The interest in CO2 installations in industrial applications has risen in recent years.The difference between commercial and industrial refrigeration is being blurred more than I can ever recall. The main reason for this is the increasing prevalence of carbon dioxide (CO2). The fact that it started in the commercial refrigeration sector means that it is expanding with the same manufacturers and contractors into the industrial sectors.
The ridiculous portmanteau “com-dustrial” is sometimes used to describe systems and equipment that are in between the two. This discussion begs the question – what exactly is commercial refrigeration? What exactly is industrial refrigeration?
Two sides of the same coin?
The first thing to consider is why we might want to distinguish these two types of applications/industries in the first place. I think it is obvious to most people that designing and building a refrigeration system with an extremely large capacity is very different than designing something very small.
An ammonia refrigeration plant with a capacity in the 1,000s of tons of refrigeration (TR) is massively different than your restaurant walk-in cooler that might be a ton or two at most. The refrigeration cycle is based on the same scientific principles, but the technology used to achieve the refrigeration can be very different and the skill set required to design and service the systems are different. Industrial is not necessarily better than commercial, but they are different.
This difference has resulted in a divergence over time that has caused a bit of a split in the industry. Are you an industrial refrigeration mechanic or a commercial refrigeration mechanic? Having done both to some extent (you could maybe call me a com-dustrial refrigeration mechanic but please don’t) and having spent years designing and analyzing industrial systems and large or mission-critical commercial systems, I can tell you that there is an application suited to most types of equipment and no magic bullets.
A frequent location for piping and pipe joint failures can be found at discharger headers on compressor rack style systems. This CO2 rack style system is intended for an industrial application.While there is, of course, no clear line between commercial and industrial, and there has never been, certain parameters can lead to a better understanding of the landscape.
Refrigeration capacity
As was already mentioned, the size of refrigeration systems can vary by several orders of magnitude. It is true that you could do a large amount of refrigeration with a whole lot of small units — this is sometimes done. This type of solution definitely improves redundancy as one or two system failures don’t have a large effect on system capacity, but it can get silly.
I have seen warehouses with more than 20 condensing units and evaporator pairs installed. Another common challenge is maintenance. It’s hard to notice when one of the systems isn’t working well. Conversely, it would make no sense to put an open drive reciprocating industrial compressor on a one TR walk-in cooler as the cost would be astronomical.
Applications
Another place you see the difference between industrial and commercial equipment is application. Some applications, like product freezing, can be extremely demanding on equipment and are more suited to an industrial solution. There are many reasons for this, but as an example, large and rapid temperature changes can easily damage less robust components and large and rapid load changes often require the ability to mitigate system upsets and manage high liquid flood-back. You tend to see more industrial equipment in more demanding environments.
Lifespan
Many restaurants and grocery stores turn over their refrigeration every 15 to 20 years or less, while a large industrial production facility may be intended to last 40-plus years. This extended lifecycle leads to a willingness to invest in equipment that is more robust and will last longer. Of course, this is not to say that industrial equipment doesn’t fail, but it is typically designed to be overhauled and repaired repeatedly. It is not abnormal to see a well-maintained industrial plant installed in the 1990s still running today as if it’s almost new.
The lines between commercial and industrial applications have never been more blurred than it is today.This lifespan is also why you see a willingness to use industrial-style equipment in civic infrastructure projects, like ice rinks. Ice rinks are not an overly large refrigeration system. You can make ice with anything from ground source heat pumps, commercial style chillers, grocery store racks, CO2 racks, to open drive ammonia or halocarbon systems. While people do employ all these options regularly, the majority of municipal projects are still built with an industrial-style system because municipalities have the desire to build facilities with much longer life cycles than much of the private industry.
Reliability
Another differentiating factor is reliability. I am aware of industrial refrigeration systems that run for years between shutdowns; there are some that have quite literally never been completely shut down in their entire existence except for during a power outage. Repairs and replacement of components, of course, but not shut down. In many large food production facilities, a shutdown is massively expensive, and money put into reliability and long-term operation is much preferred over less expensive investment in equipment.
One example of increased liability is related to the piping design. Smaller commercial equipment is not often built to comply with ASME B31.5 and instead relies on a UL rating for its pressure containing components (other than pressure vessels). This is not bad, but since UL is a test-based method compared to ASME’s much more conservative calculation-based methods, the commercial equipment does experience (in my experience) a significantly higher rate of piping and pipe joint failures. A frequent location for this is discharger headers on compressor rack-style systems. This pipe can get very hot and often doesn’t incorporate appropriate flexibility into the piping design.
I have seen dozens of cracked discharge headers or failed discharge branch piping in commercial rack-style systems in both CO2 and halocarbons. I don’t recall ever having seen failed/cracked discharge piping on a system that complies with ASME B31.5.
An industrial evaporator with an extended and insulated drain pan is not common in commercial installation but was used in this application.End of the day
As with many things in engineering or design, it comes down to lifecycle costs. I once worked on a facility that insisted on planning everything — including the spiral freezer and refrigeration system — on a five year life. They had their business reasons for doing this, and I can assure you it doesn’t make sense to use the most expensive equipment in this scenario.
Only a thorough understanding of the owner’s needs can help guide how “industrial” or how “commercial” you make the equipment. The closer you get to the grey area in between them, the harder it is to know what the right decision is. And as I mentioned at the beginning of this article, CO2 is upsetting the long-standing industry balance. There is a huge interest in using CO2 in industrial applications – and we are – but the systems are still often more “commercial” and don’t have many of the benefits that the old stick-built ammonia and R22 systems did. Over time this will change; it is changing. But in the meantime, we should all work together to make sure the word com-dustrial dies.