Customers save money with CO2 systems – Exclusive interview with S. Girotto, enEX

By Sabine Lobnig, Jul 09, 2012, 13:03 5 minute reading

enEX, the Italian company specialised in design and manufacturing of environmentally friendly air-conditioning, ventilation, refrigeration, and heat pumps, has just brought a new model range of CO2 refrigeration units on the market. talked to Sergio Girotto, Chief Executive at enEX, about energy and money savings with CO2 systems as well as the importance of safety and appropriate standards. You have just brought the new SIERRA range of CO2 refrigeration units for small commercial applications on the market. How would you define the economic benefit of using CO2 in commercial applications? Do customers save money if they opt for CO2?

Sergio Girotto: Yes. For medium and large size systems there is a price advantage, using the latest development, compared with the equivalent HFC systems, if one considers all the cost involved. This would include the cost for the refrigerant piping system, maintenance, energy consumption, periodic inspections needed for HFC systems and disposal costs.

The SIERRA unit is a “plug&play” product, so there is a real saving in installation cost. Small CO2 systems on the contrary, including in this category the condensing units with less than 10 kW refrigerating capacity, cost significantly more than HFC systems, but this situation might change in the future when the production volumes increase. What is a project or installation that you are particularly proud of?

Sergio: I would like to mention in general some advanced CO2 refrigeration concepts we have introduced in the past years and which are raising now more and more interest. Among these there is one industrial chiller for brine cooling down to -30°C using a low pressure receiver concept, a number of 2-stage internal compound type units with OFT – open flash tank – design, for deep freezing, and also quite a few refrigeration systems using the enEX economizer option. Not to forget the heat pump range for sanitary water heating: our products Airheat and Geoheat incorporate an unique and innovative self optimizing control software allowing the highest efficiency level in their category, even with water out temperature up to 90°C. Why do you consider the market potential for CO2 refrigeration to be particularly high in central and southern Europe?

Sergio: First of all in central and southern Europe the refrigeration market is big, obviously because most of the European population lives there. It is true that nobody can seriously believe to export successfully to southern Europe the design solutions used so far in the Nordic countries. However, a suitable and proven solution does also exist for the climatic conditions of Southern Europe, so the potential market is really high. How do you adapt your products to these climate zones?

Sergio: The 2nd law analysis of a transcritical cycle shows clearly what is, energetically, the weak point at the highest condensing sink temperatures. Throttling losses for CO2 transcritical systems are higher than that of the best HFCs in use today. The technique we are using is based on the removal or the reduction, depending on the type of application, of flash vapor mass flow. In other words, the vapor produced during the first expansion process is recompressed before reaching the lowest pressure of the refrigeration cycle. This is equivalent in principle to recover part of the expansion work. We have available many data from a field test that lasted for more than one year on 2 units and a report will soon be published.

A further improvement is a new design concept, which we are going to present at the next Chillventa exhibition, based on the use of an ejector for recovery of expansion energy. This new solution, which has been developed with Huurre Eco in Finland and WR Refrigeration in UK, is not only giving significant efficiency increase, but it also improves reliability and safety. Where does enEX focus R&D efforts?

Sergio: The first issue is safety. We want to be ahead of existing standards. The second issue is reliability. Simplicity is the key word to describe how to improve this aspect. It is sometimes necessary to re-consider well established concepts to get improvements in this direction.

The third element is efficiency. This one is the most attractive characteristic for the end-user, but without the 2 first it is of no use. All 3 elements must be considered in any new development. How do you see the natural refrigerant market evolve over the next 2 years?

Sergio: The main question is if these products are or can be an advantage for end users and for the whole community. My answer is yes, so I am pretty sure that in the next 2 years the market share of products with natural refrigerants will increase.

First of all refrigeration and heat pumps systems using ammonia and hydrocarbons, each one for a specific application field, are already today a very good choice for any region of the world, also economically, and the technical solutions in this case are mature.

CO2 refrigeration, which is the only possibility when the refrigerant is used directly for “cold” distribution inside spaces where people are present, required the re-development of the technology, and this is not simple so it took some time. As said there are solutions available to make it a winning solution everywhere, even if there is not yet a widespread knowledge about possibilities. What kind of initiatives from policy, industry and end-consumers are the most likely to help bring natural refrigerants faster to the market?

Sergio: A first initiative, for which could be a promoter, would be the launching of actions to further improve the safety level and the efficiency of CO2 systems used in commercial refrigeration. The purpose should be to clearly define, through an appropriate and simple guideline, the essential elements for a proper evaluation by the end-users.

The above is not in contrast with or alternative to existing and future standards. The preparation of standards is under the responsibility of Technical Committees of Standardization Bodies , but we all know that the procedure is inevitably complex. Due to that a lot of time is needed to update the standards to the latest development and applications. On the other side, the number of products using natural refrigerants is growing so fast that an appropriate and updated standard will arrive late, while it is important to do something now.

For a worldwide introduction of these new technologies I believe that a cooperative approach with developing countries could help bring them to “state of the art” level in few years. Sergio, many thanks for your insights!

Contact Sergio Girotto directly via the community: 


By Sabine Lobnig

Jul 09, 2012, 13:03

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