Electricity Production Cost Research Articles

Multi-objective optimisation of ORC–LNG systems using the novel One-shot Optimisation method

Optimisation is drawing more and more attention in the organic Rankine cycle (ORC) research field. However, as the complexity of the ORC scenarios increases, it poses challenges on operational parameter, working fluid, and configuration optimisation levels. This work first proposes an improved optimisation method, termed the One-shot Optimisation (OSO) method, which can simultaneously optimise the working fluid and configuration. Then, a two-objective optimisation is performed using the OSO method in combined ORC–LNG systems, considering up to eight operational parameters, 11 working fluids, and 16 system configurations to maximise energy efficiency and minimise the electricity production cost (EPC). Finally, the result of the optimisation is divided according to the thermodynamic weight (W1), and two typical conditions are analysed in detail: the maximum case (W1 = 1) and the balanced case (W1 = 0.5). The results show that the OSO method is capable of identifying the optimal working fluid and optimal configuration within a single optimisation process. The basic ORC configuration is preferred when W1 is lower while the recuperative ORC is preferred when W1 is higher. The balanced case can achieve an energy efficiency comparable to that of the maximum case but with a significantly lower EPC. The balanced case can achieve as much as 87. 48% of energy efficiency, requiring only 19.77% of the EPC compared to those of the maximum case.

Thermal Management Enhancement of Building-Integrated Photovoltaic Systems using Coupled Heat Pipe and Evaporative Porous Clay Cooler

The building-integrated photovoltaic (BIPV) panel systems often lead to a notable decline in PV panels efficiency and lifetime due to their temperature rise because of inadequate cooling. This study investigates the performance of innovative cooling strategy of using a coupled heat pipes and porous clay cooler and compare it with other related three BIPV cooling systems configurations including a conventional BIPV cooling with and without air gap and a pure evaporative porous clay cooling. The aim is to improve the PV panel cooling, ultimately reduce the PV temperature and enhance the overall performance of the BIPV system as well as reducing the building indoor temperature and boosting energy efficiency within the building. The system model, comprising sets of transient equations for the different system configurations, was solved using MATLAB and confirmed with previous experimental findings. The results indicate that comparing with the traditional BIPV system, using BIPV/Clay cooling systems and the hybrid BIPV/Clay-heat pipe cooling systems achieved peak PV temperature reductions of up to 14 °C and 14.7 °C, respectively. Additionally, these cooling methods led to a maximum interior room temperature reduction of approximately 14°C and an average decrease of 8°C. Moreover, the hybrid BIPV/Clay-heat pipe cooling system demonstrates superior performance compared to traditional BIPV system, achieving the highest improvements in PV electrical efficiency, output power, and exergy efficiency, with gains of 7.8%, 6.4%, and 8.4%, respectively. Further, when the hybrid BIPV/Clay-heat pipe cooling system was employed, the clay cooling efficiency and clay exergy efficiency values improved on average by 30.2% and 29.7%, respectively, compared to the BIPV/Clay cooling system in addition to the increase of the lifetime of the PV panels due to isolating it from the contact with the water/water vapor of the clay cooling system. However, this hybrid approach resulted in a rise in electricity production costs from 0.077 $/kWh to roughly 0.138 $/kWh and extended the payback time from 7.38 years to 13.6 years. But, despite its initial economic drawbacks, the hybrid BIPV/Clay-HP cooling system demonstrates considerable effectiveness and long lifetime compared to other cooling configurations.

Performance and economic analysis of various geothermal power plant systems: Case study for the Chingshui geothermal field in Taiwan

Geothermal power plants are a source of sustainable energy. However, their performance is influenced by various factors, including production temperature and well locations, and few studies have investigated the relationships between these factors. To address this research gap, the present study developed integrated models of a geothermal reservoir and a variety of power plant systems. By using COMSOL and MATLAB, we conducted simulations for the Chingshui geothermal field in Taiwan to investigate the performance and economic feasibility of five common types of geothermal power plant systems over their operational lifetime under different well configurations. The key findings of this investigation are as follows. First, the locations of production wells are a primary factor influencing production temperature. Constructing wells in low-permeability zones results in considerable increases in the pressure differential in the injection pump; thus, wells should not be constructed in such zones. Second, as system flow rate and well depth decrease, production temperature remains relatively stable, net power output decreases, and system efficiency increases. This efficiency increase is caused by decreases in pumping power requirements at lower flow rates and shallower well depths. Finally, among the investigated systems, the organic Rankine cycle system had the lowest electricity production cost and shortest payback period within the enthalpy range of 500–1000 kJ/kg. Double-flash (DF) and DF–binary systems are also viable options when the mass flow rate is 10–20 kg/s and the enthalpy is 700–800 kJ/kg. Overall, the results of this study offer valuable insights for the design of geothermal power plants, thereby contributing to the optimization of renewable energy systems.

Simultaneous Optimization of Exergy and Economy and Environment (3E) for a Multistage Nested LNG Power Generation System

The study introduces an innovative three-stage nested power generation system that enables the cascading utilization of LNG cold energy. It makes the most of wasted energy by using ship jacket cooling water (JCW) and exhaust gas (EG) as heat sources, a trans-critical carbon dioxide cycle as internal circulation, and utilizing the pressure exergy of LNG. We choose two azeotrope mixing fluids that match the requirements and create four cases for the outer and middle cycle working fluids in the three-stage nested system. To discover the ideal system performance from the perspectives of exergy (E), economy (E), and environment (E), four cases were subjected to multi-objective optimization using the multi-objective particle swarm optimization technique (MOPSO). Finally, the optimal solution was found by applying the TOPSIS decision-making method. Through comparative analysis, the optimal system is selected among the four optimization results. R170 (22.66%) and R1150 (77.34%) are used as the outer circulating working medium, while R170 (90.86%) and R1270 (9.14%) are utilized as the inter-cycle working fluid. The net output work is 575.75 kW, the optimal exergy efficiency is 46.09%, the optimal electricity production cost is $0.04009 per kWh, the carbon dioxide emissions can be reduced by 36,910 tons, and the payback period is 2.548 years. After optimization, a more energy-efficient and environmentally friendly power generation system is obtained.

Thermal Power Plant Performance Analysis by Estimating Boiler Efficiency via Indirect Method: A Case Study

The performance of power plants is very critical since it is directly related with operating and electricity production costs. Among the other different type of power plants, coal-fired ones have advantages such as reliability and low cost fuel. In this paper, a coal (lignite) fired thermal power plant having capacity of 160 MW is taken into consideration and the impact of condenser pressure, moisture content of lignite, excess air coefficient, efficiency of turbine pressure and heater numbers on power plant thermal efficiency is investigated. It is aimed to determine performance losses of each equipment by means of the thermodynamics and economic analysis. In this scope, it is expected that the power plant operator will be able to evaluate the reduction potential of equipment performance losses and ensure more effective use of the power plants by correctly planning the maintenance and rehabilitation needs and times. In the calculations, the boiler efficiency was determined with EN 12952-15 standard (indirect method) since this method has higher accuracy in coal fired boilers. It is seen that the condenser pressure and excess air coefficient increments have not significant impact on power plant efficiency compared to moisture content of lignite, excess air coefficient, efficiency of turbine pressure and heater numbers. The significant effect is observed for fuel moisture content which rises from 22% to 47% and the power plant efficiency falls from 40% to 28%. The variation of the power plant thermal efficiency in case of failure of heaters is investigated and the power plant efficiency has decreased from 40.17% to 36.09% when the pre-heaters are no longer in to be in use because of any reason. In addition, revenue losses are estimated for each main equipment efficiency reduction for better use of power plant capacities and electricity lowering production costs.

The superiority of feasible solutions-moth flame optimizer using valve point loading

The optimal power flow (OPF) problem deals with large-scale, nonlinear, and non-convex optimization challenges, often accompanied by stringent constraints. Apart from the primary operational objectives of an energy system, ensuring load bus voltages remain within acceptable ranges is essential for providing high-quality consumer services. The Moth-Flame Optimizer (MFO) method is inspired by the unique night flight characteristics of moths. Moths, much like butterflies, undergo two distinct life stages: larval and mature. They have evolved the ability to navigate at night using a technique called transverse orientation. This article presents a methodology for determining the optimal energy transmission system configuration by integrating power producers. The MFO, Grey Wolf Optimizer (GWO), Success-history-based Parameter Adaptation Technique of Differential Evolution - Superiority of Feasible Solutions (SHADE-SF), and Superiority of Feasible Solutions-Moth Flame Optimizer (SF-MFO) algorithms are applied to address the OPF problem with two objective functions: (1) reducing energy production costs and (2) minimizing power losses. The efficiency of MFO, SF-MFO, SHADE-SF, and GWO for the OPF challenge is evaluated using IEEE 30-feeder and IEEE 57-feeder systems. Based on the collected data, SF-MFO demonstrated the best performance across all simulated instances. For instance, the electricity production costs generated by SF-MFO are $845.521/hr and $25,908.325/hr for the IEEE 30-feeder and IEEE 57-feeder systems, respectively. This represents a cost savings of 0.37 % and 0.36 % per hour, respectively, compared to the lowest values obtained by other comparative methods.

Performance Analysis and Rapid Optimization of Vehicle ORC Systems Based on Numerical Simulation and Machine Learning

The organic Rankine cycle (ORC) system is an important technology for recovering energy from the waste heat of internal combustion engines, which is of significant importance for the improvement of fuel utilization. This study analyses the performance of vehicle ORC systems and proposes a rapid optimization method for enhancing vehicle ORC performance. This study constructed a numerical simulation model of an internal combustion engine-ORC waste heat recovery system based on GT-Suite software v2016. The impact of key operating parameters on the performance of two organic Rankine cycles: the simple organic Rankine cycle (SORC) and the recuperative organic Rankine cycle (RORC) was investigated. In order to facilitate real-time prediction and optimization of system performance, a data-driven rapid prediction model of the performance of the waste heat recovery system was constructed based on an artificial neural network. Meanwhile, the NSGA-II multi-objective algorithm was used to investigate the competitive relationship between different performance objective functions. Furthermore, the optimal operating parameters of the system were determined by utilizing the TOPSIS method. The results demonstrate that the highest thermal efficiencies of the SORC and RORC are 6.21% and 8.61%, respectively, the highest power outputs per unit heat transfer area (POPAs) are 6.98 kW/m2 and 8.99 kW/m2, respectively, the lowest unit electricity production costs (EPC) are 7.22 × 10−2 USD/kWh and 3.15 × 10−2 USD/kWh, respectively, and the lowest CO2 emissions are 2.85 ton CO2,eq and 3.11 ton CO2,eq, respectively. The optimization results show that the RORC exhibits superior thermodynamic and economic performance in comparison to the SORC, yet inferior environmental performance.

Green energy: a modern view in conditions of environmental safety

Expansion of the use of renewable energy sources (RES) became possible due to technical progress in this area, which allowed, first of all, to significantly reduce the cost of electricity production by wind and solar power plants of various types. Since 2000, wind power has developed with an average annual growth rate of more than 21%. In the early years of wind power deployment, Europe was the key region for global wind turbine installations. In 2010, the region accounted for 47 % of global onshore wind turbine deployments. After 2010, other regions, especially China, have seen rapid wind energy development. By 2018, China had overtaken Europe to become the largest onshore wind energy market with nearly one-third of the world's installed capacity. Some experts estimate that onshore wind power installations will need to have an average annual growth rate of more than 7 % over the next three decades. Offshore wind energy technologies allow countries to exploit generally higher and sometimes more stable wind resources, by implementing gigawatt projects near densely populated coastal areas common in many parts of the world. This makes wind power an important addition to the portfolio of low-carbon technologies available to the energy sector in many countries. Green energy, in terms of environmental impact, leads to a more environmentally friendly process. Energy obtained from naturally occurring sources such as wind, sun and water, i.e. renewable energy is better for the environment because energy production does not produce greenhouse gases – gases that enter the atmosphere, trap heat and cause global warming. The main goal of our work is to analyze the experience of large-scale development of renewable energy sources in a number of countries, its impact, including negative ones, on traditional generation and the electricity market, with the development of relevant specific recommendations for overcoming specific challenges and ensuring environmental safety in each country

Thermoelectric generator for energy production from renewable sources

Thermoelectric generators (TEG) produce electrical energy from a temperature difference between the cold and hot side of TEG modules (Seebeck effect); in principle, they can be used at temperature differences greater than 3 K [1]. Thermoelectric energy generation is primarily known for supplying self-sufficient sensors or in exhaust systems of motor vehicle internal combustion engines [2], where high temperature differences of up to 700 K are used. In this paper, basic investigations are carried out in order to expand the power range of thermoelectric energy generation and their potential for the energy transition. To this end, the area of application should be expanded to include medium and small temperature differences. The output characteristic of a TEG module has a power maximum, which increases quadratically with the temperature difference and linearly with the module area. At a temperature difference of 40 K, an output of 250 W/m2 can be generated. A solar module can generate 150 W/m2 in full sunlight; this output is only available for 12 % of the year given the 1000 full-load hours of sunshine that are usual in our latitudes. A continuous thermoelectric energy source could provide energy all year. Under optimal conditions, an annual usage time of 5000 hours and a service life of 10 years, electricity production costs of around 10 Cents/kWh can be expected [3]. This price is quite comparable to other renewable energy sources (photovoltaics, wind).

Valorization of rice husk for electricity production by enzymatic hydrolysis and microbial fuel cell

This work described a combined bioprocess of enzymatic hydrolysis and microbial fuel cell (MFC) for electricity production from rice husk (RH). It was found that glucose was produced from RH by enzymatic hydrolysis and reached 1.72 g/L within 20 min. RH hydrolysate was then used as substrate in MFC for electricity production. The peak voltage output of 369 mV and power density of 27.78 mW/m2 were recorded at external resistance of 1000 Ω. The glucose consumption rate could reach 99.6%. A combined bioprocess plant with capacity of 3 t/d RH for electricity production was simulated for economic analysis. The total capital cost (TCC) and annual operating cost (AOC) of the plant were US$ 40565.7 and US$/y 45819, respectively. The unit production cost (UPC) of electricity from RH was 285.3 US$/kW·h. Sensitivity analysis indicated that electricity generation was the largest determinant of the UPC. This study provided a promising way and economic analysis for biofuels production from biomass.

Off-design performance and economic analysis in coupled binary cycle with geothermal reservoir and turbo-expander

This study presents a thermo-hydro-mechanical reservoir model of the Chingshui geothermal field, coupled with a thermodynamic model of the binary cycle. A one-stage axial turbo-expander was designed and analyzed in three dimensions using ANSYS-CFX. The results were used to train the artificial neural network model, providing the mass flow rate of the working fluid, isentropic efficiency (ηis,exp), and shaft power of the turbo-expander under off-design conditions to the thermodynamic model of the binary cycle. When the mass flow rate of the geofluid (m˙geo) exceeded 30 kg/s, ηis,exp gradually increased from its lowest value over the operation time and approached the design value. The performance of the power cycle degraded substantially owing to the decrease in the production temperature and considerable increase in the power consumption of the injection pump (W˙pgeo). Owing to effect of W˙pgeo, the decrease ratios of the first- and second-law efficiencies at m˙geo = 40 kg/s from the 1st to the 30th year were 5.7 % and 4.2 % for the cycle, and 23.2 % and 21.9 % for the total system, respectively. Finally, six scenarios of decreased m˙geo were examined. The decreased m˙geo had a relatively small impact on the payback period, and significantly affected the electricity production cost.

Optimization of the PVT performance with various orientations of jets and MFFNN-RSA prediction model for smart buildings

The combined thermal and photovoltaic technology in PV/T systems is considered as a greatly promising technology for smart buildings. Thus, investigations for enhancing the PV/T performance are still proceeding. This research presents an investigation for novel configurations of cooling jets for the PVT system. The linear and circular distribution for the inlet jets considering regular and irregular positioning for all the jets as new cooling configurations are implemented. Moreover, the proposed geometrical configurations are optemized regarding the performance to identify the most suitable configuration that achieves the optimum efficiency and temperature. Furthermore, a novel hybrid ANN model is presented for predicting the performance of the PVT systems. This model combines the multi-feedforward neural network (MFFNN) with an optimization technique called reptile search algorithm (RSA). The proposed model can process the studied parameters to predict the PVT performance parameters (top surface temperature, temperature un-uniformity, outlet temperature, and efficiencies). The proposed MFFNN-RSA model minimized the mean square error to less than 0.4857×10-3. The maximum temperature decrease achieved by the presented configuration reached 60.62K compared to the uncooled case, while the minimum temperature un-uniformity reached 1K and 6K for 400 and 1000 W/m2, respectively. The increase of the ambient temperature found to decrease the temperature un-uniformity in all the cases. The irregular jet with the linear distribution was found to achieve the optimum performance of the overall, thermal, and electrical efficiencies of 63.5%, 49.6%, and 14.25%, respectively. Furthermore, the electricity production cost was reduced by 11.6%, and the yearly CO2 emissions were reduced by 215.3 kg/m2 compared to the normal PV system. The proposed irregular-line distribution of the jets is found to be the best configuration regarding the temperature of the PV model and the overall efficiency considering the pumping losses.

A techno-economic framework for optimizing multi-area power dispatch in microgrids with tie-line constraints

Fuel-fired power plants are the primary electricity sources in Saudi Arabia. This investigation aims to reduce the overall costs and emissions of electricity production from thermal units operated by the Shuqaiq Water and Electricity Company. It also considers practical thermoelectric constraints, such as power losses, ramp-rate constraints, and environmental optimization functions, to align with the sustainability goals of Saudi Vision 2030. Optimizing electric energy delivery is crucial within an energy control center. The focus of this work is to develop an advanced computational technique that reduces reliance on fossil fuels and minimizes the production cost of electricity, while also considering environmental emissions as an optimization function. An examination was conducted through two distinct practical case studies with power demand of 850 MW—one involving renewable sources and the other without—to assess the effectiveness of the hybrid crow search and JAYA optimization algorithm in optimizing performance. This system includes a multi-area setup with limitations on the tie-line power flow constraints. Additionally, the study also involved RETScreen modelling to assess the practical financial, emission, and benchmark analysis of a proposed integrated solar plant. This analyses offers a thorough assessment of the facility’s performance and reliability in practical situations. This study serves as a motivating factor for energy operators, stakeholders, governmental organizations, and grid administrators to invest resources in environmentally-friendly initiatives. The simulation results showed that the proposed approach successfully reduced the electricity cost by 2.29% and 3.70% in hybrid energy networks while effectively handling the system constraints. In addition, the analysis revealed that the optimization algorithm effectively decreased toxic emissions from power plants while also supporting the sustainability objectives of United Nations SDG-7 and Saudi Vision 2030 through the successful integration of renewable sources.

Decarbonization pathways in Latin America: Assessing the economic and policy implications of transitioning to renewable energy sources

The Paris Agreement's ambitious target of limiting the global temperature rise to 1.5°C remains elusive, with the world falling short of its climate commitments. The electricity sector, responsible for a substantial 39% of global carbon emissions, plays a pivotal role in curbing climate change. Transitioning to renewable energy sources is not just an environmental imperative but also a pressing economic challenge, especially for governments tasked with financing renewable projects. This study explores the economic dimensions of decarbonizing electricity grids, shedding light on the costs and benefits. This research quantifies the costs of current fossil fuel-based electricity production versus achieving net-zero emissions across ten Latin American countries by evaluating annual electricity generation costs and estimating the expenses of transitioning to renewables. We find that decarbonizing these countries’ electricity grids would lead to annual savings close to USD 21 billion annually, potentially contributing positively to their economies. The study also compares the energy policies for each of the ten Latin American nations included, evaluating the role of renewable-oriented policies in decarbonizing power generation. We also find that policies vary in effectiveness across countries, and have to be in line with geographical constraints and economic realities.

Forest resource distribution and transport cost optimization-based economic evaluation of gasification and steam-turbine biomass power generation systems

The economics of decentralized gasification and centralized steam turbine systems with optimized harvesting, chipping, and transportation costs of unutilized forest biomass were analyzed within the context of the spatial distribution of forest biomass resources using a geographic information system in the Fuji area of Shizuoka Prefecture, Japan. The optimized harvesting, chipping, and transportation costs were 62.50 USD/dry-t for the decentralized system and 65.86 USD/dry-t for the centralized system, confirming that the decentralized system was less expensive than the centralized system. However, electricity production costs for centralized systems, ranging from 0.137 USD/kWh (capacity: 5,000 kW), were found to be more economical than that for decentralized systems, at 0.151–0.165 USD/kWh (capacity: 482 kW), resulting in the higher costs of decentralized systems because of expensive initial investment than that of the centralized system. The rate of heat sold, which lowers the electricity production costs of gasification below those of centralized systems, was 20–40 % for all such plants. To lower the electricity production cost of gasification plants below that of steam-turbine systems, a heat sales rate of approximately 10% and a minimum staff of 0.2 persons for remote operation of the gasification system. Higher heat sales rates further decrease the cost of gasification, making it cheaper than steam-turbine systems even at lower operating rates. To achieve this cost advantage at current low utilization rates, a heat sales rate of 50% and a utilization rate of 90%, based on a unit price of 0.05 USD/kWh, are required.

Performance and economic analyses of a geothermal reservoir model coupled with a flash–binary cycle model

A reservoir model was coupled with a flash–binary cycle model to investigate the performance and economics of a geothermal system. The production temperature Tpro of the reservoir decreased with an increase in the operation time, which affected the net output power of the system; thus, a method for calculating the electricity production cost (EPCM) and payback period (PBPM) was developed. The net output power decreased with an increase in the operation time because of the effect of Tpro. This decrease resulted from the combined effect of a considerable decline and marginal increase in the net output power of a single-flash cycle (decline of 1278.86 kW) and an organic Rankine cycle (increase of 68.6 kW), respectively, with an increase in the operation time. For high flash pressure, the decreases in the output power, firs- and second-law efficiencies of the system (Wtot,net, ηtot,I, and ηtot,II, respectively) from the 1st to the 30th year of operation were 52.08 %, 34.53 %, and 24.53 %, respectively, with the percentage decrease in Wtot,net being greater than those in ηtot,I and ηtot,II. The system with a flash pressure of 800 kPa was discovered to achieve the best EPCM and PBPM values of 0.129 USD/kWh and 12.503 years, respectively.

Energy efficiency improvement of heavy-load hydraulic fine blanking press for sustainable manufacturing assisted by multi-stages pressure source system

The fine blanking process has the highest forming accuracy in the field of metal forming and its production volume has increased sharply. However, hydraulic fine blanking presses (HFBP) – the core equipment of the fine blanking process, have suffered from significant energy loss due to the inefficient hydraulic system. To enhance the energy efficiency of the hydraulic system, this study introduced a novel approach – a multi-stage pressure source system comprised of distinct pump-accumulator groups, each operating at varied supplied pressures to narrow the mismatch of the installed and demanded power. This adaptive system is capable of automatic adjustments to align with the required pressure, thereby mitigating energy losses while concurrently preserving superior dynamic working performance. First, this study commenced with a theoretical analysis of the system configuration and energy characteristics of HFBP. Subsequently, a comprehensive exploration into the inherent inefficiencies of the hydraulic system is undertaken by formulating a precise energy consumption model. Finally, a novel energy-saving optimization design was carried out on the fast-approaching subsystem. The results demonstrated that the implementation of the proposed system led to a notable reduction of 76.87% in energy loss within the flow-regulating module, and an overall diminution of 13.53% in energy dissipation compared to the conventional system. This study will significantly advance sustainable manufacturing practices within the metal-forming domain by reducing electricity consumption and production cost.

Development of a Solar-Powered Barley Sprouting Room

The study aims to develop a sprouting room for barley powered by solar energy instead of traditional alternating-current rooms to suit remote areas. The cooling, lighting, and irrigation systems were developed and replaced with another that operates on 12 V DC. An air cooling device based on the Peltier module has been developed as an alternative to air conditioning devices. Four cooling units of the air cooler were tested with three lighting durations of 6, 9, and 12 h and three irrigation rates of 1.7, 1.85, and 2 m3 ton-1. The measurements included evaluating the performance of the developed air cooler device. The vegetative and quality characteristics and a chemical analysis of sprouted barley for the solar-powered room compared to the room before the modification were estimated. The solar room's productivity and electrical energy consumption rates were estimated, and an economic evaluation of the development was conducted. The maximum electrical power consumption for the solar-powered sprouting room was 63.275 kWh ton-1, compared with 117.19 kWh ton-1 for the alternating current-managed room before modification. The interaction between the utilized developing DC air cooling, lighting, and irrigation achieved standard rates for the produced barley vegetative and quality characteristics. The maximal productivity from sprouted barley was 1.22 tons, per 7 days with an increment ratio over control of 31.97%. The net earnings for the developed sprouting room were maximized relative to the significant decrease in electrical production costs. The developed room fits the livestock sector by providing good economic alternative fodder sources.

Assessment of evaporative porous clay cooler for Building-Integrated photovoltaic systems via energy, exergy, economic and environmental approaches

A thorough study has been conducted for the energy, exergy, economic and environmental analysis to investigate the feasibility of utilizing an evaporative porous structure cooler for the building-integrated photovoltaic (BIPV) system at different building’s sides and directions. Photovoltaic panels within the BIPV systems dissipate their heat to the building’s sides which contribute to rise the interior building’s temperature. In the proposed system, a water-saturated evaporative porous clay cooler is being installed on the back surface of the PV panels to absorb and dissipate their heat by latent evaporation through an evaporation cooling process. A transient numerical heat and mass transfer model based on energy, exergy, economic and environmental approaches was proposed to assist the feasibility of cooling BIPV system via evaporative porous structure cooler. The model was also validated experimentally in the present study. The results exhibited that, comparing with conventional BIPV systems, the presented BIPV/Clay cooling system achieved a peak photovoltaic temperature reduction of 19.1 °C, with a maximum enhancement in the photovoltaic system’s electrical efficiency, electrical power, and exergy efficiency of 9.8 %, 12.6 % and 11.8 %, respectively. The ultimate reduction in the building’s annual thermal load was around 53.8 % when the clay evaporative cooling approach is applied, while the cost of electricity production reduced ultimately by 7.9 %, (from 0.151 $/kWh to 0.134 $/kWh). Further, the payback period decreased by 2.33 years and the annual amount of CO2 emissions decreased by 10.4 % for the utilized BIPV/Clay cooling system compared with the conventional BIPV system.

Performance enhancement of porous clay cooler for BIPV applications using hollowed clay structures and metallic extended fins as evaporation and thermal conductivity enhancers

This paper investigates the employing of a passive evaporative cooling approach to mitigate the temperature rise of PV panels within building-integrated photovoltaic (BIPV) systems. The investigation explores enhancing the heat transfer capabilities of composite clay layers by incorporating thermal conductive materials such as iron-oxide and zinc-oxide. This enhancement aimed to improve the overall thermal properties of the composite clay structures, thereby boosting heat transfer rates. Additionally, two distinct designs were evaluated as well: one integrating hollowed clay layer and the other featuring a clay layer with extended fins to enhance both heat and mass transfer rates within the evaporative porous clay structure. A series of experiments conducted under real conditions using prototyped building rooms to simulate real BIPV systems to assess the cooling performance of the presented scenarios. The results revealed that the hollowed clay layer achieved the most substantial decrease in PV panel temperature, with a reduction of 16.5 % compared to the findings with a solid clay layer. In contrast, the composite Iron-oxide/clay layer demonstrated the smallest decrease in PV temperature at 11 %. Moreover, utilizing the hollowed clay structure led to a 6.3 % increase in average PV output power, as well as around 4.5 % enhancement in average photovoltaic’s efficiency compared to the outcomes observed with the solid clay layer. Moreover, incorporating the hollowed clay layer resulted in the most significant decrease in the building's annual load, achieving a reduction of 79.6 %. This signifies approximately a 2 % higher enhancement in cooling capabilities compared to utilizing solid clay layer. Further, the cost of electricity production decreased by 7.7 % (from 0.104 $/kWh to 0.096 $/kWh) following the incorporation of the hollowed clay layer, while the payback time was reduced by roughly 0.8 years compared to utilizing the solid clay layer and by 1.7 years in comparison to the non-cooled BIPV system.