MISSING THE "SPARK GAP ": FEASIBILITY STUDY FOR A TRIGENERATION SYSTEM IN A FISH FREEZING INDUSTRY IN PORTUGAL

The Project "Inovenergy - energy efficiency in the Agrofood industrial sector" consists of the characterization, auditing and simulation studies with the main goal of providing specific energy efficiency measures that might help small-to-medium enterprises (SME's) cut their energy costs. As part of the study for Best Available Practices and Technologies (BAPT), this short paper describes the feasibility study for a trigeneration system capable of producing cold at about 33o C − in a fish freezing plant, aiming to replace the base-load vapour compression chiller that is responsible for about 65% of the plant's annual energy requirements. A brief introduction to thermally activated technologies is presented focussing on classic vapour compression and the ammonia absorption cycle which is currently the only marketed technology capable of reaching freezing temperatures. Considerations are made regarding the required electricity to heat cost of the two cycles and it is found that the required "spark gap" must be under 2.5. For the study-case of a state-of-the-art fish freezing industry, it is concluded that this technology is not able to compete with the traditional ammonia compression system.