Space Cooling  »  CHCP systems

Summary

Short description of the solutionGävle Energy AB and its subsidiaries are considering replacing a 5 MW oil-fired boiler at a confectionary factory and a 2 MW oil-fired boiler at a nearby paper mill with a 7.6 MW biomass-fired CHP plant that would provide electricity and heat for the process needs of the two enterprises and for export during periods of surplus, particularly for electricity. They are considering whether or not to turn this into a trigeneration project by increasing the size of the proposed biomass-fired CHP unit, adding absorption chillers and piping for a district cooling network to reach the city centre.

Basic information
The confectionary factory and downtown area had assessed cooling loads of 11 MW and would require a main cooling pipe to be built 1.3 km from the proposed CHP plant site. Single-effect and double-effect absorption chillers were evaluated in order to identify the most economic solution. The system configurations evaluated comprised 3 double-effect Carrier-Sanyo TSA-16NK- 81 absorption chillers, each rated at 6.2 MW with 5 Carrier-Sanyo TSA-16TJ- 53 absorption chillers rated at 2.7 MW each. The double-effect chillers were identified as the most economic solution, because although they are 23% more expensive, they reduce operating costs over 10 years by 44%.

Energy and cost performance
The energy and economic performance of the modelled trigeneration system is summarised in the following table. Initial investment costs are significantly higher due to the costs of the absorption chillers and district cooling piping. However, the project has a payback period of 10 years for the equipment.

Summary of Energy Performance and Costs