Maximum Annual Energy Research Articles

Array Optimization for a Wave Energy Converter with Adaptive Resonance Using Dual Bayesian Optimization

A novel Dual Bayesian optimization strategy is formed for an array of wave energy converters with adaptive resonance to maximize the annual performance through the energy conversion processes from irregular waves to electricity. A wave energy converter with adaptive resonance changes the natural frequency of power take-off dynamics for varying irregular waves, resulting in the maximum annual energy production. The first step of the two-step Dual Bayesian optimization determines the geometric layout of the array, which maximizes the first energy conversion to the total array excitation for irregular waves occurring annually. The second step optimizes the operational parameters of individual wave energy converters in the optimized array to maximize the power generation in varying sea states through simultaneous conversion to mechanical and electrical energy. The coupled hydrodynamics are solved in the frequency domain, and the power performance is evaluated by solving the Cummins’ equation in the time domain extended for multiple floating bodies, each strongly coupled with nonlinear power take-off dynamics. The proposed method is applied to a surface-riding wave energy converter, already optimized for single unit operation at individual sea states. Investigating two array layouts, linear and random, the optimized arrays after Step 1 increase the excitation spectral area by up to 40% relative to the single unit operation, indicating the synergy enhancing the first energy conversion. Subsequently, the dual-optimized linear layout attained a q-factor up to 1.13 in commonly occurring sea states, achieving improved average power generation in 60% of the evaluated sea states. The performance of the random layout exhibited the average power fluctuating along the wave spectra with a peak q-factor of 1.07. The individual adaptive resonance is confirmed in the optimized arrays, such that each surface-riding wave energy converter of both layouts adaptively resonates with the peak of the wave excitation spectra, maximizing the power generation for the different irregular waves.

Techno-Economic Analysis of Central Receiver Plants According to the Optical Error of the Solar Field

Among the concentrated solar power technologies (CSP), the central receiver (CR) technology is the most promissing to achieve the lowest levelized cost of energy (LCOE) and the one expected to play one of the major roles in the energetic mix in the next years. For that purpose, succesful CR projects are needed, starting by the contruction and erection of a reliable heliostat field that fulfils its design specifications. In this work, the loss of energy production and the consequently rise of LCOE is investigated as function of the optical error of the heliostats. For that, a reference CR plant is defined in which the heliostat field layout and the receiver are optimized to collect the maximum annual energy. An aiming strategy is also implemented to obtain more realistic results. For instance, for a reasonable deviation of about 40-50% compared to the optical reference error, the annual collected energy can drop to a considerable 5%.

Assessing the viability of a grid-connected PV power plant in Mubi, Adamawa State, Nigeria

This paper is based on a techno-economic analysis and the environmental impact of a proposed 1 MW solar photovoltaic (PV) power plant at the main campus of the Federal Polytechnic Mubi (FPM) in north-eastern Nigeria. A photovoltaic power plant converts solar radiation into electricity that can be used as a source of electrical power to meet the daily energy requirements of homes, equipment, and all tertiary institutions. RETScreen Expert software was used to evaluate the techno-economic and environmental sustainability of installing a grid-connected PV power plant. The research results revealed that with an annual solar radiation of 5.74 kWh/m2/day, the maximum annual energy production was estimated to be 1,550.98 MWh. It was discovered that the maximum energy production in March was 146.89 MWh. The project’s profitability and economic sustainability were determined with a good internal rate of return (IRR) of 11.9% and a positive net present value (NPV) of $681,164. The proposed PV power plant has a simple payback period of 11.4 years. The maximum greenhouse gas (GHG) emission reduction is 670.9 tCO2, equivalent to 61.7 ha of forest-absorbing carbon emissions.

Design procedure of stationary compound parabolic concentrator with flat plate absorber for effective year-round performance – Response Surface Methodology and Tracepro as tools

The stationary Compound Parabolic Concentrators (CPC) with a low concentration ratio (C<2) are suitable for pre-heating processes in industrial applications. The reported literature does not analyze the radiation available or the solar angles for whole year towards design of CPC which could provide maximum annual energy. This paper optimizes the design factors of CPC, such as acceptance half-angle (θa) and truncation ratio (TR), to yield maximum energy around the year, maximize optical efficiency and minimize reflector material. Annual irradiation data for the location - Tiruchirappalli, Tamilnadu, India (ϕ- 10°45′36″ N) is considered for the present study. The raw irradiation data is processed to get monthly average daily data, which is used as input for the TracePro v21.1. The experimental design (DOE) is made in response surface methodology (RSM) by considering the factors of θa - 18.5 to 28.5° and TR - 0.5 to 1.0. Nine Geometric models were created using Solidworks based on the combination of parameters given by RSM and simulated using TracePro to estimate the annual energy collection and average optical efficiency. Using the TracePro analysis month wise energy collection is calculated and reported. Further, a model relating θa and TR to the annual energy collected was obtained. According to the results obtained from the multi-objective optimization, the optimum concentration ratio is 2 with the θa of 28.5° without truncation. The results also indicate that the deviation from the average energy collected by the optimized design over the year is less when compared to the other designs.

Useful energy, economic and reduction of greenhouse gas emissions assessment of solar water heater and solar air heater for heating purposes in Gaza, Palestine

This study investigated the crisis of energy from which Gaza has been suffering over the past years. It ventured to highlight the growing needs for energy and the urging need to use renewable and sustainable sources of energy such as solar thermal energy. Much specifically, it gave much importance to the solar water heater (SWH) as well as the solar air heater (SAH). These two important tools rely on clean and renewable source of energy, and their use in the Gaza Strip would greatly help in bringing about an environmental conservation and sustainable economy. The result obviously shows that both SWH and SAH systems are very suitable for space heating for buildings. The maximum annual heating energy gained is 20360.7 kWh at an inclination angle of the solar collector of 30° for SWH. While for SAH the best value of heating delivered was 19268.9 kWh at a tilt angle of 45°. Besides, the result exposes that the use of SWH and SAH systems can potentially save up to $3461.3 and $3275.7 respectively of energy cost annually. The payback achieved on the investment in SWH and SAH is 4.4 and 4 years respectively. Additionally, the utilization of SWH and SAH systems can ultimately save energy as well as potentially reduce emission of air pollution. For instance, using SWH and SAH can reduce 17306.6 and 16378.57 kg/year of CO2 emissions respectively.

Improving the energy efficiency of wind turbines for charging batteries

The article describes the method for determining the optimal angular velocity and the number of turns of the generator winding on permanent magnets powered by a wind turbine operating in specific operating conditions according to the wind speed regime. The optimization criterion is the maximum potential of energy that can be used to charge the battery. The permissible power of the generator and wind turbine, current and battery charging voltage are accepted as limiting factors. The restriction is provided by connecting a ballast resistor to the generator output. The power developed by the turbine is determined taking into account the wind energy utilization factor, which depends on the angular velocity of its shaft and wind speed. Two variants of power limitation are compared: by limiting the angular velocity by aerodynamic means and by stopping the wind turbine. The return of energy to charging in both cases is determined taking into account the distribution of wind speeds, obeying the Weibull probability distribution law. As an example, the calculation of the possible annual power generation for charging a battery with a capacity of 200 A∙h with a voltage of 24 volts from a synchron generator with a number of poles of 48 driven by a wind turbine with a radius of 2 meters, operating in an area with an average wind speed of 5 m/s. The calculation shows that for the parameters and operating conditions of the electrical installation used in the example, the maximum annual energy output (3.3 × 103 kWh) is observed at optimal 11 turns of the winding at each of the poles of the generator. The deviation of the number of turns from the optimal one in both directions by 2 times leads, with the same dimensions of the wind turbine, to a decrease in annual energy output by 3...5 times, which is a clear proof of the need to carry out such a calculation for each specific wind turbine.

Advanced Method of Variable Refrigerant Flow (VRF) System Design to Forecast on Site Operation—Part 3: Optimal Solutions to Minimize Sizes

Outdoor air conditioning systems (ACS) are used as autonomic systems as well as in combined outdoor and indoor ACS of the variable refrigerant flow (VRF) type, with variable speed compressors (VSC) as their advanced version. Methods for determining the optimal value of refrigeration capacity and providing the maximum rate of the summarized annual refrigeration energy generation increment, according to its needs at minimum compressor sizes and rational values, are applied to reveal the reserves for reducing the designed (installed) refrigeration capacity, thus enabling us to practically achieve maximum annual refrigeration energy generation as the primary criterion at the second stage of the general design methodology previously developed by the authors. The principle of sharing the total thermal load on the ACS between the ranges of changeable loads for outdoor air precooling, and a relatively stable load range for further processing air are used as its basis. According to this principle, the changeable thermal load range is chosen as the object for energy saving by recuperating the excessive refrigeration generated at lowered loading in order to compensate for the increased loads, thereby matching actual duties at a reduced designed refrigeration capacity. The method allows us to determine the corresponding level of regulated loads (LRL) of SRC and the load range of compressor operation to minimize sizes.

Performance investigation of solar assisted desiccant integrated Maisotsenko cycle cooler in subtropical climate conditions

Air conditioning has become an integral part of buildings due to climate change and global warming. About 40% of the world energy is being consumed by the building sector, with around 50% share of HVAC applications. In the current study, the simulation-based performance of solar desiccant integrated Maisotsenko cycle cooling system is analyzed in subtropical climate conditions. Initially, an office building model is developed in TRNBuild to generate hourly dynamic year around air-conditioning loads. Afterwards a simulation model of the SDI-MC is developed for maximum cooling capacity of 24 kW in TRNSYS and validated with experimental data. Additionally, an effective control strategy is also implemented to efficiently meet the air-conditioning demand. The main performance parameters include COP, cooling capacity, useful energy gain, efficiency of solar water heating system, auxiliary energy share, and solar fraction of the system. The result revealed that the COP of the system ranges from 0.78 to 1.13 due to variation in system inlet humidity and temperature. Regeneration temperature requirement varies from 60 °C to 78 °C while cooling capacity of system ranges from 8 KW to 24 KW. Similarly, the results revealed an average annual efficiency of evacuated tube solar thermal collectors around 35.80% with total annual energy gain of 113.96 MJ. Furthermore, the maximum annual auxiliary energy share required for regeneration is 12.5%.

Modelling the Development of Above-Ground Biomass Energy Reserves of Four Economically Important Coniferous Woody Species

The goal of renewable energy is to replace energy production from fossil fuels. In that sense, forest biomass is essential renewables. This article presents the results of the development of energy reserves in fractions, increments and the total above-ground biomass of coniferous stands (spruce, fir, pine, larch) during their economic cycle. The experimental material comes from 22 forest stands located mainly in Central Slovakia, to a lesser extent also in Western and Eastern Slovakia. Energy reserves of coniferous stands were calculated based on the volume production of above-ground biomass fractions taken from mathematical models of yield tables and average values of their basic density and calorific value were determined. The research showed that as the age of the stands increased, the share of energy in the wood fraction increased, while it decreased in the bark fraction, and especially the branch fraction. The curves constructed in relation to the age of the stand and site index have a very similar shape to the curves of the total current annual energy increment of coniferous stands. The energy reserves of stands grew faster at the age of 40 to 80 years than at the age of 80 to 140 years. Spruce had the highest total mean energy increment, followed by fir, larch and pine. As the age of the stands increases, the energy reserves of the increments slightly decrease and the efficiency of solar energy significantly decreases. It peaks practically at the age of reaching the maximum annual energy increment.

EARTHQUAKES of 2016–2017 FELT in MOLDOVA (Romania–Moldova)

All earthquakes felt in 2016–2017 on the territory of Moldova occurred outside its borders, in the Vrancea region (Romania), with intermediate depths in the range hрР = 95–135 km. In 2016, the population of Moldova felt 2 earthquakes: September 23th with Mw=5.7, hрР=95 km and December 27th with Mw=5.6, hрР=100 km. For them, data on quakes in 113 and 150 localities, respectively, were collected, according to which isoseismal maps were made. The earthquake of September 23, 2016 was most evident in the eastern and southern parts of Romania. But it was also felt in the north of Bulgaria, in Moldova and the south-west of Ukraine, in Serbia and Macedonia. The echoes of the earthquake reached Istanbul in the south, Tirana in the west, Gomel in the north and Mariupol in the east from the epicenter. The maximum intensity of 6 points on the Mercalli scale was noted in Buzau. The earthquake of December 27, 2016 was most evident in the eastern and southern parts of Romania, as well as in northern Bulgaria, Moldova, southwestern Ukraine and Serbia. The maximum intensity of I=5 on the Mercalli scale was noted in Vanatori. In 2017, the population of Moldova felt 4 earthquakes: February 8th, May 19th, August 1st and 2nd. The earthquake on February 2nd with Mw=4.5 and hрР=126 km manifested itself in Romania and in the Republic of Moldova with an intensity of I=2–3. The earthquake on May 19 with Mw=4.3 and hрР=124 km was felt in the eastern and southern counties of Romania (in 6 localities), in the central and southern regions of the Republic of Moldova. Tremors from the August 1st earthquake with Mw=4.3 and hрР=107 km were felt in the eastern and southern counties of Romania, as well as in the central and southern regions of Moldova (Cahul and Chisinau, I=2–3). The earthquake on August 2nd with Mw=4.9 and hрР=135 km was felt in the eastern and southern counties of Romania, in Cahul with an intensity I=3 and in Chisinau – I=2. The solutions of the focal mechanism given in the article indicate that all the considered earthquakes occurred under the influence of the prevailing compression close to horizontal. It is noted that the value of the total seismic energy released in 2016 in the focal area of Vrancea is the maximum annual energy for this area in the 21st century.

A wind turbine blade leading edge rain erosion computational framework

Blades are one of the most important components, in terms of capital and operational costs, of wind turbines. The experienced acquired by the industry in the latest decades has shown that leading edge erosion is a problem of concern that impacts the reliability of the blade and the power production of the turbine, among others. This study provides a framework to estimate leading edge erosion evolution and energy production degradation throughout time to apply in operation and maintenance decision making. It is based on the generation of synthetic wind and rain data based on observations from the site and ERA5 reanalysis data, whirling arm test data of erosion protection coatings, along with aerodynamic polar curves for clean and eroded airfoils of the blade. Rain erosion is calculated based on impingement, and assumed to be linearly accumulated using the Palmgren–Miner rule. Synthetic wind and rain time series are used to evaluate 25-year erosion degradation and energy production scenarios. A case study using the 5MW NREL’s wind turbine located in the North Sea has been analysed with the proposed framework showing maximum annual energy production losses in the range of 1.6–1.75% and first erosion failure between years 2 and 6.

Off-design performance analysis with various operation methods for ORC-based compression heat recovery system in cryogenic air separation units

Off-design performance of the ORC-based compression heat recovery system in cryogenic air separation units (ASU) with various operation methods is conducted in this paper, in order to explore the energy-saving potential during annual off-design operation. An operation method considering the temperature matching between the heat source and working fluid is proposed and compared with the other four operation methods (i.e., constant superheat operation method, constant pressure operation method, sliding pressure operation method and free operation method). With a 60,000-Nm3/h scale cryogenic ASU taken as the study case, the proposed operation method has the best energy-saving effect in all cases with a maximum annual energy saving reaching 13.83 GWh, corresponding to an energy-saving ratio of 9.6%, which produces a maximum energy-saving difference of 1.47 GWh with the other operation methods. At the same time, the system with the proposed operation method can realize normal operation under all annual working conditions. This study may provide guidelines for the design and operation of the compression heat recovery system in cryogenic ASU along with other waste heat recovery systems.

A general algorithm for the optimization of photovoltaic modules layout on irregular rooftop shapes

Although the installation of photovoltaic systems on roofs is a successful investment, rooftop space availability has been identified as a significant limiting factor in achieving zero-energy buildings, especially by building components such as chimneys, elevator machine rooms, fans, plumbing vents, etc. This study presents a general algorithm for the optimal deployment of photovoltaic module rows installed on irregular flat roof shapes. The presented algorithm takes into account the irregular rooftop shape, the self-shading of photovoltaic modules, the inclusion of building components, commercial photovoltaic modules with different sizes, mounting systems with different configurations, distances required for maintenance, and the technical reports to minimize shading effects. The proposed algorithm allowed to increase in the amount of solar energy received by the photovoltaic modules. The optimization process takes into account the weather conditions at the specific location. The optimization algorithm was implemented using a specific Mathematica™ code in which the commands used in the development of the code were introduced to facilitate its replication. The optimization algorithm output provides the essential parameters for the optimal photovoltaic system design such as: the optimum number of mounting systems and their configuration, the optimum tilt angle of the mounting system and its dimensions, the photovoltaic module model, the maximum total area of the photovoltaic field and the maximum annual energy captured by the photovoltaic modules. We compared the mounting system layout obtained with the proposed algorithm with the tilt angle photovoltaic module layout recommended by three technical papers ( IDAE Technical Report, Lorenzo’s equation and Jacobson’s equation) with respect to photovoltaic field area gain, energy gain and levelized cost of energy .The optimal photovoltaic module layout obtains the maximum photovoltaic field area gain of 35.52% with respect to the Jacobson’s equation and the minimum of 32.29% with respect to the IDAE Technical Report. The optimal photovoltaic module layout obtains the maximum energy gain of 27.83% with respect to the Jacobson’s equation and the minimum of 24.84% with respect to the IDAE Technical Report. The levelized cost of energy of the optimal P V module layout is lower than that of the other arrangements studied. The algorithm presented may be useful for decision-makers or policymakers in determining the optimal distribution of photovoltaic modules on irregular rooftop shapes. • Algorithm for the optimal PV modules layout on irregular rooftop is presented. • Building components and irregular roof shapes are considered in the research. • The influence of the mounting system configuration is investigated. • The algorithm obtains 28% more energy than the obtained by a classical method. • The LCOE efficiency of optimal PV module layout is the best.

A novel estimation chart method based on capacity value calculated by using energy pattern factor to determine rated wind speed

ABSTRACT The nominal rated wind speed is the most important parameter on the energy production of a wind turbine. However, when the literature studies are examined, there are no studies that have formulations directly related to nominal wind speed. Therefore, the aim of this study was to determine the nominal wind speeds that will obtain the maximum power from wind turbines. Nominal wind speeds were determined by analyzing the capacity values that were calculated directly by using the energy pattern factor. Thus, new and practical charts were created for the selection of the wind turbines with the most appropriate nominal wind speed to achieve maximum annual energy production. In the case study, it was observed that the selection of turbines with values below the appropriate nominal wind speeds decreases the annual energy production by 30.1%. This shows how the selection of turbines with the correct and appropriate nominal wind speeds in the areas where the wind energy power plants are planned to be installed is important in a general energy production.

Performance analysis of solar water heater system with heat pipe evacuated tube collector on Moha soft drink industries in Ethiopia

Hot water is a crucial demand for many of Ethiopia's industrial and household heating systems. Most industries are using boilers powered by conventional energy sources to meet the demand for hot water. Due to the environmental impact of conventional energy sources usage and the rise in fossil fuel prices, the utilization of solar energy as a source of energy become a promising candidate for various applications. We use MATLAB/SIMULINK software to carry out this study of solar water heating systems with heat pipe evacuated tube collectors. Comparisons of total solar radiations were made at various optimum tilt angles for the selected locations. The adjustment of tilt angles has a great impact on the collection of useful energy. The maximum average annual energy savings are 1.21E+06 kWh/year for Addis Ababa at monthly and seasonal optimum tilt angles, 1.26E+06 kWh/year for Dire Dewa at a monthly optimum tilt angle, and 1.21E+06 kWh/year for Hawassa at a monthly optimum tilt angle. This means it will reduce 326,700 kg of CO 2 , 340,200 kg of CO 2, and 326,700 kg of CO 2 emissions per year respectively. The efficiency increases as the heat transfer fluid flow rate increases. The maximum annual cost savings are at monthly optimum tilt angles of the collector (6.12E+04 $/year, 6.36E+04 $/year, and 6.11E+04 $/year for Addis Ababa, Dire Dewa, and Hawassa cities, respectively with a payback period of 6.43 years, 6.18 years and 6.44 for Addis Ababa, Dire Dewa and Hawassa cities, respectively.

Energy consumption prediction using Petri Nets-ANFIS development technique

Energy consumption has always been considered one of the major issues in the six Gulf Cooperation Council (GCC) countries. Therefore, the predicted energy consumption can respond based on several factors and conditions, where which will help in response to plan saving energy for the future. The significant contribution of the present study is the development of software merging the Petri-Nets and ANFIS to become a comprehensive model to find the maximum annual load demand estimation of the GCC countries based on the historical data of the countries. The ANFIS-Petri Nets have expected modeling to represent knowledge and help in rule-based expert systems. The data has several parameters/conditions (factors), where these factors are temperature, humidity, GDP, pressure, and energy consumption. The results lead to a fast and accurate figure have developed an energy estimated system that works by tracking, analyzing, and controlling conditions of the energy system. The Petri-Nets ANFIS developed technique targeting the estimated maximum annual energy consumption believes that obtaining the values is satisfactory for the future of GCC states. In addition, the developed and obtained models have great application for the GCC countries. This might help to develop the models of other countries.

Wind Resource Assessment by Analyzation and Simulation in WAsP for Electricity Generation in Chiang Mai, Thailand

The purpose of this study is to assess and analyse the potential wind energy in Chiang Mai, the northern province of Thailand. The calculation in this paper is based on ten-minutes interval data at 10m height recorded for three years data from 2017 to 2019 at Thai meteorological station, Thailand. Weibull model is applied to evaluate the wind distribution by utilizing wind atlas analysis and application program (WAsP). Meanwhile, the average wind speed and the average power density was recorded at 1.48 m/s and 15 W/m2. The prominent wind direction is from the south west to north east. The two potential sites showed the maximum annual energy production 1401.419 MWh and 1913.410 MWh by using Bonus 300kW Mk III wind turbine with LCOE $382.64 / MWh and $274.63 / MWh respectively. This paper suggests the suitable sites for the electricity generation in Chiang Mai. Hence, it will not only reduce the stress on conventional methods but also create awareness regarding the potential of wind energy.

Theoretical concentration limit and maximum annual optical efficiency of static/low-concentration CPV for horizontal integration to vehicle bodies.

This study proposes an extended theoretical formula to characterize the relationship between the geometrical concentration ratio Cg and arbitrary incidence-angle range to objectively understand the theoretical limit performance of vehicle-integrated concentrator photovoltaics (VICPVs), i.e., static and low-concentration CPVs installed on a horizontal surface. Theoretical analysis revealed that the maximum annual optical efficiency (maximum annual solar energy yield) can be achieved by selectively collecting the sunlight incident only from a specific incidence-angle range of θ1-θ2 (θ1 ≠ 0°), regardless of the geographical location, which is associated with the angular distribution of the annual solar energy on the concentrator aperture. Moreover, the results of the solar concentrator design based on the obtained formula clarified that the annual optical efficiencies of the optical systems with aspheric lens or dielectric-filled crossed compound-parabolic-concentrator lens were 64-89% of the theoretical limit depending on the location for Cg = 3.5×. Nevertheless, the concentrator design can be further improved for practical applications.

Investigation of enhancement in the thermal response of phase change materials through nano powders

A major problem faced by Phase Change Materials (PCM) based latent heat thermal energy storage systems is the slow thermal response. In this study, the feasibility of nano phase change materials composites is investigated experimentally by using various types of nanoparticles in PCM, to improve thermal response by increasing the thermal conductivity. Heat transfer enhancement of PCM composites (RT26 and coconut oil) is achieved by acquiring better thermophysical properties through seeding nanoparticles in PCM. RT26 and coconut oil are beneficial due to the absence of corrosion to metallic containers. A thermal response investigation is conducted with a flat slab type latent heat thermal energy storage unit. It was observed that the increase in thermal conductivity of PCM by seeding nanoparticles is useful for the improvement of heat transfer. Carbon nanotubes have shown better performance as compared to Al2O3 and Fe3O4 nanoparticles. It was further analyzed that at a 1 wt percent concentration of nanoparticles, the maximum heat transfer enhancement in RT26 caused by Fe3O4, Al2O3 and carbon nanotubes nanocomposites is up to 20.01, 36.68 and 64.21% respectively. The maximum heat transfer enhancement in coconut oil caused by Fe3O4, Al2O3 and carbon nanotubes nanocomposites is up to 8.83, 14.84 and 33.38% respectively. Therefore, it is revealed that RT26 has more potential for heat transfer enhancement as compared to coconut oil. This is due to the percentage improvement in the thermophysical response of RT26 as compared to coconut oil. The economic and environmental analysis was conducted to compare the performance of latent heat thermal energy storage unit with and without the application of nanoparticles in PCM, to estimate the most viable candidate among various nano composites. The economic analysis presented the lowest annual energy running cost and Net Present Value(NPV) for nanocomposite of carbon nanotubes in RT26 is Rs.-4381 and RS.-36375 respectively. Whereas the maximum annual energy cost and NPV for pure RT26 are Rs.-12240 and Rs. -75548 respectively. The NPV for Fe3O4 and Al2O3 is Rs.-62207 and Rs.-53062 respectively. The cost and NPV were Rs.-6646 and Rs.-55226 in the case of carbon nanotubes in coconut oil. It shows that the trend is the same in the case of Fe3O4 and Al2O3 nanoparticles in both RT26 and coconut oil, unlike of carbon nanotubes. The environmental analysis shows that the maximum and minimum payments of carbon dioxide by carbon nanotubes and Fe3O4 nano composites respectively in RT26, are Rs.7000 and Rs.2176. While the corresponding values are Rs.2975 and Rs.798 in the case of coconut oil. Hence, carbon nanotubes in RT26 have the highest economic and environmental viability. Accordingly, the enhancement in heat transfer using these nanoparticles will be helpful in air conditioning applications like animal houses.

Performance Analysis of 120 kWp Grid-Connected Rooftop Solar Photovoltaic System in Central Java

This study examines the performance of a solar power plant with a total capacity of 125 KWp, which operates for one year in Blora, Central Java. The ability of this power plant is a total of PV modules with 20 kWp, ten kWp, and five kWp capacities spread across eight locations. The annual performance of the rooftop solar power plant is measured automatically by the converter installed in each module. The resulting data from inverters are compared to the meteorological conditions from the meteorological agency. This research will investigate the influence of climate on the power generated, the efficiency of the equipment in a power plant, and the effect of pseudo motion of the sun. It was found that there were variations in energy output throughout the year, and it was concluded that the maximum annual energy was produced in July-August. In addition to weather, other factors need to be investigated further to determine the causes of variations in solar PV output.