The environmental friendliness and “best practice” energy performance of low-charge ammonia systems help corporations meet the United Nations Sustainable Development Goals (SDGs), said Andy Pearson, Group Managing Director at Scottish OEM Star Refrigeration.
The company has more than 30 years of industrial ammonia (R717) refrigeration systems manufacturing experience. Star Refrigeration was co-founded by Andy Pearson’s late father, Forbes Pearson, in 1970.
Pearson outlined the advantages of Star’s low-charge ammonia systems, including its ability to support business growth with easy relocation, at the 16th Gustav Lorentzen Conference, held at the University of Maryland from August 11‒14.
Applicability to SGDs: Pearson found a direct connection between low-charge ammonia systems and all 17 SGDs. He focused on four areas.
- Affordable and clean energy: “Over the life of a monitored and maintained plant, low-charge ammonia modules deliver ‘best practice’ performance in terms of efficiency,” he said.
- Decent work and economic growth: “These systems are good for end-user business and supply the workforce with a safe and clean environment,” Pearson noted.
- Responsible consumption and reduction: traditional industrial ammonia equipment has a longer lifespan than some of the other technologies being transferred from the commercial sector, according to Pearson. “Maintaining good performance over a lifetime reduces capital upgrades and conserves scarce resources.”
- Climate action: as a natural refrigerant, ammonia has no ozone depletion, global warming or PFAS (per- and polyfluoroalkyl substances) potential.
System portability and design: “I estimate that about 25% of the low-charge ammonia systems that we’ve installed are not where we delivered them,” Pearson said. “The customers are taking them elsewhere because their business has grown, and, thus, the package retains its value longer than a stick-built system that has to be left behind.”
- Pearson said Star eliminates the possibility of an ammonia leakage inside a building by installing only the evaporators inside the facility and through reducing the ammonia charge to roughly 200kg (441lb) per outdoor package.
- Using a reverse cycle, the system is operated as a heat pump to defrost evaporators.
- With two compressors in a package, the OEM maximizes the heat exchange surface to improve performance over using a single on/off compressor.
- An air-cooled condenser provides better seasonal efficiency than an evaporative one.
Case study: In a different presentation at the same conference, Pearson outlined the 2023 performance data of a low-charge ammonia system installed in a 300,560m2 (3,253,200ft2) automated warehouse in England in 2021.
- Two packages, each providing 672kW (191TR) of cooling capacity with two screw compressors for redundancy, met the calculated 1,242kW (353TR) load in the new warehouse, with a storage temperature setpoint of −21°C (−5.8°F).
- Over the year, the facility used 1,364,200kWh of energy, giving it a specific energy consumption (SEC) of 4.54kWh per cubic meter. According to Pearson, that is a 17% bump in performance over the best practices benchmark set by Star in 2019 for a warehouse of that size.
- The new facility saves £750,000 ($981,000/€890,000) in annual energy costs compared to a similar warehouse in the area with a stick-built ammonia system constructed by Star in 1996 with an SEC of 15kWh/m3.
Quotable: “I found something relevant in every one of the 17 SDGs outlined by the United Nations to low-charge ammonia systems,” Pearson said. “We have to take this message to the finance people and the business managers to get them engaged.”
“Over the life of a monitored and maintained plant, low-charge ammonia modules deliver ‘best practice’ performance in terms of efficiency.”
Andy Pearson, Group Managing Director at Star Refrigeration
