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Article #2089Re: Why not 120 VDC ? Why invert?
From: Anmar Caves
Date: Wed, 27 Jan 1993 15:18
Date: Wed, 27 Jan 1993 15:18
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In article <1k0635INNrkq@gap.caltech.edu> carl@SOL1.GPS.CALTECH.EDU writes: >In article <1993Jan25.014943.1904@michael.apple.com>, ems@michael.apple.com (E. Michael Smith) writes: >>>True. However, if you care anything at all about energy efficiency, you don't >>>use resistive heat sources. >> >>Blanket statements don't always hold ... speaking of which, what >>non-resistive electric blankets are you aware of? ;-) >> >>There ARE places where resistive heat continues to make sense... > >Electric blankets (except, perhaps, in hospitals) don't fall into one of those >places. Maybe an electric blanket is useful when treating someone for >hypothermia. For any application where the person using the blanket is capable >of generating heat, other alternatives work equally well. For moderate (i.e., >above -20 degrees F) conditions, simple wool blankets are quite useful (you >might need to use a few of them, but they work). For lower temperatures, a >blanket with an aluminum core works quite well. Maybe for you Carl, but this doesn't extrapolate well. Specific examples are elderly people, IE people who are prone to developing chronic hypothermia, you know, those people who keep their houses at 80F. Many of these people *don't* generate enough heat at basal metabolism to keep warm unless they're in a very warm environment. Other examples are people with poor peripheral circulation. These people will have cold legs and feet no matter how many blankets they have. This includes a large percentage of the female population. Personally, I like it cold, and generally don't like electric blankets, but that's just my prference. >Jus how is it that you, known, unless I'm confusing you with someone else, for >favoring energy conservation, are now advocating electric blankets in >situations where they're not required? I can see it quite easily. Someone can have an electric blanket which may use 500-600 watts over the night (most blankets are between 100-150 watts and may have a duty cycle of 50-70%), and be able to keep the house cooler during the night, or keep a lower overall temp in the house, or avoid heating at all in warmer climes. In that case such an item would be appropriate to conservation. Please note that I'm not saying that it's appropriate in all cases, merely that it's not as innappropriate as you seem to think. > >So you're going to run TWO sets of wires throughout your home, one for AC and >one for DC? Once you've committed to the expense of having an inverter in the >first place, the cost of increasing the capacity of the unit under >consideration is relatively small. Running both makes a lot of sense from the efficiency standpoint. Low demand items such as doorbells, DC clocks, answering machines, some lighting such as closets or marker lights, etc, can be run a lot more efficiently on low voltage because they were designed that way from the start. I've only done one all-120VAC design, I've done dozens of mixed designs and a couple of small low voltage only designs. As far as inverters go, I'd rather my inverter set be able to go into sleep mode when there is no draw than to have it constantly running supplying all those low draw appliances. The best designs have a dedicated inverter for the lighting circuit, and another for the high demand items like the fridge or microwave or the like. This stuff is fun to play with because it can be mixed and matched to suit an individuals needs and wants, in other words, no absolutes. -- Anmar Mirza # Chief of Tranquility #My Opinions! NotIU's!#Purveyor of EMT-D # Base, Lawrence Co. IN # Legalize Explosives!#nontraditional N9ISY (tech) # Somewhere out on the # Politicians prefer #family values Networks Tech.# Mirza Ranch.C'mon over# unarmed peasants. #Space For Rent
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Newsgroups: sci.energy Path: arc1-ca.pugleaf.net!sparky!uunet!news.univie.ac.at!scsing.switch.ch!univ-lyon1.fr!ghost.dsi.unimi.it!rpi!gatech!emory!sol.ctr.columbia.edu!usenet.ucs.indiana.edu!bronze.ucs.indiana.edu!amirza From: amirza@bronze.ucs.indiana.edu (Anmar Caves) Subject: Re: Why not 120 VDC ? Why invert? Message-ID: <C1IqI4.Fnz@usenet.ucs.indiana.edu> Sender: news@usenet.ucs.indiana.edu (USENET News System) Nntp-Posting-Host: bronze.ucs.indiana.edu Organization: Indiana University References: <1jr751INN16a@gap.caltech.edu> <1993Jan25.014943.1904@michael.apple.com> <1k0635INNrkq@gap.caltech.edu> Date: Wed, 27 Jan 1993 15:18:04 GMT Lines: 69