Technological recovery potential of waste heat in the industry of the Basque Country

Abstract

The growing costs and the availability of fuels make it necessary to reduce energy consumption in industrial processes. The use of residual heat recovery technologies is an effective way of achieving an energy saving and, consequently, better efficiency in their use. In order to appropriately value the recovery potential of residual heat, it is necessary to know the detailed flow characteristics. It is also necessary to examine in depth the different heat recovery technologies, such as heat exchangers, Rankine and Brayton cycles, heat pumps, absorption cooling, expanders, burners and cogeneration systems, in order to be able to integrate the set (residual heat-recovery technology-useful flow). Using the available data of the Basque Country database and other databases of thermodynamical properties, the energy and exergy of waste heat for 10 industrial sectors of the Basque Country has been determined. They have been classified according to their type (gases, liquid effluents and sensible heat in solids), and also according to their thermal level (from under 353 K up to 1473 K). A methodology has been developed in order to assess the application potential of these eight heat recovery technologies. For this, software has been developed which takes into account the limitations of each technology, and makes a preliminary selection, indicating those recovery technologies that are potentially suitable for any industry. The results of this selection made for the industry of the Basque Country show that of the eight studied, heat exchangers and heat pumps are the technologies with the greatest potential for application.