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12 May 2022
The era of CO2 refrigeration is coming – interview for Plast Echo

The newest issue of the Plast Echo magazine has already been released from printing presses, including an interview with Maurycy Szwajkajzer on energy-efficient cooling.

Full text below.

In the processing industry, cold is not the most important thing, but without it most plastic products will not be created. That is why we decided to talk about energy-saving refrigeration with Maurycy Szwajkajzer – an engineer and owner of a company dealing with modern CO2 refrigeration.

Mr. Maurycy, let’s start with the details. How many percent of energy can be saved on cooling from chillers?

From 25 to over 45 …

Hmm… I think we should talk about it in more detail, because the values ​​you are talking about are significant and readers will need more information to understand where they come from. Maybe let’s start with the basics. Why are you looking for savings in refrigeration?

Refrigeration is present in most of the products around us, ie in the food, pharmaceutical and agricultural industries … And, of course, also in the processing of plastics. I clearly remember the end of my second year of studies at the Warsaw University of Technology, when I was choosing my specialization. I felt… or in fact I knew then that cold in the form of air conditioning or process cold is one of the basic media that create contemporary prosperity. There is also some magic in the fact that it is possible to take heat from a lower temperature and return it to a higher temperature. After graduation, I worked in some very interesting companies building refrigeration installations, until the moment came when I decided that I had to go on my own. I was a somewhat recalcitrant worker, and I like to keep my hands on everything. This way I am where I am. I run a company dealing in energy-efficient refrigeration. Sometimes this means hybrid adiabatic towers and sometimes a super effective CO2 chiller.

Hybrid adiabatic tower, chiller. How are these technologies different?

The cold source must be matched to the required temperature. A temperature of approximately 25 ° C is used to cool the oil. Of course, it can be achieved with a chiller, but it will be much cheaper to use popular free cooling. When the air temperature exceeds 20oC, the air flow alone is not enough to maintain the set parameter. Then we use adiabatic cooling – with the use of water. A properly selected device will allow you to maintain the assumed 25oC without using energy for the operation of the chiller, will minimize water consumption and will not require treatment. On the other hand, a temperature between 7 ° C and 15 ° C is usually used to cool the molds. This parameter cannot be maintained all year round by cooling only with external air – free cooling. It is therefore necessary to use a chiller with a cooling circuit.

How are CO2 chillers different from those used today? I am not sure if the processing industry will want to experiment with them.

CO2 refrigeration technology is widely used in trade, food processing and logistics. It can be said that in cooling capacities from 20 kW to about 2,000 kW, CO2 is the first choice – it is a proven and appreciated technology. The energy savings achieved are confirmed by specific measurements. I have designed and made dozens of such systems. When I’m in the role of a project engineer, part of my job is to confirm the parameters that are being achieved. CO2 devices work partially, in a similar refrigeration cycle as F-gas chillers, but they have a supercritical mode, and the best ones will have flooded evaporators.

You have already written about technical issues in our magazine.

Even twice! On this occasion, thank you for giving me the floor. I gave specific information especially in the article on the cost of cooling a plastic brush. My children were bringing items made of “plastic” and I weighed them on a household scale. I was doing calculations, and in the end, it came out in zlotys or pennies.

Back to the topic. You say this is a technology that is present in other industries. So why in our – plastics processing – we do not meet these devices yet? Do you think they’ll catch on?

Editor, I know that they will catch on … Let me tell you about the beginnings of CO2 refrigeration in the commercial industry – in supermarkets. Back then, regulations that would phase out F-gases were just on the horizon. Nobody believed that they would finally come into force. Electricity was not expensive. The word ecology was considered ugly, and someone wrote about me on the Internet that I was sponsored by unknown foreign funds! Time has passed, regulations have become a fact, electricity has become more expensive, technology has started to pay off very much, and ecology is a nice addition. Now let’s look at the current condition of the plastics processing industry. Electricity is expensive, but we know it will be even more expensive. There is talk of the F-Gas II Act in the EU Parliament. Ecology is welcome but no one is going to put their business at stake for her. There are… there are known and popular F-gas chillers. CO2 cooling, also that produced by modern adiabatic towers, is cheaper and that’s it. Initially, it will be decided by innovators and brave entrepreneurs. Thanks to this, they will have a competitive advantage over the rest of the industry. In this way, step by step, energy-efficient refrigeration will also win over this market sector.

What are the disadvantages of this technology?

At the moment, it is primarily an investment cost. The CO2 chiller itself is more expensive than a similar F-gas device. When we conduct this conversation, i.e. in the first half of 2022, this difference is about 1.6 times. So my job is to justify a larger OPEX with a smaller CAPEX. Simply put, I am convincing the industry to invest more now for future savings – in electricity costs. It is not an easy task, but as I have proven many times in my articles, including in the pages of “Plast Echo”, the calculations are very precise, and the experiences of other industries confirm that they are also reliable. I do not use a simple COP which gives the amount of cold produced with 1 kWh of electricity at one point. I calculate energy consumption for 8760 points a year – for each hour for a specific location.

Okay, but the cold in plastics processing isn’t just a chiller, right?

Of course not. A typical system will include a cooling source, a primary pump unit, a buffer tank which is also a clutch, a secondary pump unit, piping, and eventually exit points to the machines. This entire plant will be the same, whether the chiller is F-gas or CO2. All these items cost money. And it’s salty! The effect is that and yes, the CO2 chiller itself is much more expensive than the existing technology, but as it becomes part of the overall installation, the difference becomes slight. (repeat)

I see. And how do you assess the situation regarding these non-chillers? All those pumping units, tanks, pipelines?

This is an interesting point. In my practice, I have performed many hundreds of refrigeration audits in industrial facilities and over a dozen in plastic processing plants. When studying such an object, I can see its beautiful story, which often begins with the proverbial “garage” and a man with a vision. The factory grows as the mushrooms bud. New rooms are built, new machines and devices are added, and the cooling system is modified and modified. As a result, what was a very good solution in the past, today, after too many modifications, becomes an energy “monster”. The task of water or glycol systems is to transport cold, and in fact heat. This should be done with the lowest possible loss of temperature, electricity in pumps, etc. Contrary to appearances, a lot of energy is often wasted in incorrectly controlled pumps, too small pipeline diameters, unnecessary exchangers and various types of supplies.

Transport of cold, and in fact heat? It sounds intriguing! Can you explain that?

Cooling is the removal of heat from the product or oil. This heat, through water or glycol pipelines, reaches the chiller, where the temperature parameter is raised to a level that allows it to be transferred to a warmer environment than water in the mold or to oil cooling. There is another potential in raising the temperature – heat recovery. CO2 chillers have a unique feature. Equipped with heat recovery, they can heat water up to over 90oC without increasing electricity consumption! 1kWh of heat from gas is about PLN 0.21. That is, to the savings on the cooling production side, we can easily add savings on the heat side. Heat used to heat a building or domestic hot water.

Reducing the consumption of electricity and gas – this is where you see the aforementioned ecology?

Also, but also in the very factor that is applied. I will explain it through an anecdote. Suppose we want to circle the Earth at the equator with a typical small family car. 40,000 km x 0.2 kgCO2 / km = 8,000 kg CO2 emitted to the atmosphere. The same emission of CO2 into the atmosphere can be obtained by releasing 3.8 kilograms of the popular f-gas r410A. 3.8 kilograms! These chemicals are really harmful! A customer who uses CO2 refrigeration with GWP 1 – versus 2088 for r410, can only drive the largest cars with old V8 engines in the company, all employees can drive such cars… and will still be greener than a neighbor with standard cold production. Currently, it is the greenest technology available on the market.

All right. If, as you say, this technology pays off, is ready for implementation and is still environmentally friendly – it should probably take root soon enough. What are the biggest difficulties with its implementation?

Many years ago I wrote about the phenomenon of “Late Adopters”. It consists in the fact that at a time when the economy is in good shape, companies get richer. There are spare funds, investment funds, etc. on the account. There is a natural tendency to use this good. A company that, at the time of having funds, will not invest in reducing operating costs for the future, will lose accumulated stock over time, because the “innovative” competition will save more, reducing production costs, product costs, etc. As a result, when the implementation of energy-saving technologies is necessary due to the risk of being “on the line”, there may not be money for its implementation. It is a phenomenon that repeats itself cyclically, just as cyclically the economy goes up and down.

I am convinced that most of the issues raised in our conversation will be worth developing in the future. As an absolute layman in the field of refrigeration, I hope that in our magazine we will host your texts explaining the intricacies of cooling technology.

This is how I actually like to talk. After all, these are interesting topics!

Maurycy Szwajkajzer

for Plast Echo may 2022