Complete Report - University of New South Wales

ARCPHOTOVOLTAICSCENTRE OFEXCELLENCE2010/11ANNUAL REPORTSeventy SPREE students illustrated their final year thesis work on 22 October2010 in the largest yet of the school’s graduating classes.roof of the UNSW Electrical Engineering building.The students worked on realistic conceptualapplications such as toilet flushing in the buildingwith excess stormwater, water supply for a ruralvillage or stock watering on a cattle station. Fortheir demonstration project, they were requiredto provide nominal flow rate and storage todemonstrate the concept. The skills learnt aredirectly applicable to solar water pumping fora wide range of applications, including in ruralvillages around the world.5.1.2.5 Solar Thermal Water HeatingProjectIn our daily life, we are using lots of hot water fordifferent purposes, needing a considerable amountof electrical or other energy sources. In this projectthe students learned how to use solar thermalenergy to heat cold water. In this project studentstudied the basic principle of solar heating systemand designed a new water heating system. Theyhave also learned what materials should be usedin the systems and investigated the possibilitiesto improve the design for better conversionefficiency. They built their designed systems usingtheir selected materials, as shown in the followingfigures. They tested their systems and collected andanalysed data to find conversion efficiency, costevaluation, etc.5.1.2.6 UNSW Sunswift ProjectOver the past year, second year SPREE studentshave helped to design and build several majorcomponents of the UNSW solar car, which placedthe first in the silicon class in the 2009 Global GreenChallenge (GGC), the premier international solar carrace. The result was the best result achieved by theteam in its 14 year history.Students were involved in two solar car relatedprojects – design and construction of thephotovoltaic array that powers the car, andconstruction of the lightweight compositecomponents that reduce the weight, and hence theenergy usage of the car.ArrayThe solar array is essentially an off-grid solarsystem, with the added complications of veryfragile modules, and the requirement that it mustwithstand the conditions of driving 3000km ofdusty, bumpy road.The students designed the module and array sizingto conform to the race regulations, and selectedthe appropriate cabling and bypass diodes. Theyalso performed array calculations and simulationsin order to calculate the optimum wiring schemethat allowed for maximum output power, themost efficient battery charging, and maximumrobustness against shading.Two types of cells were used for maximumefficiency, standard industrial cells, and UNSWproducedTopcell cells. The team characterisedthe Topcells, initially by open-circuit voltagemeasurements, and later by full IV sweeps. The cellswere then encapsulated, with assistance from CSGSolar, and assembled into modules.Finally, the array team and other Sunswift membersassembled the array, mounting and soldering thefragile modules onto the solar car.CompositesCarbon fibre composites are extremely strong,lightweight materials, which are currently used,e.g. in aeroplanes and wind farms, to increase theenergy conversion efficiency of the systems.The composites team had the substantial job ofbuilding the carbon fibre composite componentsfor a car which was almost entirely carbon fibre.These included the top shell, which housed thesolar array, the bottom shell, which formed thestructural chassis to safely house the driver, andthe structural components which held the braking,steering and suspension systems. The team alsosuccessfully constructed the first new carbon fibrewheels for the car in 8 years. The wheels are themost complicated composite part to construct,require a great deal more care and attention, andmust be thoroughly tested. The new wheels were110