Search Results (9)

This paper reviews recent advancements in integrated thermoelectric power generation and water desalination technologies, driven by the increasing global demand for electricity and freshwater. The growing population and reliance on fossil fuels for electricity generation pose challenges related to environmental pollution and resource depletion, necessitating the exploration of alternative energy sources and desalination techniques. While thermoelectric generators are capable of converting low-temperature thermal energy into electricity and desalination processes that can utilize low-temperature thermal energy, their effective integration remains largely unexplored. Currently available hybrid power and water systems, such as those combining conventional heat engine cycles (e.g., the Rankine and Kalina cycles) with reverse osmosis, multi-effect distillation, and humidification–dehumidification, are limited in effectively utilizing low-grade thermal energy for simultaneous power generation and desalination, while solid-state heat-to-work conversion technology, such as thermoelectric generators, have low heat-to-work conversion efficiency. This paper identifies a key research gap in the limited effective integration of thermoelectric generators and desalination, despite their complementary characteristics. The study highlights the potential of hybrid systems, which leverage low-grade thermal energy for simultaneous power generation and desalination. The review also explores emerging material innovations in high figure of merit thermoelectric materials and advanced MD membranes, which could significantly enhance system performance. Furthermore, hybrid power–desalination systems incorporating thermoelectric generators with concentrated photovoltaic cells, solar thermal collectors, geothermal energy, and organic Rankine cycles (ORCs) are examined to highlight their potential for sustainable energy and water production. The findings underscore the importance of optimizing material properties, system configurations, and operating conditions to maximize efficiency and output while reducing economic and environmental costs. Full article

Different approaches have been suggested for the waste heat recovery of high-temperature exhausted gas of a solid oxide fuel cell (SOFC). In such systems, mostly gas turbine (GT) and organic Rankine cycle (ORC) are added as bottoming systems to the SOFC (Configuration 1). However, the SOFC-GT-ORC has a considerable amount of waste energy which can be recovered. In the present research, the waste energy of ORC in the heat rejection stage and the residual exhausted gas of the system were recovered by a thermoelectric generator (TEG) and a hot water unit, respectively. Then, the extra produced power in the TEG was directed to a proton exchange membrane electrolyzer and a reverse osmosis desalination unit (RODU) for hydrogen and potable water outputs. The performance of SOFC-GT, Configuration 1, and Configuration 2 was compared through a 4E (energy, exergy, exergy-economic, and environmental) analysis. In the best performance point, the exergy efficiency and unit cost of product (UCOP) of SOFC-GT were obtained as 69.41% and USD 26.53/GJ. The exergy efficiency increased by 2.56% and 2.86%, and the UCOP rose by 0.45% and 12.25% in Configurations 1 and 2. So, the overall performance of Configuration 1 was acceptable and Configuration 2 led to the highest exergy efficiency, while its economic performance was not competitive because of the high investment cost of RODU. Full article

This research work synthetizes the energy, economic, and environmental aspects of a novel configurational analysis of four polygeneration schemes designed to fulfill the demands of a multi-family building that includes 12 dwellings. The design aims to meet the requirements (water, electricity, heat and cold air) from Renewable Energy Sources (RESs), in particular by selecting photovoltaic and photovoltaic-thermal panels, thermoelectric generators, and biomass as auxiliaries. Electricity is available from the grid, and no electrical storage is planned. Water and cooling may be produced by alternative technologies that configure the polygeneration alternatives. The case study is in Valencia, a coastal Mediterranean city in Spain. The Design Builder Clima estimated demand calculations, and the system performance was modeled in TRNSYS. Desalination was linked by using EES models. Results show that the suggested schemes offer substantial energy and CO₂ savings. The innovative life-cycle analysis applied further enhances the cumulative CO₂ savings across the four configurations if the impact of the installations is compared with the conventional external supply. The electric option (combining heat pump and reverse osmosis for cooling and desalination) emerged as the most appealing solution due to its reliability, lower investment cost, and environmental impact. Full article

When it comes to seawater desalination in the small- to medium-electricity ranges, the organic Rankine cycle (ORC) powered by solar energy stands out as the most energy-efficient technology currently available. Various solar techniques have been developed to capture and absorb solar energy. Among them, the parabolic trough collector (PTC) has gained recognition as a low-cost solar thermal collector with a long operating life. This study investigates the thermodynamic performance and economic parameters of a PTC-powered ORC using Dowtherm A and toluene as working fluids for the solar cycle and ORC cycle, respectively. Thermo-economic multi-objective optimization and decision-making techniques are applied to assess the system’s performance. Four key parameters are analyzed for their impact on exergy efficiency and total hourly cost. Using TOPSIS decision-making, the best solution from the Pareto frontier is identified, featuring an ORC exergy efficiency of 30.39% and a total hourly cost of 39.38 US$/h. The system parameters include a mass flow rate of fresh water at 137.7 m³/h, a total output net power of 577.9 kJ/kg, and a district heating supply of 1074 kJ/kg. The cost analysis reveals that the solar collector represents approximately 68% of the total hourly cost at 26.77 US$/h, followed by the turbine, thermoelectric generator, and reverse osmosis (RO) unit. Full article

In 2019, Schilling et al. claimed that they achieved the supercooling of a body without external intervention in their thermoelectric experiments, thus arguing that the second law of thermodynamics was bent. Kostic suggested that their claim lacked full comprehension of the second law of thermodynamics. A review of history shows that what Clausius referred to as the second law of thermodynamics is the theorem of the equivalence of transformations (unfairly ignored historically) in a reversible heat–work cycle, rather than “heat can never pass from a cold to a hot body without some other change” that was only viewed by Clausius as a natural phenomenon. Here, we propose the theorem of the equivalence of transformations for reversible thermoelectric cycles. The analysis shows that the supercooling phenomenon Schilling et al. observed is achieved by a reversible combined power–refrigeration cycle. According to the theorem of equivalence of transformations in reversible thermoelectric cycles, the reduction in body temperature to below the ambient temperature requires the body itself to have a higher initial temperature than ambient as compensation. Not only does the supercooling phenomenon not bend the second law, but it provides strong evidence of the second law. Full article

In line with the decarbonization of the domestic sector to meet the 2050 climate neutrality targets, this paper describes the energy, economic, and environmental analysis of a set of different novel configurations of polygeneration installations to provide electricity, air conditioning, domestic hot water, and desalinated water for a building of 80 dwellings. All arrangements were designed to cover 100% of the five demands required in the building with renewable energy only, from photovoltaic (PV) and photovoltaic-thermal (PVT) panels and biomass backup boilers (BB). Electricity can be sold to or purchased from the grid without electrical storage with batteries. Additional electricity generation with thermoelectric generators (TEG) coupled to the PVTs, and the BB was explicitly analyzed. The choice of electrically or thermally activated technologies (heat pump, HP/single-effect absorption chiller, SEAC for cooling and multi-effect distillation, MED/reverse osmosis, RO for desalination) created four configurations from the basic structure based on solar and biomass sources. Thus, the paper has studied four designs in detail and applied them to three case studies corresponding to different locations in Spain. They were modeled with TRNSYS and included specific models for desalination technologies. Both structures provide important energy and CO₂ savings concerning the conventional supply of the building demands. The novel life-cycle analysis approach further increases the lifetime CO₂ savings for all configurations as well. The electric option (the combination of HP and RO for cooling and desalting) was, by far, the most attractive solution in terms of liability and lower investment required in the three case studies. Full article

With regard to safety, efficiency and lifetime of battery systems, the thermal behavior of battery cells is of great interest. The use of models describing the thermoelectric behavior of battery cells improves the understanding of heat generation mechanisms and enables the development of optimized thermal management systems. In this work, a novel experimental approach is presented to determine both the irreversible heat due to ohmic losses and the reversible heat due to entropy changes directly via heat flow measurements. No additional information about thermal properties of the battery cell, such as heat capacity or thermal conductivity, are required. Thus, the exothermic and endothermic nature of reversible heat generated in a complete charge/discharge cycle can be investigated. Moreover, the results of the proposed method can potentially be used to provide an additional constraint during the identification process of the equivalent circuit model parameters. The described method is applied to a 23 $\mathrm{A}$$\mathrm{h}$ lithium titanate cell and the corresponding results are presented. Full article

Increasing the energy efficiency of residential and non-residential buildings is a crucial point towards the development of the sustainable cities of the future. To reach such a goal, the commonly employed intervention measures (for instance, on facades and glass) are not sufficient and efforts in reaching a fully renewable energy generation are mandatory. In this context, this paper discusses the applicability of a system with solar and biomass as the main energy sources in different climates for heating, cooling, domestic hot water and electricity generation in office buildings. The energy system includes solar thermal collectors with thermoelectric generators, a biomass boiler, a reversible heat pump/organic Rankine cycle and an adsorption chiller. The results showed that the system can operate with a share of renewables higher than 70% for all energy needs, with up to 80% of the overall energy demand supplied only by solar and biomass sources even in the northern locations. Full article

Life Cycle Assessments (LCAs) of thermoelectric plants frequently focus on impacts related to fuel and water consumption. The purpose of this research was to determine the environmental impact of the chemicals used for water conditioning in a Combined-Cycle Gas Turbine (CCGT) plant in Mexico. An LCA of the electricity generation process was carried out using the SimaPro software with the ReCiPe method, which includes 18 midpoint environmental impact categories. The process was broken down into stages, which were analyzed separately. To complete the study, an analysis of the fuel cycle and the materials used for maintenance works were included. Results showed that the most affected impact categories were water depletion (9.77 × 10⁻¹ m³/MWh), due mainly to the high volume of water consumption in the cooling systems and the reverse osmosis process; freshwater, marine, and terrestrial ecotoxicity (1.59 × 10⁻² kg 1,4 -DB eq/MWh), and human toxicity (1.1 × 10⁻¹ kg 1,4-DB eq/MWh)—due to the production and consumption of the chemicals used. One such chemical is hydrazine, which is a highly toxic compound to humans and other living organisms. It is worth mentioning that traces of some chemicals in wastewater discharges could be considered as emerging pollutants because of their potential health hazards, which have not been reported yet. Full article