For the first time ever an absorption refrigeration system is to operate onboard a large fishing vessel.
Until now refrigeration systems onboard fishing vessels have utilised traditional compressor technology. Grenco, however, began a study 10 years ago into the use of the absorption principle for marine applications. This work has resulted in the first order for the well-known innovator Stig Remøy and his Norwegian company Olympic Prawn. The new ship, yet to be named, will be built at Havyard Solstrand in Norway, and the ST-118 design is worked out by Skipsteknisk in Ålesund. The sum of the contract value will be in the area of €2 million which includes the absorption system, compressor for redundancy, control system and installation work.
Fuel saving
While traditional refrigeration systems are powered by electric energy, the absorption system is powered by surplus heat from a diesel engine. Knowing that electrical energy onboard a ship is generated through burning of increasingly more expensive fuel, use of surplus heat provides substantial savings. In daily operation this new vessel will save approximately 80% electrical energy, compared to traditional use of the compressor the refrigeration. On an annual basis this adds up to a saving of more than two hundred thousand litres of fuel.
Emissions reduction
Compared to the traditional refrigeration system, use of the absorption system will reduce the annual NOx emission with 4 tons and CO2 emission of more than 500t.
Redundancy
For redundancy reasons the vessel will also be equipped with some compressor capacity. This will be used when sufficient surplus heat is not available for the required refrigeration capacity. This may occur for short periods of peak load or when the ship is laying in harbour.
Development
Absorption refrigeration has been used in onshore applications for many years. These plants are however not applicable for use onboard ships. Grenco and its partners have made substantial efforts in developing the absorption system for marine applications.
The Grenco introduction of the absorption refrigeration system is in line with other fuel efficient and environmental friendly developments. Grenco was the first company ever to install an Ammonia/CO2 refrigeration system on a fishing vessel, using only screw compressors.
