• Energy Research

Numerous researchers have proposed phase change materials (PCMs) as an alternative for increasing the autonomy of solar water heaters (SWHs). Many studies have considered SWHs with PCMs in three main configurations: PCMs inside the solar thermal collector, inside a coupled heat storage unit, and within the water storage tank. A wide range of topics has been explored within studies assessing SWHs with PCMs in recent years, including but not limited to enhancement techniques for improving heat transfer, optimization strategies, economic factors, weather exposure on performance, and the application of design methodologies. This article reviews and discusses recent work on these trending topics, identifies research opportunities, and suggests promising research efforts toward more mature SWHs with PCM technology, focusing on long-term performance, scalability, economic, and technical feasibility.

Numerous researchers have proposed phase change materials (PCMs) as an alternative for increasing the autonomy of solar water heaters (SWHs). Many studies have considered SWHs with PCMs in three main configurations: PCMs inside the solar thermal collector, inside a coupled heat storage unit, and within the water storage tank. A wide range of topics has been explored within studies assessing SWHs with PCMs in recent years, including but not limited to enhancement techniques for improving heat transfer, optimization strategies, economic factors, weather exposure on performance, and the application of design methodologies. This article reviews and discusses recent work on these trending topics, identifies research opportunities, and suggests promising research efforts toward more mature SWHs with PCM technology, focusing on long-term performance, scalability, economic, and technical feasibility.

This research addressed a need for technical evaluation of the oceanic scenario of Panama for the use of Ocean Thermal Energy Conversion (OTEC). Its bathymetry and location can potentially lead to the exploitation of OTEC, diversifying the energy matrix and helping achieve sustainability. Nevertheless, site selection for OTEC can be a complex task since it involves various alternatives, with different quantitative and qualitative criteria, which may conflict in some cases. Optimization and multiple criteria (MCD) methods have been used lately to address these issues; however, their use is still limited. Here, Analytic Hierarchical Analysis (AHP) is proposed as a MCD method for site selection. Six sites of interest were considered as the alternatives for a plant installment. These sites were chosen, excluding the environmentally and aboriginal protected areas. The quantitative criteria considered were surface and deep-water temperatures, coastline distance, gross and net efficiency. Those variables related to the efficiency, such as the water temperatures, can be considered the most influential, leading to Punta Burica, located on Panama’s Pacific coast, as the best option (96.17%).

This research addressed a need for technical evaluation of the oceanic scenario of Panama for the use of Ocean Thermal Energy Conversion (OTEC). Its bathymetry and location can potentially lead to the exploitation of OTEC, diversifying the energy matrix and helping achieve sustainability. Nevertheless, site selection for OTEC can be a complex task since it involves various alternatives, with different quantitative and qualitative criteria, which may conflict in some cases. Optimization and multiple criteria (MCD) methods have been used lately to address these issues; however, their use is still limited. Here, Analytic Hierarchical Analysis (AHP) is proposed as a MCD method for site selection. Six sites of interest were considered as the alternatives for a plant installment. These sites were chosen, excluding the environmentally and aboriginal protected areas. The quantitative criteria considered were surface and deep-water temperatures, coastline distance, gross and net efficiency. Those variables related to the efficiency, such as the water temperatures, can be considered the most influential, leading to Punta Burica, located on Panama’s Pacific coast, as the best option (96.17%).

The utilization of phase change materials (PCMs) in solar water heating systems (SWHS) has undergone notable advancements, driven by a rising demand for systems delivering superior performance and efficiency. Extensive research suggests that enhancing heat transfer (HTE) in storage systems is crucial for achieving these improvements. This review employs a bibliometric analysis to track the evolution of HTE methods within this field. While current literature underscores the necessity for further exploration into hot water generation applications, several methodologies exhibit significant promise. Particularly, strategies such as fins, encapsulation, and porous media emerge as prominent HTE techniques, alongside nanofluids, which hold the potential for augmenting solar water heating systems. This review also identifies numerous unexplored techniques awaiting investigation, aiming to pave new paths in research and application within the field of hot water generation. It highlights methods that could be used independently or alongside predominantly used techniques.

The utilization of phase change materials (PCMs) in solar water heating systems (SWHS) has undergone notable advancements, driven by a rising demand for systems delivering superior performance and efficiency. Extensive research suggests that enhancing heat transfer (HTE) in storage systems is crucial for achieving these improvements. This review employs a bibliometric analysis to track the evolution of HTE methods within this field. While current literature underscores the necessity for further exploration into hot water generation applications, several methodologies exhibit significant promise. Particularly, strategies such as fins, encapsulation, and porous media emerge as prominent HTE techniques, alongside nanofluids, which hold the potential for augmenting solar water heating systems. This review also identifies numerous unexplored techniques awaiting investigation, aiming to pave new paths in research and application within the field of hot water generation. It highlights methods that could be used independently or alongside predominantly used techniques.

This document presents a qualitative analysis of surface temperatures of the oceanic territory of Panama. These temperatures represent an indication of the potential of the thermal resource in the oceanic territory of Panama and could generate benefits for the success and stability of the national economy facing the current and growing challenges of the society. The OTEC technology is promising for countries located in tropical regions, where sea temperature differentials are ideal for efficient operability. Currently, this technology has low efficiency levels. Therefore, to evaluate its possible implementation in Panama, a theoretical thermodynamic analysis has been carried out. An organic Rankine cycle (ORC) simulation for the net production of 100KW was performed. It considered the temperature differentials of the oceanography of Panama and used refrigerants R717 and R134a as working fluids. Considering the database of Physical Oceanography Distributed Active Archive Center (PODAAC) for the year 2018, the ocean territory of Panama in the Gulf of Chiriqui reflects seawater surface temperatures (SST) of approximately 27.5 °C to almost 29.5 °C. Besides these values they do not reflect representative anomalies in the critical points with respect to the seasons of the year. The importance of the study in this area is its proximity to the deep cold sea waters, considering the Panama bathymetry map, since its SST are not very variable through the year or through the territory?

This document presents a qualitative analysis of surface temperatures of the oceanic territory of Panama. These temperatures represent an indication of the potential of the thermal resource in the oceanic territory of Panama and could generate benefits for the success and stability of the national economy facing the current and growing challenges of the society. The OTEC technology is promising for countries located in tropical regions, where sea temperature differentials are ideal for efficient operability. Currently, this technology has low efficiency levels. Therefore, to evaluate its possible implementation in Panama, a theoretical thermodynamic analysis has been carried out. An organic Rankine cycle (ORC) simulation for the net production of 100KW was performed. It considered the temperature differentials of the oceanography of Panama and used refrigerants R717 and R134a as working fluids. Considering the database of Physical Oceanography Distributed Active Archive Center (PODAAC) for the year 2018, the ocean territory of Panama in the Gulf of Chiriqui reflects seawater surface temperatures (SST) of approximately 27.5 °C to almost 29.5 °C. Besides these values they do not reflect representative anomalies in the critical points with respect to the seasons of the year. The importance of the study in this area is its proximity to the deep cold sea waters, considering the Panama bathymetry map, since its SST are not very variable through the year or through the territory?

In recent years, phase change materials (PCMs) have been presented as a suitable alternative for thermal energy storage (TES) systems for solar water heater (SWH) applications. However, PCMs’ low thermal conductivity and the high dependence on external conditions are the main challenges during the design of TES systems with PCMs. Design actions to improve the performance of the TES systems are crucial to achieve the necessary stored/released thermal energy and guarantee the all-day operation of SWHs under specific system requirements. In this study, a TES with PCM in the configuration of a heat exchanger was redesigned, focused on achieving two main targets: an outlet water temperature over 43 °C during discharging time (15 h) and efficiency over 60% to supply the hot water demand of two families (400 L). A four-step redesign methodology was proposed and implemented through numerical simulations to address this aim. It was concluded that the type, encapsulation shape, and amount of PCM slightly impacted the system’s performance; however, selecting a suitable sensible heat storage material had the highest impact on meeting the system’s targets. The redesigned TES reached 15 operating hours with a minimum outlet water temperature of 45.30 °C and efficiency of 76.08%.