Application of high-temperature heat pumps in the ceramic tiles manufacturing sector for waste heat harnessing

• HTHPs to recover and upgrade waste heat in ceramic tile production processes. • Cyclopentane offers optimal performance with COPs of 2.0–2.4 for heat recovery. • Up to 75 % of waste heat is recovered, reducing primary energy use by 18.6 %. • CO 2 emissions cut by up to 37.5 kg/h per ton of ceramic tiles produced. The ceramic tile industry is highly energy-intensive, presenting significant opportunities for waste heat recovery. This study investigates the use of high-temperature heat pump (HTHP) technology to enhance energy efficiency by upgrading waste heat into process heat, reducing natural gas consumption and CO 2 emissions. A comprehensive methodology combining thermodynamic modelling, working fluid selection, and system design is applied. An innovative waste heat recovery system leveraging HTHP technology to preheat air for the drying and firing stages, recovering waste heat in two configurations, is proposed. Cyclopentane, identified as the optimal working fluid, enables the HTHP to achieve a coefficient of performance (COP) of 2.0 while preheating air to 173 °C, recovering waste heat from drying, firing, and cooling stages. In an alternative configuration recovering heat only from drying and cooling, the HTHP reaches a COP of 2.4 with air preheated at 119 °C. The designed system recovers up to 75 % of total waste heat in the first configuration, and 48 % in the second. Fuel savings are estimated at 13.6 kg/h per tonne of tiles (18.6 % of the energy demand) and 8.89 kg/h per tonne of tiles (14.7 %) for the two configurations, respectively, with corresponding CO 2 emission reduction of 37.5 kg/h and 24.4 kg/h per tonne of tiles. Economic analysis confirms HTHP implementation can achieve a return on investment within three years, aligning with current industrial HTHP costs. Results highlight HTHP technology as promising for energy efficiency and decarbonization in ceramic tile manufacturing, supporting sustainable solutions in energy-intensive industries.