Decarbonization of heat through low-temperature waste heat recovery: proposal of a tool for the preliminary evaluation of technologies in the industrial sector

In an industrial energy scenario increasingly focused on decarbonization and energy cost containment, waste heat is a resource that is no longer negligible. Despite the great abundance of waste heat, its recognized potential, and numerous technologies available for its use, the rate of waste heat recovery (WHR) is still low, especially at low temperatures (<230 degrees C). Non-technological barriers, such as the lack of knowledge and support tools, strongly limit the diffusion of WHR technologies. The work presented in this paper aims to overcome non-technological gaps by developing a simple and operational tool that can support companies in the preliminary stages of evaluating a WHR application. The methodology followed involved the development of specific data-based models for WHR technology sizing by correlating waste heat input characteristics with dimensional and economic parameters of the technologies evaluated. We considered the most representative technologies in the WHR scenario: organic Rankine cycles for electric power generation, heat pumps for thermal power generation, absorption chillers for cooling generation, and plate heat exchangers for low-temperature heat exchange applications. One of the significant strengths of the tool is that it was developed using real and hard-to-find technologies performance and cost data mainly collected through continuous interactions with WHR technology providers. Moreover, the interaction with the technology providers allowed contextualization and validation of the tool in the field. In addition, the tool was applied to three large companies operating in the Italian industrial sector to test its effectiveness. The tool applications made it possible to propose cost-effective solutions that the companies had not considered before, despite the high level of attention with which they were already approaching energy efficiency improvements. The result obtained demonstrates the applicability and innovativeness of the tool.