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- distributed recycling of waste polymer into reprap feedstock
- photovoltaic powered small system
- photovoltaic powered small system -desalination
- photovoltaic powered +distributed +"small system"
- low cost DC to AC converter for photovoltaic power conversion in residential applications
- Combined low-cost, high-efficient inverter, peak power tracker and regulator for PV applications
- "open source" photovoltaic power
- photovoltaic powered system "stand alone"
- photovoltaic powered decentralized
- stand alone photovoltaic system "portable" "mobile"
Literature[edit | edit source]
Distributed recycling of waste polymer into RepRap feedstock[edit | edit source]
[1]C. Baechler, M. DeVuono, and J. M. Pearce, "Distributed recycling of waste polymer into RepRap feedstock," Rapid Prototyping Journal, vol. 19, no. 2, pp. 118–125, Mar. 2013.
Purpose – A low‐cost, open source, self‐replicating rapid prototyper (RepRap) has been developed, which greatly expands the potential user base of rapid prototypers. The operating cost of the RepRap can be further reduced using waste polymers as feedstock. Centralized recycling of polymers is often uneconomic and energy intensive due to transportation embodied energy. The purpose of this paper is to provide a proof of concept for high‐value recycling of waste polymers at distributed creation sites.
Design/methodology/approach – Previous designs of waste plastic extruders (also known as RecycleBots) were evaluated using a weighted evaluation matrix. An updated design was completed and the description and analysis of the design is presented including component summary, testing procedures, a basic life cycle analysis and extrusion results. The filament was tested for consistency of density and diameter while quantifying electricity consumption.
Findings – Filament was successfully extruded at an average rate of 90 mm/min and used to print parts. The filament averaged 2.805 mm diameter with 87 per cent of samples between 2.540 mm and 3.081 mm. The average mass was 0.564 g/100 mm length. Energy use was 0.06 kWh/m.
Practical implications – The success of the RecycleBot further reduces RepRap operating costs, which enables distributed in‐home, value added, plastic recycling. This has implications for municipal waste management programs, as in‐home recycling could reduce cost and greenhouse gas emissions associated with waste collection and transportation, as well as the environmental impact of manufacturing custom plastic parts.
Originality/value – This paper reports on the first technical evaluation of a feedstock filament for the RepRap from waste plastic material made in a distributed recycling device.
Notes:
- Time to extrude: 10.27min/100g of extruded plastic
- 269 W peak power drawn, 66.45 percent of energy per unit length from heating
- 65% of filament within desired diameter of 2.28 mm
- Three challenges: physical assistance required to draw filament from extruder, inconsistent rate of extrusion, extrusion affected by size and type of recycled plastic ex. thin pieces of HDPE did not extrude as well as thick pieces
A Fuzzy-Logic-Controlled Single-Stage Converter for PV-Powered Lighting System Applications[edit | edit source]
[2]T.-F. Wu, C.-H. Chang, and Y.-K. Chen, "A fuzzy-logic-controlled single-stage converter for PV-powered lighting system applications," IEEE Transactions on Industrial Electronics, vol. 47, no. 2, pp. 287–296, Apr. 2000.
This paper presents a fuzzy-logic-controlled single-stage converter (SSC) for photovoltaic (PV)-powered lighting system applications. The SSC is the integration of a bidirectional buck–boost charger/discharger and a class-D se- ries resonant parallel loaded inverter. The designed fuzzy logic controller (FLC) can control both the charging and discharging current, and can improve its dynamic and steady-state perfor- mance. Furthermore, a maximum power point tracker (MPPT) based on a perturb-and-observe method is also realized to effec- tively draw power from PV arrays. Both the FLC and the MPPT are implemented on a single-chip microprocessor. Simulated and experimental results obtained from the proposed circuit with an FLC have verified the adaptivity, robustness, and feasibility.
Notes:
- PV Modules-16 SOLAREX MAGA SX-60, peak output 960W, Voc=138.6 V, Isc=7.6 A
- battery bank to store excess energy
- SRLPI-series resonant parallel loaded inverter
- PV voltage of 120-160V
- fuzzy logic used because it doesn't require accurate mathematical model of converter
- inexpensive single-chip controllers
Photovoltaic converter system suitable for use in small scale stand-alone or grid connected applications[edit | edit source]
[3]J. A. Gow and C. D. Manning, "Photovoltaic converter system suitable for use in small scale stand-alone or grid connected applications," Electric Power Applications, IEE Proceedings -, vol. 147, no. 6, pp. 535–543, Nov. 2000.
Of the commercially-available solutions for the conversion of energy from photovoltaic arrays into a usable form, a large number consist of systems which have been developed for a dedicated application and are thus very inflexible. Those that are available as a generic module for use in a variety of environments are often restricted to a single mode of operation, for example utility supply only. A generic modular photovoltaic power conversion system is presented, aimed at single-phase applications which can supply passive AC and DC loads with a regulated voltage or by way of a maximum power tracking system with the maximum power available from the array. In addition a live AC load such as the utility can be supplied with maximum array power. The system is small, light and can be constructed from readily available components.
Notes:
- Low-cost, low-maintenance, modular system for smaller PV applications ex. residential power system 1-3 kW
- DC-DC converter -> inverter controlled for either "live" or "dead" AC loads
- PV sources have unique terminal voltage and current at which max power is produced and can be seen as a combo of voltage and current source
- peak-power tracking system
- a multiuse PV power conversion system for small applications is viable
- propsed control techniques could form a useful basis for commercial applications
Performance analysis of a directly coupled photovoltaic water-pumping system[edit | edit source]
[4]M. Kolhe, J. C. Joshi, and D. P. Kothari, "Performance analysis of a directly coupled photovoltaic water-pumping system," IEEE Transactions on Energy Conversion, vol. 19, no. 3, pp. 613–618, Sep. 2004.
The application of a stand-alone directly coupled photovoltaic (PV) electromechanical system for water pumping has increased in remote areas of developing countries. In this work, the performance of a PV-powered dc permanent-magnet (PM) motor coupled with a centrifugal pump has been analyzed at different solar intensities and corresponding cell temperature. The results obtained by experiments are compared with the calculated values, and it is observed that this system has a good match between the PV array and the electromechanical system characteristics. Through manual tracking (i.e., changing the orientation of PV array, three times a day to face the sun) the output obtained is 20% more compared to the fixed tilted PV array. It has been observed that the torque-speed curve at low solar intensities for a PV electromechanical system should be steeper than at higher solar intensities, and the load torque-speed curve should be as steep as possible in the operating region with low starting torque. The performance analysis will be helpful to select the suitable PV electromechanical system for water-pumping applications.
Notes:
- PV array (20 modules) connected in series and parallel (4*5) for desired V and I
- array orientation manually adjusted 3 times daily
- mechanical load should be so that max power is drawn from PV array at all solar intensities
- system began to operate at 150 W/m^2 and ran for most of the day
- Voc did not vary greatly with change in solar intensity, while Isc did
- Voc decreases with increase in cell temperature
- overall reduction in PV efficiency with increase in temperature
- 20% more water pumped with 3x daily manual tracking as opposed to fixed orientation
- max pump efficiency observed around 700 W/m^2 intensity
Improved Energy Capture in Series String Photovoltaics via Smart Distributed Power Electronics[edit | edit source]
[5]L. Linares, R. W. Erickson, S. MacAlpine, and M. Brandemuehl, "Improved Energy Capture in Series String Photovoltaics via Smart Distributed Power Electronics," in Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition, 2009. APEC 2009, 2009, pp. 904–910.
This paper proposes an improved module integrated converter to increase energy capture in the photovoltaic (PV) series string. Prototypes for self-powered, high efficiency dc-dc converters that operate with autonomous control for tracking the maximum power of solar panels locally and on a fine scale are simulated, built and tested. The resulting module is a low-cost, reliable smart PV panel that operates independently of the geometry and complexity of the surrounding system. The controller maximizes energy capture by selection of one of three possible modes: buck, boost and pass-through. Autonomous controllers achieve noninteracting maximum power point tracking and a constant string voltage. The proposed module-integrated converters are verified in simulation. Experimental results show that the converter prototype achieves efficiencies of over 95% for most of its operating range. A 3-module PV series string was tested under mismatched solar irradiation conditions and increases of up to 38% power capture were measured.
Notes:
- MIC-module integrated converters
- DC-DC converter steps up voltage from <1 V output of modules to required voltage, then inverted
- max power point tracking for each module->MIC efficiency above 95%
- each module separately determines max power point without regard to other modules in string
Low cost DC to AC converter for photovoltaic power conversion in residential applications[edit | edit source]
[6]U. Herrmann, H. G. Langer, and H. Van der Broeck, "Low cost DC to AC converter for photovoltaic power conversion in residential applications," in , 24th Annual IEEE Power Electronics Specialists Conference, 1993. PESC '93 Record, 1993, pp. 588–594.
The development and experimental results of a low-cost 500-W DC-AC power converter for photovoltaic power conversion in residential applications are described. The converter uses low-cost technology usually applied in consumer products. The DC-AC converter is specially designed for operation at a wide DC input voltage range (30-170 V) in order to allow optimal power conversion with an arbitrary number of series connected solar arrays. A step-up chopper is used for MPP tracking and provides a constant 200-V DC link for the following push-pull power converter. This galvanic isolating power converter operates at 100 kHz and controls the current in the mains sinusoidally. A thyristor bridge alternates the current after each half line period. The required auxiliary power is kept below 7 W and is taken from the choke of the step-up chopper
Notes:
- low cost, residential scale alternative to expensive industrial scale converters decreases cost of installing private solar array
- 500 W DC to AC converter
- three power stages: step up chopper, push-pull converter, thyristor inverter
Combined low-cost, high-efficient inverter, peak power tracker and regulator for PV applications[edit | edit source]
[7]J. H. R. Enslin and D. B. Snyman, "Combined low-cost, high-efficient inverter, peak power tracker and regulator for PV applications," IEEE Transactions on Power Electronics, vol. 6, no. 1, pp. 73–82, Jan. 1991.
A novel compound power converter that serves as a DC-to-AC inverter, maximum power point tracker (MPPT), and battery charger for stand-alone photovoltaic (PV) power systems is introduced. A theoretical analysis of the proposed converter is performed, and the results are compared with experimental results obtained from a 1.5 kW prototype. The overall cost of PV systems can thus be reduced by using load management control and efficiency-optimization techniques. Power flow through the converter is controlled by means of a combination of duty cycle and output frequency control. With load management, large domestic loads, such as single phase induction motors for water pumping, hold-over refrigerators, and freezers, can be driven by day at a much higher energy efficiency. This is due to the high efficiency of the inverter with high insolation, and because the inverter uses the energy directly from the solar array. The battery loss component is thus reduced
Notes:
- improved system efficiency using paralleled power conditioning system compared to cascaded conditioning system
- capacitor in series with PV array and battery
Mobile Open-Source Solar-Powered 3-D Printers for Distributed Manufacturing in Off-Grid Communities[edit | edit source]
[8]D. L. King, A. Babasola, J. Rozario, and J. M. Pearce, "Mobile Open-Source Solar-Powered 3-D Printers for Distributed Manufacturing in Off-Grid Communities," 18-27, Oct. 2014.
Manufacturing in areas of the developing world that lack electricity severely restricts the technical sophistication of what is produced. More than a billion people with no access to electricity still have access to some imported higher-technologies; however, these often lack customization and often appropriateness for their community. Open source appropriate technology (OSAT) can overcome this challenge, but one of the key impediments to the more rapid development and distribution of OSAT is the lack of means of production beyond a specific technical complexity. This study designs and demonstrates the technical viability of two open-source mobile digital manufacturing facilities powered with solar photovoltaics, and capable of printing customizable OSAT in any community with access to sunlight. The first, designed for community use, such as in schools or makerspaces, is semi-mobile and capable of nearly continuous 3-D printing using RepRap technology, while also powering multiple computers. The second design, which can be completely packed into a standard suitcase, allows for specialist travel from community to community to provide the ability to custom manufacture OSAT as needed, anywhere. These designs not only bring the possibility of complex manufacturing and replacement part fabrication to isolated rural communities lacking access to the electric grid, but they also offer the opportunity to leap-frog the entire conventional manufacturing supply chain, while radically reducing both the cost and the environmental impact of products for developing communities.
Notes:
- PV power is particularly useful for remote off-grid applications
- modest power requirements for 3d printers
- 35-40 W for RepRap printer
- 2 220W solar panels and 4 120 Ah batteries for a printing time of 35 hours on single charge
- DC from PV and batteries inverted and sent to power bar
- Ultraportable application: FoldaRap connected to charging unit controlled by Arduino Uno board, DC/DC charge controller used instead of inverter, Li-ion laptop batteries
- community-scale and suitcase-scale PV powered 3d printing applications were viable
Open-source development of solar photovoltaic technology[edit | edit source]
[9]A. J. Buitenhuis and J. M. Pearce, "Open-source development of solar photovoltaic technology," Energy for Sustainable Development, vol. 16, no. 3, pp. 379–388, Sep. 2012.
The rise of solar photovoltaic (PV) technology as a driver of rural electrification in the developing world and a contributor to climate change mitigation suggests that innovations enhancing PV efficiency and scalability could make considerable strides in reducing both poverty and greenhouse gas emissions. The nearly global access to the solar resource coupled to innovation-driven decreases in the costs of PV provides a path for a renewable energy source to accelerate sustainable development. Open-source software development has proven to produce reliable and innovative computer code at lower costs than proprietary software through sharing development responsibility with a large community of invested individuals. Concepts of open-source design have been applied to other fields in an attempt to reap the same benefits realized within software development; however, applying open-source strategies to solar PV research is uncommon. This paper reviews and examines how open-source design can be utilized to catalyze rapid innovation in the PV industry. The results show how successful open design and development methods can be created and utilized by identifying business models that provide PV researchers, turnkey suppliers and solar PV module manufacturers with the opportunity to utilize open-source design principles to accelerate innovation.
Notes:
- goal-share as much intellectual property as possible in order to sustain aggressive growth in PV technology
- benefits of open-source software are well established, concepts would similarly affect solar PV industry
- projected half of global energy needs by 2060
High-Performance Stand-Alone Photovoltaic Generation System[edit | edit source]
[10]R.-J. Wai, W.-H. Wang, and C.-Y. Lin, "High-Performance Stand-Alone Photovoltaic Generation System," IEEE Transactions on Industrial Electronics, vol. 55, no. 1, pp. 240–250, Jan. 2008.
This study develops a high-performance stand-alone photovoltaic (PV) generation system. To make the PV generation system more flexible and expandable, the backstage power circuit is composed of a high step-up converter and a pulsewidth-modulation (PWM) inverter. In the dc-dc power conversion, the high step-up converter is introduced to improve the conversion efficiency in conventional boost converters to allow the parallel operation of low-voltage PV arrays, and to decouple and simplify the control design of the PWM inverter. Moreover, an adaptive total sliding-mode control system is designed for the voltage control of the PWM inverter to maintain a sinusoidal output voltage with lower total harmonic distortion and less variation under various output loads. In addition, an active sun tracking scheme without any light sensors is investigated to make the PV modules face the sun directly for capturing the maximum irradiation and promoting system efficiency. Experimental results are given to verify the validity and reliability of the high step-up converter, the PWM inverter control, and the active sun tracker for the high-performance stand-alone PV generation system.
Notes:
- PV modules are low voltage, so dc-dc high gain converter needed
- sun tracking done by measuring open circuit voltage instead of using light sensors, simplifying circuitry
- high step-up converter can be applied well to low-voltage PV sources even under inconsistent irradiation
- max conversion efficiency of step-up converter over 96.5%
- inverter total harmonic distortion less than 3.2% for different loads
- high efficiency conversion, large voltage gain, high quality AC power control in a stand alone system
- can be applied to grid-connected system
A photovoltaic-powered seawater reverse-osmosis system without batteries[edit | edit source]
[11]M. Thomson and D. Infield, "A photovoltaic-powered seawater reverse-osmosis system without batteries," Desalination, vol. 153, no. 1–3, pp. 1–8, Feb. 2003.
An efficient cost-effective batteryless photovoltaic-powered seawater reverse-osmosis desalination system is described. The system has a modest 2.4 kWp photovoltaic array and yet promises to deliver 3 m3/d throughout the year in an example location in Eritrea, operating from borehole seawater (at 40,000 ppm). Existing demonstrations of photovoltaic-powered desalination generally employ lead-acid batteries, which allow the equipment to operate at constant flow. In practice however, batteries are notoriously problematic, especially in hot climates. The system employed here operates at variable flow, enabling it to make efficient use of the naturally varying solar resource, without need of batteries. The system employs standard industrial inverters, motors and pumps, which offer excellent energy and cost efficiency. Maximum power point tracking (MPPT) for the photovoltaic array is provided by a novel and extremely simple control algorithm, developed by CREST. Performance and cost estimates from laboratory testing and extensive modelling are presented.
Notes:
- Existing systems use large lead-acid battery banks to provide constant power
- special PV power electronics (inverters) are expensive
- substantial cost reduction and performance improvement compared to existing PV powered reverse osmosis systems due to smart selection of components and control strategy
