A meat processing factory in Geldern, Germany, has reduced its electricity use by 492MWh with the installation of an ammonia/NH3 (R717) absorption chiller, according to Massimiliano Santini, International Business Development Specialist at AKM Industrieanlagen, the chiller’s manufacturer.
Energy savings have been achieved by using waste heat recovered from the facility’s two gas engine cogeneration units to trigger the cooling process without using a compressor, he explained.
In reducing the energy consumption, the ammonia absorption chiller has cut the end user’s electricity bills by more than €100,000 (US$107,000) and greenhouse gas emissions by 180 metric tons of CO2e each year, he added.
Santini presented a case study of the installation during a refrigeration session at the ATMOsphere (ATMO) Europe Summit on natural refrigerants. The conference took place November 15–16 in Brussels and was organized by ATMOsphere, publisher of Ammonia21.com.
Low energy consumption
The ammonia absorption chiller, which has been in operation since 2019, receives 880kW (250TR) of recovered heat in the form of 95°C (203°F) hot water. From here, it provides 380kW (108TR) of cooling at -7°C (19.4°F) for the processing facility’s cold rooms and air-conditioning systems.
Because of the use of waste heat, the only electricity needed to run the chiller is a 18kW pump, which results in very low energy consumption, said Santini.
He explained that the energy savings achieved at the meat processing facility would have been much higher if all the site’s cooling demands were served by the absorption chiller. However, the operator continues to use several compressor units for other cooling applications.
Thanks to lower electricity bills, the absorption chiller has a payback period of around 3.5 years, but this is likely to be reduced as rising energy costs result in additional cost savings, he added.
Cooling with waste heat
In absorption cooling, waste or renewable heat sources are used to activate the refrigeration cycle, reducing energy demand and CO2 emissions due the absence of compressors, explained Santini.
Heat sources for an absorption chiller can include cogeneration, like recovered heat from engines or turbines; industrial processes, like waste steam or heat from furnaces; district heating; or renewable heat from solar or geothermal sources, for example.
While AKM Industrieanlagen focuses on ammonia-based absorption chillers, having installed the technology at approximately 60 sites, Santini explained that lithium bromide chillers could be a more efficient option for certain applications.
“Lithium bromide chillers have higher efficiency, around 0.75–0.8, but they cannot reach temperatures below 0°C (32°F),” he said. “When required temperatures are above 0°C, you’d use lithium bromide instead of ammonia.”
