Prospects for the Improvement of Energy Performance in Agroindustry Using Phase Change Materials

This work was partially supported by the Fundação para a Ciência e Tecnologia, UIDB/00066/2020 (CTS – Center of Technology and Systems).The use of Phase Change Materials (PCMs), able to store latent heat, represents an opportunity to improve energy efficiency in the agroindustry by means of thermal energy storage. PCMs provide higher energy density then sensible heat storage mediums, thus paving the way to multiple applications, like supporting the integration of renewables or allowing for new storage architectures, decentralized and directly installed in the chain production equipment, creating e.g. the opportunity to recover and value low-grade operational heat sub-products. Such new and decentralized architecture, not currently applied in agroindustry, is proposed in this work. A chocolate tempering machine using an organic PCM is conceived and analyzed using ANSYS Fluent software for computational fluid dynamics simulations, comparing the main aspects in the storage capacity and discharging process with a conventional sensitive heat storage solution that uses water. PCMs allows improving the stored energy, keeping the chocolate in the working temperature after being tempered for more than four times longer than using only hot water. If the PCMs are charged by renewables, the self-consumption ratio can be improved while providing energy flexibility to the user.authorsversionpublishe

Review of exercise-induced physiological control models to explain the development of fatigue to improve sports performance and future trend

News. — Sports performance is the pursuit of excellence where a sportsman measures his or her performance quantitatively or qualitatively to move towards his or her desired goal. Several physical aspects can influence sport performance. One of these aspects is the neuromuscular factor Tsolakis and Tsolakis (2008) that arises from the relationship between the nervous system, and the musculoskeletal system. Moreover, in many sports (for example, running and cycling), the establishment of an effective rhythm will keep an athlete organised, and physically efficient for an excellent performance. Subsequently, this rhythm will impose a cadence on musculoskeletal activity, mental control as well as psychological factors. These psychological factors can be self-motivation, level of alertness and mental acuity that are the product of a number of integrated factors like physical fatigue or other unrelated sport stresses such as environmental conditions that are not within the athlete's personal control. The athlete is required to have the ability to adapt in these unexpected environmental factors. Another aspect is coaching and external support/assistance for the athlete (in terms of nutrition, sport technique, tactics and training) to the aspiring competitor for success to occur. Amidst all these factors which influence sports performance, there is one crucial factor which cannot be overlooked and it is the exercise-induced fatigue which causes a reduction in physical and mental performance. Conclusion. — Therefore, in this review, we describe and discuss the various physiological theoretical models of exercise-induced fatigue, and the way forward to assess these theories using mathematical models and analysis of biosignals