UPDATE Part 1: First 100% CO2 cooling installation in southern Spain – Carrefour Alzira achieves 10% energy savings

By Janaina Topley Lira, May 16, 2014, 13:24 3 minute reading

Despite the warm Southern Spanish climate, the Carrefour Alzira hypermarket in Valencia has been equipped with a transcritical CO2 booster system following its refurbishment in November 2013. The system is 35% more energy efficient and saves 90% more CO2 than cooling systems using synthetic coolants. In part 1 of this story we look at the details of the Alzira project. Update: The installation is the sou

The Carrefour Group recognised early on the possible long-term cost savings of introducing CO2 cooling systems, due to changing regulations on fluorinated refrigerants, and now have several installations in different European countries. Although until now CO2 systems were not believed to be adapted to hot climates, such as in southern Europe, the Carrefour Alzira store has proven efficient. The first results on energy consumption already confirm the savings expected from simulations. 
"We’re looking to install more CO2 refrigerant solutions as part of our strategy to gradually substitute hydroflurocarbon-based refrigerants in our facilities since 2013,” said José Francisco Mollá, technical director, Carrefour España. “We’ve already installed four full CO2 systems in stores across Spain, and have been happy with the outcomes in terms of energy efficiency. We’re particularly interested in how this installation will compare, given the difference in ambient climate to our other installations to date, which are located in northern Spain.”
CO2-only energy efficient cooling solution for warm ambient temperature
In Alzira, Valencia, the challenge was to come up with an energy efficient cooling solution using only CO2 that would be able to cope with both the extremely hot temperatures during the summer period, and the warm yearlong average temperatures. Valencia is one of the warmest regions in Europe. 
The answer: a system that pairs parallel compression with an air-cooled flash-gas sub-cooler, also working with the natural refrigerant propene (R1270).
The integration of a CO2 sub-cooler makes it possible to maintain the output temperature of the gas-cooler at +26°C all year long, while the flash-gas is evacuated from the manifold through the parallel compression at an evaporating temperature 9°C above a positive circuit. 

By incorporating mechanical hydrocarbon sub-coolers and economizers in the transcritical CO2 booster system, Carrier's solution will allow food retail stores situated in higher-temperature regions to install natural refrigerant solutions that can reduce greenhouse gas emissions and consume less energy than traditional systems using hydrofluorocarbon (HFC) refrigerants.

CO2-only system achieves 10% energy savings
The energy efficiency system is responsible for a cut in electrical consumption of more than 100,000 kWh per year (10% savings compared to a conventional cooling system using HFCs). When compared to the previous system installed, with a 270kW of cooling capacity for MT refrigeration and 65kW for the LT refrigeration, the savings reach 35%.

“The successful installation of our CO2OLtec system in Alizira demonstrates the high performance of our leading technology in warmer climates,” said Manuel López Monge, sales director, Carrier Commercial Refrigeration Ibérica. “It represents our commitment to reducing greenhouse gas emissions and our ambition to provide supermarkets with cost-effective natural refrigerant solutions worldwide.”
Heat recovery for hot water production
Whilst previously th refrigeration system’s excess heat was mostly lost and sent directly into the atmosphere, it is now recovered and used to warm around 5,000L of sanitary water per day. This significantly reduces the store’s fossil fuel consumption, therefore generating less indirect CO2 emissions. 
A reduction of 10 million kilograms of CO2 emissions over 15 years will be achieved by the system, which is equal to the exhaust emissions of 4,600 medium-size cars.
CO2 rollout for Carrefour in Europe
There are currently 115 CO2 installations, including 23 using only CO2 across Carrefour supermarkets and hypermarkets. These installations are located in all of the European countries where the Carrefour Group operates. The Alzira store proves that the rollout of CO2 technologies can happen regardless of the climate, although technical adjustments will be required to reach the optimum energy efficiency in particular temperatures in order to maintain a short payback time. 
Frigo-Consulting SA. Best Practices Programme
In collaboration with the International Technical and Support Team of the Carrefour Group, Frigo-Consulting SA put in place a “Best Practices” Programme to support innovations, refrigeration technologies and energy technologies, in the following applications:
  • Planning interdisciplinary buildings concepts
  • Designing, Sizing and Creation of sustainable refrigeration systems 
  • Innovative and efficient recovery of waste heat 
  • Innovations and world premieres for saving primary energy 
  • Training and upgrading



By Janaina Topley Lira

May 16, 2014, 13:24

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