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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hardware-in-the-loop Simulation of a Pumping Station : Design and implementation of a Python-based simulation program / Hardware-in-the-loop-simulering av en Pumpstation : Design och implementering av ett Python-baserat simuleringsprogram

Liang, Katrina January 2022 (has links)
The use of simulation enables testing of a system without the need for a complete physical system, while also having the advantages of lower cost and fewer practical limits compared to field tests. Hardware may be integrated into the simulation loop, such a simulation is defined as a Hardware-in-the-loop (HIL) simulation. The pump is the most energy-consuming part of a pumping station, thus improvement and assessment of the pump controller are two of the main considerations in the development of pumping stations. Nevertheless, the developers do not always have access to a real pumping station to run tests on. A HIL simulator that imitates parts of a pumping station while including a real controller in the simulation is therefore desirable for the development of pump controllers.In this thesis, a mathematical model of a pumping station was built based on the physical features of different components, and a HIL simulation was implemented with the programming language Python, in which a real controller was integrated into the simulation loop. Through a three-hour-long simulation run, the functionality of the simulator has been analyzed, and the simulation accuracy was evaluated by comparing simulated results to real data. The results showed that among the 10 800 simulated data points of the water level, there were \(43\) (\(\approx 0.39\%\)) that had a relative change larger than \(30\%\) or less than \(-30\%\) with respect to the field data. This thesis contributes to the field of Python-based simulation of a pumping station, and serves as a foundation for future improvement for the host company. / Användningen av simulering möjliggör testning av ett system utan ett komplett fysiskt system, till en lägre kostnad och färre praktiska begränsningar jämfört med fälttester. Hårdvara kan integreras i simuleringsloopen, en sådan simulering kallas för en hardware-in-the-loop (HIL) simulering. Pumpen är den mest energikrävande delen i en pumpstation, därför är förbättring och utvärdering av pumpstyrningen två av de viktigaste faktorerna vid utvecklingen av pumpstationer. Dock har utvecklarna inte alltid tillgång till en fysisk pumpstation att köra tester på. En HIL-simulator som imiterar delar av en pumpstation, till vilken en pumpstyrning kan kopplas, är därför önskvärd för utvecklingen av pumpstyrningar.I detta examensarbete konstruerades en matematisk modell av en pumpstation utifrån de fysiska egenskaperna hos olika komponenter. En HIL-simulator var sedan implementerad i programmeringsspråket Python, där en riktig pumpstyrning integrerades i simuleringsloopen. Genom en tre timmar lång körning har simulatorns funktionalitet analyserat, och simuleringsnoggrannheten utvärderades genom att jämföra simulerade resultat med verkliga data. Resultaten visade att \(43\) av de 10 800 (\(\approx 0,39\%\)) simulerade datapunkterna för vattennivån hade en relativ förändring större än \(30\%\) eller mindre än \(-30\%\) med avseende på fältdata. Detta arbete bidrar till området inom Python-baserad simulering av en pumpstation och agerar som en grund för framtida utvecklingar hos värdföretaget.
2

Improving Photovoltaic Panel Efficiency by Cooling Water Circulation

Joseph, Jyothis 12 1900 (has links)
This thesis aims to increase photovoltaic (PV) panel power efficiency by employing a cooling system based on water circulation, which represents an improved version of water flow based active cooling systems. Theoretical calculations involved finding the heat produced by the PV panel and the circulation water flow required to remove this heat. A data logger and a cooling system for a test panel of 20W was designed and employed to study the relationship between the PV panel surface temperature and its output power. This logging and cooling system includes an Arduino microcontroller extended with a data logging shield, temperature sensing probes, current sensors, and a DC water pump. Real-time measurements were logged every minute for one or two day periods under various irradiance and air temperature conditions. For these experiments, a load resistance was chosen to operate the test panel at its maximum power point. Results indicate that the cooling system can yield an improvement of 10% in power production. Based on the observations from the test panel experiments, a cooling system was devised for a PV panel array of 640 W equipped with a commercial charge controller. The test data logger was repurposed for this larger system. An identical PV array was left uncooled and monitored simultaneously to compare the effect of cooling, demonstrating that the cooled array provided up to an extra 132W or 20% of maximum power for sunny weather conditions. Future expansion possibilities of the project include automated water level monitoring system and water filtration systems.
3

Extension, Evaluation, and Validation of Load Based Testing for Residential and Commercial HVAC Equipment

Parveen Dhillon (14203079) 02 December 2022 (has links)
<p>With rising temperatures, urbanization, population growth, improving economic wellbeing, decarbonization and electrification efforts, the demand for space cooling and heating equipment is continuously increasing around the world. To counteract the effect of rising demand for air conditioners and heat pumps on total energy consumption, peak electricity demand, and emissions, it is crucial to promote the development and market penetration of energy-efficient systems. Establishing minimum energy performance standards (MEPS), energy labeling and utility programs are some of the effective and tested methods for achieving this goal. The technical basis for these energy efficiency standards is a testing and rating procedure for estimating equipment seasonal performance from laboratory tests. Although the current rating procedures provide standardized metrics to compare different equipment performances, they fail to appropriately characterize the field representative performance of systems by not considering the effects of: 1) test unit embedded controls, thermostat, and realistic interactions with the building load and dynamics; 2) different climate zones and building types; and 3) and other integrated accessories for improving energy efficiency such as economizer for rooftop units (RTUs). Therefore, current approaches for performance ratings neither incentives the development and implementation of improved system and control designs nor consumers with a metric that represents the advanced systems' actual energy savings. To address this, a load-based testing methodology that enables dynamic performance evaluation of equipment with its integrated controls, thermostat, and other accessories was recently proposed. The test methodology is based on the concept of emulating the response of a representative building conditioned by the test unit in a test lab using a virtual building model. </p> <p>In this work, the proposed load-based testing methodology was further extended, evaluated, and validated for residential heat pumps to integrate it into next-generation energy efficiency testing and rating procedures and to serve as a tool for engineers to develop and validate improved control algorithms in a laboratory setting. Further, a load-based testing method for evaluating the dynamic performance of RTUs with integrated economizers was also developed and demonstrated.</p> <p>A load-based testing approach previously developed for residential cooling equipment is extended for heat pump heating-mode and demonstrated for a variable-speed system. The heat pump's typical dynamic behaviors are captured along with controller imperfections that aren't reflected in current testing approaches. Further, a comprehensive comparison was performed between the proposed load-based testing approach to the current steady-state testing approach in the U.S., AHRI 210/240, based on performance evaluation of three residential variable-speed heat pumps to understand the differences and their significance for the next-generation rating procedure. For cooling mode, steady-state testing estimates higher seasonal performance, but for heating mode, the steady-state testing approach estimates higher seasonal performance for warmer climates and is comparable for colder climates. The load-based testing methodology was validated by comparing the laboratory performance of a heat pump to that of a residential building in a controlled environment. The virtual building modeling approach for building loads and thermal dynamics effectively captured these characteristics of the house. The heat pump's cycling rate response with run-time fraction, which represents the unit's overall dynamic response, matched well between lab load-based tests and house tests. The test unit's COP difference for cooling and heating tests was within 3% between the two facilities, except for 9% in 95°F and 6% in 104°F cooling dry-coil test intervals. To evaluate the applicability of the developed load-based testing methodology as next-generation rating standards, its repeatability and reproducibility were assessed based on multiple heat pump round-robin tests conducted in two labs. Overall, reasonable to good repeatability was observed in load-based test results in both labs, however, poor reproducibility was observed except for one heat pump heating mode results. A root cause analysis of the observed differences along with recommendations for a next-generation rating approach are presented. This work aided in the development of a CSA (Canadian Standards Association) standard EXP07:19 and its subsequent revision for equipment rating based on load-based testing.</p> <p>The application of the load-based testing methodology as a tool for the development and evaluation of a residential heat pump controller design was demonstrated. Further, a load-based testing methodology was developed and demonstrated for the dynamic performance evaluation of RTUs with integrated economizers in a test laboratory setting. Recommendations for future work to further develop and improve the repeatability, reproducibility, and representativeness of the load-based testing and rating approach for residential and commercial air conditioners and heat pumps are summarized at the end of the dissertation. </p>

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