Supermarket cuts costs with CO2/HFO cascade

ITALY: A cascade system twinning CO2 with the HFO refrigerant 1234ze is providing all the refrigeration, ac and heating demands for a supermarket in Parma, Italy.

The system used in the U2 supermarket was designed by Milan-based refrigeration consultancy Technologie del Freddo (TDF) in cooperation with refrigerant producer Honeywell. The eCold cooling system delivers all the store’s building service requirements in one solution, making boiler, chiller and air handling unit unnecessary.

In addition, using two refrigerants with GWP’s of around 1, the system meets the European F-gas regulation which will ban commercial refrigeration systems with capacities of 40kW or more using refrigerants with GWPs above 150.

The U2 store has a sales area of 1,500m² and has been operational since December 2014. Early indications are that the energy requirement will reduce by around 45,000kW with anticipated energy savings of around 35% over comparable stores.

A charge of 150kg of Honeywell’s R1234ze brand refrigerant Solstice ze is used as the primary refrigerant for cooling a pumped CO2 MT system, with 400kg of CO2 then cascaded to the LT system to deliver the required performance.

The waste heat from the system is then recovered to heat the store, provide hot water and cool the store environment in summer. Not only does this system reduce capital outlay and energy costs, its compact design takes up less supermarket floor space.

“This system design, along with Solstice ze, enables commercial enterprises, including supermarkets, to plan beyond 2020, safe in the knowledge that their investment will not only deliver a more sustainable solution it will also stand the test of time,” commented TDF’s Natale Mandelli.

While transcritical CO2 systems have become the preferred option in new supermarket systems, their efficiency is questioned in the high ambient climates found in southern Europe. This system  has been designed to take account of all the climate variables, says TDF, making it advantageous from an energy point of view in any geographical condition even where external temperatures exceed +50ºC.

The local council is said to be assessing the environmental benefits of the U2 installation as an example of best practice for stores across its area, particularly as the new European Directive governing refrigerant leakage (EN378) is likely to permit a higher charge of Solstice ze (up to 70kg) in public places.

Last year, Honeywell highlighted similar work with R1234ze in a cascade system with CO2 at a bakery in Germany.

Related stories:

Bakery rises to 1234ze/CO2 challenge – May 8, 2015
GERMANY: A refrigeration system using the low GWP HFO R1234ze in a cascade system with CO2 has been successfully applied for the first time at a bakery in Germany. Read more…