Technicals & Contractors

What the refrigeration technician needs to know about co₂

Every time that the market innovates and transforms itself, several opportunities open for professionals. In the case of the commercial refrigeration sector, it is no different.

A great example of new possibilities which arose and that are in constant evolution is in the supermarket sector. With a continuous reduction in size due to the restriction of space, these establishments have to learn to work in compact places and, consequently, use refrigeration systems which adapt to these places.

Less space, more technology

From the problem of lack of space, smart solutions arise. One of them is the compressors incorporated in the refrigeration equipment, which gain a place related to systems with machine rooms or remote refrigeration. A solution which also brings the advantage of maintenance simplification. 

This has also occurred with wholesales/retail stores and super/hypermarkets, but the requirement of large thermal loads and availability of a larger space means that the stores in these formats use other solutions already consolidated in the market, such as CO₂ and propane, for example.

Increasing use of natural cooling fluids

It is not only the format of the stores that is changing. One alternative that is being applied is the use of natural cooling fluids instead of synthetic refrigerants – due to new regulations and greater environmental awareness of society. 

As a result, the use of refrigerants such as propane (R290) and CO₂ has become more frequent. Propane can be used in large systems (semi-hermetic compressors) or those with a smaller size (equipment incorporated), while CO₂ is the great trend for machine rooms and remote refrigeration.

Opportunity for refrigeration technicians

It is at this moment that the refrigeration technician can make use of the market innovations to be able to specialize himself/herself and offer specialized services. The earlier that knowledge is sought, the quicker the return will be.

But what does CO₂ have to do with this?

Everything! If in one hand the supermarkets gain new options of suppliers of refrigeration systems, the refrigeration professionals and technical assistance companies have a new field of activity.

“Today, we have the great opportunity of being part of a historical transition/change of concept in the refrigeration sector in our country, something which has not happened for at least 20 years. This moment is also making the installations smarter and more reliable”, states Sidney Mourão, sales manager of Embraco.

Important points which the refrigeration technician needs to know about CO₂?

Here in this text you can know more about CO₂ and propane in the refrigeration market.

Below, we summarize the important points which the refrigeration technician needs to know about CO₂:

– Refrigeration systems which use CO₂ are the global trend for racks of supermarkets – ecological appeal and high energy efficiency for milder climates.

The systems with CO₂ can be divided as follows: Hybrid or with 100% CO₂:

– Hybrid: they are the ones which use CO₂ at the low temperature (frozen), while we have another fluid doing its condensation at the medium temperature. The most common application is the cascade system.

– Systems with 100% CO₂ are more common in countries with milder external temperature conditions (ambient temperature less than 21°C), and they are called Transcritical systems, due to the condition of CO₂ in the condensation.

How do these systems operate?

Transcritical System: CO₂ operates in a different way from halogenated cooling fluids. While in the halogenated ones the condensation of the fluid occurs, in the transcritical CO₂ systems a cooling of the fluid occurs in the gas cooler, as the temperatures exceed the critical temperature of CO₂. In these systems we have work pressures at high pressure which can attain 90 bar or 1305 PSIG. The cooling fluid is then stored in the liquid tank and afterwards distributed to the system of low temperature and medium temperature. This is always at the low part of the tank, so as to send only liquid to the system. At the medium temperature it leaves the tank, passes by the expansion valve and by the evaporator and then is sucked in by the compressors of medium temperature. In the system of low temperature, the refrigerant also passes by the expansion valve and by the evaporator, but before it is sucked in by the compressors of low temperature. These compressors make the pressure lower for the frozen item conditions. Only then is the fluid sent to the suction of the compressors of medium temperature and thus the circuit is closed.

  

Transcritical System

Subcritical System or Cascade: In this case, the CO₂ is used in the circuit of low temperature and another cooling fluid – such as R290 (Propane), R134a, R404A or R717, for example – is used in the circuit of high temperature. Thus, the condensation of CO₂ occurs with the evaporation of the other fluid, raising COP (coefficient of performance) of the cycle. In other words, the with CO₂. This condenser is usually a plate exchanger. One interesting advantage in this system is that the pressure conditions are similar to R410A and the system can operate in any type of climate, with external temperatures greater than 21°C.

 

Cascade System: Cascade

Embraco strong in supermarkets

Embraco has closely followed up the evolution on the supermarket sector and has developed solutions which meet the requirements.

See below some of the technologies developed:

– The variable speed compressor Fullmotion FMFT413U, which uses propane and is ideal for incorporated freezers;

– The sealed unit Plug n’ Cool using a conventional or Fullmotion compressor, with propane, indicated for vertical displays with doors; 

– The Dorin line of semi-hermetic compressors, with 100 years’ history, consolidated in Europe and growing in Brazil. It is present in the main supermarket networks.

Be prepared for this new era!

And so, refrigeration technician, are you prepared for these opportunities in the supermarket sector, especially in the new commercial refrigeration systems which use CO₂? 

Golden tips: Be qualified to know how to work with systems which use cooling fluids and always be aware of the changes. Here in the Refrigeration Club Website you can find everything you need to know about the market. Enjoy your reading!

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