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Bad idea. All that would happen would be that you'd discover that the distribution of emperatures in the fridge are not what you'd like them to be, but that since all you have is on/off switches for the compressor, fan, and defrost heater, there's little you can do about it.
But if you're also adding some mechanically operated vents, and some additional fans, then now you're talking.
Sylvia.
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d oAt least all around the heat exchanger and pipes.
We can control how much to defrost, by measuring temperature changes based on compressor and fan timings and loads. There are plenty of parameters we can measures and to adjust in heatings.
I would add additional hot water pipes. It's more cost efficient than electric heat.
Eveb Apple gets better, and cheaper. Your point?
Apple has chosen not to compete on price, and have had staggering profits. Much corporate medical care in the US also does not compete on price, if at all.
As a larger issue, when people drill down into the details, competition as we generally think of it rarely matters much - differences in cost of orders of magnitude will matter while differences of even as much as 2x will not.
But the more something is a commodity, especially a commodity that has high volume, the more small differences in price matter.
Medical care is a craft good, and the farthest thing there is from a commodity. Will that change? Probably.
Specific to medical care 1) we do not have competitive provision of medical care in the US, and 2) universal care ala Yurp has actuarial effects very much in favor of it.
-- Les Cargill
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They don't. If the defrost time isnt properly controlled, its bound to end up being a compromise, too long most of the time but on occasion too short. That's when the system ices.
The temp the evporator reaches dont matter to the compressor, the latter has plenty of thermal capacity and some leeway.
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not at all, ice doesnt conduct heat well, so removing a thin layer of ice makes the cooling more energy efficient.
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f nAnd heat it up, just to cool it down later. I can't believe the fridge industry is still using inefficient timer based open loop control.
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Its a nonissue. If you wanted to get every last drop of energy efficiency, the compressor could be run backwards to defrost the evaporator, thus making good use of the heat built up within it. Bu that wuold mean more cost, so its not done.
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eIt is done in some high end refrigeration system, with rerouting pipes, rather than reversing the compressor. Some even try to capture the heat build up by the compressor for defrosting.
I don't understand.
Are Apple computers not ever better, cheaper, and faster too? The first Mac, with 128k of memory and a pokey MC68K--sold for $2,495 in
1984. Is the latest iPad not wireless, cheaper, faster, and better in almost every conceivable way?Apple charges more, but is not Apple just one competitor among many? Have no other choices sprung up, each with different combinations of price and features, to suit the infinitely diverse spectrum of individual preferences and needs? Something for everyone?
Clearly, I don't understand the question.
-- Cheers, James Arthur
When did they let you out of the asylum, Philly? Your absence was not taken for granted.
--
news.astraweb.com!border6.newsrouter.astraweb.com!news-xfer.nntp.sonic.net!feeder.erje.net!de-l.enfer-du-nord.net!feeder1.enfer-du-nord.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
Though on further examination, by the time you've paid the higher cost for the chip, the postage from the UK, and either bought or made the cable, it's considerably cheaper just to buy a programmer from a local supplier.
PICAXE is probably good for people who've little or no experience in programming, particularly at assembler code level.
Sylvia.
er,
50/),
5 nGet the PICKIT 3 for $7 more, in case you want to program PIC24 or PIC32. Not sure if PICKIT 2 can program them.
On Thu, 15 Dec 2011 10:22:50 +1100, Sylvia Else wrote:>>
I did, but I've formed the view that if I were going to do this, I'd include the thermostat as well, and choose a better point in the thermostat hysteresis at which to start the defrost cycle, rather than having a random relationship as is the situation now.
Sylvia.
Yes, we should have a thermistor for the room temperature, one for the inside temperature, one at the beginning of the heat exchanger and one at the end. This way, we can measure the temperature gradient based on compressor and heater run time, and control them. This should reduce unnecessary heating and cooling cycles.
--- And, for the ASCIImatic (thanks, Steve :-):
. +V . | . 4060 Vcc +----+ . +------+ | U3C |K | O---->C . +-887K--|Rs MR|-------|------+-A / DIODE COIL]- -|K1 . | | | | | Y-+ | | O-> |NC . +-442K--|Rt | 10k +-B | +----+ | . | | | | | | | +-------->NO . +-0.1µF-|Ct Q13|--10nF-+ +-A | C . +------+ | | Y-+--1k--B 2N2222 . U1 | +-B \ E . U3A +-A | U3D | . 4081 Y-+ GND . +-B | . | | . | B-+ . +-Y U3B . | A-+ . 4060 | | . +------+ | Vcc | . +-976k--|Rs MR|-------+ | | . | | | | | . +-527k--|Rt | 10k | . | | | | | . +-1.0µF-|Ct Q13|--[10nF]--+---+ . +------+ . U2
-- JF
st
al
2/The US Department of Energy sponsored research into improving refrigerator efficiency. Here are a couple of starter links:
The main thing was increasing insulation from 1/2" to 2". Adaptive defrost is mentioned too (in the 2nd link).
The ultimate in efficient refrigerators is a chest freezer, home- converted into a fridge.
-- Cheers, James Arthur
cost
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nYes, that's exactly what i am thinking about.
Or a regular fridge turned sideway, with door pointing up.
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