- ItemOpen AccessOptimal control of a solar-driven seasonal sorption storage system through deep reinforcement learning(Elsevier, 2023) Crespo, Alicia; Gibert Llauradó, Daniel; Gracia Cuesta, Alvaro de; Fernàndez Camon, CésarDeep reinforcement learning (DRL) has demonstrated its effectiveness in the control of energy systems, although it has not yet been applied to sorption thermal energy storage (TES) systems. The operation of sorption TES systems is notably more complicated compared to other TES variants. The discharge of a sorption TES occurs at a particular desorption and evaporation temperature. Achieving a continuous and efficient discharge of a sorption TES is a challenging control task if heat required at the evaporator is obtained from the sun or the environment. Its operation is especially complicated during winter, because of the limited availability of solar irradiation and low ambient temperatures. Thus, this study analyzes for first time in the literature the competitiveness of deep reinforcement learning to control a solar-driven seasonal sorption TES system and compares it against traditional optimized rule-based control strategy. The system, located in Central Europe, supplied domestic hot water and space heating to a single-family house. Two DRL models were developed and trained to operate the system under two different sets of data: 120 winter consecutive days and 60 winter non-consecutive days. The results showed that the DRL control strategy reduced the system operational costs by 28% in a 60 winter days scenario. For a 120 winter days scenario, the operational cost savings decreased to 13% because the smart control performed worst once the sorption TES was fully discharged. These results were derived from a four-year validation data set, bolstering their robustness. The study demonstrates the successful application of DRL in controlling a solar-driven seasonal sorption TES system, yielding considerable economic savings compared to an RBC strategy. Subsequent work will consist of implementing the smart control strategy at prototype level to assess its performance.
- ItemOpen AccessExperimental evaluation of different macro-encapsulation designs for PCM storages for cooling applications(Elsevier, 2023) Rehman, Omais Abdur; Palomba, Valeria; Vérez, David; Borri, Emiliano; Frazzica, Andrea; Brancato, Vincenza; Botargues, Teresa; Ure, Zafer; Cabeza, Luisa F.Extensive research has been conducted on utilizing phase change materials for cooling applications, making it one of the most explored techniques in this domain. This research paper presents a comprehensive performance evaluation of a latent heat thermal energy storage unit featuring three distinct macro-encapsulation designs for phase change materials. The study aims to assess the thermal performance, efficiency, and practical applicability of these macro-encapsulation designs in a storage system. The PCM macro-encapsulation designs under investigation include cylindrical and rectangular shapes, each possessing different geometry. Two different configurations have been considered in this study. One configuration contains same PCM mass in order to have similar storage capacity while the other configuration has maximum PCM mass that can be inserted inside the tank. The used phase change material is a salt hydrate with melting temperature of 17 °C. The experimental setup consists of a controlled test rig that simulates real-world conditions and enables the comparative analysis of the three designs. Key performance parameters such as the charging and discharging time, temperature profiles, heat transfer rate, and energy storage/retrieval rates are measured and analysed. The results obtained from the experimental study provide valuable insights into the thermal behaviour, energy storage capacity, and overall effectiveness of the three macro-encapsulation designs. It is important to mention that use of an encapsulation design is highly dependent on application. The findings of this study contribute to the understanding of the impact of different macro-encapsulation designs on performance of thermal energy storage units. The results serve as a basis for optimizing macro-encapsulation designs, improving the efficiency and reliability of latent heat storage systems, and promoting their wider adoption in various energy management applications.
- ItemOpen AccessDevelopment of a new collagen gel product for leather finishing(MDPI, 2023-11-08) Zhang, Xinping; Sorolla, Sílvia; Casas, Concepció; Bacardit i Dalmases, AnnaLeather finishing is a critical process in the leather industry, as it significantly influences the final appearance, durability, and quality of leather products. Traditional leather finishing techniques often involve the use of synthetic chemicals, which may lead to environmental concerns and potential health hazards. In this study, we investigate the feasibility and effectiveness of a new collagen-based product for leather finishing. Collagen, a natural protein found abundantly in animals, has shown promise as an environmentally friendly and sustainable alternative for leather finishing. The new collagen gel product obtained from bovine hide waste by using an alkaline extraction method with lime was functionalized through an enzymatic treatment that allows to achieve a finishing product suitable for coating formulations, and at the same time, a biodegradable finishing. The collagen gel product was optimized by varying parameters, such as temperature, pH, and enzyme quantity. The optimized collagen gel product exhibits a wide particle size range and retains the triple-helical structure of collagen. The leather samples treated with the collagen gel product show enhanced properties compared to those with conventional finishes. The results show that the collagen gel product enhances water vapor permeability, color stability, and touch in the finishes. However, a low resistance to wet rubbing is obtained; therefore, it is necessary to study how to improve this parameter.
- ItemOpen AccessGeopolymer as an Innovative Material for Green Roofs - A State-of-the-Art Review(EDP Sciences, 2023-10-11) Saba, Marianne; Pérez, Gabriel; Coma Arpón, Julià; Polls, MireiaTo help minimize water temperature variations and stop excessive evaporation, effective insulation materials are frequently needed during the design and construction of ponds. In contrast to conventional materials, geopolymer mortars have great insulating qualities, making them an attractive option. An alkaline activator and aluminosilicate materials react chemically to create geopolymers, which have a three-dimensional network structure and high thermal insulation properties. Geopolymer mortars are used in ponds to promote energy efficiency and sustainability while also improving temperature stability and reducing water loss from evaporation. An alkaline activator and aluminosilicate materials react chemically to create geopolymers, which have a three-dimensional network structure and high thermal insulation properties. The use of geopolymer mortars as an insulating material in pond construction is discussed in this abstract, along with its composition, characteristics, and advantages over more conventional choices. Geopolymer mortars are used in ponds to promote energy efficiency and sustainability while also improving temperature stability and reducing water loss from evaporation. The utilization of geopolymers as cutting-edge insulating materials for structures with green roofs is thoroughly examined in this publication. As sustainable construction techniques become more prevalent, selecting the right insulating materials is essential for enhancing energy efficiency and overall building performance. Geopolymers, which can be produced from industrial waste or natural resources, offer appealing properties for green roofs, such as the ability to lessen the impact of urban heat islands, superior thermal insulation, and fire resistance. This study assesses the advantages, challenges, and potential impact of geopolymer-based insulating materials on green construction practices.
- ItemOpen AccessRemote Control Device to Drive the Arm Gestures of an Assistant Humanoid Robot(MDPI, 2023-10-09) Rubies, Elena; Bitriá, Ricard; Clotet Bellmunt, Eduard; Palacín Roca, JordiThis work presents a remote control device designed to drive the arm gestures of an assistant humanoid mobile robot. The remote control is a master device with two passive arms configured to replicate the four degrees of freedom of each arm of the original assistant humanoid robot and send this information to the robot. This configuration allows the mobile robot to directly replicate the position of the arms on the remote controller. The objective of this proposal is to provide the robot with enhanced non-verbal and pointing communication capabilities during human interaction or assistance. The master device registers the angular position of each joint of its passive arms and transmits this information to the mobile robot, which replicates it. The experimental evaluation of the system has shown that the humanoid robot is able to successfully replicate any gesture on the remote controller. The positions of the arms have been sampled at a frame rate of 20 ms, and the average telecontrol delay obtained in the gesture experiments has been 549 ms, without appreciable jumps or irregularities in the gestures. The conclusion is that the direct manipulation of the passive arms of the remote control device provides the APR-02 humanoid robot with enhanced non-verbal and pointing communication capabilities during human interaction or assistance.