New R-448A/CO2 cascade system installed at the Romans-sur-Isère Hyper U supermarket

The Hyper U supermarket in Romans-sur-Isère got an upgrade !


This U supermarket currently employs 130 people and had turnover of 32 million euros in 2016. The goal is to reach 40 million euros after the renovation. A large island of cases for fresh and frozen products was installed. The refrigeration system for these cases uses energy efficient and more sustainable solutions (choice of refrigerant, recovery of heat for the store's hot water, refrigerated cases that close). Total electricity consumption has been reduced from 20% to 30%, with more natural lighting and smart management. This new people-centric store with optimised accessibility is designed for the comfort of customers and employees.

Built in 1997, this U supermarket was once bustling. However, turnover has been falling at the store for the past few years, creating the need for serious change. Gary and Philippe Doire acquired the store in January 2017 with a clear goal: « give the store a makeover and revitalise it for better energy-efficiency and improved profitability ».

At U supermarkets, better management of the planet's resources involves action on many different fronts, including preserving marine resources, encouraging eco-friendly construction, reclaiming waste from stores, and reducing energy consumption. The company has deployed a rigorous energy optimisation policy based on improved management of energy consumption at all U supermarkets, making energy optimisation tools available to promote best practices, and incentivising renovations that improve energy-efficiency. The Doire family took these significant measures, into account for their Hyper U expansion project in Romans-sur-Isère, a town in Drôme department, France.



The store expansion project 

The new Hyper U management decided to expand 3,960 m² floor space to 4,500 m² in order to introduce new products and in-store services (butcher, cheese counter, bakery, etc.). Construction began in February 2017 with a reverse-scheduling plan carefully drawn up under the shrewd guidance of the senior Mr Doire, who coordinated all contractors. So started the seven months of work !


The store was previously equipped with a direct expansion system with two retrofitted R-22 units, a more recent R-404A above-zero unit, and many independent units for departments such as the bakery. The renovation and layout-update plan for the store included changes to cooling systems for refrigerated sections and hot water. The store's existing rooftop heating and air conditioning systems were left unchanged. A cascade system was planned, with the peace-of-mind provided by a CO2 unit for sub-zero refrigeration.

« At U supermarkets, store managers are educated about new technologies. As such, it was important to propose a solution that was both energy-efficient and sustainable, » said Christophe Luna, Manager of Reynet Froid.

Implementation of the R-448A / CO2 cascade system

The Bonnet Névé-brand glass-door and other refrigerated cases were selected directly by the store manager. The system has a Profroid sub-zero unit with a capacity of 38 kW, equipped with four Bitzer compressors and loaded with 90 kg of R-744. This refrigeration system primarily chills chests of frozen products and the cold storage rooms.

Once the product displays were put into operation, the second stage of work began connecting refrigeration equipment and all cooling systems across fresh product (deli meats, dairy, etc.) food preparation and chilled product (seafood, meat, ready meals, etc.) aisles.

Two Profroid above-zero refrigeration units, each with 280 kg of R-448A (Solstice® N40) cover all refrigeration needs. The two units are equipped with four Bitzer compressors and variable speed drives.

A Carel monitoring system is used to control tem¬perature, pressure, and humidity in refrigerated equipment.

Heat is recovered from the above-zero refrigeration units to generate hot water, with a 1,000-litre tank. All of the new equipment is installed on the upper level of the store to open up the former plant room, which has been converted to sales floor space.



« Construction took more than 150 nights of work across all of our contractors, » says the Hyper U manager.. « It was a very long, well-organised phase and it took longer than expected to implement. The project was essential for improving store sales and for customers comfort. ». The supermarket now awaits approval of the application for energy-saving certifications and is getting ready « to welcome customers into a store that is adapted to modern shopping habits and that has the goal of connecting economic performance with environmental performance, » concludes Gary Doire.


R-448A /CO2 cascade system experience


Christophe Luna
, Manager of Reynet Froid et Climatisation
« Working with the R-448A refrigerant hasn't changed our habits at all. It's a refrigerant with low GWP, classified as A1, supplied in standard cylinders that are easy to use. As for settings, we haven't encountered any particular issues. Indeed, the feedback that we have received with this refrigerant has been very positive. ».

« It's different for CO2. We had to adapt to this high-pressure refrigerant. Profroid, our unit supplier, has helped us implement sub-zero units.

This type of system requires special precautions for installation and it was important to have the manufacturer present ».