Institute for Integrated Energy Systems (IESVic)

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The Institute for Integrated Energy Systems at the University of Victoria (IESVic) promotes feasible paths to sustainable energy systems by developing new technologies and perspectives to overcome barriers to the widespread adoption of sustainable energy. Founded in 1989, IESVic conducts original research to develop key technologies for sustainable energy systems and actively promotes the development of sensible, clean energy alternatives.

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IESVic's mission is to chart feasible paths to sustainable energy.

Institute's web page http://www.iesvic.uvic.ca/

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Active magnetic regenerator experimental optimization
(2009-11-30T16:59:27Z) Tura, Armando; Rowe, Andrew Michael
A technology that has the potential to create more efficient and compact refrigeration devices is an Active Magnetic Regenerative Refrigerator (AMRR). An AMRR can operate over a broad range of temperatures, as long as the appropriate refrigerant is implemented. Thus this flexible technology can be used for small, efficient, and simple room temperature refrigerators, as well as efficient gas liquefaction plants (AMRLs). Active Magnetic Regenerator Refrigeration exploits the magnetocaloric effect displayed by magnetic materials whereby a reversible temperature change is induced when the material is exposed to a magnetic field. By using the magnetic materials in a regenerator as the heat storage medium and as the means of work input, one creates an Active Magnetic Regenerator (AMR). In this work, an experimental study of Active Magnetic Regenerators composed of single and multi-materials is carried out. AMRs made up of Gd, Gd.74Tb.26, and Gd.85Er.15 are studied in cycles rejecting heat between 270 K and 311 K. A variety of operating conditions were tested and regenerator performance with respect to heat load, utilization, and frequency was examined. AMR behavior was qualitatively interpreted and a path for performance improvement and future investigations laid.
Aero-elastic Energy Harvesting Device: Design and Analysis
(2015-10-02) Pirquet, Oliver Johann; Nadler, Ben; Crawford, Curran
An energy harvesting device driven by aeroelastic vibration with self-sustained pitching and heaving using an induction based power take off mechanism has been designed and tested for performance under various operating conditions. From the data collected the results show that the device achieved a maximum power output of 48.3 mW and a maximum efficiency of 2.26% at a dimensionless frequency of 0.143. For all airfoils tested the device was shown to be self-starting above 3 m/s. A qualitative description relating to the performance of the device considering dynamic stall and the flow conditions at optimal dimensionless frequency has been proposed and related to previous work. Performance for angles off the wind up to 22 degrees and was observed to have no reduction in power output due to the change in angle to the wind. The device has shown evidence of having a self-governing capability, tending to decrease its power output for heavy windpspeeds, a thorough examination of this capability is recommended for future work.
Affinity purification of NAD+-dependent formate dehydrogenase (EC 1.2.1.2) and activity of FDH in miniature enzyme bioreactors
(2010-04-07T19:56:14Z) Sanderson, Dan; Levin, David Bernard
Formate dehydrogenase from Mycobacterium vaccae (MycFDH) was cloned and expressed from various plasmid constructs that incorporate hexahistidine tags onto the N-and C-termini of the protein. The most successful FDH variant, dual-tagged FDH L-S expressed from pET28a+, was batch-purified using ammonium sulphate precipitation and IMAC to achieve 96% homogeneity. A significant proportion of the expressed protein was insoluble, and the expression protocol did not respond to solubility optimization efforts. Expression of an FDH-NusA fusion variant appeared to be vulnerable to proteolytic degradation in the cell. None of the strains expressing tagged-FDH variants produced clarified lysate activity levels that were consistently as high as those from the original pUC 119 vector. However, it is likely that the protein aggregation problems encountered are due to overloading of the protein production machinery or related causes, rather than to the presence of the tags themselves. A bioengineered FDH protein closely related to MycFDH was also investigated. FDH GAV was immobilized in polyacrylamide gel to create gel discs or hollow cylinder mini-reactors. The apparent Km(formate) for this enzyme was 15.6 ± 3.6 mM in the immobilized state, and 17.2 ± 1.9 mM in aqueous solution. The activity of FDH GAV was reversibly inhibited by the presence of acrylamide monomer but was not affected by ammonium persulfate or TEMED (alone or in combination) after incubation for one minute. The activity of the immobilized enzyme system was determined to be at least partially limited by diffusion. FDH GAV was also included in an in vitro analysis of the Methanol Linear Dissimilation Pathway (MLDP), a three enzyme system of NAD+ - dependent dehydrogenases that oxidize methanol sequentially to CO2. Horse liver alcohol dehydrogenase (EC 1.1.1.1) appeared to be the rate-limiting enzyme under the conditions used in these experiments, most likely due to its limited activity on methanol. The applicability of FDH and the MLDP to industry and bioelectronics is also considered.
Algorithm development for electrochemical impedance spectroscopy diagnostics in PEM fuel cells
(2008-04-10T06:05:02Z) Latham, Ruth Anne.; Harrington, David A.
Analysis and development of a three body heaving wave energy converter
(2009-05-01T20:04:40Z) Beatty, Scott, J.; Buckham, Bradley, Jason; Wild, Peter Martin
A relative motion based heaving point absorber wave energy converter is being co-developed by researchers at the University of Victoria and SyncWave Systems Inc. To that end---this thesis represents a multi-faceted contribution to the development effort. A small scale two-body prototype wave energy converter was developed and tested in a wave tank. Although experimental problems were encountered, the results compare reasonably well to the output of a two degree of freedom linear dynamics model in the frequency domain. A two-body wave energy converter design is parameterized as a basis for an optimization and sensitivity study undertaken to illustrate the potential benefits of frequency response tuning. Further, a mechanical system concept for frequency response tuning is presented. The two degree of freedom model is expanded to three degrees of freedom to account for the tuning system. An optimization procedure, utilizing a Sequential Quadratic Programming algorithm, is developed to establish control schedules to maximize power capture as a function of the control variables. A spectral approach is developed to estimate WEC power capture in irregular waves. Finally, as a case study, the modeling, optimization, and spectral methods are applied to predict performance for a large scale wave energy converter deployed offshore of a remote Alaskan island. Using archived sea-state data and community electrical load profiles, a wave/diesel hybrid integration with the remote Alaskan community power system is assessed to be technologically feasible.
Assessing the impact of hybrid heating systems in combination with off-peak EV charging on grid capacity requirements
(IESVic Energy Brief, 2025) Knittel, Tamara; Lowry, Colton; Wild, Peter; Rowe, Andrew
Key messages: - Future capacity requirements are driven by electrification of heating and road transportation. - Hybrid heating systems switching from electric to gas heating operations during cold weather events reduce electricity demand for residential space heating. - Electric vehicle charging control can significantly limit capacity requirements of the electricity grid.
Assessing the impacts of wind integration in the Western Provinces
(2012-12-06) Sopinka, Amy; Van Kooten, G. C.
Increasing carbon dioxide levels and the fear of irreversible climate change has prompted policy makers to implement renewable portfolio standards. These renewable portfolio standards are meant to encourage the adoption of renewable energy technologies thereby reducing carbon emissions associated with fossil fuel-fired electricity generation. The ability to efficiently adopt and utilize high levels of renewable energy technology, such as wind power, depends upon the composition of the extant generation withinthe grid. Western Canadian electric grids are poised to integrate high levels of wind and although Alberta has sufficient and, at times, an excess supply of electricity, it does not have the inherent generator flexibility required to mirror the variability of its wind generation. British Columbia, with its large reservoir storage capacities and rapid ramping hydroelectric generation could easily provide the firming services required by Alberta; however, the two grids are connected only by a small, constrained intertie. We use a simulation model to assess the economic impacts of high wind penetrations in the Alberta grid under various balancing protocols. We find that adding wind capacity to the system impacts grid reliability, increasing the frequency of system imbalances and unscheduled intertie flow. In order for British Columbia to be viable firming resource, it must have sufficient generation capability to meet and exceed the province’s electricity self-sufficiency requirements. We use a linear programming model to evaluate the province’s ability to meet domestic load under various water and trade conditions. We then examine the effects of drought and wind penetration on the interconnected Alberta – British Columbia system given differing interconnection sizes.
Assessing the multi-value benefits of transmission expansion
(IESVic Energy Brief, 2024) Seatle, Madeleine; McPherson, Madeleine
Key messages: - Transmission should be seen as much as an adaptation initiative as a mitigation initiative - Interprovincial transmission provides significant reliability improvements to the system - The value of transmission cannot be quantified purely through export revenues
Barriers and enablers to the adoption of buildings and energy efficiency initiatives in Greater Victoria
(IESVic Energy Briefs, 2024) Masemann, Charlotte; Krawchenko, Tamara; Rhodes, Ekaterina
Key messages: - Focus group participants identify funding from provincial and federal governments as adequate and as enabling alongside staffing interactions. - Staffing resources, the legislative, regulatory and political environment alongside governance and information and data management were identified as both barriers and enables. - Political will and information exchange enable existing climate action, but municipalities lack of autonomy over the most effective policy instruments.
Big government, big trouble? The role of government size in climate policy support
(IESVic Energy Brief, 2024) Andrew, Kevin; Rhodes, Ekaterina
Key messages: - Size of government is studied as a new country-level contextual factor determining citizen support for climate policy. - Larger size-of-government is associated with lower climate policy support. - GDP-per-capita and emissions are positively associated with policy support. - High-tax countries have an aversion to environmental tax increases.
Case study of wave power integration into the Ucluelet area electrical grid
(2009-12-07T23:36:17Z) St. Germain, Louise Anne; Rowe, Andrew Michael; Wild, Peter Martin
Technologies exist that can capture and convert wave energy but there are few studies examining systemic integration of wave energy devices. This work examines the potential to use wave energy as a renewable energy resource on Vancouver Island, specifically in the Tofino/Ucluelet area. A model of a wave energy conversion (WEC) device was developed as a module within TRNSYS™ where it can be coupled to a load as well as to a storage medium. For this particular study, wave profiles generated from hourly average data for a location on the west coast of Vancouver Island are used as a resource input. An analysis of the potential to use wave energy is carried out with an emphasis on overall system efficiency and resulting device scaling. The results of the wave energy conversion with and without storage, as well as the general economics of these scenarios, are used to make recommendations regarding technical feasibility of wave power projects on Vancouver Island.
A Comparison of methods for sizing energy storage devices in renewable energy systems
(2013-01-15) Bailey, Thomas; Rowe, Andrew Michael; Wild, Peter Martin
Penetration of renewable energy generators into energy systems is increasing. The intermittency and variability of these generators makes supplying energy reliably and cost effectively difficult. As a result, storage technologies are proposed as a means to increase the penetration of renewable energy, to minimize the amount of curtailed renewable energy, and to limit the amount of back-up supply. Therefore, methods for determining an energy system’s storage requirements are being developed. This thesis investigates and details four existing methods, proposes and develops a fifth method, and compares the results of all five methods. The results show that methods which incorporate cost, namely the Dynamic Optimization and the Abbey method, consistently yield the most cost effective solutions. Under excellent renewable energy conditions the results show that the cost-independent methods of Korpaas, Barton, and the Modified Barton method produce solutions that are nearly as cost effective but have greater reliability of energy supply than the Dynamic Optimization and Abbey solutions. This thesis recommends a new path of research for the Modified Barton method: the incorporation of cost through the confidence level. This thesis also recommends the development of new sizing methods from various aspects of the methods presented.
Computational modeling and optimization of proton exchange membrane fuel cells
(2007-11-13T22:40:51Z) Secanell Gallart, Marc; Djilali, Ned; Suleman, Afzal
Improvements in performance, reliability and durability as well as reductions in production costs, remain critical prerequisites for the commercialization of proton exchange membrane fuel cells. In this thesis, a computational framework for fuel cell analysis and optimization is presented as an innovative alternative to the time consuming trial-and-error process currently used for fuel cell design. The framework is based on a two-dimensional through-the-channel isothermal, isobaric and single phase membrane electrode assembly (MEA) model. The model input parameters are the manufacturing parameters used to build the MEA: platinum loading, platinum to carbon ratio, electrolyte content and gas diffusion layer porosity. The governing equations of the fuel cell model are solved using Netwon's algorithm and an adaptive finite element method in order to achieve quadratic convergence and a mesh independent solution respectively. The analysis module is used to solve two optimization problems: i) maximize performance; and, ii) maximize performance while minimizing the production cost of the MEA. To solve these problems a gradient-based optimization algorithm is used in conjunction with analytical sensitivities. The presented computational framework is the first attempt in the literature to combine highly efficient analysis and optimization methods to perform optimization in order to tackle large-scale problems. The framework presented is capable of solving a complete MEA optimization problem with state-of-the-art electrode models in approximately 30 minutes. The optimization results show that it is possible to achieve Pt-specific power density for the optimized MEAs of 0.422 $g_{Pt}/kW$. This value is extremely close to the target of 0.4 $g_{Pt}/kW$ for large-scale implementation and demonstrate the potential of using numerical optimization for fuel cell design.
Cost and capacity requirements of electrification or renewable gas transition options that decarbonize building heating in Metro Vancouver, British Columbia
(Energy Strategy Reviews, 2022) Palmer-Wilson, Kevin; Bryant, Tyler; Wild, Peter; Rowe, Andrew
Northern countries face a unique challenge in decarbonizing heating demands. This study compares two pathways to reduce carbon emissions from building heating by (1) replacing natural gas heaters with electric heat pumps or (2) replacing natural gas with renewable gas. Optimal annual system cost and capacity requirements for Metro Vancouver, Canada are assessed for each pathway, under nine scenarios. Results show that either pathway can be lower cost but the range of costs is more narrow for the renewable gas pathway. System cost is sensitive to heat demand, with colder temperatures favouring the renewable gas pathway and milder temperatures favouring the electrification pathway. These results highlight the need for a better understanding of heating profiles and associated energy system requirements.
Coupled operation of a wind farm and pumped storage facility: techno-economic modelling and stochastic optimization.
(2011-12-22) Wild, Kristin; Crawford, Curran; Djilali, Nedjib
This thesis applies a stochastic programming approach to the techno-economic analysis of a wind farm coupled with a pumped storage facility. The production of an optimal day-ahead generating schedule is considered. Wind forecasts contain an element of random error, and several methods of addressing this uncertainty in the optimization process are compared. The methods include robust and reliability-based design optimization in addition to a combination of both approaches, and results indicate that reliability-based design optimization is best-suited to this particular problem. Based on a set of wind forecast error scenarios and historical data, a probability-weighted forecast wind generation scenario set is developed. Reliability constraints are imposed to meet a minimum of 80% of the generating schedule time intervals. This methodology is applied to a case study on Vancouver Island. Preliminary results show that when compared to the base case of a standalone wind farm on Vancouver Island, a wind farm coupled with pumped storage can prove to be economically competitive with pumped storage capital costs below $1.53 million/MW installed pumped storage capacity and a firm energy price of $130/MWh.
Dead Volume Effects in Passive Regeneration: Experimental and Numerical Characterization
(2015-09-17) Liu, Yifeng; Rowe, Andrew Michael
The regenerator is the key component in magnetic cycles for refrigeration and heat pumping. It works as temporal thermal energy storage and separates two thermal reservoirs. Regenerators are typically made up of porous structures which may create complex flow pathways for the heat transfer fluid through the regenerator. The periodically reversing flow allows the thermal energy exchange with the packing material in the regenerators. The performance of such thermal devices depends greatly on the geometry of the porous structure, material properties as well as operating conditions. This thesis is a study about the thermo-hydraulic properties of passive regenerators under oscillating flow conditions. The first part of the thesis presents a passive regenerator testing apparatus used to measure temperature distribution and pressure drop for various types of regenerators. Three kinds of loose spheres packed regenerator beds are characterized, and the regenerator effectiveness is evaluated. In the second part of the thesis, a numerical model is developed for the predictions of pressure drop and temperature field, and the theoretical findings are applied to experimentally obtained data to interpret regenerator performance. The dead volume is investigated quantitatively and considered to affect the regenerator performance adversely.
Design and Analysis of a Nested Halbach Permanent Magnet Magnetic Refrigerator
(2013-08-19) Tura, Armando; Rowe, Andrew Michael
A technology with the potential to create efficient and compact refrigeration devices is an active magnetic regenerative refrigerator (AMRR). AMRRs exploit the magnetocaloric effect displayed by magnetic materials whereby a reversible temperature change is induced when the material is exposed to a change in applied magnetic field. By using the magnetic materials in a regenerator as the heat storage medium and as the means of work input, one creates an active magnetic regenerator (AMR). Although several laboratory devices have been developed, no design has yet demonstrated the performance, reliability, and cost needed to compete with traditional vapor compression refrigerators. There are many reasons for this and questions remain as to the actual potential of the technology. The objective of the work described in this thesis is to quantify the actual and potential performance of a permanent magnet AMR system. A specific device configuration known as a dual-nested-Halbach system is studied in detail. A laboratory scale device is created and characterized over a wide range of operating parameters. A numerical model of the device is created and validated against experimental data. The resulting model is used to create a cost-minimization tool to analyze the conditions needed to achieve specified cost and efficiency targets. Experimental results include cooling power, temperature span, pumping power and work input. Although the magnetocaloric effect of gadolinium is small, temperature spans up to 30 K are obtained. Analysis of power input shows that the inherent magnetic work is a small fraction of the total work input confirming the assumption that potential cycle efficiencies can be large. Optimization of the device generates a number of areas for improvement and specific results depend upon targeted temperature spans and cooling powers. A competitive cost of cooling from a dual-nested-Halbach configuration is challenging and will depend on the ability to create regenerator matrices with near-ideal adiabatic temperature change scaling as a function of temperature.
Design Principles and Performance Metrics for Magnetic Refrigerators Operating Near Room Temperature
(2014-02-19) Arnold, Daniel Sean Robert; Rowe, Andrew Michael
In the past decade, active magnetic regenerative (AMR) refrigeration technology has progressed towards commercial application. The number of prototype systems and test apparatuses has steadily increased thanks to the worldwide research efforts. Due to the extensive variety of possible implementations of AMR, design methods are not well established. This thesis proposes a framework for approaching AMR device design. The University of Victoria now has three functional AMR Refrigerators. The newest system constructed in 2012 operates near-room-temperature and is intended primarily as a modular test apparatus with a broad range of control parameters and operating conditions. The design objectives, considerations and analysis are presented. Extensive data has been collected using the machines at the University of Victoria. Performance metrics are used to compare the devices. A semi-analytical relationship is developed that can be used as an effective modelling tool during the design process.
A Detailed Analysis of Guard-Heated Wall Shear Stress Sensors for Turbulent Flows
(2013-07-30) Ale Etrati Khosroshahi, Seyed Ali; Bhiladvala, Rustom
This thesis presents a detailed, two-dimensional analysis of the performance of multi-element guard-heated hot-film wall shear stress microsensors for turbulent flows. Previous studies of conventional, single-element sensors show that a significant portion of heat generated in the hot-film travels through the substrate before reaching the fluid, causing spectral and phase errors in the wall shear stress signal and drastically reducing the spatial resolution of the sensor. Earlier attempts to reduce these errors have focused on reducing the effective thermal conductivity of the substrate. New guard-heated microsensor designs proposed to overcome the severe deficiencies of the conventional design are investigated in this thesis. Guard-heaters remove the errors associated with substrate heat conduction, by forcing zero temperature gradient at the edges and bottom face of the hot-film, and hence, block the indirect heat transfer to the flow. Air and water flow over the sensors are studied numerically to investigate design, performance and signal strength of the guard-heated sensors. Our results show, particularly for measurements in low-conductivity fluids such as air, that edge guard-heating needs to be supplemented by a sub-surface guard-heater, to make substrate conduction errors negligible. With this two-plane guard-heating, a strong non-linearity in the standard single-element designs can be corrected, and spectral and phase errors arising from substrate conduction can be eliminated.
Determining the quality and quantity of heat produced by proton exchange membrane fuel cells with application to air-cooled stacks for combined heat and power
(2010-07-19T17:43:38Z) Schmeister, Thomas; Wild, Peter Martin; Djilali, Nedjib
This thesis presents experimental and simulated data gathered specifically to assess air-cooled proton exchange membrane (PEM) fuel cells as a heat and electrical power source for residential combined heat and power (CHP). The experiments and simulations focused on the air-cooled Ballard Nexa fuel cell. The experimental characterization provided data to assess the CHP potential of the Nexa and validate the model used for the simulations. The model was designed to be applicable to any air-cooled PEM fuel cell. Based on hourly load data, four Nexa fuel cells would be required to meet the peak electrical load of a typical coastal British Columbia residence. For a year of operation with the four fuel cells meeting 100% of the electrical load, simultaneous heat generation would meet approximately 96% of the space heating requirements and overall fuel cell efficiency would be 70%. However, the temperature of the coolant expelled from the Nexa varies with load and is typically too low to provide for occupant comfort based on typical ventilation system requirements. For a year of operation, the coolant mean temperature rise is only 8.3 +/- 3.4 K above ambient temperature. To improve performance as a CHP heat engine, the Nexa and other air-cooled PEM fuel cells need to expel coolant at temperatures above 325 K. To determine if PEM fuel cells are capable of achieving this coolant temperature, a model was developed that simulates cooling system heat transfer. The model is specifically designed to determine coolant and stack temperature based on cooling system and stack design (i.e. geometry). Simulations using the model suggest that coolant mass flow through the Nexa can be reduced so that the desired coolant temperatures can be achieved without the Nexa stack exceeding 345 K during normal operation. Several observations are made from the presented research: 1) PEM fuel cell coolant air can be maintained at 325 K for residential space heating while maintaining the stack at a temperature below the 353 K Nafion design limits chosen for the simulations; 2) The pressure drop through PEM cooling systems needs to be considered for all stack and cooling system design geometries because blower power to overcome the pressure drop can become very large for designs specifically chosen to minimize stack temperature or for stacks with long cooling channels; 3) For the air-cooled Nexa fuel cell stack, heat transfer occurring within the fuel cell cooling channels is better approximated using a constant heat flux mean Nusselt correlation than a constant channel temperature Nusselt correlation. This is particularly true at higher output currents where stack temperature differences can exceed 8 K.

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