Day-ahead economic dispatch of coupled desalinated water and power grids with participation of compressed air energy storages

Nowadays, water and electricity are closely interdependent essential sources in human life that affect socio-economic growth and prosperity. In other words, electricity is a fundamental source to supply a seawater desalination process, while fresh water is used for cooling this power plant. Therefore, mutual vulnerability of water treatment and power generation systems is growing because of increased potable water and electricity demands especially during extremely-hot summer days. Hence, this paper presents a novel framework for optimal short-term scheduling of water-power nexus aiming to minimize total seawater desalination and electricity procurement cost while satisfying all operational constraints of conventional thermal power plants, co-producers and desalination units. Moreover, advanced adiabatic compressed air energy storage (CAES) with no need to fossil fuels can participate in energy procurement process by optimal charging during off-peak periods and discharging at peak load hours. A mixed integer non-linear programming (MINLP) problem is solved under general algebraic mathematical modeling system to minimize total water treatment cost of water only units and co-producers, total fuel cost of thermal power plants and co-generators. Ramp up and down rates, water and power generation capacities and balance criteria have been considered as optimization constraints. It is found that without co-optimization of desalination and power production plants, load-generation mismatch occurs in both water and energy networks. By incorporating CAES in water-power grids, total fuel cost of thermal units and co-producers reduce from $1222.3 and$24933.2 to $1174.8 and$24636.8, respectively. In other words, application of CAES results in $343.9 cost saving in benchmark water-power hybrid grid

Increasing the Operation Efficiency of Air Conditioning System for Integrated Power Plant on the Base of Its Monitoring

Increasing the Operation Efficiency of Air Conditioning System for Integrated Power Plant on the Base of Its Monitoring / E. Trushliakov, A. Radchenko, S. Forduy, A. Zubarev, A. Hrych // Advances in intelligent systems and computing. – 2020. – Т. 1113 AISC . – P. 351–360Abstract. The efficiency of reciprocating gas engines of integrated energy systems (IES) for combined electricity, heat and refrigeration generation is strictly influenced by their cyclic air temperatures. To evaluate the effect of gas engine cyclic air deep cooling, compared with conventional its cooling, the data on dependence of fuel consumption and power output of gas engine JMS 420 GS-N.L on its inlet air temperature at varying ambient air temperatures at the entrance of the radiator for scavenge air cooling were received. The results of treatment of gas engine efficiency monitoring proved non-effective operation of conventional chilling all the ambient air, coming into the engine room, because of increased air temperature at the inlet of turbocharger (TC), caused by heat influx from surroundings in the engine room. A new method of gas engine inlet air two-stage cooling at increased ambient air temperatures and advanced cyclic air cooling system with absorption lithium-bromide chiller and refrigerant ejector chiller was proposed. With this chilled water from absorption lithiumbromide chiller is used as a coolant in the first high-temperature stage of engine inlet air cooler and boiling refrigerant of ejector chiller in the second lowtemperature stage

Thermodynamic and thermoeconomic analysis and optimization of a novel dual-loop power/refrigeration cycle

Exploration of the ejector refrigeration cycle (ERC) in the combination with well-known power cycles to produce cooling output as well as power output is highlighted in recent decades. Since organic Rankine cycle (ORC) is practically usable than other power cycles, a combination of the ORC/ERC in a novel form is presented. Power and refrigeration sub-cycles are combined by a common condenser in separate loops to form dual-loop power/refrigeration cycle. The exhaust of the turbine is mixed with the outlet flow of the ejector, and then the mixed flow is fed into the condenser. Thermodynamic and thermoeconomic analysis of the proposed cycle are carried out with different working fluids (i.e., isobutane, isobutene, butene, cis-2-butene, n-butane, R236fa, and R245fa) showing that among all working fluids isobutane is the best one from thermodynamic, thermoeconomic, and environmental viewpoints. The results of exergy analysis showed that among all components generator accounts for the biggest exergy destruction rate followed by the heater for all selected working fluids. In addition, multi-objective optimization of the proposed cycle is carried out by considering of generator pressure, heater pressure, evaporator temperature, and condenser temperature as decision variables, using the genetic algorithm (GA). The results of the optimization demonstrated that the proposed cycle performs in an optimum state based on the selected objective functions when generator pressure, heater pressure, evaporator temperature, and condenser temperature work at 3 MPa, 1 MPa, 280 K, and 299.8 K, respectively, as isobutane is used. In this case, the optimum net output power, cooling output, thermal efficiency, exergy efficiency, total SUCP (sum unit cost of the product) of the system are calculated 15.22 kW, 61.99 kW, 39.02, 25.09, and 86.04 /GJ, respectively. To better understand the effect of various parameters on system performance, a comprehensive parametric study of some key parameters on performance criteria is carried out. It is shown that the net output power, exergy efficiency, and total SUCP of the system can be optimized based on the generator pressure. In addition, the total SUCP of the system can be minimized by evaporator temperature, too. Also, it is shown that higher cooling output, net output power, thermal efficiency, and exergy efficiency can be obtained at lower heater pressures as well as condenser temperatures. Moreover, at higher generator pressures and evaporator temperatures, a higher cooling output and thermal efficiency can also result. © 2018 Elsevier Lt

Recent Advances in Hydrogen Production Using MXenes-based Metal Sulfide Photocatalysts

At present, the composition and crystalline structure of transition metal nitrides or carbides (MXenes) and their derivatives are continuously expanding due to their unique physicochemical properties, especially in the photocatalytic field. Advances over the past four years have led to improved preparation of new MAX phases, resulting in new MXenes with excellent photo-thermal effect, considerable specific surface area, long-term stability and optimum activity. Since MXenes have good electrical conductivity and their bandgap is adjustable under the visible light range, this group is one of the best promising candidates for hydrogen production from photo-splitting of water as an environment-friendly method of converting sunlight to chemical energy. Progress in noble metal-free photocatalyst associated with more understanding of the fundamental mechanism of photocatalysis has enabled a proper choice of cocatalyst with better efficiency. In this study, the photocatalytic production of hydrogen through MXens as a support and co-catalyst on metal sulfide is summarized and discussed. Recent advances in the design and synthesis of MXenes-based metal sulfide nanocomposites to increase the efficiency of photocatalytic hydrogen production are then highlighted. Finally, the challenges and future prospects for the development of MXenes-based metal sulfide composites are outlined

Public services and the consumer: Empowerment or control?

This discussion provides a critical perspective on the growth of consumerism in social policy and public life. Debates around consumer and producer interests are examined before suggesting that a 'responsible consumer' has emerged: A service-user increasingly expected to take on a greater role in managing the conditions under which services are provided. It is argued that such consumerism, far from empowering the individual consumer, has served to co-opt service-users into the management of scarcity, rationing, and/or technological change. It is further argued, on the basis of empirical observations in three public service areas, that different groups of people differ in the degree to which they are able, or willing, to take on the new responsibilities of the consumer. This is linked to an outline of how further empirical research may be developed. A typology is offered which seeks to illuminate the act of consumption-including the importance of language, the introduction of technology and the widening physical separation of producer and consumer. It is suggested that the boundaries between producer and consumer responsibility are far from settled. However, as consumers have been expected to take on greater responsibilities, and as the public organization has become more flexible, we have witnessed a process of producer empowerment rather than consumer empowerment