Compound parabolic concentrators

Compound parabolic concentrators (CPCs) are a class of concentrators that consist of rotated parabolic sections which have a concentration factor for planar receivers which is the thermodynamic limit: 1/sin(θa) where θa­ is one-half of the angle within which the reflectors direct all the light incident onto the aperture down to the receiver. Compound parabolic concentrators (CPCs) can be additions to solar water stills, solar water pasturizers, and solar cookers. CPCs can increase the output of these devices along with their efficiency by concentrating the sunlight to make the device more effective.

Recently research has shown that by incorporating compound parabolic concentrators (CPCs) for augmenting the light collection of a solar still^[1] and a solar water pasteurizer,^[2] the efficiency and throughput can be improved.

Abstract CPCs for Solar Stills[edit | edit source]

As regional shortages of fresh water become more prevalent, solar distillation using a single-effect basin holds promise as a method to bring low-cost, clean, and ecologically-responsible water to remote area dwellers. Compound parabolic concentrators (CPCs) can be used to direct more light onto the still increasing the throughput and efficiency of these passive solar devices. A computer program has been developed that uses the properties of materials and the solar energy characteristics of the site to calculate the increase in output of water due to reflectors of different height. For reflector 2.5 times the width of the still, the output per unit area per day roughly triples with only ~10% increase in cost and moderate maintenance (weekly tilts), indicating that CPCs have a significant economic advantage in producing solar distilled water. For full paper

Abstract CPCs for Solar Water Pasteurizers[edit | edit source]

Many people in less developed countries drink water with microbial contamination, which leads to the annual death of 5 million children. Although some people currently boil water, all microbes that cause disease in humans do not survive at temperatures >65ºC, which solar water pasteurizers can easily produce. These pasteurizers are similar to box solar cookers, and typically have a small rectangular reflector. The objective of this work is to calculate the increase in output due to compound parabolic concentrators (CPCs) using numerical simulation. A CPC concentrates the maximum amount of radiation on a planar receiver consistent with the laws of thermodynamics. Since the average water temperature is nearly independent of the solar radiation, the heat losses are nearly constant. Therefore, higher concentration factors yield significantly higher efficiencies. Depending on climate, CPCs increase output by 1,000%-4,000%, while the additional reflector would only ~double the cost and necessitate weekly tilting. For full paper.

CPCs used for Solar Cookers[edit | edit source]

COMPOUND Parabolic reflectors for solar cookers

See also[edit | edit source]

Compound parabolic reflectors for solar cookers

External links[edit | edit source]

http://images.wikia.com/solarcooking/images/c/cd/Granada06_Joshua_pearce.pdf http://images.wikia.com/solarcooking/images/2/2e/Granada06_david_denkenberger.pdf

Reference[edit | edit source]