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[jsr363-experts] Re: Request for clarification on Unit commensurability
- From: Werner Keil <
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- To: "
" <
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- Subject: [jsr363-experts] Re: Request for clarification on Unit commensurability
- Date: Tue, 16 Dec 2014 15:00:11 +0100
Actually it's very easy to run all of the underlying page through Google
Translate:
https://translate.google.de/translate?sl=de&tl=en&js=y&prev=_t&hl=de&ie=UTF-8&u=http%3A%2F%2Fwww.dagego.de%2Finfo_grundlagen_waermeuebertragung.html%23Groessen&edit-text=
It explains, the only constant (3600) is the factor to calculate seconds to
hours. Actually something Quantity can handle by itself via
Quantities.getQuantity(60, SECOND).to(HOUR) ;-D
I may revisit the code if I have time (probably not before Christmas) but I
hope it helps you understand which quantities they used.
Werner
On Tue, Dec 16, 2014 at 2:51 PM, Werner Keil
<
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wrote:
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Maybe this helps you:
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http://www.energysavingtrust.org.uk/content/our-calculations
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It refers to a "W/m2K" which goes alongside a sentence and further
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formulas in the Dagego sample
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>Interessant ist auch die Frage, um wie viel Kelvin die Temperatur in
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einer Stunde in einem 1000L Speicher steigt, wenn man >nur 9,5 KW zur
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Verfügung hat. Dafür ist es nötig, die Formel umzustellen nach:
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Translated:
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"How many K per hour does the temperature rise in a 1000 l boiler if you
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have 9.5 KW to heat?"
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Another simple calculation:
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http://www.endmemo.com/physics/heatengine.php
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based on Carnot's work, it contains some "constant" 1, which as of now,
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we could not deal with either.
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Quantity.subtract(Quantity) exists, so as a workaround we do have
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AbstractQuantity.ONE.subtract(someQuantity);
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Werner
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On Tue, Dec 16, 2014 at 1:51 PM, Martin Desruisseaux <
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wrote:
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> Le 16/12/14 21:39, Werner Keil a écrit :
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> We don't make money from this, but I don't think the company that does (
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> http://www.dagego.de/) got this totally wrong.
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> I do not said that they are wrong. I said that I'm pretty sure that the
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> Boltzmann constant (or something equivalent) is hidden somewhere in their
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> equations. They may have managed to rewrite their equations in such a way
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> that the numerical value of their constant become 1, and consequently
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> omitted it. This may be bright. But a numerical value of 1 does not mean a
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> dimensionless quantity: we can have 1 second, 1 metre, 1 kWh, etc. So the
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> fact that we can omit a multiplication in the computation of a
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> *numerical* value does not mean that we can omit that multiplication in
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> the computation of the *unit* of that value.
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> Martin
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