GOVPH

 

Erees Queen Macabebe

Sex: Female

Education:

Doctor of Philosophy in Physics, Nelson Mandela Metropolitan University 2009

Masters in Physics, Ateneo de Manila University, 2005

Bachelor of Science in Physics, Ateneo de Manila University

Bachelor of Science in Computer Engineering, Ateneo de Manila University

Field of Specialization

Solar Cells

Researches:

 

Article title: Next Day Power Forecast Model Using Smart Hybrid Energy Monitoring System and Meteorological Data

Authors: Christine May Creayla, Felan Carlo Garcia, Erees Queen B. Macabebe

Publication title: Procedia Computer Science, 105, 256-263, December 2017

 

Abstract:

The increase in contribution of renewable energy sources into the grid is part of smart grid initiatives. The integration of renewables such as solar energy into the electrical network is a challenge for grid operators because of its intermittency due to weather variations. Despite this, the installed capacity of solar PV globally continues to increase. Thus, forecasting is becoming an important tool for system grid operators to manage solar photovoltaic (PV) energy production and satisfy the demand of energy consumers. This work aims to develop a forecasting model for solar irradiance that can be used in calculating next-day energy generation of solar PV systems. Site-specific solar irradiance and meteorological parameters were used as inputs to a machine learning algorithm. It is shown that the prediction model fits the measured data with a value of R² equal to 85.89%. This model was validated through the measured data of power generation from a hybrid connected solar PV system, installed in Quezon City, Philippines.

 

Article title: Development of an Intelligent System for Smart Home Energy Disaggregation Using Stacked Denoising Autoencoders

Authors: Felan Carlo Garcia, Christine May Creayla, Aries Queen B. Macabebe

Publication title: Procedia Computer Science 105:248-255, December 2017

 

Abstract:

Energy sustainability remains one of the biggest challenges for the Philippines’ energy sector with 51% of the demand coming from the residential and commercial sectors. Intelligent energy monitoring systems play a key role with the opportunity to contribute sizeable amount of energy savings by providing meaningful consumption feedback to home owners. While smart meters provide an ideal ubiquitous energy monitoring solution, these devices lack appliance-level feedback. In this study, we present a concept of augmenting smart utility meters with an energy disaggregation method using Stacked Denoising Autoencoders to provide appliance-level feedback to home owners. We evaluate the results using absolute mean loss and proportion of energy correctly assigned as metrics for the signal disaggregation. The results show that the model was able to decompose an aggregate appliance signal and provide an itemized appliance-level power consumption.

 

Article title: A review of community-based solar home system projects in the Philippines

Authors: Erees Queen B. Macabebe, Reynaldo C. Guerrero, Aleta Domdom, Aison S. Garcia, et al.

Publication title: MATEC Web Conferences 70:12002, January 2016

 

Abstract:

Solar Home Systems (SHS) are easy to deploy in island and in remote communities where grid connection is costly. However, issues related to maintenance of these systems emerge after they are deployed because of the remoteness and inaccessibility of the communities. This study looked into community-based programs in the Philippines and investigated the following: (1) social preparation, (2) role of the community in the project, and (3) sustainability of the program. In this paper, three communities under two government programs offering SHS are presented. These programs are the Solar Power Technology Support (SPOTS) program of the Department of Agrarian Reform (DAR) and the Household Electrification Program (HEP) of the Department of Energy (DOE). A focused group discussion and key informant interviews were conducted in two communities in Bukidnon province and in a community in Kalinga to obtain information from the project beneficiaries and SHS users on the preparation, implementation and maintenance of the projects. The results revealed that emphasis on the economic value of the technology, proper training of the locals on the technical and management aspects of the project, as well as the establishment of a supply chain for replacement parts are crucial factors for the sustainability of the programs.

 

Article title: Hotspots Detection in Photovoltaic Modules Using Infrared Thermography

Authors: April M. Salazar, Erees Queen B. Macabebe

Publication title: MATEC Web of Conferences 70:10015, January 2016

 

Abstract:

An increased interest on generating power from renewable sources has led to an increase in solar photovoltaic (PV) system installations worldwide. Power generation of such systems is affected by factors that can be identified early on through efficient monitoring techniques. This study developed a non-invasive technique that can detect localized heating and quantify the area of the hotspots, a potential cause of degradation in photovoltaic systems. This is done by the use of infrared thermography, a well-accepted non-destructive evaluation technique that allows contactless, real-time inspection. In this approach, thermal images or thermograms of an operating PV module were taken using an infrared camera. These thermograms were analyzed by a Hotspot Detection algorithm implemented in MATLAB. Prior to image processing, images were converted to CIE L*a*b color space making k-means clustering implementation computationally efficient. K-means clustering is an iterative technique that segments data into k clusters which was used to isolate hotspots. The devised algorithm detected hotspots in the modules being observed. In addition, average temperature and relative area is provided to quantify the hotspot. Various features and conditions leading to hotspots such as crack, junction box and shading were investigated in this study.

 

Article title: Parameter extraction from IV characteristics of PV devices

Authors: Erees Queen B. Macabebe, Charles Johannes Sheppard, Eugene Ernest Van Dyk

Publication title: Solar Energy 85(1), January 2011

 

Abstract:

Device parameters such as series and shunt resistances, saturation current and diode ideality factor influence the behaviour of the current-voltage (I-V) characteristics of solar cells and photovoltaic modules. It is necessary to determine these parameters since performance parameters are derived from the I-V curve and information provided by the device parameters are useful in analyzing performance losses. This contribution presents device parameters of CuIn(Se,S)- and Cu(In,Ga)(Se,S)-based solar cells, as well as, CuInSe, mono- and multicrystalline silicon modules determined using a parameter extraction routine that employs Particle Swarm Optimization. The device parameters of the CuIn(Se,S)- and Cu(In,Ga)(Se,S)-based solar cells show that the contribution of recombination mechanisms exhibited by high saturation current when coupled with the effects of parasitic resistances result in lower maximum power and conversion efficiency. Device parameters of photovoltaic modules extracted from I-V characteristics obtained at higher temperature show increased saturation current. The extracted values also reflect the adverse effect of temperature on parasitic resistances. The parameters extracted from I-V curves offer an understanding of the different mechanisms involved in the operation of the devices. The parameter extraction routine utilized in this study is a useful tool in determining the device parameters which reveal the mechanisms affecting device performance. (author)

Full text available upon request to the author

 

Article title: Pre-conceptions of Newton’s Laws of Motion of Students in Introductory Physics

Authors: Erees Queen B. Macabebe, Ivan Culaba, Joel T. Maquiling

Publication title: AIP Conference Proceedings 1263(1), August 2010

 

Abstract:

The Force and Motion Conceptual Evaluation (FMCE) developed by R.K. Thornton and D. R. Sokoloff was utilized to evaluate the conceptual understanding of Newton’s Laws of Motion. The test was administered to 100 freshman university students enrolled in introductory physics courses. The aim is to find out the conceptual understanding of the students prior to university level instruction. Results show that the Aristotelian notion prevails despite having taken physics in their senior year in high school. This study emphasizes the importance of training high school physics teachers and the significance of a change in the teaching techniques for university level introductory physics.

Full text available upon request to the author

 

Article title: Opto-electronic analysis of silicon solar cells by LBIC investigations and current–voltage characterization

Authors: N.M. Thantsha, Ereees Queen B. Macabebe, Frederik Vorster, Eugene Ernest Van Dyk

Publication title: Physica B. Condensed Matter 404(22):4445-4448, December 2009

 

Abstract:

A different laser beam induced current (LBIC) mapping technique has been used for the measurements of spatial variation of light generated current of a solar cell. These variations are caused by parasitic resistances and defects at grain boundaries (GBs) in multicrystalline silicon solar cells (mc-Si). This study investigates and identifies the regions within mc-Si solar cells where dominating recombination and lifetime limiting processes occur. A description of the LBIC technique is presented and the results show how multicrystalline GBs and other defects affect the light generated current of a spot illuminated mc-Si solar cell. The results of the internal quantum efficiency (IQE) at wavelength of 660 nm revealed that some regions in mc-Si solar cell give rise to paths that lead current away from the intended load.

Full text available upon request to the author

 

Article title: Device and performance parameters of Cu(In,Ga)(Se,S)2-based solar cells with varying i-ZnO layer thickness

Authors: Erees Queen B. Macabebe, Charles Johannes Sheppard, Eugene Ernest Van Dyk

Publication title: Physica B Condensed Matter 404(22):4466-4469, December 2009

 

Abstract:

In pursuit of low-cost and highly efficient thin film solar cells, Cu(In,Ga)(Se,S)2/CdS/i-ZnO/ZnO:Al (CIGSS) solar cells were fabricated using a two-step process. The thickness of i-ZnO layer was varied from 0 to 454 nm. The current density–voltage (J–V) characteristics of the devices were measured, and the device and performance parameters of the solar cells were obtained from the J–V curves to analyze the effect of varying i-ZnO layer thickness. The device parameters were determined using a parameter extraction method that utilized particle swarm optimization. The method is a curve-fitting routine that employed the two-diode model. The J–V curves of the solar cells were fitted with the model and the parameters were determined. Results show that as the thickness of i-ZnO was increased, the average efficiency and the fill factor (FF) of the solar cells increase. Device parameters reveal that although the series resistance increased with thicker i-ZnO layer, the solar cells absorbed more photons resulting in higher short-circuit current density (Jsc) and, consequently, higher photo-generated current density (JL). For solar cells with 303–454 nm-thick i-ZnO layer, the best devices achieved efficiency between 15.24% and 15.73% and the fill factor varied between 0.65 and 0.67.

Full text available upon request to the author

 

Article title: Blend composition study of poly(3,3‴-didodecylquaterthiophene)/[6,6]-phenyl C61 butyric acid methyl ester solution processed organic solar cells

Authors: Avery P. Yuen, John Stewart Preston, Abdel-Hadi Hor, Erees Queen B. Macabebe, et al.

Publication title: Journal of Applied Physics 105(1):01615-016105-3, February 2009

 

Abstract:

Photovoltaic devices made from blends of poly( 3,3^‴ -didodecylquaterthiophene) (PQT-12) and [6,6]-phenyl C ₆₁ butyric acid methyl ester have been fabricated and characterized. By varying the polymer loading in the blend, an optimal power conversion efficiency (PCE) of 0.70% has been achieved for a blend consisting of 15 wt  % PQT-12, which is an order of magnitude higher than the PCE for a 50 wt  % blend. The apparent reason for the large difference is the fact that blends with higher PQT-12 loading are transport limited, with much larger hole-to-electron mobility ratios.

Full text available upon request to the author

 

Article title: Effects of different selenization conditions on the device parameters of CuIn(Se,S) 2 solar cells

Authors: Erees Queen B. Macabebe, Charles Johannes Sheppard, Vivian Alberts, Eugene Ernest Van Dyk

Publication title: Thin Solid Films 517(7):2380-2382, February 2009

 

Abstract:

Parameter extraction can be used as a tool to determine the optimum chalcogenization condition of the absorber layer in manufacturing thin film solar cells. In this paper, CuIn(Se1−y,Sy)2 solar cells fabricated at different selenization conditions using a two-step process were characterized. Device and performance parameters of the solar cells were determined from the current density–voltage (J–V) characteristics of the devices. The J–V curves were analyzed using the two-diode solar cell model. Devices selenized for 40–60 min exhibit relatively low series and shunt resistances, low fill factor and conversion efficiency. Better performance was observed for solar cells with absorber layer selenized for 10 to 20 min.

Full text available upon request to the author

 

Article title: Analysis of performance and device parameters of CIGS PV modules deployed outside

Authors: Chantelle Radue, Eugene Ernest Van Dyk, Erees Queen B. Macabebe

Publication title: Thin Solid Films 517(7):2383-2385, February 2009

 

Abstract:

Two 20 W copper indium gallium diselenide photovoltaic modules were subjected to a thorough indoor assessment procedure, followed by outdoor deployment at the Nelson Mandela Metropolitan University as part of an ongoing study. The initial indoor measurement of maximum power output (PMAX) of one of the modules was considerably higher than the manufacturer's rating (E.E. van Dyk, C. Radue and A.R. Gxasheka, Thin Solid Films 515 (2007) 6196). The modules were deployed on a dual-axis solar tracker and current–voltage characteristics were obtained weekly. In addition to the normal PV parameters of short-circuit current, open-circuit voltage, PMAX, fill factor and efficiency, shunt and series resistances were also monitored. The performances of the two modules are compared and analyzed and the results presented in this paper.

Full text available upon request to the author

 

Article title: Parameter extraction from dark current-voltage characteristics of solar cells

Authors: Erees Queen B. Macabebe, Eugene Ernest Van Dyk

Publication title: South African Journal of Science 104(9-10):401-404, October 2008

 

Abstract:

Electrical properties derived from the dark current–voltage (I–V) characteristics of solar cells provide essential information necessary in the analysis of performance losses and device efficiency. Device parameters of crystalline silicon solar cells were determined using the one-diode and two-diode models. The parameters extracted from the dark I–V curve of the solar cells were series resistance, shunt resistance, saturation currents and ideality factors. Iteration and approximation techniques were used to determine the device parameters of the solar cells. The method, which considered a finite shunt resistance in the high current region of the curve, made the implementation different from other techniques. Standard deviation, R2 values and a fitting routine that provides a graphical representation of the output were implemented to determine the best set of parameters. Comparison of the extracted device parameters against the simulated values suggests that the two-diode model is more suitable than the one-diode model in describing the behaviour of the dark I–V curve. The two-diode model also provides more information necessary to explain the mechanisms governing the I–V curve under dark conditions.

Full text available upon request to the author

 

Article title: Extraction of device parameters from dark current‐voltage characteristics of PV devices

Authors: Erees Queen B. Macabebe, Eugene Ernest Van Dyk

Publication title: Physica Status Solidi 5(2):616-619, February 2008

 

Abstract:

Solar cells are p-n junction diodes and are prone to parasitic resistances. High series resistances of a few ohms degrade the device performance, as do low shunt resistances. It is therefore necessary to determine these parameters since they are useful in analyzing performance losses. A method to extract these and other device parameters of solar cells from the dark current-voltage (I-V) characteristics is presented in this paper. The following parameters were determined using the proposed method: saturation current, series resistance, shunt resistance and the ideality factor. A program was created to implement the method which utilized the one-diode equivalent circuit model. Curve-fitting was also employed to provide a graphical representation of the results. Evaluation of the method was done using simulated data and actual dark I-V data obtained from monocrystalline and multicrystalline silicon solar cells. The program algorithm is discussed and results are presented. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Full text available upon request to the author

 

Papers Presented:

 

Article title: Water Consumption Monitoring with Fixture Recognition Using Random Forest

Authors: James Somontina, Felan Carlo Garcia, Erees Queen B. Macabebe 

Conference title: TENCON 2018-2018 IEEE Region 10 Conference

 

Abstract:

Water is a limited resource that is essential for sustaining life but is often wasted. By monitoring water consumption in real time, users become aware of the amount of water that they utilize. This contribution presents a water monitoring system that determines the volume of water consumed for the following events: use of faucets, toilet flush, and shower. The system utilized a non-intrusive, single point sensing technique. The sensor was interfaced to a microcontroller to monitor fluid dynamics in real-time. Data was collected and processed by a microcomputer that uploads to a graphics user interface for easy viewing and online access. Random forest was used so that the system can identify and determine how much water each faucet or fixture uses. The volume of water used for every event was determined with 92.91 % accuracy and the fixture recognition algorithm resulted in 63% precision.

Full text available upon request to the author

 

Article title: A Single Point Sensing Approach for Residential Power Monitoring with Appliance Recognition Using Random Forest

Authors: Sheanne Eric P. Cabantac, Felan Carlo Garcia, Erees Queen B. Macabebe 

Conference title: TENCON 2018-2018 IEEE Region 10 Conference

 

Abstract:

This work utilized machine learning, specifically Random Forest, as a classifier to recognize appliance signal from an aggregate energy consumption signal obtained using a single point, nonintrusive load monitoring approach. Appliance level feedback allows energy consumers to make informed decisions and employ energy management strategies to reduce the use of electricity. A mixture-of-experts approach was applied and the appliance models were trained to recognize appliance signals both from pure and aggregate signals of up to three appliances at the same time. Consumption signals of appliances with highly differentiated and slightly differentiated wattages were considered in this study. The Random Forest algorithm resulted in high scores averaging between 97 % to 100 % for both precision and recall for the desired appliance signal.

Full text available upon request to the author

 

Article title: Isolating Defects in Light Beam Induced Current Maps of Solar Cells

Authors: Genevieve Ngo and Erees Queen B. Macabebe 

Conference title: TENCON 2018-2018 IEEE Region 10 Conference

 

Abstract:

The advances in solar technologies has lead higher device conversion efficiency and lower production costs. Ensuring the quality of the solar cells, however, remains a challenge and automation of defect identification in solar cells can potentially make the process efficient. Light Beam Induced Current (LBIC) mapping is a high-resolution imaging technique that allows researchers to see defects in solar cell. LBIC maps show the spatial distribution of the short-circuit current of a solar cell. In this study, surface and sub-surface defects in an LBIC image were identified using watershed segmentation, image dilation and inpainting. The image processing model on the image presented resulted in an Intersection over Union score of 41.33%. The model was able to highlight features on the LBIC map that are potential defects and further investigation can be made on these areas to understand the underlying cause of these defects.

Full text available upon request to the author

 

Article title: Inferring Appliance Energy Usage from Smart Meters using Fully Convolutional Encoder Decoder Networks

Authors: Felan Carlo Garcia and Erees Queen B. Macabebe 

Conference title: 2017 ACM on Conference on Information and Knowledge Management.

 

Abstract:

Energy management presents one of the principal sustainability challenges within urban centers given that they account for 75% of the energy consumption worldwide. In the context of a smart city framework, the use of intelligent urban systems provides a key opportunity in addressing the energy sustainability issue as an informatics problem where the goal is to deliver energy usage feedback to the users as a means of enabling behavioral change towards energy sustainability. In this paper we present a method to provide appliance energy usage feedback from smart meters using energy disaggregation. We put energy disaggregation in the context of a source separation and signal reconstruction problem in which we train a fully convolutional encoder decoder network to separate appliance energy usage from aggregate whole house electricity consumption data. The results show that the proposed fully convolutional encoder decoder model can achieve competitive accuracy compared with several state-of-the-art methods.

Full text available upon request to the author

 

Article title:  Image segmentation using K-means color quantization and density-based spatial clustering of applications with noise (DBSCAN) for hotspot detection in photovoltaic modules

Authors: Genevieve Ngo and  Erees Queen B. Macabebe 

Conference title: TENCON 2016-2016 IEEE Region 10 Conference

 

Abstract:

The increasing demand for the use of solar energy as an alternative source of energy to generate electricity has multiplied the need for more photovoltaic (PV) arrays. With the growth of the PV manufacturing industry, automation for defect detection is seen as a great potential in ensuring the quality of these PV modules. Hotspot formation due to defects is detrimental to the performance of PV devices. Thus this research aims to detect and isolate hotspot areas in PV modules by applying two machine learning techniques, namely K-means color quantization for pre-processing, and density-based spatial clustering of applications with noise (DBSCAN) for processing, in the images captured by an infrared camera. In the preprocessing, K-means clustering algorithm produced a quantized color image represented by the contours while in the processing or clustering part, DBSCAN resulted in the segmentation of the image, isolating the hotspot. Further investigation of the PV module through visual inspection found a crack in one of the solar cells where the hotspot occurred.

Full text available upon request to the author

 

Article title: Electrical PV Array Reconfiguration Strategy Against Partial Shading

Authors: R.A.S. Peña, Erees Queen B. Macabebe, Davide Del Col

Conference title: ISES Solar World Congress 2015

 

Abstract:

Partial shading presents a huge problem for photovoltaic (PV) arrays because of mismatch losses. One way to maximize power output is to make the arrays dynamic. These dynamic PV arrays change configuration depending on shading pattern and strength. This work evaluates the electrical PV array reconfiguration (EAR) strategy in dynamic arrays that use total-cross tied topology through modeling and simulation. The approach searches for the optimum configuration which has the most equal row irradiance averages. A static 3×3 PV array model and a dynamic PV array model, which uses the EAR algorithm, were developed. The models were tested for binary- and random-irradiance shading. Results show that the EAR strategy suits some shading patterns and that the irradiance distribution affects improvement in power output. The simulations performed demonstrate both the limitations and benefits of using the EAR strategy in PV array reconfiguration.

Full text available upon request to the author

 

Article title: Feasibility Study on Thermoelectric Conversion to Improve Photovoltaic Operation

Authors: M.L. Montayre and Erees Queen B. Macabebe

Conference title: ISES Solar World Congress 2015

 

Abstract:

Thermoelectrics (TE) is an emerging technology with a wide range of potential applications namely recapturing energy lost as wasted heat from burning fossil fuels as well as serving as a cooling agent. One viable application is to integrate thermoelectric devices with photovoltaic (PV) modules that suffer from performance issues because of heat. This study proposes a model where the TE device can help lower the temperature of the PV modules which will optimize its performance through an increase in generated output. The same device can also increase the total output power from the combined PV-TE system when the TE acts as a generator. The PV-TE system was simulated using Matlab software and results show that there is potential in using TE technology as coolant and generator improve the performance of the PV device. Experiments and actual deployment also reveal an improved output for the combined PV-TE system.

Full text available upon request to the author

 

Article title: Cost-effective LBIC system for solar cell characterization

Authors: Jeric Lim, Paul Lorenzo, Erees Queen B. Macabebe

Conference title: TENCON 2015-2015 IEEE Region 10 Conference

 

Abstract:

Defects in solar cells such as localized shunts greatly reduce the efficiency of the device by diverting current away from the output. Laser beam induced current (LBIC) technique is a non-destructive characterization tool to identify the spatial distribution of defects by measuring the generated current of the cells. This technique determines the defects by scanning a laser beam onto the cell while measuring the generated current as a function of position. This contribution presents the development of a cost-effective LBIC system using three wavelengths: 650 nm, 532 nm, and 450nm. LBIC resolution is optimized by varying the spot size of the light source and the step size of the machine. LBIC maps generated from different laser wavelengths show variations in image quality and details.

Full text available upon request to the author

 

Article title: Effects of shading on current, voltage and power output of total cross-tied photovoltaic array configuration

Authors: Beryll Justin G. Montano, Dion Januel F. Rombaoa, Robert Alfie S. Pena, Erees Queen B. Macabebe

Conference title: TENCON 2015-2015 Region 10 Conference

 

Abstract:

The Philippines, being a tropical country, has a high photovoltaic (PV) energy generation potential that can help meet demand due to impending power supply shortage in the coming years. One factor that limits solar PV generation is nonuniform illumination or partial shading. Partial shading causes voltage and current mismatch which affect the performance of PV arrays. Partially shaded PV systems cannot operate at maximum efficiency because of shadows cast by the surrounding structures, foliage and cloud cover. In this study, the researchers observed the effects of partial shading on the voltage, current and power output of the total cross-tied (TCT) array configuration using 16 shading patterns. Results show that the TCT configuration has the ability to balance out the effects of uneven irradiance on the PV modules. This results in higher power output. However, this effect optimizes the power output most if shaded modules complete columns. Such cases minimize current mismatch among the rows in the array.

Full text available upon request to the author

 

Article title: Real-time energy monitoring system for grid-tied Photovoltaic installations

Authors: Genevieve Ngo, Judd Kristian I. Floriza, Christine May Creayla, Erees Queen B. Macabebe, et al.

Conference title: TENCON 2015 - 2015 IEEE Region 10 Conference

 

Abstract:

A real-time energy monitoring system for grid-tied Photovoltaic (PV) installations was developed and deployed in a household located at Barangka, Marikina. The system consists of a BeagleBone Black which serves as the device to processes the measured data from the two power analyzers and the DC sensor. It also features a Mobile and Web-based monitor and analytics platform for end user utilization, and provides a forecasting algorithm for the user's projected monthly bill. One of the receiving ends is a server that stores the data and hosts the web application which aggregates, analyzes and presents the general power generation and grid consumption to the user. The other receiving end, an Android application, displays the real-time graph of the generated solar energy and the total energy consumed by the load, in this case, a residential load.

Full text available upon request to the author

 

Article title: Performance of a 3-kWp grid-tied photovoltaic system in a water refilling station

Authors: Erees Queen B. Macabebe, Marianne S. Paloma, Danilo P. Villarey III 

Conference title: 5th International Conference on Sustainable Energy and Environment (SEE 2014): Science, Technology and Innovation for ASEAN Green Growth

 

Abstract:

Due to the recurring power interruptions and the increasing monthly electricity rates in Metro Manila, residents and business owners need to start using renewable energy. Solar photovoltaic (PV) is the most viable and widely available source of energy. To quantify the benefits of using solar PV systems, the performance of a 3 kWp grid-tied photovoltaic system with back-up battery bank installed in a commercial water refilling station was monitored and analyzed. The battery bank provided an uninterrupted source of energy. The calculations for the monthly savings and the potential rebates of the establishment if net metering were applied are included. Despite negative effects due to the non-implementation of the net metering scheme, the grid-tied PV system significantly reduced the monthly electricity bill by 50%. Information obtained within the 3-month duration of the study was used to make necessary modifications in the system.

Full text available upon request to the author

 

Article title: Development of an Arduino-based I–V curve tracer for performance testing of photovoltaic modules under outdoor conditions

Authors: Erees Queen B. Macabebe, Robert Alfie S. Peña, Ian Christopher Gamara, Keir Alexis Pareja

Conference title: Photovoltaic Science and Engineering Conference (PVSEC-23), 2014

 

Abstract:

Performance parameters of photovoltaic (PV) modules derived from their current-voltage (I–V) characteristics are significant in the design of PV systems. In commercially available PV modules, parameters such as maximum power (Pmax), open-circuit voltage (VOC), short-circuit current (ISC) and conversion efficiency (η) are supplied by the manufacturers. However, these values were obtained under laboratory environment at standard testing conditions (1000 W/m2, A.M. 1.5, 25 °C). Actual outdoor conditions vary and fluctuate. To optimize and monitor the performance of the system, it is important to evaluate the performance of the modules under outdoor conditions. For this purpose, a portable, battery-powered, Arduino-based I–V curve tracer was developed with SD card functionality. The device takes advantage of the operation of a metal-oxide-semiconductor field-effect transistor (MOSFET) as a fast-varying electronic load to the PV module which addresses the need for a fast response curve tracer. It also has a sensor module for measuring temperature and a program was written to extract the performance parameters from the measured I–V curve. The design and the use of Arduino allow for easy interfacing with other computer systems.

Full text available upon request to the author

 

Article title: Effect of collaborative learning in Interactive Lecture Demonstrations (ILD) on student conceptual understanding of motion graphs

Authors: Erees Queen B. Macabebe, Eleanor Alma D. Jugueta

Conference title: International Conference on Physics Education, 2014

 

Abstract:

To assess effectively the influence of peer discussion in understanding concepts, and to evaluate if the conceptual understanding through Interactive Lecture Demonstrations (ILD) and collaborative learning can be translated to actual situations, ten (10) questions on human and carts in motion were presented to 151 university students comprising mostly of science majors but of different year levels. Individual and group predictions were conducted to assess the students’ pre-conceptual understanding of motion graphs. During the ILD, real-time motion graphs were obtained and analysed after each demonstration and an assessment that integrates the ten situations into two scenarios was given to evaluate the conceptual understanding of the students. Collaborative learning produced a positive effect on the prediction scores of the students and the ILD with real-time measurement allowed the students to validate their prediction. However, when the given situations were incorporated to create a scenario, it posted a challenge to the students. The results of this activity identified the area where additional instruction and emphasis is necessary.