Giacomo Bigozzi, Dorin's Commercial Representative for Mexico
Giacomo Bigozzi, Dorin, at ATMO LATAM Summit 2023

ATMO LATAM: Natural Refrigerants Are More Efficient in Latin America Than R449A, Says Dorin

The Italian OEM said its study shows there is ‘no problem’ using CO2 refrigeration systems in Latin America.

Italian OEM Dorin has said it has modeled the energy efficiency of refrigeration systems using R449A and natural refrigerants, including CO2 (R744), in seven Latin American cities and found that naturals offer the highest energy efficiency.

“There is no problem using CO2 systems in Latin America,” said Giacomo Bigozzi, Dorin’s Commercial Representative for Mexico.

Bigozzi presented the findings of the study at the ATMOsphere (ATMO) LATAM Summit 2023. The event, hosted by ATMOsphere, publisher of R744.com, was held in November in Mexico City.

Dorin ran an energy efficiency comparison of a 1,000kW (284TR) refrigeration system, using R449A as the baseline, for various technologies. The comparison was conducted across seven cities in Central and South America: Santiago, Chile; Buenos Aires, Argentina; La Paz, Bolivia; Mexico City, Mexico; Lima, Peru; São Paulo, Brazil; and Bogotá, Colombia.

The study compared systems using R449A with an evaporative condenser, ammonia (R717) with an evaporative condenser, CO2 with flash gas bypass (FGB), CO2 FGB with an evaporative condenser, CO2 with only parallel compression and CO2 parallel compression with an evaporative condenser.

For São Paulo and Bogotá, the ammonia system was the most efficient, using 27‒28% less energy than the R449A baseline. However, ammonia systems often have additional restrictions in the region, Bigozzi noted.

CO2 with parallel compression and an evaporative condenser offered the highest efficiencies for all seven cities, ranging from 25‒28% less energy usage than the baseline.

“That doesn’t include the additional 20‒25% energy reduction from the latest CO2 technologies like adiabatic cooling, injectors, valves, etcetera,” Bigozzi remarked. “With all of these, CO2 can manage tropical weather conditions.”

Bigozzi cited “an interesting experience” with a utility company in Cartagena, Colombia, after installing a new CO2 system. “The utility wondered if its equipment was malfunctioning since it showed the facility using 40% less energy than before,” he said.

Drawing a parallel

During his presentation, Bigozzi highlighted the experience of Surgital, an Italian frozen food company, with natural refrigerants.

Since 1980, Surgital has operated a plant requiring a cooling capacity of 1.2MW (341TR) for −40°C (−40°F) freezing tunnels, a −30°C (−22°F) cold room and 0°C (32°F) chillers in the northern Italian province of Ravenna where ambient temperatures can reach up to 42°C (107.6°F).

Bigozzi said the Surgital plant initially employed 50 screw compressors using 2,000kg (4,409lbs) of R22 refrigerant with a 0.65 coefficient of performance (COP). In its first 20 years, the freezing tunnels were renovated using various HFC refrigerants, including R-409A, R422B, R422D and R424A.

In 2000, along with demolishing and renovating its existing tunnels, the plant required eight new tunnels. Inspired by a Nestlé plant that moved from R22 to a CO2/ammonia refrigeration system, the company received authorization for a system using 5,000kg (11,023lbs) of CO2 and 500kg (1,102lbs) of ammonia with a 1.16 COP.

Within 15 years, Bigozzi said Surgital needed to revamp each tunnel with 300kW (85.3TR) of cooling capacity. With the size too small to make a CO2/ammonia solution feasible, the company, in conjunction with its refrigeration contractor Gencold, ran tests to determine the most efficient CO2 options. Tests of CO2 cascade systems with HFCs (R507, R134a and glycol with R134a) had 19‒27% COP reductions compared to the CO2/ammonia system.

A transcritical CO2 booster using parallel compression offered a 1.15 COP.

“The CO2 booster was the best option,” Bigozzi said. The CO2 system, with eight Dorin compressors for transcritical/subcritical operation, took only two days to install.

“We don’t have 40 years of experience here [in Latin America], but we can see where Surgital stood and where they arrived,” Bigozzi said. “We don’t need to be afraid of this technology; natural refrigerants are energetically efficient and easy to use.”

“We don’t need to be afraid of this technology; natural refrigerants are energetically efficient and easy to use.”

Giacomo Bigozzi, Dorin’s Commercial Representative for Mexico  

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