How can I fridge when I cant even solar at night? energy

I see many posts here about saying "well you cant use PV because it cant power my fridge at night, therefore it's useless." not only is the conclusion untrue, but even the assumption that it cant keep your fridge (and all your mountain dew) cold.

"But /u/reallybloodylongname , how can this be so?"

A long time ago, before fridges were in every house, before even refrigeration came along, humans still needed somewhere to keep their dew cold. As far back as 400BC, the Persians had figured out that summer heat sucked, and having a chilled treat might be awesome. To this end, large stores of ice were collected from mountains and stored in huge insulated buildings. Unfortunately this cost a huge amount to do, so only royalty got any.

Ice harvesting finally peaked in the 1900s, with large scale icecutting operations (see some ice cutters, sans song from frozen here ) , combined with delivery systems, meant that household chilled stores were a reality.

In order to have cold food, Ice would be bought from an Iceman to put in your Icebox to keep your dew cool. If you find a really old person they might remember this.

In the 1930s, the convenience of modern refrigerators replaced this system, and the Icemen went on the dole.

"Cool story bro, what does this have to do with solar?"

Everything.

Your meat doesn't know how it is cooled, nor your milk, cheese or dew. As long as it is kept between 0- 4C, it doesn't give a damn.

Conveniently, water freezes at 0C, and dumps a huge amount of heat (known as the latent heat of fusion.) It dumps 334KJ for every KG, or 33fl oz of ice formed. When it melts, it sucks up that same huge amount of energy.

Say you have a huge fridge, in the shape of a cube, 1000 liters, or 264 gallons. how many gallons of dew, would you need to sacrifice out of your fridge and replace with ice, to keep the remainder cold for 18 hours, if it has walls of polystyrene foam 5cm (2 inches) thick, and the temperature outside is 50C (122F)?

6m² * 50C difference*0.03/0.05m thick = 180watts

180watts*18 hours = 11664KJ,

11664kj/334 = 34.92KG ice.

"But /u/reallybloodylongname, I need icecream too!"

Never fear Redditor, frozen goodies can be cooled with phase change materials that change at lower temperatures.

Submitted November 30, 2014 at 01:09PM by reallybloodylongname http://www.reddit.com/r/energy/comments/2ntvat/how_can_i_fridge_when_i_cant_even_solar_at_night/ energy