r/refrigeration

91 degrees today and everything just went to shit. Just P1 after P1 I gotta find a new job lol.

Hi everyone on reddit!,

First of all I am fairly new to industrial refrigeration systems, I am doing a engineering study.

I am working on a graduation thesis in industrial refrigeration. The project is about a standardized evaporator valve station for an ammonia system. The system is based on R717 pumped-overfeed evaporators with hot-gas defrost.

The valve station is divided into four functional sections:

• Liquid Feed
• Wet Return
• Hot Gas Defrost
• Defrost Drain

The goal is not to certify a real installation, but to prove in my thesis that the proposed P&ID is functionally plausible and can operate in different modes, such as:

• normal cooling
• part-load operation
• pump-down / isolation before defrost
• hot-gas defrost
• defrost drain / pressure equalisation
• return to cooling

I am struggling with how to prove this properly to my tutor. I can make calculations for mass flow, pressure drop and Kv values, and I can compare component sizing with Danfoss Coolselector². I can also make an operating-mode matrix that shows which valves are open or closed in each mode.

However, I do not have a real installation available for live testing, and even then there are no inline flow meters in the system.

My question is:

What would be a technically acceptable way to validate this kind of P&ID for a graduation thesis?

I am especially interested in how engineers normally prove that a valve arrangement is functionally correct before it is built or commissioned.

Any help would be greatly appriciated!

I’m getting sick and tired of where I currently work. I applied to a bunch of places and I got a call back from a place with an open spot just going facilities and they’re under the IUOE. Just wondering if anyone had any experience with the operating engineers.

Has anyone worked on Master-bilt SPLIT-PAK units before that are for both walk in coolers and freezers they share the condenser coil into two different circuits.
I’ve been working on several of them recently for McDonald’s and have been told by my boss and several of my coworkers that for the walk in freezers that use EEV’s you shouldn’t clear the sight glass
I’ve also noticed that they don’t have receivers on them from factory
Also I’ve noticed that if you slightly over or undercharge the system it will not act right and the EEV won’t know what’s going on and keep opening and closing it’s self constantly
Could someone explain in more detail as to why it doesn’t have a receiver? Or why it’s designed that way?
I would assume it’s because the EEV basically it’s acting like a receiver in some sort of way backing up refrigerant when needed and allowing more in based on the superheat which could be the reason the sight glass isn’t fully cleared or having problems when over or undercharged

Hey guys i just became a 2nd year electrician here in Calgary. I’m currently still working as an electrician apprentice and have been thinking a lot about switching into refrigeration/HVAC. I somewhat enjoy electrical work, but refrigeration seems interesting because it combines electrical, mechanical, and troubleshooting work all together

Any have issues with the kegerator not restarting after the run phase. I replaced the compressor because it over heated. When I plug into power the kegerator runs as it should. After a few run stop sequence’s fails to restart and compressor hot to the touch. Unplug power, wait 24 hours, process starts up again then fails.

I currently work service doing ammonia but looks like data center may be an opportunity soon. Am I making a career step back or pivot? I think its a step forward looks interesting to me

is it possible for a 32 year old with no prior engineering experience to become a fully qualified refrigeration engineer without an apprenticeship and if so how would I go about it?. thanks for any replies

Why is refrigeration equipment still this unreliable in situations where it absolutely shouldn’t be?

I’m not talking about minor inconvenience like not having ice, I’m talking about food going bad overnight, small businesses losing stock, people opening a fridge expecting cold air and getting nothing. Why is that still happening?

I saw it firsthand at a small shop where I went to get groceries, Everything looked fine from the outside, clean setup, decent equipment, nothing unusual. I needed to get frozen chicken from the refrigeration and realized it just didn’t hold temperature and called the attention of the shop owner he said he didn’t notice any prior issues, no warning, no obvious failure. Just enough of a drop to ruin what was inside and he just shrugged it off.

Why do we accept that?

This isn’t some luxury feature, This is basic functionality to keep things cold and that’s the job. So why does it feel like consistency is optional?

And then we wonder why nothing changes.

When you start digging into it, it gets even more frustrating. You’ll see people comparing builds, talking about components, sourcing differences. AIibaba comes up in those conversations too, not as a solution, just as part of the bigger picture of how refrigeration equipment is made, distributed, and somehow ends up performing so differently even when it looks the same on paper.

Why is that normal?

Why is it okay that two units with similar specs can behave completely differently in real use?

And then we wonder why nothing changes.

It shouldn’t feel like a gamble to rely on something this essential. Not for businesses, not for homes, not for anything that depends on it working properly.

But somehow, here we are still treating inconsistency like it’s part of the deal.

How do you check for a low charge on a prep table?

I have one that is acting slow on pull down. LRA is 28.55 (4.75 RLA) and it's drawing 4 amps. Delta T is like 2 to 5 degrees.

The problem is it's r450a and I don't stock that. The nearest wholesaler is 4 hours away and as far as I know this is the only piece of equipment that I service that runs that specific refrigerant. After I hit post I am going to check the p/t chart

We are tasked to have a case study in our thermo 2 class on topics rankine/vapor system, gas system/brayton-otto-diesel-dual, and refrigeration system. We are to chose either of these topics.. Usually it involves finding the efficiency/cop of the component. Please, if someone could really help us get data from their industrial workplace. Thank you so much.

Did my first A2L system today. Went to charge unit and my dam hose wouldn’t connect to new tank 454A. Turns out need a reverse thread adapter or new hose. I didnt read anything about that and wholesaler didn’t give me a heads either. Waiting till Tuesday now to start freezer once I get my hands on adapter. Kinda irritating I go back to finish

Hey guys,

Looking to move to Canada from NZ, been in industrial refrigeration for 11 years.

Worked on ammonia systems, co2 systems as well as freon, from installs to rebuilds to service work.

Just wondering what kind of tickets or qualifications I might need to go through if I moved over there?

Would a company ever sponsor someone through these quals when over there?

Cheers