are real.

[GCAP CoolCast]

also here on slide #24 you can see they hold with the same stat of 40% savings

http://www.slideshare.net/ozonaction...-final-4665979

[Segei]

I'm suprised that you will buy into the global warming with little or no tangible evidence but doubt energy savings of using CO2. I'll attempt to provide you with the necessary data to back up that claim.

I did make a mistake, -40 degree rooms see a 30% energy savings, you dont reach 40% untill you get below -50 degrees C

Compared with conventional two-stage or economized single-stage systems,
a CO₂ /NH₃ System uses significantly less power.

you can see some of this information at
http://mmrefrigeration.com/co2compressor.html

Also here is the PDF file M&M Refrigeration sent us containing actual data from a US Cold Storage plant they installed a CO2 system in.

http://www.gcapcoolcast.com/20101001101734532.pdf

I have spoken with the engineer of this facility before and he assures me that the savings are real.

Couple years ago at IIAR conference a technical paper was presented. It shown that there is no difference in efficiencies until -40F. I asked manager of US Cold Storage. Why does CO2 system has much better efficiency at part load then NH3 system? He didn't have a answer.

[GCAP CoolCast]

Couple years ago at IIAR conference a technical paper was presented. It shown that there is no difference in efficiencies until -40F. I asked manager of US Cold Storage. Why does CO2 system has much better efficiency at part load then NH3 system? He didn't have a answer.

yes that paper was written by Joe Phillis who if I remember correctly works for Frick or maybe Johnson Controls.

PG&E in california put out an 86 page report march 30 of 2009 using real world testing at a US Cold Storage facility that conflicts with Joe's report.

they did a 5 month study using flow meters, power meters, etc. they found that the CO2 cascade system using recips was at a much lower kW/Cube than a two stage ammonia system.

another independant study was done as well by Vacom Technologies. Their website is http://www.vacomtech.com/

also Greg Robinson from M&M refrigeration asked me to post his phone number so that anyone who had question or doubts about CO2's energy efficiency could give him a call for more information.

Greg Robinson
Email gregr@mmrefrigeration.com
Work 410-754-8005

[Peter_1]

This smells more and more to hidden publicity, dressed up with nice graphs which you can make with Excel or Photoshop but no figures.
Again, it's impossible to prove this pure thermodynamically in a theoretical cycle, then how it can be done in real life with even more difficult conditions?

[Segei]

yes that paper was written by Joe Phillis who if I remember correctly works for Frick or maybe Johnson Controls.

PG&E in california put out an 86 page report march 30 of 2009 using real world testing at a US Cold Storage facility that conflicts with Joe's report.

they did a 5 month study using flow meters, power meters, etc. they found that the CO2 cascade system using recips was at a much lower kW/Cube than a two stage ammonia system.

another independant study was done as well by Vacom Technologies. Their website is http://www.vacomtech.com/

also Greg Robinson from M&M refrigeration asked me to post his phone number so that anyone who had question or doubts about CO2's energy efficiency could give him a call for more information.

Greg Robinson
Email gregr@mmrefrigeration.com
Work 410-754-8005

One end user, one contractor, one consultant. It looks like they work as a team.
I didn't see this report. However, to do it right they should compare apple and apple. It looks like CO2 recip. compressors were compared to NH3 screw compressors. Definitely, part load efficiency of recip. is better than part load of screw. However, if you put VFD for screw it will be close. Another issue is condensing pressure. NH3 system require hot gas defrost. Some people do defrost at 150 psig, others at 120 psig. I saw plant that was defrosted at 80 psig of condensing pressure. What pressure did they choose for this study? Probably, 180 psig for NH3 plant and 100 psig for CO2. In this case you will get 30% of energy savings. CO2 plant has electrical defrost. No limitation to the condensing pressure. However, they have to change elec. heaters very often.