Annual Electrical Energy Research Articles

Investigation of photovoltaic-hydrogen power system for a real house in Turkey: Hydrogen blending to natural gas effects on system design

In the study, the effects of hydrogen mixing studies at the rate of 20% to the natural gas system which is an ongoing study in Turkey, on the photovoltaic system (PV) is investigated using a real house consumption. Providing the annual electrical energy consumption (1936,83 kWh) and 20% of natural gas consumption (62,4 m3) of a real house with hydrogen is included in the study. A PV-hydrogen system is theoretically investigated to provide the energy required for hydrogen production from solar panels. Hydrogen blending effects on PV size, capacity usage, and carbon footprint are analyzed. Thus, the contribution was also made to the “green hydrogen” works and reduction of the carbon footprint of the house. It was found that the required hydrogen for electricity can be provided 52,5 m2 solar panel area and 14,28% increase in this area and installed power can provide an amount of hydrogen that need for 20% hydrogen blending to the natural gas system. The overall system capacity usage decreased when the system is used for 20% hydrogen blending to the natural gas system. The carbon footprint of the house was decreased by 67,5%. If the hydrogen has not been blended with 20% natural gas, this ratio would have been 59,2%.

INFLUENCE OF OPAQUE PHOTOVOLTAIC SHADING ON MICROCLIMATE AND GROWTH OF STRAWBERRY IN GREENHOUSES

The effect of photovoltaic PV panels on strawberry growth and the greenhouse microclimate has been studied meanwhile; the annually generated electric energies were estimated by the PolySun program. The peak power of the opaque PV was 310 W. There were four PV panels distributed on the top of greenhouse south plastic roof at a vertical distance of 0.08 m as an isolated air layer under the PV panels at a tilt angle of 30 . Meanwhile at a horizontal distance between panels of 1.1 m to allow the solar light entering greenhouse. Results revealed that the greenhouse air temperature and solar radiation under the un-shaded greenhouse were higher than that of the shaded greenhouse by opaque PV. Moreover, the opaque PV temperatures ranged from 45 ᵒC to 47.5 ᵒC. The simulation results showed that the annual generated electric energy of the opaque PV panels was 3195 kWh which could cover approximately 30.4% of the annual electric energy demand for environmental control. In addition, there were no significant differences in the number of leaves, flowers including fruits, and chlorophyll contents between strawberries under the shaded and un-shaded greenhouses. In a word, the integration of opaque PV at a specific distribution is highly recommended to provide the required light for photosynthesis and energy for greenhouse without harming the growth of strawberries.

The Effect of Building Orientation on Utilization of Solar Energy in Dairy Cattle Barns

In Turkey and the World, energy demand is continuously increased. In addition to the rapid depletion of fossil fuel resources used to supply the energy needs, ambient temperatures is risen, glaciers are melt and natural disasters are occured in our planet. In addition, people, animals and plants are greatly damaged due to the adverse effects of soil, water and air pollution. Solar energy is renewable, clean and easily accessible energy. Our country is more advantageous in terms of solar energy potential in comparison to many other countries and benefitting from this potential is very important. With the increasing importance of renewable energy sources, photovoltaic (PV) panels, which are able to convert solar energy directly into electrical energy, are not polluting the environment and easy to implement, are become more common. The inclination angle and position of the photovoltaic panels are the parameters that directly affect the production of electrical energy. Electrical energy is extensively used in agricultural production activities, as in every field. Especially, in animal production systems, the cost of electrical energy is an important input due to the high mechanization and the use of automation. This study was carried out in the dairy cattle barn with a capacity of 50 head in Bursa province. It was aimed to determine the amount of electrical energy produced by photovoltaic (PV) panels, located on the barn roof in four different directions (North-South, East-West, Northeast-Southwest, Northwest-Southeast), and also to find out whether produced energy is sufficient or not to meet the energy requirement of the barn. The electrical energy produced by the panels to be placed on the roofs was determined by using PVSOL software. According to the results, the amount of electrical energy produced from the panels with North-South (N), East-West (E), Northeast-Southwest (NE) and Northwest-Southeast (NW) orientation was determined as 179.453,0 kWh, 159.655,0 kWh, 175.950,0 kWh and 138.245,0 kWh, respectively. The annual electrical energy requirement of the barn with 50 head capacity was calculated as 25.200,0 kWh. In this case, it was calculated that the energy produced from the N, E, NE and NW orientations met the requirements of the barn by 5 to 7 times.

An approach to select an energy-efficient shading device for the south-oriented façades in heritage buildings in Alexandria, Egypt

The different shading devices originally used in heritage buildings (if existed) might not be the optimal shading device to conserve the electrical energy consumed by the heating, ventilation, and air conditioning systems (HVAC). However, finding a suitable shading device that can improve thermal comfort without compromising the electrical energy consumption is considered a challenge since utilizing an inappropriate one could result in consuming more electrical energy than it should. This study aimed to propose an approach to selecting the best shading device between external and internal alternatives with controlling the HVAC system temperature setpoint to increase energy efficiency and achieve thermal comfort in south-oriented façades of heritage buildings in Alexandria in Egypt. The results showed that using the external horizontal blinds and microlouvre at certain HVAC temperature setpoints could save up to 46% and 35% of the HVAC annual electrical energy consumption and achieving thermal comfort on 228 and 261 days, respectively. Meanwhile, applying the optimal annual operating schedule approach achieved 365 thermally comfortable days, saving around 35% of the HVAC annual electrical energy consumption.

Scenarios for offshore wind power production for Central California Call Areas

AbstractIn response to the growing interest in offshore wind energy development in California, the U.S. Bureau of Ocean Energy Management delineated three Call Areas for potential leasing. This study provides a comprehensive characterization and comparison of offshore wind power potential within the two Central California Call Areas (Diablo Canyon and Morro Bay) using 12‐ and 15‐MW turbines under different inter‐turbine spacing and wind farm size scenarios. Our analysis shows similar daily and seasonal patterns of wind power produced within the Call Areas, which peak in spring and during evening hours. Per‐turbine power production is higher in the Morro Bay Call Area due to slightly higher hub‐height wind speeds, whereas total power production is higher in the Diablo Canyon Call Area due to its larger size. Turbine type had a negligible impact on average power production per‐unit‐area because while larger turbines produce more power, they require greater inter‐turbine spacing. Combined power production from the two fully built out Call Areas could equal nearly a quarter of California's current annual electrical energy production. A commercial‐scale wind farm with a realized power output of 960 MW would require a footprint of at least half of the Morro Bay Call Area or at least a quarter of the Diablo Canyon Call Area. These results provide guidance on offshore wind development over the Central California Coast, and the framework demonstrated here could be applied to other wind data sets in other regions.

Optimal management of energy sharing in a community of buildings using a model predictive control

Exporting generated electricity by on-site renewable energy systems from buildings to the grid is only slightly profitable in many countries. Therefore, it is required to investigate the benefits of sharing generated energy in a microgrid within a community of buildings. Exploiting the benefits of peer-to-peer energy exchange between prosumers in a community can make the best use of the on-site generation while reducing their bills. This study elaborates the potential of energy management to minimize the electricity cost of a community consisted of multiple buildings and connected to a microgrid. To implement this, an energy management system is designed based on non-linear economic model predictive control and successive linear programming for sharing the on-site surplus generated electricity between the buildings in the community. Four buildings are simulated and studied as an example of a small community. These buildings are dissimilar in their age, thermal mass, insulation, heating system and on-site renewable energy systems. It is shown that considering the community of buildings as a single entity, the novel model predictive control can be efficiently used for minimizing the energy cost of the community that has various sources of energy generation, conversion and storage, including significant non-linear interactions. Three different scenarios of the energy management system for the studied community are investigated, and the results indicate that the annual electricity energy cost for single buildings can be reduced by 3.0% to 87.9%, depending on the building and its systems, and by 5.4% to 7.7% on the community level.

On the impact of stochastic modeling of occupant behavior on the energy use of office buildings

The reliability of building performance simulation is hindered by several uncertainties, with aleatory uncertainty due to occupant behavior being one of the most critical. The present study aims to assess the propagation of uncertainty due to the adoption of stochastic models for modeling Occupant Presence and Actions (OPAs) available in the literature on the annual electric energy use of a reference office building. To this purpose, a global sensitivity analysis was designed and carried out by analyzing model inputs and energy outputs of 144 permutations of 15 different stochastic models for OPAs for a total of 7200 simulations. Building energy use computed considering stochastic OPAs modeling resulted in being sensibly higher than the reference value estimated assuming scheduled occupancy and rule-based occupant’s actions as suggested by reference standards. The median value of the electric energy use was 58.6% higher than the base case electric energy use. Furthermore, the stochastic models used to model window operation have the highest effect on energy output, followed by light switch-off, and occupancy models. Light switch-on models showed a lower influence on the overall building energy performance. Furthermore, the Generalized Estimating Equations method was adopted to assess the interdependence among stochastic models for OPA and showed that changing the stochastic model in window operation, occupancy estimation, and light switch-off behavior generates a considerable difference in building’s energy performance. Contrariwise, the available stochastic models for light switch-on and blind operation perform quite similarly among each other and have a limited impact on a building’s energy performance.

Linear Regression Analysis and Techno-Economic Viability of an Air Source Heat Pump Water Heater in a Residence at a University Campus

This study quantifies the potential of a 4.0 kW air source heat pump (ASHP) unit retrofitted to a 12.0 kW, 1000 L electric boiler coupled to a 1000 L storage tank. A data acquisition system was built to monitor the performance of the electric boiler and the ASHP water heater. The annual electrical energy saving and the load factor reduction from the electric boiler because of the ASHP unit retrofit was 34,805.94 kWh and 0.124. The net present value payback period of the ASHP system was 1.60 years. A Wilcoxon rank sum test was employed to compare both the volumes of hot water and electrical energy consumed by the two systems. Linear regression models of the daily volumes of hot water and electrical energy consumed by both systems were established. The results should be of great value to the management of universities that are considering energy-efficient interventions with a significant return on investment.

A Techno-Economic Comparative Study of a Grid-Connected Residential Rooftop PV Panel: The Case Study of Nahr El-Bared, Lebanon

Lebanon suffers from daily electricity shortages. The country has paid much attention to renewable energy sources, particularly solar, to gradually replace conventional energy. Installing a photovoltaic (PV) system becomes increasingly attractive for residential consumers due to the rising electricity tariff rates while it reduces the dependency on domestic power generators. No known study has dealt with the investigation of potential grid-connected rooftop PV systems with various sun-tracking modes and PV technologies in Nahr El-Bared, Lebanon. Consequently, the main objective of the current paper is to investigate the feasibility of a 5kW grid-connected PV system of various technologies (mono-crystalline silicon and poly-crystalline silicon) and sun-tracking modes including fixed tilt and 2-axis systems for rooftop households in Lebanon. The Nahr El-Bared camp was the case study was of the paper. RETScreen Expert software was used to evaluate the techno-economic performance of the proposed systems. The results show that the annual electrical energy from a fixed 5kW PV panel tilted at an optimal angle ranged from 8564.47kWh to 8776.81kWh, while the annual electrical energy from the PV tracking system was within the range of 11511.67-12100.92kWh. This amount of energy output would contribute significantly to reduce the energy shortage in the country. A typical household was selected to establish a load profile and load supply during both grid availability and outage periods. The highest energy consumption that can be covered by the PV systems was recorded during the spring and summer seasons. Also, the average energy production cost ranged from 0.0239 to 0.0243$/kWh for all the proposed systems. It was concluded that a 5kW grid-connected rooftop PV system could be economically justifiable. Finally, this study tried to increase the awareness about utilizing PV sun-tracking systems and the feasibility of small-scale grid-connected rooftop PV systems in the selected regions. The results of this research can help investors in the energy and building sectors.

An integrated renewable energy based plant with energy storage for a sustainable community

Development and deployment of nature-friendly power technologies are recognized as vital to liberate humankind from disputes spinning around the production, consumption, and sharing of hydrocarbon-based energy sources. In this study, a novel integrated renewable energy plant is developed, simulated and analyzed for the Caribbean Island Nation of Antigua and Barbuda. In this regard, energy is produced from free, clean and abundant wind and solar via wind turbine and concentrated solar power tower technologies. The system’s annual electric energy production is evaluated at around 341 GWh corresponding to 110% of the country’s current annual electricity consumption. The proposed system comprises underwater balloons to store excess energy from wind and solar arrays via compressed air for later power generation. In addition, stored compressed air in underwater balloons is a source of energy to fuel 140 city-driving pneumatic vehicles with a range of 80 km on a daily basis. As well, the proposed system employs a multistage desalination unit to provide 376 tons of fresh water to the region daily. Furthermore, the integrated energy system is scalable to deliver additional potable water production and compressed air to power additional pneumatic vehicles. Overall energy and exergy efficiencies of the proposed system are computed as 52.53% and 43.65%, respectively.

Investigating the Impact of Integration the Saudi Code of Energy Conservation with the Solar PV Systems in Residential Buildings

The demand for air conditioning is increasing day by day in the world’s hot and humid climate areas. Energy conservation in buildings can play a vital role in meeting this high cooling demand. This paper attempts to consider the impacts of energy efficiency and renewable energy measures on the energy demand of Saudi Arabia’s residential buildings. The energy analysis and economic feasibility analysis of thermal insulations are performed in this paper by investigating the effect of residential buildings’ thermal insulations on the economic feasibility of grid-connected photovoltaic systems. This was the combined effort of building owners and government, and buildings were examined if a photovoltaic system and thermal insulation were used. The study was conducted in the three climate zones in Saudi Arabia. The results showed that the building base case’s annual electrical energy consumption in Riyadh city was 67,095 kWh, Hail 57,373 kWh, and Abha 26,799 kWh. For the basic case-building in Riyadh, 69% of the total electrical energy was used for cooling and heating. Applying the Saudi Building Code requirement for Riyadh will provide only 18% of the total energy used for cooling and heating. RETScreen 6.1 software was used to design a photovoltaic system; the analysis was done using technical and economic indicators. The annual yield factor for Riyadh, Hail, and Abha was 1649 kWh/kWp/year, 1711 kWh/kWp/year, and 1765 kWh/kWp/year, respectively. The capacity factors for Riyadh, Hail, and Abha were 18.8%, 19.5%, and 20.1%, respectively. The Unified photovoltaic Levelized energy costs were 0.031, 0.030, and 0.029 $/kWh for Riyadh, Hail, and Abha, respectively. Finally, the Net Present Value and greenhouse gas emissions reduction have been estimated.

Estimation of the energy production of a parabolic trough solar thermal power plant using analytical and artificial neural networks models

The accurate estimation of a concentrated solar power plant production is an important issue because of the fluctuations in meteorological parameters like solar radiation, ambient temperature, wind speed, and humidity. In this work, three models were conducted in order to estimate the hourly electric production of a parabolic trough solar thermal power plant (PTSTPP) located at Ain Beni-Mathar in Eastern Morocco. First, two analytical models are considered. The first analytical model (AM I) is based on calculating the heat losses of parabolic trough collectors (PTCs), while the second analytical model (AM II) is based on the thermal efficiency of PTCs. The third model is an artificial neural networks (ANN) model derived from artificial intelligence techniques. All models are validated using one year of real operating data. The simulation results indicate that the ANN model performs much better than the analytical models. Accordingly, the ANN model results show that the estimated annual electrical energy is about 42.6 GW h/year, while the operating energy is approximately 44.7 GWh/year. The frequency of occurrence shows that 86.77% of hourly values were estimated with a deviation of less than 3 MW h. The developed ANN model is readily useable to estimate energy production for PTSTPP.

Thermal Performance Optimization for Residential Buildings in Basra City

The present study investigates many parameters in the design of a residential building consisted of 6 floors with a construction area 240m2 located in Basra city. This study aims to reduce electric energy consumption utilized for cooling and heating of the building. The parameters which studied included: the effect of building façade, the exterior color of the external walls, the glazing distribution and the shape of the building. eQuest energy simulation program is used to simulate the annual building energy consumption, the program uses the hourly annual collected weather data. The results show that orientation the building façade toward the north direction is the best in the design of the building. The saving in annual electric energy consumption is about 11%. Moreover, the external color of the building has a strong effect on building cooling and heating energy consumption. By utilizing white exterior wall color, the annual electric energy consumption reduced by about 12%. The results also showed that by utilizing proper glazing distribution the electric energy consumption could be reduced by 3%. When all enhancements were combined an optimum building case were found. For the optimum case, the annual electric energy consumption was reduced by 35% compared to the base building case.

Energy Saving Strategies and On-Site Power Generation in a University Building from a Tropical Climate

This paper compares the potential for building energy saving of various passive and active strategies and on-site power generation through a grid-connected solar photovoltaic system (SPVS). The case study is a student welfare unit from a university campus located in the tropical climate (Aw) of Guayaquil, Ecuador. The proposed approach aims to identify the most effective energy saving strategy for building retrofit in this climate. For this purpose, we modeled the base line of the building and proposed energy saving scenarios that were evaluated independently. All building simulations were done in OpenStudio-EnergyPlus, while the on-site power generation was carried out using the Homer PRO software. Results indicated that the incorporation of daylighting controls accounted for the highest energy savings of around 20% and 14% in total building energy consumption, and cooling loads, respectively. Also, this strategy provided a reduction of about 35% and 43% in total building energy consumption, and cooling loads, respectively, when combined with triple low-e coating glazing and active measures. On the other hand, the total annual electric energy delivered by the SPVS (output power converter) was 66,590 kWh, from where 48,497 kWh was supplied to the building while the remaining electricity was injected into the grid.

WIND FARM LOCATION SELECTION AT THE SOUTHERN COAST OF YOGYAKARTA PROVINCE FOR ENERGY SUPPLY OF HYDROGEN FUEL PRODUCTION

The depletion of non-renewable energy reserves and increased awareness of environmental damage caused by fossil-based fuel use have encouraged the world’s efforts to develop and utilize new and renewable energy sources, including in Indonesia, especially in the special region of Yogyakarta. The potential for wind power plants can be developed in 3 districts in the southern part of Yogyakarta, bordering the Java Sea, to be converted into hydrogen through an electrolysis process. The three research locations were Bugel Beach in Kulon Progo, Pandansimo Baru Beach in Bantul, and Baron Techno Park at Baron Beach in Gunung Kidul. The selection of the most optimum location was made employing the Analytic Hierarchy Process (AHP) method by considering three factors, namely technical, location, and socio-economic factors. The first factor includes the potential for electricity generation from wind power and the available land area. The second one consists of sub-factors, namely access to the location and the distance to the PLN electricity distribution line. Then the last one includes conflicts with tourism and the economic activities of the surrounding community. After obtaining the most suitable location, planning is carried out for the wind farm that is built, the amount of electrical energy produced, the cost of generating electricity, and the cost of producing hydrogen from the electrolysis process. Pandansimo Baru Beach is an ideal location, with an average wind speed of 4.833 m/s. Five Vestas V80 2000/80 wind turbines were selected according to the available land. The annual electrical energy that can be produced from this system is 161,677,216 kWh/year with a generation cost of 0.118 USD/kWh and is capable of producing 230,960 kgH2 of hydrogen at 4.35 USD/kg.

Energy and exergy analysis of solar photovoltaic thermal system: experimental and numerical verification

In this study, the electrical and thermodynamic performance of a flat-plate liquid PV/T system was investigated, and the experimental results were verified with a numerical model implemented. The simulation analyses showed that the increasing inlet and ambient temperature had a negative effect on thermal efficiency and the highest thermal efficiency was obtained at 800 W/m2 solar radiation. The optical efficiency of the experimental system was verified with the simulation and reported as 45.8% and 47.9%, respectively. Hourly electrical, thermal, and total energy efficiencies obtained hourly on a daily basis were calculated and varied between 12-13.8%, 36.1-45.2%, and 49.1-58.4% respectively on daily basis. The hourly exergy analyses were also carried out and the results showed that the exergy efficiencies changed between 13.8-14.32%. The annual total thermal and electricity energy outputs were calculated as 1,912 kWh and 556.8 kWh respectively.

Techno-economic assessment of performance-enhanced parabolic trough receiver in concentrated solar power plants

Solar-to-thermal conversion efficiency of the parabolic trough collector significantly degrades at high operating temperatures, which exerts seriously negative effects on the development of parabolic trough collectors. To solve this knotty problem, based on the theory of the negative thermal-flux region, a novel parabolic trough solar receiver with a radiation shield was proposed, manufactured, and tested. In this framework, the proposed solar receiver is employed in the concentrated solar power plants using solar salt as the heat transfer fluid to analyze its feasibility in real solar power plants. In this study, the mathematical models of heat collection and economic assessment are established, and the simulation results yield a good agreement with the experimental data. The techno-economic performances of the solar power plants installing the proposed solar receivers in three typical areas under different installed capacities and thermal storage capacities are comprehensively investigated. The results demonstrate that the proposed solar receiver has a great potential for significant enhancement of the techno-economic performance of the solar power plant. The solar power plant with the proposed solar receivers located in Dunhuang can effectively improve the annual net electrical energy production by 9.77%, reduce the levelized cost of energy by 8.67%.

Performance evaluation of a novel PVT-GSHP heating system on energy-efficient poultry houses: long-term monitoring

Abstract The case study presented in this paper is an innovative ground source heat pump (GSHP) system constituted by a hybrid Photovoltaic Thermal (PVT) solar system for poultry houses. Farmers tend to not to apply GSHPs because of the high prices of excavation and time consumption. The innovative heat pump system assessed in this study comprises of a new type of heat exchangers; a thin-tube solar polyethylene heat exchanger installed between roof tiles and PV panels and a novel vertical ground heat exchanger to utilize the heat stored in the soil. The heating system applied to a poultry house are monitored and evaluated under a variety of environmental and operating conditions to achieve annual/long-term efficiency of the heating system in Kirton, UK. The maximum heating demand of the poultry house is determined 34.4 MWh/PC while the minimum is 11,1 MWh/PC. The monitored results show that the heat pump produced 15.02 MWh of thermal energy per annum. Solar PV and heat pump worked very well together with solar PV covering all the heat pump’s annual electrical energy requirement and generated 8.74 MWh of extra electricity exported to the grid. The seasonal coefficient of performance is found 3.73 through a year. The novel PVT-GSHP heating system is a very promising solution for high fossil fuel consumption in the agriculture industry and the energy savings of the whole system can be noticeably increased dependent up on the system controlling.

Assessment and optimization of solar absorption-subcooled compression hybrid cooling system for cold storage

The solar absorption-subcooled compression hybrid cooling system is an economically viable energy-saving solution for cold storage refrigeration system. However, the thermodynamic and economic performance of this system has not been assessed specifically for cold storage. Additionally, the system performance strongly depends on the appropriate design of critical parameters, which has not been previously analyzed either. Therefore, a technical and financial evaluation of the solar absorption-subcooled compression hybrid cooling system for cold storage is implemented systematically in this study based on the simulation of the typical days. The effects of the absorption subsystem size and storage tank volume are analyzed. Furthermore, global optimization is performed using the genetic algorithm. It is determined the optimal design is as follows an absorption subsystem size of 0.04–0.06 kW/m2 with a storage tank volume of 40–60 L/m2 for the case in which the collector area (2000 m2) is half the available area. The peak annual electric energy savings is 68.8 kWh/m2. The solar absorption-subcooled compression hybrid cooling system is economically viable for cold storage without any subsidy and the minimum payback period is 4.96 y. This study can be beneficial for the effective and feasible reduction of the energy consumption of cold storage refrigeration systems.

Automatic and rapid calibration of urban building energy models by learning from energy performance database

Urban building energy modeling (UBEM) is attracting increasing attention in the energy modeling filed. Unlike modeling a single building using detailed building systems information, UBEM generally uses limited high-level building stock data to infer default assumptions about building characteristics and operations. This practice inherently brings uncertainty to UBEM. This study introduced a novel method of automatic and rapid calibration of UBEM based on the annual electricity and natural gas energy use data by learning the correlations between crucial model input parameters and the building energy use from the reference building models. A case study was presented to calibrate 72 large office buildings built before 1978 in San Francisco. Seventeen model parameters were selected and Monte Carlo sampling was used to create 1000 samples that reasonably represent the parameter space. Then 1000 simulations were performed for the reference building model to create an energy performance database. The results showed that by learning from the energy performance database, it took less than four simulation runs on average to calibrate a building model. After the calibration, the distributions of each parameter were obtained to replace their single predefined default values. For example, the default lighting power density of 21.39 W/m2 was calibrated to be 7.50 W/m2 on average. The case study successfully demonstrated the effectiveness of the novel calibration method for UBEM in the mild climate. The method will be further tested in future for other climate zones and other building types.