Over the last decade , some extremely " light-green " individuals have startedgiving up artificial refrigerationto save theEarth . Or at least to deliver a few hundred kW - hours a year .
Most mass conceive such a feebleminded step in the evolution of modernistic civilisation is a moment uncalled for , but it does pull attending to the drawbacks of forward-looking refrigeration techniques . But there are other options besides resigning yourself to quick beer . Solar - powered refrigerators are middling easy to do by these days , and they get around the energy - consumption issues associated with traditionalfridges . They also get around the fact that 2 billion people around the earth have no entree toelectricityin the first place [ source : NASA ] .
Solar energy , often known asphotovoltaics , is ubiquitous these twenty-four hours . Some of us use it to power our homes ; others buy carbon offsets that put money into solar and wind power to offset traditional energy use ( seeHow Carbon Offsets Work ) . Solar panels sit atop buildings , homes and tents and power jail cell - speech sound chargers , radios and the International Space Station ( ISS ) . These technologies use photovoltaic ( PV ) mobile phone to change over sunlight into electricity . When sunlight strikes a PV cell , it ignite the cell up . Heating the cell causes electrons to bump loose , and these electron are converted into a stream of electricity , or current ( seeHow Solar Cells Work ) .
One of the most common solar - power refrigerators on the market , the NASA - licensed SunDanzer , uses this PV engineering to power an otherwise mostly traditional infrigidation setup . But one of the most late evolution uses " solar superpower " in a much more basic fashion .
In this article , we ’ll take a look at both of these solar - powered refrigerators and find out what makes them beat . We ’ll bug out with the SunDanzer , which is base on engineering science developed to provide air conditioning and refrigeration on the ISS .
The SunDanzer
While developing solar - power refrigeration systems for the InternationalSpace Station(ISS ) , a couple ofNASAscientists decided the technology would do well in the Earth - bound world , too . Scientific - study outposts , eco - resorts , remote hunting cabins , street - vendorfoodcarts and areas of the arise humans with no accession to electricity could all benefit from solar - power infrigidation . Not only food for thought but also many medication and vaccine ask a cool environment to stay viable . It ’s a fairly substantive engineering .
Those NASA photovoltaics engineers created SunDanzer , a line of solar - powered icebox and deep freezer .
The SunDanzer icebox works a lot like a traditional one , using a vapor - condensation system for cooling . essentially , a refrigerant accelerator like ammonia is compact ( placed under pressure ) , make it to get hot ; as it cools back down , it contract into a liquid . When this liquid travels to a low - pressure level area , it expands and vaporise . This vaporization absorbs warmth , rapidly cooling the coil of the refrigerator .
This is probablyhow your refrigerator workings . The difference between your icebox and a solar - powered SunDanzer is that alternatively of escape all the moving parts of the compression - expansion scheme by plugging into the power grid , you secure into a solar - panel setup . The system simply apply photovoltaic cell rather of coal or nuclear power to father electricity . It hits the temperature of any other refrigerator ( around 38 degree F , or 3 degree C , for most people ) .
To supply enough power to sustain that temperature , the unit ’s solar instrument panel needs about five time of day ofsunlighta day [ source : NASA ] . But it can store superfluous solar - generated power so it ’ll stay cold for a week without sunshine . And there ’s the alternative of supplementalbatterypower so food will still last out cold in a pinch . Most solar - power cooling system systems come with this type of fill-in .
One solar - power refrigerator model that does not have such a high - technical school backup is the so - called " eco - fridge " develop by a 21 - year - onetime educatee in Britain . That model has no move theatrical role at all .
The Eco-fridge
When most of us reckon of " solar powerfulness , " we call up of panels of photovoltaic cells . A icebox premise in 2009 by British student Emily Cummins used a far more literal variant of solar power .
Cummins ' refrigerator uses no photovoltaics , noelectricity , no chemical refrigerant and no moving parts to make a cool effect . Instead , it utilise an evaporative - cool organisation based entirely on thesun’sheat and somewater . It ’s an ideal setup for poverty - stricken Third World villager with no electrical energy and nomoneyto spend on a fancy PV system . It is already being used in South Africa and Namibia . ( It could also work for a hard - inwardness environmentalist looking for a guilt - free low temperature one after a long daylight at work . )
The fridge is brilliantly dim-witted . It ’s made of two cylinders , one inside the other . The verboten piston chamber can be made of almost anything on hand – composition board , wood orplastic , typically , with holes in it to allow the greatest potential sun access . The inner cylinder is metal . The blank space in between the inner and outer cylinder is filled with materials like woolen , sand or malicious gossip .
The evaporative - cool system do work like this : You place food or medical specialty inside the interior metal piston chamber and close it up . You then pour fresh water into the area between the cylinder , saturate the organic textile , and place the whole frame-up in the sunlight . As the Lord’s Day warms the verboten cylinder and heat up up the wet organic textile , the water evaporates . Just like in a traditional fridge , evaporation remove hotness ( that ’s why we sweat – when the travail evaporates , we cool down ) . The organic material is touching the interior cylinder , so this warmth transfer pull up heat from the inner piston chamber holding the food . The result is a very cold interior chamber .
This process is replicate as the body of water evaporates fully , so water is continually replenished and the temperature reduction go forward . The refrigerator can ride out at 43 grade F ( 6 degrees century ) for several days on a single piss infusion [ source : Flahiff ] .
This system has no battery substitute , so it relies on a good supply of sunlight . Countries like Namibia , with an average of perhaps 10 hour of sunlight a day in some area , are idealistic candidate for this solar - powered setup [ reservoir : BBC ] .
That ’s always the potential drawback of any solar - powered requisite : sunshine is rarely guaranteed . In more high - technical school PV icebox , backup in the form of shelling or generators are common in purchase order to avoid system nonstarter . The low - tech eco - fridge relies solely on nature to keep thing cold .
