Emiliano Borri

Thermal energy storage (TES) systems play a very important part in addressing the energy crisis. Therefore, numerous researchers are striving to improve the efficiency of TES tanks. The TES technology has the potential to reach new heights when the biological behavior of nature is incorporated into the design of TES tanks. By mimicking the branched vein pattern observed in plants and animals, the heat transfer fluid (HTF) tube of a TES tank can enhance the heat transfer surface area, hence improving its thermal efficiency without the need to add other enhancements of heat transfer methods. Accordingly, in this study, a unique additive-manufacturing-based bio-inspired TES tank was designed, developed, and tested. A customized testing setup was used to assess the bio-inspired TES tank’s thermal performance. A comparison was made between the bio-inspired TES tank and a conventional shell-and-tube TES tank. The latent TES system’s thermal performance was significantly enhanced by the biomimetic approach for the design of a TES tank, even before the optimization of its design. The results showed that, compared to the shell-and-tube TES tank, the bio-inspired TES tank had a higher discharging rate and needed 52% less time to release the stored heat.

The tanning industry is one of the highly polluting sectors, and it is only in the last few years that studies on the energy improvement of tanneries started to proliferate in the literature. Even though the energy cost of a tannery is only a small fraction of the total cost, many tanners became aware of the importance of improving energy efficiency and reducing the environmental footprint to keep the business afloat and be more competitive in the market. This paper presents a study on increasing the sustainability of a tannery located in the region of Catalonia, Spain. Several measures to increase its energy efficiency and reduce its primary energy consumption were proposed and analysed including, among others, the implementation of solar thermal collectors and photovoltaic panels. A cost analysis of the most promising solutions was carried out and discussed. The results show that the tannery should invest between EUR 2 to 2.5 M to obtain the highest energy savings, with an estimated payback period between 5 and 7 years. However, acceptable energy savings can be obtained with a lower investment cost of between EUR 1 to 1.5 M, with a shorter payback period of between 2 and 4 years.