Italian OEM Rivacold met several refrigeration needs in a hotel on the Spanish island of Majorca with chillers supported by Emerson’s new propane (R290) scroll compressor.
This installation shows R290 compressors have applications beyond the small R290 condensing units used in chilled display cases.
Olivier Liégeois, Director of Marketing Refrigeration for Emerson, described the hermetic design and capacity of the YB-K1G R290 scroll compressor at the November 2022 ATMOsphere (ATMO) Europe Summit in Brussels. The design configuration, installation and performance of the chiller were detailed by Matteo Bettoni, Project Manager for Rivacold. ATMO Europe was organized by ATMOsphere, publisher of Hydrocarbons21.com. (U.S.-based Emerson recently announced an agreement to sell a majority stake in its refrigeration business to private equity funds managed by New York-based Blackstone.)
Emerson started with 1kW (0.3TR) fixed-speed small-capacity scroll compressors for display cases. It now has 230,000 scroll compressors installed in over 5,000 stores. After ten years in the business, its “new products go up to 20+kW [5.7+TR] refrigeration with variable speeds,” said Liégeois. The new YB-K1G R290 scroll compressor is a high-capacity 22kW (6.3TR) system for mid-range applications with evaporation temperatures of -10°C (14°F) in ambient temperatures of 43°C (109.4°F).
In this application, a compressor with a “charge greater than 500g [1.1lbs] of propane with variable-speed compression provides very efficient solutions,” he said.
A key advantage of the hermetic scroll compressor, said Liégeois, is its compactness. Compared to an equivalent semi-hermetic compressor operating at the same volume and capacity, the R290 scroll compressor is half the weight and takes up almost half the footprint space. Moreover, this large scroll compressor offers additional safety regarding the flammable refrigerant when installed in an outside installation.
R290 chillers + CO2 condensing units
The Tui Blue Alcudia Pins hotel in Majorca required refrigeration for medium and low-temperature display cases in a store and a medium-temperature cold room and a low-temperature cold room in the kitchen area.
Rivacold’s chiller design used the Emerson R290 scroll compressor to chill a water/glycol (brine) mix to the -6°C (21.2° F) set point with a variation of plus or minus 0.5°C (0.9°F). The chilled brine is circulated to the different utilities.
The chilled brine is used “to refrigerate medium-temperature utilities, but then we can use the brine to maintain the condensation of a CO2 [R744] subcritical system to refrigerate [the] low-temperature cold room,” reported Bettoni. Using the chilled brine improves the efficiency of the CO2 subcritical condensing units.
In total, four Rivacold chillers, with a combined capacity of 76kW (22TR), were employed with one hydronic kit and three CO2 condensing units to serve 15 medium-temperature and three low-temperature loads.
“We confirmed the efficiency, even in high ambient temperatures as recorded [from] this summer of 43.1°C [109.6°F],” said Bettoni, with historical data and remote monitoring of the system. The set point for the chilled brine was maintained at about -6°C.
Using the R290 scroll compressor to chill circulating brine and support the CO2 subcritical system was not only more environmentally friendly, but it also saved energy. “To compare this to HFC chillers, we see an energy savings of 26%,” said Bettoni. In addition, when compared to a CO2 transcritical system, there were energy savings of 11%, and 2% savings compared to CO2 transcritical in parallel compression.
In cooperation with independent organizations, Rivacold analyzed the safety of the R290 system using computational fluid dynamics. The hermetic or sealed design of the R290 scroll compressor improved safety by preventing possible leaks of R290. “Installation can be done in a safe way, especially with the chiller outside of the building and using the glycol mixture refrigerant on the internal part,” said Bettoni.
Tui Blue Alcudia Pins “felt like this was the winning choice for them,” according to the installer, iFred iClima. “The Rivacold propane group guarantees efficiency and reliability even with the high temperatures we have on our island. The circulating brine temperature is stable and close to the set point.”
Moreover, they found the maintenance easier than traditional systems where the refrigerant circulates throughout the installation. Furthermore, this environmentally friendly solution helps them avoid the high HFC tax.
“We confirmed the efficiency, even in high ambient temperatures as recorded [from] this summer of 43.1°C [109.6°F].”Matteo Bettoni, Rivacold.