An Embraco propane (R290) variable-speed compressor controlled by internet of things (IoT) technology has reduced the energy consumption of Polish OEM ES System K’s INSÙ Gelato cabinet by 32% compared to a propane on/off Embraco compressor.

“This case study is a final demonstration that variable-speed technology with propane is the solution for commercial refrigeration,” said Marino Bassi, Key Account Senior Advisor at Embraco, a brand of Nidec Global Appliance.

Bassi added that the technology also applies to “other applications like ultra-low freezers used in medicine.”

Bassi presented details of the compressor’s performance at the ATMOsphere (ATMO) Europe Summit 2023 in September alongside Robert Pędzik, Technical Director at ES System K, who shared details of the ice cream cabinet’s unique design. ATMOsphere is the publisher of Hydrocarbons21.com.

The INSÙ Gelato cabinet from ES System K, which designs and manufactures refrigeration equipment, is equipped with an IoT control module with an algorithm that optimizes the performance of the Embraco compressor. The cabinet’s internet connectivity also provides technicians and store staff remote access to monitor and change operating parameters. 

During the development of what would become the INSÙ Gelato cabinet in 2018, ES System K flipped the design from horizontal to vertical, with space for 12 products contained in individual glycol-cooled drawers. According to Pędzik, the cabinet runs with static circulation, with each of its three levels operating with a designated evaporator.

ES System K’s INSÙ Gelato cabinet; Photo Credit Reddot.

The company saw a 54% reduced energy consumption compared to its traditional horizontal cabinet with the INSÙ Gelato using the same R452A on/off compressor, dropping from 27.4kWh/24 hours to 12.5. Pędzik said that the company’s motto of “respecting tomorrow” drove it to seek a green alternative and switching to an Embraco R290 on/off compressor (11kWh/24 hours) brought an additional 12% savings in energy consumption.

Pędzik said an Embraco R290 variable-speed compressor was installed in a cabinet in 2021 upon a client request for better temperature stabilization. The R290 variable speed compressor (9kwH/24 hours) provided temperature stabilization and reduced energy consumption by an additional 18%. The IoT variable-speed controls (7.5kWh/24 hours) provided another 17% energy savings. Finally, adding enhanced glass (IG Front Glass) to the front of the case (6.6kWh/24 hours)  decreased the energy consumption by another 12%.

Fine-tuning controls

According to Bassi, Embraco offers three control modes for its variable-speed compressors: smart drop-in, with the control algorithm embedded into the inverter; frequency control, with the inverter controlled by an external controller; and serial control, with feedback exchanged on compressor operation.

“Fine-tuning all the control logic with an integrated system of hardware components and software algorithms achieves the highest efficiency possible with the variable speed compressors,” Bassi said.

Outside of the IoT aspect, the main advantage of the propane variable-speed compressor is its narrow thermal load balance, Bassi noted.

“The outlet temperature in the cabinet stays incredibly stable with the variable-speed compressor,” Pędzik said, displaying a graph from July 21, 2023, of overnight hours with a flatlined outlet temperature. A graph of the on/off compressor outlet temperature with the same overnight hours on July 22 showed variations of up to 2.5°C (4.5°F).

U.K.-based Unilever, with three million plug-in ice cream cabinets worldwide, has also seen an energy reduction of up to 17% using Embraco variable-speed compressors in its propane-based cabinets over comparative on/off units, said Berty Jacob, Senior Research and Design Manager at Unilever, at the ATMO Europe Summit 2023.

“We are immediately moving forward installing variable speed compressors on our flagship models,” said Jacob. “The compressors enable us to meet the new European energy labeling guidelines and to stretch our energy targets.” 

Headquartered in Wolbrom, Poland, around an hour north of Kraków, ES System K was founded in 1995 and has refrigeration equipment in more than 50 countries.

“This case study is a final demonstration that variable-speed technology with propane is the solution for commercial refrigeration.”

Marino Bassi, Key Account Senior Advisor at Embraco