Estimating induction motor efficiency under no-controlled conditions in the presences of unbalanced and harmonics voltages

This paper presents the application of a method to determine the output power, losses, and efficiency of induction motors, working in no-controlled conditions, in the presences of unbalanced and harmonics voltages. The method uses the steady state equivalent circuits, with some considerations for the analysis of motor performance, fed with unbalanced and harmonic voltages. The parameters of circuits are determined with low invasiveness, by applying a Bacterial Foraging Algorithm as technique of evolutionary search. With this, the efficiency and other operational parameters can be estimated at any operating point. The method was tested in a 12.6 kW motor working in an industrial network, with harmonics and voltage unbalanced

CARACTERIZACIÓN ENERGÉTICA DEL FUNCIONAMIENTO DE UN EQUIPO DE AIRE ACONDICIONADO EN UN LOCAL DADO

El control del consumo y eficiencia energética de los equipos de aire acondicionado es de vital importancia, sobre todo en lugares como la ciudad de Barranquilla con altas temperaturas y humedades relativas, lo cual genera en ésta un alto consumo de energía eléctrica. Se presenta en el siguiente trabajo un sistema de mediciones digitales que permite la caracterización energética completa del régimen de trabajo de un equipo de 2 toneladas de aire acondicionado en el enfriamiento y deshumidificación de un local de laboratorio de 98,7 m3 de volumen. Para esto se usan sensores digitales de temperatura y humedad relativa, con los cuales se registra el decremento de la temperatura y la humedad relativa en el tiempo. Con estos datos se calculan el calor sensible, el latente y la entalpía del aire húmedo que se extrajo de la habitación. Simultáneamente, se va registrando con un analizador de red digital el consumo de energía eléctrica por el equipo de aire acondicionado. Luego, el cociente entre calor sensible, el latente y la entalpía con la de energía eléctrica consumida da la eficiencia con que el equipo de aire acondicionado enfría el local (sensible), la eficiencia con que lo deshumidifica (latente) y la total respectivamente. Es importante destacar que este método de caracterizar y evaluar la eficiencia energética de aires acondicionados es aplicable a cualquier equipo y local que se quiera estudiar

CARACTERIZACIÓN ENERGÉTICA DEL FUNCIONAMIENTO DE UN EQUIPO DE AIRE ACONDICIONADO EN UN LOCAL DADO

El control del consumo y eficiencia energética de los equipos de aire acondicionado es de vital importancia, sobre todo en lugares como la ciudad de Barranquilla con altas temperaturas y humedades relativas, lo cual genera en ésta un alto consumo de energía eléctrica. Se presenta en el siguiente trabajo un sistema de mediciones digitales que permite la caracterización energética completa del régimen de trabajo de un equipo de 2 toneladas de aire acondicionado en el enfriamiento y deshumidificación de un local de laboratorio de 98,7 m3 de volumen. Para esto se usan sensores digitales de temperatura y humedad relativa, con los cuales se registra el decremento de la temperatura y la humedad relativa en el tiempo. Con estos datos se calculan el calor sensible, el latente y la entalpía del aire húmedo que se extrajo de la habitación. Simultáneamente, se va registrando con un analizador de red digital el consumo de energía eléctrica por el equipo de aire acondicionado. Luego, el cociente entre calor sensible, el latente y la entalpía con la de energía eléctrica consumida da la eficiencia con que el equipo de aire acondicionado enfría el local (sensible), la eficiencia con que lo deshumidifica (latente) y la total respectivamente. Es importante destacar que este método de caracterizar y evaluar la eficiencia energética de aires acondicionados es aplicable a cualquier equipo y local que se quiera estudiar

Factors Affecting the Electricity Consumption and Productivity of the Lead Acid Battery Formation Process. The Case of a Battery Plant in Colombia

This study identifies the main factors affecting the electricity efficiency and productivity of the lead acid battery formation process. A representative sample of 12,286 battery formation processes, developed between June 2014 and June 2015, were used in a statistic analysis. As a result, an energy performance indicator was developed to assess the electricity consumption of battery formation. Given that there are several formation circuits in the formation area, an energy performance indicator was developed for each circuit. The influence of the operational practices, operational teams, workings shift starting time and technical condition of the circuits were analyzed. The influence of the operational practices and the technical conditions of the formation circuits were identified as the main factors affecting the productivity and the electricity consumption. These factors cause a time waste, affecting productivity between 2% and 5%, and increasing the electricity consumption. As a result it is recommended to improve maintenance and operational practices towards higher productivity and electricity efficiency

A methodology to estimate baseline energy use and quantify savings in electrical energy consumption in higher education institution buildings: Case study, Federal University of Itajubá (UNIFEI)

Accurately forecasting energy consumption in a building is an important strategy for achieving the goal of reducing energy demand and improving energy efficiency. University campuses represent specific groups of diverse buildings with significant energy consumption. Therefore, they provide an excellent testbed to characterize and understand the energy consumption of a group of mixed-use buildings. This paper presents a novel methodology that considers the recommendations of ISO 50001: 2011 and ISO 50006: 2014 for establishing energy baselines and energy performance indicators in higher education institution buildings to identify electrical energy consumption reduction potentials in buildings and establish energy management strategies related to electricity use. The study was implemented in three buildings at the Federal University of Itajubá (José Rodrigues Seabra Campus). Several methods and indicators were evaluated to monitor and measure energy performance in buildings. A wide range of factors that influence operating system energy consumption in the buildings were studied and taken into account, such as the types of activities carried out in the building, weather conditions, building materials, air conditioning system and occupancy, since these contribute directly and indirectly to the difficulty of accurately measuring the building’s energy consumption. The results showed that potential annual savings in electric energy consumption for the campus could be around 9.6%, which translates into a R$ 93,647.2 economic value and a 20.3 tCO2eq emissions reduction without economic investment. It was concluded that the methodology proposed for establishing and monitoring an energy efficiency indicator can be applied to any institute of higher education because it is flexible and adaptable since each institute can define the period of analysis for the indicator. This research is expected to provide theoretical guidance and a practical data reference for relevant evaluations of building energy efficiency

Experimental Study and Analysis of Thermal Comfort in a University Campus Building in Tropical Climate

Producción CientíficaThis study presents the evaluation of the performance and acceptability of thermal comfort by students in the classrooms of a university building with minisplit-type air-conditioning systems, in a tropical climate. To carry out the study, temperature and humidity measurements were recorded, both outside and inside the selected classrooms, while the students were asked to complete thermal surveys on site. The survey model is based on the template proposed by Fanger and it was applied to a total number of 584 students. In each classroom, the Predicted Mean Vote (PMV) and the Predicted Percentage Dissatisfied (PPD) were estimated according to Fanger’s methodology, as well as the Thermal Sensation Vote (TSV) and the Actual Percentage Dissatisfied (APD), which were obtained from the measurements and the surveys. The results of this study showed that the PMV values, although they may vary with the insulation of the clothing, do not affect the TSV. Furthermore, comparing PMV vs. TSV scores, a 2 °C to 3 °C difference in operating temperature was found, whereby the thermal sensitivity for TSV was colder, so it could be assumed that the PMV model overestimates the thermal sensitivity of students in low-temperature conditions. In addition, an acceptability by 90% with thermal preferences between 23 °C and 24 °C were also found. These results indicate that it is possible to increase the temperature set point in minisplit-type air-conditioning system from 4 °C to 7 °C with respect to the currently set temperatures, without affecting the acceptability of the thermal environment to the students in the building

A look to the Electricity Generation from Non-Conventional Renewable Energy Sources in Colombia

This study discusses the potentialities and current situation of the electricity generation from non-conventional renewable energy sources (NCRES) in Colombia. In particular, three scenarios considering the increment of NCRES electricity based generation installed capacity are discussed. The three scenarios are compared to the 2020 forecast of the Energy and Mining Planning Unit ((UPME). Overall, it id shown that Colombia has a significant unused NCRES potential, which makes possible to realize the 6% target for NCRE based electricity generation capacity installed by 2020. In particular, the photovoltaic energy is foresee to account for over half of the NCRE mix. Even though the law 1715 is a progress towards integrating NCRE to the National Electric System, more policies and developments are required, to further the NCRE based installed generation capacities

Shaft power estimation in induction motor operating under unbalanced and harmonics voltages

In this work the application of a method to estimate the shaft power of induction motors operating in the presences of unbalanced and harmonics voltages is presented. The method uses the steady state equivalent circuits, with some considerations for the analysis of motor performance, fed with unbalanced and harmonic voltages. The parameters of circuits are determined with low invasiveness, by applying a Bacterial Foraging Algorithm as technique of evolutionary search. With this, the shaft power can be estimated at any operating point. The method was tested in a 12.6 kW motor working in an industrial power supply grid, with harmonics and unbalanced voltag

Selection of HVAC technology for buildings in the tropical climate case study

In this paper, the integral performance indicator for selecting HVAC systems (ACPI) is applied to select the Air Conditioning (AC) system with better results in their life cycle for a typical building in Barranquilla, Colombia. The AC systems under study were: direct expansion system (Split and VRF), air-cooled system (VAC and VAV), and water-cooled system (Chiller). Of the six selection criteria of ACPI, the energy consumption index (EC) and thermal comfort (TC) were calculated through energy simulation of buildings, the regulations were used for IAQ and carbon emissions (CE), and were estimated the investment costs (IC) and operating and maintenance costs (OMC). The best-performance AC system for the building was the air-cooled AC system got the best ACPI values between 25 % and 22.4 %, followed by the water-cooled system with 22.3 %, and finally the direct expansion systems between 16.8 % and 13.5 %, influencing in this level of priority the IAQ and IC criteria. This study contributes to introducing in Colombia a multifactorial analysis to select the more proper AC system technology according to the building and location conditions

Energy Performance of a University Building for Different Air Conditioning (AC) Technologies: A Case Study

The study uses four AC technologies to assess the energy performance—this is a case study of an educational building in Barranquilla, Colombia. The building currently has split AC technology high-energy consumers. Therefore, it was necessary to assess a replacement with more efficient technology. Because of the non-seasonal climate in the building location, one month of monitoring of energy consumption was the reference for developing an energy model for the building using EnergyPlus and DesignBuilder software. The model was applied to forecast the building energy performance of our more efficient AC technologies available in the Colombian market, and valuable according to building specifications (Split, VRF, VAV, and Chiller). Results show a reduction in energy consumption of approximately 30% with the technology change and 15% savings in life cycle costs (LCCs), even though the building is already considered to have a low energy consumption according to national regulations. The findings of this study underscore the potential for widespread applicability across all types of buildings, regardless of their energy consumption profile, be it low, medium, or high. This extensive applicability not only highlights the adaptability and versatility of the technology but also underscores its significance in achieving substantial energy savings and cost reductions across the entire building industry, contributing to a more sustainable and economically efficient future