It is now widely confirmed by scientific evidence that greenhouse gas emissions must be reduced to counteract the effects of global warming. The production of heat for industrial purposes is responsible for 36.8% of world energy-related emissions due to the widespread use of fossil fuels. Heat pumps are a key technology in the transition towards more sustainable industrial processes. In this paper, a systematic review of the literature produced in the last 5 years in international journals regarding the integration of heat pumps in industrial processes is presented. Firstly, papers presenting innovative configurations for high temperature heat pumps (HTHP), i.e., heat pumps delivering temperatures in the range between 100 °C and 200 °C, suitable for many industrial processes but still under development, are reviewed. Then, papers reporting innovative solutions for the integration of heat pumps in specific industrial processes and sectors (e.g., distillation, drying, desalination, etc.) are analyzed. Finally, the literature about alternative low-GWP refrigerants for industrial heat pumps, both pure compounds and mixtures, is described. It is concluded that many progresses have been realized in the last 5 years (2020–2024) regarding the identification of innovative heat pumps for industrial applications, but further research is certainly required.

Paraffin PCMs (Phase Change Materials) are widely used for thermal energy storage due to their homogeneity and stability. However, one of their main drawbacks lies in their poor thermal conductivity, usually around 0.2 W·m⁻¹·K⁻¹. In the context of the Horizon Europe project “ECHO” (Efficient Compact Modular Thermal Energy Storage System), the integration of metal foams within paraffin PCM was investigated in order to increase the overall thermal conductivity, thus speeding up the melting and solidification phases. Tests were carried out in a thermostatic bath using at first pure aluminum foam. Then, considering the consistent price these materials usually have, other commercial and much cheaper foams were also tested, namely a stainless-steel foam and a brass one. As expected, pure aluminum had the best performance among the three foams. However, the behavior of the brass foam was quite close to that of pure aluminum, which means that interesting improvements can be achieved even with low-cost materials. As regards the stainless-steel foam, barely any improvement is observed.

Regulations like the F-gas Regulation (EU) 2024/573 and the Kigali Amendment to the Montreal Protocol, along with efforts to mitigate climate change, drive research into alternatives to fluorinated greenhouse gases for high-temperature heat pumps and power generation. Ideal refrigerants should have low GWP, high efficiency, non-flammability, non-toxicity, material compatibility and cost effectiveness. HCFOs have emerged as promising candidates, both as pure fluids and in mixtures with HCs. These blends show efficiency and potential non-flammability for high-temperature applications, but experimental data on their thermophysical properties remain scarce. This study presents the first experimental measurements on the {n-pentane (R601) + trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E))} binary system. In particular, the compressed liquid density of three mixture compositions have been measured employing a vibrating tube densimeter within the temperature range from 283.15 K to 423.15 K and at pressures ranging from 1 MPa to 12 MPa. A novel technique was applied to ensure a combined uncertainty (k=2) not greater than 0.0003 mol $$\cdot$$ · mol $$^{-1}$$ - 1 in the mixture composition, leading to final combined uncertainty (k=2) on the liquid density of no more than 0.2%. Finally, a new mixture model based on the Helmholtz-energy-explicit Equation of State has been developed from such experimental data. This model accurately represents the behaviour of the binary mixture, enhancing the available understanding of its thermodynamic properties.