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• Hybrid solar desalination system. • Active mode operation and passive mode operation. • Solar desalination systems efficiency and economic analysis. • Trend in distillate cost, and yield by hybrid solar desalination systems. • Innovation type, feedwater, weather variabilities, operation mode impact on distillate quantity. In this paper, a hybrid solar desalination system was fabricated and incorporated with a water heater powered by a photovoltaic (PV) system. It was experimentally evaluated at Universiti Teknologi Petronas, Malaysia. Daytime operating conditions without the use of a PV system were considered for the conventional operation, while the use of PV alone or combined with direct solar radiation was considered as the modified system. This study was carried out to determine the freshwater yield, weather variabilities impact on yield, economic analysis, and system efficiency of hybrid solar desalination systems. An encyclopaedic review of five years of different researchers from different countries was critically analysed and compared with this study to see their trends and relationship. Within the study period, solar still distillate cost ranges from 0.0051 to 0.8857$/L, and 0.006 to 0.789$/L for the modified and conventional systems respectively. Similarly, the distillate cost for this study is 0.0374$/L and 0.0892$/L for the conventional and modified systems respectively. Also, the distillate yield ranges from 0.93 to 24.3 L/m2.day with an average of 12.1 L/m2.day, for the modified system, and 0.55 to 6.63 L/m2.day with an average of 3.35 L/m2.day for the conventional systems. The hourly system efficiency is 30.07 %, and 8.29 % for the modified and conventional systems respectively. Solar still is economically reasonable with good efficiency as obtained from the result. The findings also suggested that researchers should target a distillate yield of at least 6 L/m2.day and a distillate cost of 0.2$/L or lower for innovation, for a good and economical system. [ABSTRACT FROM AUTHOR]

Currently, we are trying to get electricity in alternative ways. Many solar powered water heaters have come up to use water heaters. However, these tools are not 100 percent fully effective. The device we have manufactured is an automatic device that runs in the direction of sunlight. The device runs automatically in the morning facing east and in the evening facing west. In this instrument, the defective one-inch tube lamp and the three-quarter-inch tube lamp are put together and connected in series. In this paper, a smart deep learning model was proposed to improve the performance of the solar water heater. The gap between the tube lights is filled with methane gas, and the tube inside is filled with water. The water thus filled is heated by sunlight. Methane gas acts as a fast conductor of solar heat. An electronic control device is placed to determine the temperature of the hot water and to expel the hot water. This device can heat at least 10 liters of water in 15 minutes. Increasing the number of incandescent tube lights can heat up a large amount of water when this device is set up, or it can be designed by replacing tube lights with a series of large glass tubes using the same technology. This tool can be manufactured at low cost so that people from all walks of life can use it. [ABSTRACT FROM AUTHOR]

This paper introduces a flexibility concept in development of a novel multigeneration energy system driven by a renewable energy heat source. Nevertheless, the energy system can be upgraded to a highly productive system by incorporating other subsystems for achieving more production such as domestic hot water and freshwater. A novel design is proposed for a system comprising organic Rankine cycle, absorption compression heat pump, liquid natural gas to natural gas converting system, domestic water heater, and humidifier-dehumidifier desalination to exploit the Sabalan geothermal source for multigeneration purposes. Due to its high-efficient and environmentally friendly characteristics, n-pentane is utilized in the organic Rankine cycle. Also, the Ammonia-water is employed in the absorption compression heat pump subsystem. Energy, exergy, and thermoeconomic analysis is conducted on the plant along with multi-objective optimization based on the parametric study of key variants. According to the results, the novel step-by-step flexibility analysis can give a wide viewpoint to the designers to make the best multiple plant. The results of multi-objective optimization indicate that the freshwater production increases from 0.803 kg/s to 0.834 kg/s, the capacity of the domestic water heater rises from 1254 kW to 1265 kW, and the net output power surges up by 137.96 kW. However, the heating production falls from 1276 to 1088 kW. Furthermore, the total energy and exergy efficiencies increase by 6.43% and 4.47% with a 2.08 $/GJ reduction in the unit cost of the product. [ABSTRACT FROM AUTHOR]

Marketing teaching is still largely based on theoretical teaching. This kind of teaching mode is difficult to greatly improve the marketing practice teaching, students' practical ability, innovative thinking ability, and so on. At the same time, the teaching arrangement of marketing training is not standardized, which makes it difficult to provide effective guidance for students. This paper attempted to reform the traditional teaching methods of marketing courses in universities, and deeply studied the teaching methods of traditional college students' marketing courses under the background of the network, as well as conducted marketing practice according to two different Internet algorithm marketing strategy models. The experimental data showed that the average teaching quality score of the traditional marketing course teaching mode was only 6.9, while the teaching quality score of the marketing course teaching mode under the Internet background was 8.15; the market share of water heaters under the neural network-based marketing strategy increased by 8.1% within 4 months, while the market share of water heaters under the data mining-based marketing strategy decreased by 4.8%. Therefore, it can be seen that the marketing course teaching mode under the Internet background can improve the teaching quality, and the marketing effect of the neural network-based marketing strategy is better. [ABSTRACT FROM AUTHOR]

• A novel open-loop air cycle heat pump drying system is proposed. • The mathematical model built is verified to be both accurate and feasible. • Compared with electric heating drying system, the energy-saving rate of air cycle heat pump water heater system is 15∼27%. • The impact of different working conditions on system performance was determined. Different from conventional drying technology, the novel technology of an air cycle heat pump drying (ACHPD) system, using air as its working medium, is proposed to solve the problems of low energy efficiency, HCFC refrigerant use, and so on. A mathematical simulation model is constructed to evaluate system performance under various working conditions, and its verification via experimental results from a constructed test bench produced errors of temperature within ±1.6%, of drying rate within ±0.01%, and of system power within ±7%. Compared with a conventional electric heater drying (EHD) system, the energy-saving rate of the ACHPD system reaches about 15–27% when the mass evaporation rate increases from 0.75 kg h −1 to 3.45 kg h −1. Under set working conditions, an increase of inlet air flow rate (150–400 kg h −1) improved the dehumidification energy efficiency ratio (MER) by about 1%. However, the increase of inlet air temperature (10–40 °C) and relative humidity (30–80%) reduced MER by about 7% and 21% respectively. The efficiency improvements of heat exchanger (0.3–0.8) can improve the energy efficiency of system by 20%; however, the efficiency improvements of expander (0.55–0.8) and compressor (0.4–0.9) can deteriorate the energy efficiency of system by 17% and 36% respectively. These results would provide new technical references for the application of heat pump technology in drying field from a different perspective. [ABSTRACT FROM AUTHOR]

Characterizing the refrigerant side of heat pump water heaters (HPWHs) can be intrusive and expensive. On the other hand, direct external measurement techniques can be unfeasible, particularly in commercial HPWHs for residential applications. Non-intrusive in situ characterization methods have already been successfully implemented in subcritical heat pumps. They provide the refrigerant mass flowrate and the equipment energy performance, by using contact temperature sensors and electric power meters. Subcritical suction and discharge-specific enthalpies necessary to apply the method can be obtained from the measured temperatures and their corresponding saturation pressures. Nevertheless, this approach does not apply to the transcritical CO2 HPWHs. In the supercritical region, temperature and pressure are independent variables, and an iterative process regarding the compressor isentropic efficiency has to be considered. However, when isentropic efficiency data are not available, an additional procedure is required, using a validated gas cooler model to verify the physical reliability of the numerical solutions. This work aims at presenting base thermodynamic analysis of a novel methodology for non-intrusive refrigerant side characterization of transcritical CO2 HPWHs, exploring the influence of the compressor isentropic efficiency condition. [ABSTRACT FROM AUTHOR]

The function between time and water temperature of a gas water heater was established using the heat transfer model, and the aqueous temperature of hot water pipe was calculated. The impact of intelligent water pump system on water conservation was analyzed. Several methods that are effective in shortening the waiting time for hot water are concluded as follows: (1) Increasing the water outlet temperature of the gas water heater; (2) Shortening the water pipe length from the gas water heater to the bathroom faucet; (3) Installing a hot water pipe; (4) Accelerating pumping speed of the hot water circulation pump; (5) Keeping the circulating pump and gas water heater open constantly, and the water circulation being kept in the hot water pipe when hot water is not used. [ABSTRACT FROM AUTHOR]

Due to the lower cost and compact structure, Photovoltaic Integrated Collector Storage Water heater combined (PV– ICSSWH) is an alternative form of PV/T system that differs from traditional flat-plate or vacuum tube PV/T system. An analysis was carried out to investigate the effect of operating parameters and structural factors on system performance. A numerical model was developed to predict the performance of the systems. To validate the numerical model, a prototype system was built and tested. The influence of solar radiation, ambient temperature, the thickness of systems, and the aspect ratio of systems was analyzed and the results indicate that: (a) The aspect ratio has a negligible effect on the efficiency. However, it has a significant influence on temperature stratification. (b) As the thickness of the system drops from 100 mm to 60 mm, its total efficiency descents from 55.1% to 52.7% and the relationship is given. (c) The total efficiency only decreases from 54.7% to 53.5%, when the solar radiation rises from 400 W / m 2 to 800 W / m 2. (d) As the ambient temperature increases from 283 K to 303 K , the total efficiency of the system ascends from 45.6% to 61.4%. (e) The total efficiency is about 48.0% in Lanzhou, China which is predicted. • A PVT hot water system with a more compact structure and lower cost is presented. • The ambient temperature has significant effect on the system's performance. • The aspect ratio has little effect on the thermal and electrical efficiency. • The total efficiency of the PVT system is predicted to be 48.0% in Lanzhou China. [ABSTRACT FROM AUTHOR]

A gas cooler is one of the important parts of a carbon dioxide (CO2) heat pump water heater, and it must meet the needs of not only pressurization but also heat transfer. It is important to study gas coolers. In this paper, a heat exchanger with a spiral channel is studied. ANSYS CFX software was used to analyze the flow and heat transfer characteristics of the heat exchanger (single-plate model). The influences of the cooling pressure of CO2, the mass flux of CO2, the mass flux of water and the channel radius of CO2 are discussed. In this paper, the results show that the cooling pressure of CO2, the mass flux of CO2 and the channel radius of CO2 all have a large influence on the local heat transfer coefficient: with an increase in the cooling pressure of CO2, the peak value of the heat transfer coefficient of CO2 decreases and the average heat transfer coefficient decreases; with an increase in the mass flux of CO2, the peak value of the heat transfer coefficient of CO2 increases and the average heat transfer coefficient increases; and with a decrease in the channel radius of CO2, the peak value of the heat transfer coefficient of CO2 increases. The water mass flux has only a slight effect on heat transfer, and the lower cooling pressure of CO2 corresponds to a higher peak heat transfer coefficient, which can reach 27.5 kW∙m−2∙K−1 at 9 MPa. [ABSTRACT FROM AUTHOR]

The photovoltaic thermal system has a limitation in supplying hot water at the required temperature since it requires a supplementary heating system. One such system can be an air source heat pump operated by electricity from a PV/T system, which can be used to raise the temperature of the water preheated by PV/T to the required level. Such type system can also be called a hybrid PV/T-heat pump system, and it delivers thermal (hot water) and electrical energy. The performance of the hybrid PV/T-heat pump system was analyzed using the computational model for two Ethiopian cities, namely, Addis Ababa and Dire Dawa, which represent the highland and lowland regions, respectively. The simulation was conducted by inputting climatic data, daily hot water demand, and hourly hot water consumption patterns. Also, system design parameters such as PV/T area and peak Watt, PV/T warm water tank volume, air source heat pump water heater COP as a function of ambient temperature and circulating water temperature, and heat pump hot water tank volume. Besides, the effect of hot water consumption patterns (variability effect in three dissimilar cases constant, restaurant, and motel) on the system performance was examined. In addition, the effect of electric energy supply to the compressor of the heat pump using battery storage on the system performance was also investigated. In those diverse situations, the system in most of the cases generated hot water above 55°C and scored a COP of 3. The maximum value of hot water end-use efficiency of 66% was also obtained by making the hot water tank capacity about 50% of the daily hot water consumption size. [ABSTRACT FROM AUTHOR]

Wastewater has significant potential as a source of clean energy. This energy can be used both within external sewer networks and on the scale of individual residential buildings, and the use of shower heat exchangers appears to be the most reasonable solution. However, in the case of Poland, the problem is still the unwillingness of society to use this type of solution, caused mainly by the lack of space for the installation of vertical drain water heat recovery (DWHR) units and the low efficiency of horizontal units. In response to this issue, the efficiency of a new compact shower heat exchanger designed to be mounted below the shower tray, as well as its linear counterpart, was investigated under various operating conditions. In addition, the financial efficiency of using the compact DWHR unit with average water consumption for showering was evaluated. For this purpose, discount methods were used to estimate the financial efficiency of investments. The study showed that the compact shower heat exchanger has higher efficiency than its linear counterpart. Depending on the temperature of cold water and the flow rate of both media through the heat exchanger, it achieves efficiencies ranging from 22.43% to 31.82%, while the efficiency of the linear DWHR unit did not exceed 23.03% in the study. The financial analysis showed that its use is particularly beneficial when the building uses an electric hot water heater. The investment's sensitivity to changes in the independent variables is small in this case, even with low water consumption per shower. The only exceptions are investment outlays. Therefore, the compact DWHR unit is a clean energy device, which in many cases is financially viable. [ABSTRACT FROM AUTHOR]

This article proposes a generalized energy storage model for battery energy storage systems, electric water heaters (EWH), and heating, ventilation, and air-conditioning (HVAC) systems to enable demand response control complying to Energy Star and CTA-2045 standards. The demand response control has been implemented in the DER integration testbed, which was originally developed by Electric Power Research Institute, to demonstrate that the “energy content” and “energy take” for BESS and EWH with mixing valve technology are comparable for typical residential ratings. A distribution power system was modeled using the modified IEEE 123-bus feeder system, measured residential loads, and EWH power simulated based on realistic hot water draws from CBECC-Res software. The demand response control, which complies to CTA-2045 standards was implemented to the EWHs considering the energy take values. Results demonstrate that the EWHs can be controlled to postpone the peak power at the distribution system level and provide a large amount of energy storage, while maintaining system robustness. The impact on occupant comfort was also analyzed. [ABSTRACT FROM AUTHOR]

The photovoltaic thermal integrated water source heat pump (PV/T-WSHP) water heater system can meet the demand for not only the domestic hot water but also the electricity production. To comprehensively analyze the benefits of the PV/T-WSHP water heater system, energy, exergy, economic and environmental analysis method was applied. A TRNSYS model of the PV/T-WSHP water heater system was developed based on the existing experimental setup, and validated by the experimental data. A combined system of single PV system and single air source heat pump water heater (PV + ASHP) system model was also built for comparison. The simulated results indicated the PV/T-WSHP water heater system had a 25.3% improvement in electrical conversion efficiency, a slightly lower EER of 3.71 and a significant reduction in annual exergy loss, comparing with the combined PV + ASHP system. In addition, the annual cost of the PV/T-WSHP water heater system was 217.7 yuan lower than the combined PV + ASHP system. The PV/T-WSHP heat water system and the combined PV + ASHP system could annually save the standard coal of 0.62 tons and 0.50 tons, respectively. This study provides an effective method to comprehensively analyze the performance of the PV/T-WSHP water heater system. • Annual performance of the PV/T-WSHP water heater is evaluated. • Energy, exergy, economic, environmental (4E) analysis method is used. • The comparison with the combined PV + ASHP water heater system is made. • The results showed that the PV/T-WSHP water heater system showed better performance. [ABSTRACT FROM AUTHOR]

A simulation with TRNSYS of an individual solar water heater for the hot water needs of an average family in Algeria was made; three cities of different climates were chosen to the north on the coast, in the highlands and in a desert region, the solar water heater consists of a flat panel of 4m² and a storage tank of 300 liters, a back-up electrical energy is activated when solar radiations are insufficient or during the night, the consumption of domestic hot water leaving the tank at 60 °C follows a typical profile, the results show significant performance in the south and similar data in the north and in the highlands.

Air source heat pump (ASHP) has been generally regarded as energy saving devices for winter heating, yet for low-income households, the operational costs for heating in low-temperature conditions may be prohibitively high. Solar evacuated tube water heater (SETWH) and photovoltaic/thermal are economical solar energy conversion devices. Integrating them into ASHP has been proven globally to significantly reduce heating costs. However, a performance comparison between the SETWH combined with ASHP (SETWH-ASHP) and of micro heat pipe photovoltaic/thermal (MHP-PV/T) combined with ASHP (MHP-PV/T-ASHP) heating systems remains unexplored. Therefore, for a 120 m2 building with underfloor heating water pipe, SETWH-ASHP and MHP-PV/T-ASHP heating systems were respectively developed on the TRNSYS software platform. Their accuracy was confirmed using prior experimental data, followed by performance simulation for the heating season. The result is that MHP-PV/T-ASHP heating system outperformed SETWH-ASHP heating system, showing a 19 % increase in solar fraction, a 2.2 boost in system energy efficiency ratio, a 12.3 % rise in primary energy saving rate, a 0.9-year shorter payback period, and a reduction of 494.7 kg in CO2 emissions over the heating season. The results offer practical guidance for the promotion and application of heating systems that combine efficient and low-cost solar conversion devices with ASHP. • For the first time, this study compared the performance of SETWH-ASHP and MHP-PV/T-ASHP heating systems throughout the heating season for the first time. • The performance of these two systems were simulated using TRNSYS models validated by experimental data. • A heating system that combined a more efficient and cost-effective solar conversion device with a heat pump was identified. [ABSTRACT FROM AUTHOR]

Loadshedding has become the norm in South Africa, with rolling blackouts ranging from Stage 1 to 6. This results in households experiencing disempowerment for durations spanning two to four hours daily, averaging between 1.5 to 9 h. In an unequal society like South Africa, those with higher energy consumption can afford battery backup solutions to keep their lights on. However, implementing these solutions on a large scale, without integrating solar generation, eventually alters the utility's ability to stabilise the grid and prevent blackouts through shedding the load. We analysed an electricity dataset including 6724 households to assess the impact of domestic users adopting battery backup solutions, both with and without solar components, at a 15% penetration level. The findings revealed that installing batteries with inverters (termed battery backup systems in South Africa) without a photovoltaic setup would increase the instantaneous load of zones that are exiting loadshedding due to the backup batteries being recharged from the grid. This would counteract the load reduction that is achieved by the zones that are entering loadshedding. In summer, during the evening peak, the load increase due to recharging the backup batteries would be 1.81 times the load reduction due to the loadshedding, (In winter, it would be 1.67 times.) However, households with a PV-connected inverter and a PV-connected electric water heater would experience a different outcome. In summer, during off-peak hours, the peak load reduction due to PV would be 2.27 times the load reduction due to load shedding. (In winter, it would be 0.91 times.) This suggests that during summer off-peak daylight hours, at least two stages of loadshedding (10% of the overall energy demand) can be mitigated, while in winter, nearly one stage of shedding can be avoided on a typical day. However, storage-less PV installations cannot mitigate loadshedding during the morning and evening peaks when there is little to no power generation from the solar panels. • Impact of Africa's loadshedding is fought by installing domestic battery storages. • Charging storage from the grid curtails the benefits of avoiding rolling blackouts. • Impact with 15% penetration assessed using smart meter data from 6724 houses. • Charging from the grid is detrimental even with low penetration, risking grid collapse. • Solar PV via inverters and separately to water heating ameliorates these curtailments. [ABSTRACT FROM AUTHOR]

With the development of artificial intelligence technology, various intelligent algorithms are applied in building energy system optimization. Deep reinforcement learning (DRL) algorithms have garnered substantial attention from researchers. However, all current DRL-based control methods suffer from two problems. The first problem is that current DRL-based methods require an offline training process and therefore cannot be directly applied to houses. The offline training not only increases the waiting process for occupants but also creates the risk of degrading the occupant experience. The second problem is that current DRL-based methods do not continuously learn online. As a result of the second problem, the control methods are unable to consistently execute the optimal policy in the face of changing hot water demand habits. In this study, a fast-apply deep autoregressive recurrent proximal policy optimization (FDPPO) for controlling hot water systems is proposed. In practical systems, the FDPPO can be applied directly to houses without the need for occupants to wait. The proposed FDPPO can adapt to hot water demands that change over time through continuous online learning. In addition, the proposed FDPPO that applies the model-free reinforcement learning approach does not require modeling complex water heater models. The proposed FDPPO is evaluated by actual hot water demand data of over 55 weeks collected from two typical houses. The results show that the proposed FDPPO can save between 41.24% and 59.01% of energy consumption, all the while ensuring occupant comfort and safeguarding water hygiene. • Two-point control, deep autoregressive and deep reinforcement learning are combined. • Proposed method enables direct application to house without offline training process. • Continuously changing hot water usage behaviours and water heater system are adapted. • Feature pre-extraction improves prediction accuracy and reduces training requirement. • Achieves energy savings of 41.24% to 59.01% while ensuring water comfort and hygiene. [ABSTRACT FROM AUTHOR]

Amidst worsening water scarcity in the urban region, exploring alternative water sources is crucial. Atmospheric water extraction (AWE) technology emerges as a cost-effective and efficient remedy for the escalating issue of water scarcity. The objective of this research is to experimentally explore a novel AWE system that incorporates phase change material (PCM). This system is designed to facilitate uninterrupted water generation, even when there is no solar energy. It comprises of a solar air heater based on both-sides open evacuated tube collector having an area of 4.86 m2, which is encapsulated with acetamide-PCM. Additionally, it incorporates a silica gel filled desiccant bed and an air-cooled heat exchanger for vapor condensation. The system is investigated for two different desiccant bed weights of 15 kg (case 1) and 20 kg (case 2), respectively. The system's effectiveness is examined based on rate of adsorption, rate of regeneration, thermal, overall & exergy efficiency. The economic, environmental & enviro-economic analysis is also presented to ensure the system's sustainability & feasibility for its practical use. The results demonstrate that for case 2 the system extracts 4.1 L/day (0.843 L/m2/day) fresh water with 12.65%, 10.48% and 5.65% thermal, overall and exergy efficiency, respectively, for 20 kg desiccant bed weight. The fresh water cost is 0.12 $/L with 2 years & 1 month of payback time and 4 years & 7 months of energy payback period. The environmental & enviro-economic analysis ensures the system's eco-friendliness. Additionally, rigorous quality testing of the extracted water is carried out to affirm its suitability for safe consumption. • PCM encapsulated solar air heater for atmospheric water extraction. • Both sides open evacuated tube collector produces hot air of 130.10 °C. • Maximum water extracted is 4.1 L/day using air-cooled heat exchanger. • Thermal & exergy efficiency reported is 12.65 % & 5.65 %, respectively. • Water generation cost is 0.12 $/L, with system payback time of 2 years & 1 month. [ABSTRACT FROM AUTHOR]

A large part of French electricity consumption variation is due to temperature fluctuations. While HVAC (heating, ventilation and air-conditioning) systems consumption are directly affected by the temperature, other systems (refrigerator, freezer, water heater) can also be driven by weather changes making thermal contribution to overall consumption difficult to extract. This paper presents a "by-design" unsupervised data-driven method to separate the consumptions due to the weather in the overall electricity consumption. The proposed deep-learning model is based on the separation of meteorological parameters from calendar ones within the model architecture. The performances of this model, in particular its ability to split consumption mechanisms, is tested on a synthetic dataset and on the french consumption dataset. Being relatively simple and interpretable, this approach can be generalized to other countries whereasenergy sobriety represents an important challenge we are facing. • The hourly power load of a country due to temperature is unsupervisingly identified. • Deep learning model provides Large Scale Non Intrusive Load Separation. • Engineering-driven neural network design separates weather and calendar consumption. • Model's performance is assessed on country's actual electricity consumption. [ABSTRACT FROM AUTHOR]

Renewable energy based multi-generation systems can help solving energy-related environmental problems. For this purpose, a novel solar tower-based multi-generation system is proposed for the green hydrogen production as the main product. A solar-driven open Brayton cycle with intercooling, regeneration and reheat is coupled with a regenerative Rankine cycle and a Kalina cycle-11 as a unique series of power cycles. Significant portion of the produced electricity is utilized to produce green hydrogen in an electrolyzer. A thermal energy storage, a single-effect absorption refrigeration cycle and two domestic hot water heaters are also integrated. Energy, exergy and economic analyses are performed to examine the performance of the proposed system, and a detailed parametric analysis is conducted. Multiobjective optimization is carried out to determine the optimum performance. Optimum energy and exergy efficiencies, unit exergy product cost and total cost rate are calculated as 39.81%, 34.44%, 0.0798 $/kWh and 182.16 $/h, respectively. Products are 22.48 kg/h hydrogen, 1478 kW power, 225.5 kW cooling and 7.63 kg/s domestic hot water. Electrolyzer power size is found as one of the most critical decision variables. Solar subsystem has the largest exergy destruction. Regenerative Rankine cycle operates at the highest energy and exergy efficiencies among power cycles. [Display omitted] • A novel solar tower-based multi-generation system with a new power cycle set. • Energy, exergy and economic analyses and multiobjective optimization are performed. • Effect of electrolyzer power size on the performance of a multi-generation system. • Green hydrogen is the main product besides power, cooling and domestic hot water. • Unit exergy cost of the multi-generation products is 0.0798 $/kWh. [ABSTRACT FROM AUTHOR]

Renewable energy sources have great importance to deal with environmental detriments. To clean and sustainable future, various design renewable energy-assisted plants are of great importance. The current study examines the design and investigation of a double-flash binary geothermal energy-powered integrated system for useful products. For the purpose of producing hydrogen, power, heating, and drying, the proposed work basically consists of two steam turbines, a transcritical carbon dioxide Rankine cycle (tCO 2 -RC) , a PEM electrolyzer, a domestic water heater (DHW), and a dryer. The chief target of this research study is to develop a more efficient plant as well as multigeneration productions. Additionally, detailed parametric modeling is carried out using energetically and exergetically approaches to examine this designed plant in the context of thermodynamic analysis. The variation of some parameters that influence the plant's performance, such as geothermal water temperature, flash pressure, and ambient temperature, are parametrically investigated. Subsequently, the thermodynamic simulation results show that the advised integrated plant produces 4431 kW electrical power. Also, the amount of the hydrogen generation capacity is 0.006809 kgs−1. The tCO 2 -RC sub-plant's energetic and exergetic performance is determined as 6.18% and 27.14%, respectively. Furthermore, the suggested integrated plant's energetic and exergetic performances are 26.20% and 37.49%. From the results, it can be finalized that the integration of various systems with the geothermal power plant is successfully possible and, in this way, there will be an increase in system performances. • A new double-flash geothermal power plant is proposed. • Transcritical CO 2 Rankine cycle is integrated and utilized for power generation. • Thermodynamic performance examination of for whole system and sub-system is conducted. • Proposed total system has 26.20% energetic efficiency. [ABSTRACT FROM AUTHOR]

With the pressing need to reduce greenhouse gas emissions, blending lower or zero carbon fuels like renewable hydrogen into natural gas is a promising and practical way to achieve clean energy transition. From the perspective of end users and combustion device manufactures, one of the major concerns is the influence of the renewable contents on the combustion devices performance. The possible renewable gas content percentage in pipeline also interests policy makers and gas utility companies. The present study investigates on the influence of hydrogen contents on the operating performance of a surface burner, which is widely adopted in industrial, commercial and residential applications. The interactions among heating load, excess air level and fuel contents are studied by a 3-factor∗3-level experiment design. Evaluated combustion performance characteristics include flame characteristics, burner/exhaust temperature and emissions (NO, NO 2 , N 2 O, CO, UHC, NH 3). The results showed that hydrogen addition to natural gas slightly increased the burner surface temperature but did not have significant impact on other burner performance parameters. Up to 20% (by volume) natural gas was replaced by hydrogen, and no abnormal effect was observed. Furthermore, tests carried out in a prototype water heater showed similar performance. This study gives a positive sign relative to replacing pipeline natural gas with renewable hydrogen at a low percentage without modifying the burner geometry. • A mesh burner is studied for tolerance to hydrogen/natural gas mixtures. • Hydrogen addition has little impact on NOx compared to excess air and heating load. • Correlations for burner temperatures and emissions are developed. • Burner performance in a prototype water heater is assessed. [ABSTRACT FROM AUTHOR]

Carbon-based conductive polymer composites are thriving as promising electrothermal materials for a vast array of applications. However, the low working temperature (< 100°C) of most carbon-based conductive polymer composites due to the low melting point and inferior temperature resistance of polymer matrix severely restricts their high-temperature applications. Herein, a series of thin electric heating films composed of highly thermally stable polybenzimidazole (PBI) as polymer matrix and low-cost carbon black nanoparticles (Super P, SP) as conductive fillers are successfully developed to significantly increase the maximum working temperature as high as >200°C under relatively low applied voltage. The morphology, microstructure, electrical properties, and electrothermal behavior of the PBI/SP composites are systematically studied as a function of SP content. By introducing 15–25 wt.% SP conductive fillers, SP nanoparticles with uniform spatial dispersion are tightly anchored on the surface and tip of fiber-like villous PBI matrix, forming continuous highly conductive networks. However, the conductive filler content exceeds to 30 wt.%, and SP nanoparticles tend to locally clump together in aggregation, resulting in potential safety issues. Impressively, PBI/SP composite with 25 wt.% SP content (PBI/SP-25) exhibits superior electrothermal performance, including rapid temperature responsiveness, high maximum working temperature, superior heating uniformity, and remarkable electrothermal reproducibility. As an integrated thin-film heater for water boilers, PBI/SP-25 electrothermal film heats 100 ml of water to 99.5°C within 4 min at 25 V, demonstrating great potential in household electrical appliances. [ABSTRACT FROM AUTHOR]