Carel’s fully integrated C-Store CO2 solution 

Carel presented the fully integrated results of its C-Store, a smaller format layout that focuses on the carbon footprint and environmental impact of the whole store. The company believes that CO2 barriers can be broken down to enable the natural refrigerant to seriously infiltrate the CVS market. 

“The key factors for the convenience stores are the integration of the components of the systems – from refrigeration to air conditioning to lighting,” said the company’s CO2 retail specialist Nicola Pieretti.

Carel’s compact solution C-Store is divided into these three different areas. One refrigeration area with racks made with three to five compressors (low temp and medium temp). For the air conditioning, Carel uses split units, while the alarm and energy monitoring room is used to monitor the optimisation of the store.

Pieretti explained that synchronisation of the system is an optimal way to run the store’s energy management, with Carel’s pR300T controller providing complete rack control. It has the capacity to control and monitor the E3V-C high-pressure valves, gas cooler, intercooler, parallel compression and double heat recovery.

For milder climates Carel has another solution, with a third suction line integrated for parallel compression. Here, the chillBooster evaporative cooling system facilitates the CO2 gas cooler and is also key for the integration of a subcooler.

The E3V-C high-pressure valve provides a proportional stepper valve with a rather large cooling capacity of 250kW, perfect for supermarkets or higher energy applications. Meanwhile, Pieretti highlighted Carel’s MPXPRO controller for complete management of single multiplex showcase and cold room units.

Carel’s BLDC water loop achieving 96% refrigerant leakage reduction for plug-ins

Moving on to the company’s BLDC water loop for commercial refrigeration, Diego Malimpensa presented its application in CO2 plug-in units with heat management, using a brushless, inverter-driven DC compressor. Unlike conventional systems, which commonly use the standard AC compressor, the cabinets contain water condensers on-board, no copper pipes, no compressor racks and receive around 1-2kg of refrigerant charge.

Carel’s cabinets are factory tested and avoid welding. Malimpensa said they change the format for CVS from more complex systems and provide considerably improved refrigerant leakage rates and a 25% energy saving.

“There is a 96% refrigerant leak reduction and this seems to be a very high number, but it is the reality because we are moving from multiplex systems, where the average leakage rate is about 10-15%, to integrated cabinets where the cabinets are made and tested in the factory, so the leakage rate is reduced to about 1%, with a charge reduction of 80%.”

The system provides flexibility, allowing stores to change their layouts and the possibility to change the position of the cabinets. “This creates the possibility to have a wider sales area because there is no need anymore to have a machine room,” Malimpensa said.

Sanden going ‘all in’ for CO2 

Sanden confirmed its plans to steer away from HFCs and adopt 100% CO2 technology in the coming years. Sanden Europe’s Sylvain Gillaux explained the company’s philosophy: “Wherever we have a need for heating or cooling, we want to meet this need with CO2.”

And it’s not just talk. Sanden plan to reach the 100% benchmark as soon as possible and have opened up a new office in Brittany, France to accelerate the transition. The company expects to reach €70 million in sales by 2019.

“The originality of Sanden is that we are making our own key devices; compressors or heat exchangers. In order to accelerate this transition, and not just say, ‘we’re going all CO2’ we took the decision last year to open a new office. We are not only talking about distributing products but defining the market by coming up with innovative product plans for the next years,”


Sanden’s business model is perfectly suited to smaller format stores as they concentrate almost exclusively on heating and cooling components and systems with a capacity under 25kW. With experience in Japan, where there is a high density of CVS, Sanden is now looking to translate that experience to the European market and increase their penetration with commercial and plug-in units. In Japan a Sanden CO2 installation at a convenience store lowerered energy usage by 24%.

Sanden’s approach is unique in that they have their own compressors and can maximise the efficiency of their own products. “In 2015 Sanden will be the biggest CO2 compressor manufacturer in the world. We are aiming at selling more than 1 million small CO2 compressors,” Gillaux said.

Opportunities to reduce carbon footprint with with integrated systems

In his third presentation at ATMOEurope, Advansor’s Thorben Hansen discussed the carbon footprint of Natural Refrigerant solutions, in particular the need for compact energy systems in small supermarkets and his belief industry should be focusing more on overall building efficiency.

“Are we missing the best opportunity to get the most out of these systems?” Hansen asked. “Do we include heating in the equation? Yes, we do care about energy efficiency, especially when we’re here and then we forget about it a little bit at home. There is room for more integrated solutions, you will save money and you will save energy if you work at it. We have seen no real good comparisons of real life integrated systems with COPs or about how simple can we make the whole building system; how can we integrate out energy solutions. I think we’re missing a great opportunity,” he said.

EPTA’s CO2 transcritical system integrating heating and airconditioning

Udo Görner of EPTA Deutschland presented the company’s EPTA Clima, a green, innovative adaptive management, refrigeration, air-conditioning and heating system. The integrated solution has one main control system and the company is currently investigating the cost advantages and energy consumption compared to conventional systems.

“The system is currently in operation in Central Europe, but this concept is applicable and beneficial everywhere within the CO2 equator. Conventional systems are currently being monitored but what we have already seen is that this system, the Clima is green, is competitive, efficient and cost saving for supermarkets and hypermarkets,”


Görner explained the system in winter operation, whereby if heating is needed the high-pressure offset uses the useful energy in the system. The cooling positions are assigned to specific cabinets/chillers and if the energy of heat recovery, which is normally able to cover the heating need until 0 to -5°C (outside temperature), the system can use the heat recovery of the cooling system to cover the heating need. 

“Below this temperature (-5°C) we need an additional heating source which is in this case a heat pump and compressor,” Görner said. “The compressor is running with a gliding suction pressure level in function of the outside temperature to increase the system efficiency. Also on the high-pressure side we’re working with the gliding high pressure function with the gliding heating water flow temperature. The water flow setting is a function from the ambient temperature.”

If the outside temperature is high, the water flow temperature starts from +30°C, while at 15°C ambient temperature the water is up to 40°C. The system can reach a COP of 3.6, which is very favourable compared to other high-pressure systems. 

F-Gas and Ecodesign: Drivers and challenges for CO2 smaller format systems

Christian Heerup of the Danish Technological Institute addressed his organisation’s long-term plans for developing a viable CO2 condensing unit for the market. Heerup said Danish national legislation limiting the use of HFCs had long shaped DTI’s manufacturing philosophy with natural refrigerants and that broader European F-Gas and Ecodesign directives shaping the landscape further in recent years.

Heerup noted that the F-Gas Regulation had targeted small commercial systems (CDUs), forcing suppliers to think outside the box to develop new solutions. While scaling down CO2 units for convenience stores (CVS) and integrated systems has become a window of opportunity, Heerup argued that for hydrocarbons, the charge limits in Europe could pose barriers in similar applications. 

With funding support from the Danish EPA, Green & Cool (and later Advansor) were the first companies to place CO2 CDUs on the market, specifically to meet the Ecodesign Directive. Heerup said that the projects were on the verge of abandonment given the lack of CO2 condensing on the market at the time. The Ecodesign directive outlines the stated COP requirements for CO2 condensing units from July 1, 2015 and July 1, 2018, including the seasonal energy performance ratio (SEPR):


  • Capacity 0.2-1kW: COP 1.2 required; 1-5kW: 1.4
  • 5-20kW: SEPR 2.25; 20kW-50kW: SEPR 2.35


  • 0.2-1kW: COP 1.4; 1-5kW: 1.6
  • 5-20kW: SEPR 2.55; 20kW-50kW: SEPR 2.65

In light of the values, Heerup said CDUs utilising this first generation approach might not be the best solution for hotter climates as they are ‘not quite meeting the stated capacity’. DTI and other suppliers are still working to improve the stated capacity and energy efficiency. DTI is also testing larger condensing units using CO2 and rebuilding its facility to be able to cater for it.

“The first generation CDU exceeds Ecodesign requirements, but we can improve, I believe we have the ability to match best in class. We need the (market) pressure to produce more efficient systems.”

“When we compare units, theoretical and practical data, we have to take this into account we have to communicate this to industry and we also have to be part of the evaluation for the traditional HFC products in the future,” he said.


ATMOsphere Asia 2015 events page
Sylvian Gillaux Presentation
Torben Hansen Presentation
Christian Heerup Presentation
Udo Görner Presentation
Diego Malimpensa Presentation

Author jamesranson