Low Refrigerant Charge Negatively Impacts Energy Efficiency

How an Undercharged Refrigeration System Negatively Impacts Energy Efficiency

In Articlesby Elizabeth OrtliebLeave a Comment

Energy Consumption

Low refrigerant charge is common in the commercial refrigeration world. But, of course, common doesn’t make it good. In fact, it’s a problem that you and your team should minimize to ensure proper preventative maintenance and reduce operating costs. Because an undercharged refrigeration system isn’t a well-maintained one.

This is especially true for supermarket refrigeration systems which have significant refrigerant charge sizes and a likelihood of high annual refrigerant leak rates.

That’s why, in this post, we’ll be looking at how refrigeration equipment with low refrigerant charge can negatively impact energy efficiency. Let’s get started.

Low Refrigerant Charge: A Common and Costly Occurrence

To begin, consider just how all too commonplace high refrigerant leak rates have become. Namely, the U.S. EPA states, “A typical supermarket’s refrigeration system holds a refrigerant charge of about 4,000 pounds and has an average annual leak rate of about 25%.”

While a high refrigerant leak rate does not necessarily mean a low refrigerant charge, it does provide a good indication into such an occurrence.

That is, a high refrigerant leak rate can indicate low refrigerant charge.

And what many stakeholders may not realize about low refrigerant charge is that this can dramatically increase energy costs.

The More a System Leaks, the Greater the Energy Costs

In particular, let’s take a look at “Refrigerant Loss, System Efficiency and Reliability,” a well-known paper presented at the Institute of Refrigeration’s 2013 Annual Conference and written by refrigeration expert David Bostock. Notably, this paper dedicates a section on the cost of increased energy consumption from refrigerant leaks in a refrigeration system.

In it, you will find a look into the relationship between annual electricity running costs and refrigerant leakage. What unfolds is surprising, and it will make you think twice about letting low refrigerant charge fester.

Specifically, Bostock establishes that there is a non-linear relationship between annual electricity running costs and refrigerant leakage. He notes that when a system has a 15% annual refrigerant leak rate then annual electricity running costs are increased by 10%. He goes on to explain, “This annual running cost penalty increases in a non-linear manner so that at 60% correct charge, the running cost penalty is +45%.”

Table illustrating the relationship between improper refrigerant charge and decreases in energy efficiency.

Bostock, David. “Refrigerant Loss, System Efficiency and Reliability – A Global Perspective.” Institute of Refrigeration Annual Conference 2013.

Now, granted, Bostock’s case is not the only definitive answer on what happens to energy efficiency when you have an undercharged refrigeration system; however, it indeed provides a great example of just how costly it can be.

In essence, the more and more improper the refrigerant charge gets, the greater your energy costs. Furthermore, this overall relationship is a non-linear one that benefits those who respond to leaks early and thoroughly.

It follows then that proper preventative maintenance is recommended as it regards refrigerant leak detection, and it is suggested that, by responding to and repairing leaks sooner, you can avoid a high running electricity cost penalty and thereby invest the savings in preventative leak detection, which leads us to our next point:

Achieve Refrigerant Leak Rate Reduction

The Bacharach Multi-Zone refrigerant monitor accurately detects more than 60 refrigerants (e.g., HFCs, HFOs, & natural refrigerants) down to an industry-leading 1 ppm.

Respond to an Undercharged Refrigeration System Properly

Ultimately, it’s important to focus your efforts on how you manage and respond to undercharged refrigeration systems. To put it another way, you should prioritize leak rate reduction to lessen the impact low refrigerant charge has upon energy efficiency.

This means that, in your refrigerant management program, you should:

  • Perform regular preventative maintenance
  • Conduct thorough leak checks at regular intervals
  • Install an automated leak detection system

Perform Regular Preventative Maintenance

As we’ve established by now, refrigeration equipment is designed for a very specific refrigerant charge. When that charge drops, it upsets the general operation. Such equipment will work harder and longer—using more energy—to maintain the same level of cooling as a well-maintained system that has the proper refrigerant charge.

Importantly, there’s a difference in responding to refrigerant leaks on poorly maintained equipment and on well-maintained equipment. The former is more risky and expensive.

That’s why you must recognize the importance of performing regular preventative maintenance, so that equipment is indeed well-maintained.

Accordingly, if you’re looking to better your insights on how equipment and systems are performing across all your assets and premises, check out our Parasense Platform, which offers a comprehensive energy management suite. It allows you to draw meaningful comparisons of different sites and maintainers as well as manage energy benchmarks and targets.

Moreover, the U.S. EPA states, “Regularly cleaning and inspecting refrigeration equipment helps reduce wear and tear and ensures energy-efficient operation.” And there is one crucial practice in particular that should be a part of your regular preventative maintenance—That is, conducting thorough leak checks at regular intervals.

Conduct Thorough Leak Inspections at Regular Intervals

Yes, you should be conducting leak checks that are not only periodic but also thorough in nature. First, the frequency at which you should be conducting periodic leak inspections depends on the size of the system and the system type.

Notably, in some jurisdictions, periodic leak inspections are mandatory (e.g., F-Gas and CARB). And, even more recently, per the EPA 608 update, there are new mandatory leak inspection requirements under certain circumstances.

Now, there’s an important factor in determining the success of these periodic leak checks—how thorough such leak checks are. In its “GreenChill Best Practices Guideline,” the U.S. EPA establishes, “Each technician should understand the correlation between quantity of refrigerant charge lost and the leak rate of the leak found.”

For instance, once a leak is found and identified, there should be an understanding that this leak might not be the one responsible for most of the refrigerant loss in the undercharged refrigeration system.

Install an Automated Leak Detection System

Of course, adhering to regular preventative maintenance that entails conducting thorough leak checks at regular intervals is not fully possible without having the right instrumentation on-hand and the right equipment installed. That’s where Bacharach is here to help.

Bacharach is the only company delivering both industry-leading 1ppm leak detection hardware and enterprise software dedicated to refrigerant compliance and management.

Don’t Let Low Refrigerant Charge Fester

Most importantly, at the end of the day, a poorly maintained system will have low refrigerant charge, and such a system can have far-reaching consequences.

The fact is, an undercharged refrigeration system does not perform optimally; As a result, it can widely disrupt your operations and detrimentally affect your energy costs.

So, remember to not let that low refrigerant charge fester, and you’ll be much better off in the near- and long-term.

With that, we conclude our post on how an undercharged refrigeration system negatively impacts energy efficiency. 

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