whither the ice house?

a large portion of North America is exceptionally well suited to annual storage of coolth. This was done for thousands of years, until the advent of cheap fossil-fuel power for home delivery. And with modern insulation technology, it requires much less space.

how expensive would electricity have to become, before entrepreneurs would devote time to becoming skilled at doing turn-key installations of well-thought-out, conveniently-useable ice houses in private homes, the way that there's a category of specialists who do solar-hot-water installs?

the premise here is that a well-planned installation would be _close enough_ to the usage-convenience of a kitchen refrigerator, that the "chores" aspect of the old ice house, wouldn't exist enough to stop buyers.

Reply to
dances_with_barkadas
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When I was a kid they used to have ice wagons. People used ice boxes. And for many years later, they still used it in summer for seasonal sales. The ice was cut from Lake Huron. Nobody worried about consuming the ice either. If you have the space, the insulation is child's play. Procuring the ice is labor intensive and if naturally made ice runs the risk of contamination more than in those years. There must be a better and cheaper way. One way is to do as we might with gasoline, use less of the product.

Reply to
Al Bundy

Using NREL's TMY2 ("Typical Meteorological Year") hourly weather data file for Philadelphia, one of 239 US cities listed at

formatting link

10 OPEN "tmycool" FOR INPUT AS #1 30 FOR H=1 TO 8760'read ambient temperature every hour for a year 40 LINE INPUT#1, S$'input a line from the TMY2 file 50 TEMP=VAL(MID$(S$,27,4))'ambient temp (F) 60 ATEMPT=ATEMPT+TEMP'accumulate average yearly temperature 70 IF TEMP < 32 THEN FDHT=FDHT+32-TEMP'accumulate freezing degree-hours 80 IF TEMP > 32 THEN MDHT=MDHT+TEMP-32'accumulate melting degree-hours 90 NEXT H 100 PRINT "average yearly temperature:";ATEMPT/8760 110 PRINT "freezing-degree days:";FDHT/24 120 PRINT "melting-degree days:";MDHT/24 130 CLOSE 1

this fine BASIC program yields:

average yearly temperature: 53.62591 (F), freezing-degree days: 339.4584, and melting-degree days: 8232.917,

like heating and cooling degree days (F) for 32 F houses. The number of "freezing degree days" (FDD) is the total equivalent number of days in which the outdoor temperature is less than freezing during a typical year, times the difference in degrees between 32 F and the outdoor temperature, on each of those days.

The FDD for a particular climate measures how easy it is to make ice. We can freeze a pound of water with 144 Btu at 32 F, and a water surface has a thermal conductance of about 1.5 Btu/h-F-ft^2 in still air, and a cubic foot of water weighs about 64 pounds, ie 5 pounds per inch of depth, so

1 FDD can freeze an ice layer 24hx1.5/(144x5.3) = 0.05" thick, on top of 32 F water. In Philadelphia, we might freeze a layer of ice about 339x0.05 = 16" thick on some sort of specially-designed icemaking pond...

Melting degree-days determine how big an icehouse must be to stay cold for a year. Bigger icehouses work better. An L' icecube surrounded by R40 insulation contains about 64L^3 pounds of water, ignoring the insulation thickness, and initially stores about 9200L^3 Btu of coolth with a yearly heat gain of about 24hx8200x6L^2/R40 Btu in Phila, for a minimum L = 3'. A 5x5x5 = 125ft^3 icecube inside a 10' strawbale cube might stay partially frozen all year, if it were first frozen solid and it only had to keep itself and some vegetables cool, vs say, air-conditioning a nearby building.

Freezing a 5' cube takes about 5^3x64x144 = 1.15 million Btu. An A ft^2 roofpond can make 24x339x1.5A = 1.15 million, so A = 94 ft^2, eg a 10'x10' salt water pond under IR-transparent polyethylene film in freezing weather. Winter winds and night sky radiation would cool the pond more, as would evaporation, without the poly film.

A low-power pump might flood the pond at night and let it flow back into a tray above an 8'x8'x4' thick 256 ft^3 water wall inside a 10' cubical outdoor fridge. The wall might be welded-wire mesh and 2x4 shelves under plastic film 55 gallon drum liners, as Anna Edey used to store solar heat in her Cape Cod Solviva greenhouse.

An air-antifreeze heat exchanger and fan might replace the roof pond... Something like a $35 used 1984 Dodge Omni auto radiator with its 12V fan or Magicaire's $150 2'x2' SHW 2347 heat exchanger, which can transfer

45K Btu/hour between 125 F water and 68 F air at about 800 Btu/h-F at 1400 cfm (like a window fan) with a low airflow resistance and an air pressure drop equivalent to a 0.1" column of water. A 100 watt fan might run 2.3million/(800x(32-25)) = 410 hours at 25 F to freeze the wall, consuming 41 kWh/year, ie about $4 at 10 cents/kWh, while providing 256 ft^3 of year-round refrigerated space inside the 512 ft^3 box, like 17 home fridges. Is it time for neighborhood icehouses yet? Fill them with beer to facilitate apres-lawn-mowing-male-bonding? And what will we do about lawns, after the oil runs out?

Nick

Reply to
nicksanspam

you&#39;re doing a roundoff? or 8200 was something else?

Reply to
dances_with_barkadas

Yes... 8200 is about the same as 8232.917, and a lot like 10,000.

Nick

Reply to
nicksanspam

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