Technical Corner

August 29, 2022

The ORFA continues to seek out ice arena operators who challenge traditional ways of conducting business. Recently, ORFA’s Technical Director was contacted by Brian Sauser, Manager at the Moylan Iceplex located at 12550 W Maple Rd, Omaha, NE 68164 bsauser@moylaniceplex.com to discuss his investigation into chiller replacement options. Brian approached the challenge from a different asset management angle. We asked if he could share his thoughts on the challenges he faced and conquered.

It happened to me one day in early spring of 2012. Our local mechanical contractor gave me the news.  We had freon in our glycol due to a leak in the chiller bundle, so I was looking at another major repair or a complete chiller replacement. Do I replace the bundle on an aging system and pay for a new chiller barrel plus the labor-intensive process of flushing out all the contamination in the refrigeration system caused by the leak? I had already invested quite a bit in this system; from August of 2010 through February of 2012, I had spent over $90,000 in chiller repairs and maintenance on a system that was installed in 1995.

I decided that with my aging R-22 system and the constant rate of repair it took to keep that system running, it was time for a change. Water cooled chillers are the standard in our industry and it was what we currently used, so I started to make some calls and came to the realization that a basic replacement system was going to cost me $500,000. Not an insignificant investment. I called my local Johnson Controls rep and asked the question: What is the least expensive solution you can devise for me? That’s when he suggested a 200-ton air-cooled chiller capable of making 15-degree water, which was equivalent to the system I currently had.

Why hadn't I heard about these types of systems before? If you talk to engineers, the first thing they will tell you is that air-cooled chillers are not as efficient, and, well, that is true. Using water and air to reject heat in a condenser is more efficient than just using air. There are numerous ways chillers are rated for efficiency, such as Energy Efficiency Ratio (EER), Coefficient of Performance (COP), Seasonal Energy Efficiency Ratio, (SEER), Non-standard Part Load Value, (NPLV), and Integrated Part Load Value (IPLV) . Now let me be clear on one thing: I was a CPA in my former life but when equations start to have letters instead of numbers, I am in trouble. These calculations are beyond the scope of this article and would be better explained by an engineer, but they are used to indicate the compressor efficiency of a system. Looking only at compressor efficiency if you compare a water-cooled chiller to an air-cooled chiller, the water-cooled chiller will always be more efficient.

I took a total cost approach when I was making my decision regarding what system made the most sense for me. When water chillers are rated, the energy costs to run the cooling tower fans and pumps are not considered. The other costs not often regarded are water costs, as well as the cost of chemicals to treat the water in the tower. When air-cooled chillers are rated, all the energy used to run an air-cooled chiller is factored in and there is no additional water use or cost. So, comparing the EER from an air-cooled chiller to a water chiller is not an apples-to-apples comparison.

The second aspect that needs to be considered is the cost to service and maintain. An air-cooled chiller is assembled in a factory while many water-cooled chillers are often customized and assembled on site. Chances are the tech that has to come out to work on an air-cooled chiller has worked on that model of machine before and is familiar with it. Who is going to work on your chiller because, as we all know, parts will break, and leaks will occur. Is your staff qualified enough to maintain an ammonia or Freon water chiller? If you have to bring people in to work on your system because nobody in town knows how to work on it does that make financial sense? Would it be better to give up a little bit of efficiency than to pay high repair costs?

What about the initial cost to purchase the system? In my case I needed a 200 ton system capable of cooling two sheets of ice. The least expensive water-cooled chiller package I could find would run about a half million dollars. I could get an equivalent air chiller for $125,000. What about longevity? The life cycle on an air chiller is ten to fifteen years, according to the manufacturer I purchased my chiller from.

A water chiller could last two to three times as long. This is where the CPA in me comes out. I would much rather spend $125,000 every 10 years and know that my system is brand new than spend $500,000 and need it to last 25 years. Selecting a chiller is one of the most important things that a rink needs to do. We sell ice and without a quality chiller we would have nothing to sell. There are a lot of factors that go into the purchase of a chiller and there is no right answer, as everyone's situation is different.

In my case I went with an air chiller. With installation, the total cost was just under $230,000. What did it do to my electric bill? My total KWHs used were reduced by about 15% after the install compared to my seventeen-year-old water chiller. Which means from a total system efficiency my 3-screw variable speed air chiller is more efficient than my water chiller which had 4 reciprocating compressors and a cooling tower. It should be noted that 15% reduction in energy costs does not include the savings from no longer having a cooling tower that has to be supplied with water or pay for that water to be chemically treated. The machine was installed in July of 2012, and I currently have over 80,000 run hours on it. Maintenance has remained low. I have had to replace a couple of condenser fans and had to chase down some leaks, but it has all been a fraction of what the old system needed. The best part is when I call out a tech, they know exactly what they are working on, and it is rare that they don’t figure it out right away.

So, when your mechanical contractor tells you that your aging system needs another major repair don’t dismiss replacement with an air-cooled chiller. You might be surprised with what makes the most financial sense for you when you factor in all costs. It was a win-win-win for me, lower initial purchase price, reduced operational costs and energy savings.