3 Flavors of CO2 w/ Rusty Walker

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 18 October 2018

⏱️ 70 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

In this podcast episode, Rusty Walker from Hill Phoenix talks us through the three most common types of market CO₂ systems and how they work: secondary, cascade, and booster.

Carbon dioxide (CO₂) is one of the oldest refrigerants; it is a natural refrigerant that came about when toxic refrigerants like ammonia were common. In the 1980s, we began to rediscover the benefits of CO₂ in market refrigeration, including its high latent heat capacity, low costs, and low global warming potential.

Secondary systems use an HFO or HFC on top, which acts as the primary system and helps discharge heat. These systems have large receivers with both liquid and vapor CO₂, and they resemble glycol systems quite a bit. The actual CO₂ side of the system moves a lot more heat than the primary system alone; the CO₂ side absorbs heat from open cases on the sales floor.

Cascade systems are two complete refrigeration systems tied into each other. Like secondary systems, these may use an HFC or HFO with the CO₂ system. A heat exchanger exists between the two systems and serves as the evaporator for the upper cascade or the condenser for the lower cascade.

Booster systems have an upper side and lower side. These may have multiple medium-temp and low-temp compressors. They also have a high-pressure control valve. That controller looks at drop leg temperature and pressure to regulate subcooling. These systems also have a flash gas bypass valve that discharges into the receiver or the medium-temp suction line.

Rusty and Bryan also discuss:

CO₂ and ammonia
Triple point
Supercritical fluid
Latent heat benefits
Metering devices
Thermal siphon
Heat exchangers and pressure drop
Upper vs. lower cascades
CO₂ pressures
Compression ratio
Subcritical and supercritical modes
Adiabatic operation
Climates

You can also contact Rusty by email at [email protected].

Learn more about Refrigeration Technologies HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Transcript

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0:00.0	and This episode of the HVAC School Podcast is made possible by our sponsors.
0:21.0	Navac and Navac Global.com. You can find all the great Navac tools by going to true
0:26.3	tech tools.com and use the offer code get schooled for a great discount. Also,
0:32.1	Air Oasis. You can find out more at air oasis.com. They are makers of the
0:36.4	bipolar and nano air purifier units made in the USA right in Amarillo, Texas. Also, thank you as always to refrigeration technologies at refrigidect.com.
0:47.0	Today we're talking about refrigeration and in refrigeration systems
0:50.0	we find that there's a lot of times that you want to use a little bit of thread sealant especially on pipe thread.
0:55.6	Nylog is great for use, especially on pipe threads as a little bit of a sealant and assembly lubricant.
1:02.0	Find out more by going to refrig, tech.com.
1:06.2	And finally carrier and carrier.com who has partnered with us from the very beginning.
1:10.8	Thank you to carrier. And now the man who thought dad jokes were funny before it was cool.
1:22.0	Wait, it's still not cool? Brian Orr. Hey hey
1:26.8	hey yes today it's a special day I have been chasing rusty Walker since the
1:31.6	very beginning Jeremy Smith who's been on the podcast several times and
1:34.4	has written a lot of great articles for HVACR School.com recommended that I talk to rusty about CO2.
1:40.5	He said he was one of the best educators out there on the topic and I have been chasing him down for a long time and finally he shot me an email and said he was ready to come on the podcast.
1:50.5	So big thanks to Rusty for doing this and we're going to be talking about the three flavors of CO2. So here we go. Rusty Walker.
1:58.5	Thanks for coming on Rusty.
2:00.0	Thank you. Thank you. Thank you for having me. Before we get started into what we're going to talk about today, which is the three flavors of CO2,
2:05.9	tell us a little bit about yourself and where you work and what you do.
2:09.7	I originally started at Bone, I was a lab engineer at Bone and became, I went to Hill Phoenix. I currently
2:16.8	aren't in the corporate trainer. I guess I'm an engineer out to pasture so now I'm just
	...

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