Environmental profile of latent energy storage materials applied to industrial systems

Abstract

Industry sector is an intensive-energy consumer and approximately 20-50% of industrial energy consumption is lost as waste heat. Therefore, there is a great potential for reducing energy consumption and, subsequently, decreasing the fossil fuels used if this lost energy can be recovered. Thermal Energy Storage (TES) based on Latent Heat Storage systems (LHS) using Phase Change Materials (PCMs) has become one of the most feasible solutions in achieving energy savings through waste heat recovery, especially when there is a mismatch between the supply and consumption of energy processes. In this paper, a shell and tube heat exchanger incorporating PCMs has been considered to store the excess energy available in an industrial process. Several attempts have been made to design the most appropriate system considering many cost-benefit and technical criteria to maximise the heat recovery. However, the environmental criterion also is an important factor when determining whether this technology is not only energy and cost-efficient but also environmentally friendly, considering the whole life of the system from its manufacture to its disposal. To this end, this research includes a Life Cycle Assessment (LCA) to determine whether the energy savings of conventional fuels during the operation stage are large enough to balance the environmental impact originated in an industrial TES system including the manufacture, use and disposal phases. Inputs and outputs of each management stage have been defined, and the inventory emissions calculated by SIMAPRO v7.3.2. A midpoint and endpoint approaches have been carried out using two methods, CML 2001 and Eco-indicator 99, respectively. As a preliminary result, a promising reduction in the overall impacts was obtained by the use of this technology. From the environmental impact results, a matrix of possible technical solutions is displayed, to improve the environmental performance.

Keywords: Environmental impacts; Life Cycle Assessment (LCA); Net Zero Environmental Impact Times (NZEIT); Phase change material (PCM); Thermal energy storage (TES).