If we want to make a parabolic reflector to our own particular specification i.e. Light rays coming from infinity will tend to be reflected towards a point called the focus. The constant a is known as the focal length - the distance from the origin to the focus point.įigure 1. Where y represents the distance away from the mirror centre and x represents the 'height above' the centre, see figure 1 and 2. The basic shape of a parabola is derived from the equation: You can use this energy to heat something. The parabolic mirror therefore directs the energy arriving over its surface to a 'hot spot' at the focus. When Sun light (parallel rays) falls onto a correctly aligned parabolic mirror it will be reflected back towards a single point known as the focus. The shape of the parabola is given by equation, see table 1. Apart from the screws and plastic mirror all the parabola 'bits' were made from scrap. There is a black temperature data logger at the focus which is where the solar energy is being concentrated. Two photos of a small solar heater made from plastic mirror sheet bent into a parabola shape by a wooden template. Here we explore the parabola to design solar heaters. You find them built into car headlights, spotlights as well as astronomical telescopes. Parabolic mirror surfaces are found wherever energy needs to be focused efficiently and accurately. Note: for details of talks and workshops on this topic click here: 42 (2007) 267-270 and is here reproduced by permission of IOP)
(Note: this article has been published: J. Solar heaters and other parabolic devicesīy Dr Jonathan Hare, The Creative Science Centre, Sussex University MUST BE 18 years or older to purchase.The Creative Science Centre - by Dr Jonathan P. CHILDREN OR PETS SHOULD NEVER BE IN WORK AREA! By purchasing this item, buyer agrees to accept all responsibilities and AGREES TO hold seller harmless from injury or damages resulting in the use and possible mis-use of this item. Protective clothing (fireproof) is also recommended as well as a large open space away from structures and autos. If you are crazy enough to use this for sun collection I strongly recommend wearing protective eye goggles (wielding/blow torch) to prevent eye damage. NO AFFECT ON SOLAR OR OPTICAL PERFORMANCEĪLL IMAGES AND VIDEOS © GREENPOWERSCIENCE.COM THIS MIRROR HAS MINOR MOUNTING IMPRESSIONS FROM THE CLIMB-1551 F IR THERMOMETERĮXTRA DURABLE ACRYLIC SPRAY IS ADDED TO THE BACK
* FOCAL LENGTH-20.3 INCHES FROM OUTER RIM - 23.3 INCHES FROM CENTER BASE * BEAM SIZE MAX POWER-1 INCH (additional scatter"6)adds background heat DOING SO MAY RESULT IN COPYRIGHT INFRINGEMENT. SCIENTIFIC DATA AND PHOTOS ©2008 PROPERTY OF GREENPOWERSCIENCE AND MAY NOT BE COPIED OR USED FOR OTHER EBAY LISTINGS. IT WILL LAST YEARS WITH RESPONSIBLE CARE, LONG SUN LIFE! THIS MIRROR IS DURABLE BUT WILL SCRATCH WITH MISUSE. PARABOLIC COLLECTOR VERY POWERFUL!!!!!!!!!Ī GLASS MIRROR THIS SIZE SELLS FOR $9500 AND IS VERY FRAGILE! THIS MIRROR HAS A FEW VERY MINOR IMPERFECTIONS FROM THE PROCESSĪLMOST PERFECT BUT VERY MINOR, AS GOOD AS I HAVE EVER SEEN IN ACRYLIC! ACRYLIC PARABOLIC MIRROR 35 INCH DIAMETER!ĪLMOST 3 FEET IN DIAMETER.
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