Annual Field Performance of State-of-the Art Integrated Supermarkets Working With R744, Installed in South Europe- A Review of the Multipack Project Results

This study presents a comprehensive evaluation of the annual performance of two fully integrated all‑CO₂ systems installed in supermarkets located in Southern Europe, developed within the H2020 MultiPACK project. These systems combine all thermal needs of food retail sites—low‑ and medium‑temperature refrigeration, space cooling, space heating, and domestic hot water production—into a single CO₂ unit employing state‑of‑the‑art technologies. Key features include parallel compression, multi‑ejector expansion, evaporator overfeeding, and heat‑pump functionality, enabling high efficiency even under warm climatic conditions. The aim of the work is to provide robust field data for systems whose performance is generally assessed in literature through simulations, as long‑term measured data remain scarce. Two installations, located in Trento and Rome, were monitored for more than one year; dedicated data‑processing method—based on moving averages and steady‑state detection—was applied to compute reliable Coefficients of Performance (COP) for all operating modes. Results show that the Trento installation, characterized by substantial space‑heating and cooling loads, reaches an annual integrated COP of 3.22, whereas the Rome site, dominated by refrigeration demand, achieves a COP of 3.00. Specific energy consumption benchmarks demonstrate significantly lower energy intensity than the national average for comparable Italian supermarkets, with reductions between −26% and −60%. A qualitative comparison with a nearby HFC‑based store further indicates that the integrated CO₂ system supplies all thermal services with an annual energy consumption comparable to that of conventional only-refrigeration units, confirming its suitability as a sustainable, high‑efficiency solution for warm climates.