scholarly journals Roof-mounted photovoltaic generator temperatue modeling based on common brazil roofing materials

2022 ◽  
Vol 7 ◽  
pp. 5
Author(s):  
Bernardo de Souza Guimarães ◽  
Lucas Farias ◽  
Delly Oliveira Filho ◽  
Lawrence Kazmerski ◽  
Antonia Sônia A. Cardoso Diniz
Keyword(s):  
Residential Buildings ◽  
Galvanized Steel ◽  
Average Error ◽  
Transfer Model ◽  
Pv Module ◽  
Solar Generator ◽  
Roofing Material ◽  
Belo Horizonte ◽  
Photovoltaic Generators ◽  
Pv Generator

This paper examines the performance of solar photovoltaic generators on roofs of residential buildings. The primary focus is the loss of performance due to temperature increase as function of roof material and the distance from the photovoltaic (PV) generator to the roof. A heat transfer model has been developed to predict PV module temperature, and the equations of the model were solved using the Engineering Equation Solver (EES) software. The research modeling correlates the distance of the solar generator to the roof and the roofing material with the temperature variations in the PV generator. There are many models to predict PV module temperature, but this study refines the prediction by the distance from PV module to roof and the roofing material as variables. Optimal combinations of distance and materials that minimize the heating loss in the solar generator leading to increased electrical power generation. Results show an average error of 3%–4% from the temperature predicted by the model to the temperature measured under experimental conditions in Belo Horizonte, Brazil. The minimum roof-module separation required to ensure minimal PV performance loss from heating from the roof is ∼10 cm for red ceramic and cement fiber roofs. For galvanized steel, the optimal distance is between 20 cm and 30 cm. Cement fiber shows the best predicted and measured characteristics for PV-panel roof mounting among the 3-common commercial roofs evaluated in these studies. These investigations were based on roof installations and local materials in Belo Horizonte, Brazil.

scholarly journals Application Method of a Simplified Heat and Moisture Transfer Model of Building Construction in Residential Buildings

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4180
Author(s):  
Joowook Kim ◽  
Michael Brandemuehl
Keyword(s):  
Latent Heat ◽  
Moisture Transfer ◽  
Residential Buildings ◽  
Building Energy ◽  
The United States ◽  
Building Envelope ◽  
Outdoor Environment ◽  
Transfer Model ◽  
Heat And Moisture Transfer ◽  
Heat And Moisture

Several building energy simulation programs have been developed to evaluate the indoor conditions and energy performance of buildings. As a fundamental component of heating, ventilating, and air conditioning loads, each building energy modeling tool calculates the heat and moisture exchange among the outdoor environment, building envelope, and indoor environments. This paper presents a simplified heat and moisture transfer model of the building envelope, and case studies for building performance obtained by different heat and moisture transfer models are conducted to investigate the contribution of the proposed steady-state moisture flux (SSMF) method. For the analysis, three representative humid locations in the United States are considered: Miami, Atlanta, and Chicago. The results show that the SSMF model effectively complements the latent heat transfer calculation in conduction transfer function (CTF) and effective moisture penetration depth (EMPD) models during the cooling season. In addition, it is found that the ceiling part of a building largely constitutes the latent heat generated by the SSMF model.

New Correlation for Two-Phase Flow in 90 Degree Horizontal Elbows

2010 ◽  
Author(s):  
Florencio Sanchez-Silva ◽  
Ignacio Carvajal-Mariscal ◽  
Rene Tolentino-Eslava
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Experimental Results ◽  
Galvanized Steel ◽  
Average Error ◽  
Phase Flow ◽  
Volumetric Fraction ◽  
Dean Number ◽  
Two Phase ◽  
Flow Pressure

The comparison of experimental data and results obtained from four global models — homogeneous, Dukler, Martinelli and Chisholm, used to evaluate the two-phase flow pressure drop in circular 90° horizontal elbows — is presented in this paper. An experimental investigation was carried out using three galvanized steel 90° horizontal elbows (E1, E2, E3) with internal diameters of 26.5, 41.2 and 52.5 mm, and curvature radii of 194.0, 264.0 and 326.6 mm, respectively. According to the experimental results, the model proposed by Chisholm best fitted them, presenting for each elbow an average error of E1 = 18.27%, E2 = 28.40% and E3 = 42.10%. Based on experimental results two correlations were developed. The first one is the classical Chisholm model modified to obtain better results in a wider range of conditions; it was adjusted by a dimensionless relationship which is a function of the homogeneous volumetric fraction and the Dean number. As a result, the predictions using modified Chisholm model were improved presenting an average error of 8.66%. The second developed correlation is based on the entire two-phase mass flow taken as liquid and adjusted by the homogeneous volumetric fraction ratio. The results show that this last correlation is easier and accurate than the adjusted Chisholm model, presenting an average error of 7.75%. Therefore, this correlation is recommended for two-phase pressure drop evaluation in horizontal elbows.

scholarly journals Performance Evaluation of Analytical Methods for Parameters Extraction of Photovoltaic Generators

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4825 ◽  
Author(s):  
Nader Anani ◽  
Haider Ibrahim
Keyword(s):  
Performance Evaluation ◽  
Computational Complexity ◽  
Numerical Methods ◽  
Analytical Methods ◽  
Standard Test ◽  
Pv Module ◽  
Test Conditions ◽  
Parameters Extraction ◽  
Detailed Mathematical Analysis ◽  
Photovoltaic Generators

This paper presents a succinct exploration of several analytical methods for extracting the parameters of the single-diode model (SDM) of a photovoltaic (PV) module under standard test conditions (STC). The paper investigates six methods and presents the detailed mathematical analysis leading to the development of each method. To evaluate the performance of these methods, MATLAB-based software has been devised and deployed to generate the results of each method when used to extract the SDM parameters of various PV test modules of different PV technologies. Similar software has also been developed to extract the same parameters using well-established numerical and iterative techniques. A comparison is subsequently made between the synthesized results and those obtained using numerical and iterative methods. The comparison indicates that although analytical methods may involve a significant amount of approximations, their accuracy can be comparable to that of their numerical and iterative counterparts, with the added advantage of a significant reduction in computational complexity, and without the initialization and convergence difficulties, which are normally associated with numerical methods.

scholarly journals Building energy modeling at neighborhood scale

2020 ◽  
Vol 13 (7) ◽  
pp. 1353-1386 ◽  
Author(s):  
Guglielmina Mutani ◽  
Valeria Todeschi
Keyword(s):  
Energy Consumption ◽  
Energy Balance ◽  
Residential Buildings ◽  
Energy Performance ◽  
Average Error ◽  
Monthly Basis ◽  
Support Tool ◽  
Steady State Method ◽  
Consumption Data ◽  
Neighborhood Scale

Abstract The urban climate and outdoor air quality of cities that have a positive thermal balance depending on the thermal consumptions of buildings cause an increase of the urban heat island and global warming effects. The aim of this work has been to develop an energy balance using the energy consumption data of the district heating network. The here presented engineering energy model is at a neighborhood scale, and the energy-use results have been obtained from a heat balance of residential buildings, by means of a quasi-steady state method, on a monthly basis. The modeling approach also considers the characteristics of the urban context that may have a significant effect on its energy performance. The model includes a number of urban variables, such as solar exposition and thermal radiation lost to the sky of the built environment. This methodology was applied to thirty-three 1 km × 1 km meshes in the city of Turin, using the monthly energy consumption data of three consecutive heating seasons. The results showed that the model is accurate for old built areas; the average error is 10% for buildings constructed before 1970, while the error reaches 20% for newer buildings. The importance and originality of this study are related to the fact that the energy balance is applied at neighborhood scale and urban parameters are introduced with the support of a GIS tool. The resulting engineering models can be applied as a decision support tool for citizens, public administrations, and policy makers to evaluate the distribution of energy consumptions and the relative GHG emissions to promote a more sustainable urban environment. Future researches will be carried out with the aim of introducing other urban variables into the model, such as the canyon effect and the presence of vegetation.

scholarly journals Field Measurement of PV Array Temperature for Tracking and Concentrating 1 k WpGenerators Installed in Malaysia

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. Effendy Ya’acob ◽  
H. Hizam ◽  
M. Amran M. Radzi ◽  
M. Z. A. A. Kadir
Keyword(s):  
Surface Temperature ◽  
Weather Conditions ◽  
Effect Of Temperature ◽  
Bottom Temperature ◽  
Cell Temperature ◽  
Pv Array ◽  
Pv Module ◽  
The Difference ◽  
Ground Condition ◽  
Pv Generator

The effect of temperature elements for PV array with tracking and concentrating features installed in the tropical ground condition is presented. The temperature segment covers ambient temperature and surface and bottom temperature for three types of PV generator systems, namely, Fixed Flat (FF), Tracking Flat (TF), and Concentrating PV (CPV) generators. The location of measuring the cell temperature,Tcfor the PV module is still being debated by researchers with the issue of how much the cell temperature (Tc) is being affected by the surface temperature (Ts), bottom temperature (Tb), and surrounding temperature (Ta) furthermore when it is located in fluctuating weather conditions. In this study,ΔTis calculated based on the difference between surface temperature and bottom-side temperaturewhichever the highest recorded at site for different kinds of PV generator systems but using the same CEEG 95 W monocrystalline PV module. The study embraces the direct correlation of various temperature elements in tropical-based condition withΔTvalues of 2.19°C for FF module, 2.22°C for TF module, and 2.72°C for CPV module. These values which reflect the different unique configurations are further analyzed using multiple linear regression (MLR) and analysis of variance (ANOVA) test forTarraymodels. This study supports the continuous research in adapting PV technology for Malaysia.

scholarly journals Seismic and Power Generation Performance of U-Shaped Steel Connected PV-Shear Wall under Lateral Cyclic Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hongmei Zhang ◽  
Jinzhi Dong ◽  
Yuanfeng Duan ◽  
Xilin Lu ◽  
Jinqing Peng
Keyword(s):  
Power Generation ◽  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Seismic Behavior ◽  
Residential Buildings ◽  
Shear Wall ◽  
Deformation Capacity ◽  
High Rise ◽  
Pv Module ◽  
New Form

BIPV is now widely used in office and residential buildings, but its seismic performance still remained vague especially when the photovoltaic (PV) modules are installed on high-rise building facades. A new form of reinforced concrete shear wall integrated with photovoltaic module is proposed in this paper, aiming to apply PV module to the facades of high-rise buildings. In this new form, the PV module is integrated with the reinforced concrete wall by U-shaped steel connectors through embedded steel plates. The lateral cyclic loading test is executed to investigate the seismic behavior and the electric and thermal performance with different drift angles. The seismic behavior, including failure pattern, lateral force-top displacement relationship, and deformation capacity, was investigated. The power generation and temperature variation on the back of the PV module and both sides of the shear wall were also tested. Two main results are demonstrated through the experiment: (1) the U-shaped steel connectors provide enough deformation capacity for the compatibility of the PV module to the shear wall during the whole cyclic test; (2) the electricity generation capacity is effective and stable during this seismic simulation test.

scholarly journals Assessing Rainwater Harvesting Potential in Urban Areas: A Building Information Modelling (BIM) Approach

2021 ◽  
Vol 13 (22) ◽  
pp. 12583
Author(s):  
Ahsen Maqsoom ◽  
Bilal Aslam ◽  
Sharjeel Ismail ◽  
Muhammad Jamaluddin Thaheem ◽  
Fahim Ullah ◽  
...  
Keyword(s):  
Water Scarcity ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Residential Buildings ◽  
Assessment System ◽  
Information Modeling ◽  
Small Enterprise ◽  
Human Needs ◽  
Building Information ◽  
Roofing Material

Water scarcity has become a major problem for many countries, resulting in declining water supply and creating a need to find alternative solutions. One potential solution is rainwater harvesting (RwH), which allows rainwater to be stored for human needs. This study develops an RwH assessment system through building information modeling (BIM). For this purpose, a hydrological study of Cfa-type climate cities is conducted with the example of Islamabad, Pakistan. The monthly rainfall data of three sites were assessed to determine the volume of the accumulated rainwater and its potential to meet human needs. The average number of people living in a house is taken as the household number. Household number or of the number of employees working at a small enterprise, roofing material, and rooftop area are used as the key parameters for pertinent assessment in the BIM. The data simulated by BIM highlight the RwH potential using five people per house as the occupancy and a 90 m2 rooftop area for residential buildings or small enterprises as parameters. The results show that the selected sites can collect as much as 8,190 L/yr of rainwater (48 L/person/day) to 103,300 L/yr of rainwater (56 L/person/day). This much water is enough to fulfill the daily demands of up to five people. Therefore, it is established that the study area has an RwH potential that is able to meet the expected demands. This study presents a baseline approach for RwH to address water scarcity issues for residential buildings and factories of the future.

scholarly journals Experimental Verification of a Battery Energy Storage System for Integration with Photovoltaic Generators

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Rajkiran Singh ◽  
Seyedfoad Taghizadeh ◽  
Nadia M. L. Tan ◽  
Saad Mekhilef
Keyword(s):  
Energy Storage ◽  
Output Power ◽  
Experimental Verification ◽  
Storage System ◽  
Energy Storage System ◽  
Battery Energy Storage System ◽  
Battery Energy Storage ◽  
Battery Energy ◽  
Photovoltaic Generators ◽  
Pv Generator

This paper presents the experimental verification of a 2 kW battery energy storage system (BESS). The BESS comprises a full-bridge bidirectional isolated dc-dc converter and a PWM converter that is intended for integration with a photovoltaic (PV) generator, resulting in leveling of the intermittent output power from the PV generator at the utility side. A phase-shift controller is also employed to manage the charging and discharging operations of the BESS based on PV output power and battery voltage. Moreover, a current controller that uses the d-q synchronous reference frame is proposed to regulate the dc voltage at the high-voltage side (HVS) to ensure that the voltage ratio of the HVS with low-voltage side (LVS) is equivalent to the transformer turns ratio. The proposed controllers allow fast response to changes in real power requirements and results in unity power factor current injection at the utility side. In addition, the efficient active power injection is achieved as the switching losses are minimized. The peak efficiency of the bidirectional isolated dc-dc converter is measured up to 95.4% during battery charging and 95.1% for battery discharging.

Effects of Partial Shading on the PV Module Characteristic Curves

2010 ◽  
Vol 670 ◽  
pp. 391-398 ◽  
Author(s):  
Eva Paraskevadaki ◽  
S. Papathanassiou ◽  
Georgios Vokas
Keyword(s):  
System Performance ◽  
Significant Contribution ◽  
Photovoltaic System ◽  
Partial Shading ◽  
Array Configuration ◽  
Module Design ◽  
Pv Array ◽  
Pv Module ◽  
Pv Generator ◽  
Mismatch Losses

Photovoltaic system performance is influenced by a variety of factors such as irradiance, temperature, shading, degradation, mismatch losses, soiling, etc. Especially shading, complete or partial, can have a significant contribution to the reduction of power output, depending mainly on the PV array configuration, the shading pattern and the existence of bypass diodes incorporated in the PV module design. In order to obtain the maximum power from a PV generator, it is of great importance to evaluate the complex effects of shading on the P-V and I-V curves.

scholarly journals An Improved Method Combining ANN and 1D-Var for the Retrieval of Atmospheric Temperature Profiles from FY-4A/GIIRS Hyperspectral Data

2021 ◽  
Vol 13 (3) ◽  
pp. 481
Author(s):  
Pengyu Huang ◽  
Qiang Guo ◽  
Changpei Han ◽  
Chunming Zhang ◽  
Tianhang Yang ◽  
...  
Keyword(s):  
Neural Network ◽  
Satellite Observation ◽  
Hyperspectral Data ◽  
Radiative Transfer Model ◽  
Average Error ◽  
Transfer Model ◽  
Observation Data ◽  
Temperature Profiles ◽  
Retrieval Method ◽  
The Impact

In our study, a retrieval method of temperature profiles is proposed which combines an improved one-dimensional variational algorithm (1D-Var) and artificial neural network algorithm (ANN), using FY-4A/GIIRS (Geosynchronous Interferometric Infrared Sounder) infrared hyperspectral data. First, according to the characteristics of the FY-4A/GIIRS observation data using the conventional 1D-Var, we introduced channel blacklists and discarded the channels that have a large negative impact on retrieval, then used the information capacity method for channel selection and introduced a neural network to correct the satellite observation data. The improved 1D-Var effectively used the observation information of 1415 channels, reducing the impact of the error of the satellite observation and radiative transfer model, and realizing the improvement of retrieval accuracy. We subsequently used the improved 1D-Var and ANN algorithms to retrieve the temperature profiles, respectively, from the GIIRS data. The results showed that the accuracy when using ANN is better than using improved 1D-Var in situations where the pressure ranges from 800 hPa to 1000 hPa. Therefore, we combined the improved 1D-Var and ANN method to retrieve temperature profiles for different pressure levels, calculating the error by taking sounding data published by the University of Wyoming as the true values. The results show that the average error of the retrieved temperature profiles is smaller than 2 K when using our method, this method makes the accuracy of the retrieved temperature profiles superior to the accuracy of the GIIRS products from 10 hPa to 575 hPa. All in all, through the combination of the physical retrieval method and the machine learning retrieval method, this paper can certainly provide a reference for improving the accuracy of products.

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