Eric Mele covers Rack Refrigeration: Secondary Fluids. He explores a medium-temp supermarket rack that uses glycol, a secondary fluid used to help with heat transfer in chiller systems. Although we show glycol in this video, some racks may use CO2 as a secondary fluid instead.

On the chiller side of a rack, the piping goes to the pump station and out to the store below. Chillers are actually quite similar to hydronic systems, as they have pumps and pump controllers. You can expect to see some spare glycol, electronic valves, and heat exchangers in the rack room on a glycol system. Heat transfer occurs in heat exchangers, where heat gets rejected from the refrigerant and moves to the glycol.

These racks may also put discharge heat into the glycol. That heat can then be supplied to the reheat coil in the air conditioner or used for warm fluid defrost.

When the rack puts discharge heat into the reheat circuit, it pumps the glycol using a circulating constant-volume pump, which helps the glycol go through the heating loop for the reheat coil. In the case of this rack, the lines go out of the rack at the bottom. Those lines run underneath the roofline and come back up into the A/C system across the rooftop. As with some other reheat coils, this system has a three-way valve to modulate the glycol flow through the coil.

The rack may have another heat exchanger for warm fluid defrost. The discharge gas can warm up some of the return glycol coming back from the A/C reheat coil. That discharge gas can also go down to evaporators or cases that need defrosting.

On the other side of the rack, we have the piping that allows the glycol to go down to the cases. There is also a three-way valve on the discharge line, which allows us to use discharge gas to heat water for use in the store. (These pipes have been labeled as “water heat reclaim.” They lead to heat recovery tanks specifically for hot water.)

Read all the tech tips, take the quizzes, and find our handy calculators at

Learn more about the 2022 HVACR Training Symposium at

Subscribe to Channel:

This video by HVAC School was liked: 181 times

If you like this video by HVAC School, please support their CHANNEL by clicking on the SOURCE link below and Subscribe.

SOURCE

————————————–

Featuring Your Videos:

By featuring your videos on our blog, your videos will receive hundreds of views daily from our website visitors, you get a backlink to your channel for followers to subscribe to your channel. This is a win/win for SEO for both of us. If you would like your videos or channel highlighted and premiered on our blog for FREE, please contact us.

However, if you no longer want us to premier your channel, and want us to remove your video and not feature your channel anymore, please contact us.

Video Post Disclaimer:

The information contained in the multimedia content (โ€œVideo Contentโ€) or post content in general, represents the views and opinions of the original creators of such Video Content or post, and does not necessarily represent the views or opinions of KASRefrigeration.com. The mere appearance of Video Content or the post on the Site does not constitute an endorsement by KASRefrigeration.com or its affiliates of such Video or Post Content.ย 

The Video Content or Post has been made available for informational and educational purposes only. KASRefrigeration.com does not make any representation or warranties with respect to the accuracy, applicability, fitness, or completeness of the Video or Post Content. KASRefrigeration.com does not warrant the performance, effectiveness or applicability of any sites listed or linked to in any Video Content or Post.

Affiliate Disclosure:

This post and description may also contain some affiliate links, which means that the post creator may receive a small commission at no extra cost to you if you click on some of the product links and decide to make a purchase. This channel is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com

Copyright Issue:

If you find any of your copyrighted material in this post or video, please contact us, so we can resolve the issue.

All rights reserved by respective owners.

11 thoughts on “Rack Refrigeration: Secondary Fluids

  1. Libio Sosa says:

    Good afternoon greetings from Venezuela in the video I observed a differential pressure gauge of the oil separator, could you tell me the reading of this instrument in which color it should star and in which it is wrong or indicative of the maintenance of the oil separator or replacement of the filter. Dear, I thank you

  2. Robert Wasswa says:

    Hello, HVAC school, can you kindly talk about the construction side of the trade in terms of construction heaters ( direct and indirect fired), dehumidifiers, torches and a lot of different or wider topics apart from the commercial and residential fields.
    Thank you for always being so informative with the topics.

Leave a Reply

Your email address will not be published. Required fields are marked *