Size of Heat Pump in Tons

GeorgeB

ElectroHydraulics engineer (retired)
I push people in my lab to use Newton meters for torque and radians per second for speed. At the same time when I am forced to use _metric_ (not SI units) I get ornery and ask for thinks like dodecimeters of stuff.

When I am told _use metric_ and then have to deal with 'pressure' in kg/cm^2, or speed in km/hr my CDO goes haywire (CDO, its kinda like OCD, but the letters are in proper order....)
what's a dodecimeter? Google didn't help me.<grin mode on>

radians per second is ROTARY speed, not linear; I don't understand your opposition to km/hr unless you just want to use primary units like meters/second ... or cm/sec? I see it now, speed limit something m/sec.

On pressure, would kgf satisfy your opposition, or do you want to get to Newtons/cm^2 ... a derived unit, don't we need Newtons/m^2? Or does cgs sufficiently allow cm^2?

I'm in the control of industrial fluid power world ... we think of bar as the "metric" pressure unit ... ??? and volume is in liters, not m^3 <grin mode off>
 

junkhound

Senior Member
what's a dodecimeter? probably a type, should have been duodecimeter? Then same divisor as feet to inches, etc? Babylonian base 12 system.

As far as pressure, SI is Pa, Pascals (SP?) just to obfuscate the discussion.
 

Besoeker3

Senior Member
But a separate critical aspect is how well you can convince people to _use_ the same system of units. And convincing people to _use_ units is at its core a political act.

-Jon
I disagree. The whole world apart from USA and Myanmar use SI. It makes it easier for international trade to have a common system.
 

drcampbell

Senior Member
... As far as pressure, SI is Pa, Pascals (SP?) just to obfuscate the discussion.
I'm not sure what's obfuscatory about that. Pressure is force per unit area. In SI, that's Newtons/meter², and it was given a unique name because pressure is so frequently measured.
 

StarCat

Senior Member
'The nice thing about standards is that you have so many to choose from.'

One critical aspect of units of measurement is how technically sound they are, how reliably they can be implemented or derived from basic physical quantities, how self consistent the units are, etc. By this metric, SI is hands down better than imperial units.

But a separate critical aspect is how well you can convince people to _use_ the same system of units. And convincing people to _use_ units is at its core a political act.

Is there any _technical_ benefit to making 0 longitude Greenwich rather than Paris? That selection was politics.

Is there any _technical_ benefit to the particular unit of length used in SI?

Sometimes the politics is in a very small group of people, eg. the recent vote to redefine the kilogram in terms of Plank's constant rather than something else.

IMHO technical standards are by their nature political things, and this is true for standards for units of measure.

-Jon
This is well stated and I will add a few things.....
The Metric System is based on " false " abstractions which make it an inherently " inharmonic system."
Napolean saw it and knew the trouble had started even while in exile. Its was started by policitican and for reasons of monetary control.
I remember the utility of it in the Chem lab. if you go digging on the subject you may be shocked to find out that it is in fact not so good at a great many thiings.
Bar is " Bar none " the stupidest unit of measure I have ever encountered, and useless for HVACR applications, yet there are confused people writing Mollier diagrams with it.
What this is doing is creating division and things that cannot be read by people who are well versed in Imperial units.
The metric system needs to be moved out of the USA, lock stock and barrel, and otherwise Violently Resisted.
I do not want it and there are others, though small in number who are in accord. It has created nothing but time wasting problems in my life and I have little to no use for it.
People at large need to get that some few are tired of having this thing forced on them.
 

gadfly56

Senior Member
what's a dodecimeter? probably a type, should have been duodecimeter? Then same divisor as feet to inches, etc? Babylonian base 12 system.

As far as pressure, SI is Pa, Pascals (SP?) just to obfuscate the discussion.
An extinct unit of measure, flightless, and previously distinguished by its apparent stupidity.
 

winnie

Senior Member
This is well stated and I will add a few things.....
The Metric System is based on " false " abstractions which make it an inherently " inharmonic system."
Napolean saw it and knew the trouble had started even while in exile. Its was started by policitican and for reasons of monetary control.
I remember the utility of it in the Chem lab. if you go digging on the subject you may be shocked to find out that it is in fact not so good at a great many thiings.
Bar is " Bar none " the stupidest unit of measure I have ever encountered, and useless for HVACR applications, yet there are confused people writing Mollier diagrams with it.
What this is doing is creating division and things that cannot be read by people who are well versed in Imperial units.
The metric system needs to be moved out of the USA, lock stock and barrel, and otherwise Violently Resisted.
I do not want it and there are others, though small in number who are in accord. It has created nothing but time wasting problems in my life and I have little to no use for it.
People at large need to get that some few are tired of having this thing forced on them.
I know that you are partially agreeing with me, but I believe that you take it a step too far.

SI is a perfectly valid self consistent system of units. Lots of effort has gone in to tying things together so that we don't have the problem of Watts and horsepower and tons and btu/hr etc. all being different units for the same measurement.

It is beautiful that you can multiply force times speed and get power with a conversion factor of 1.

I simply believe that a system of units is arbitrary and to some extent the selection of the _particular_ units is political, in the specific sense that not only do you need to pick a set of units, but for utility you need to convince others to use the same units. Agreeing with other people to use specific units, legislating the use of specific units, standards organizations defining units, etc. is a political process.

-Jon
 

junkhound

Senior Member
Did not meter of today start with French revolution?

Have also seen theories that prehistoric henge builders used the meter, determined by using strings, sticks, an artificial horizon, the movement of stars, and using a meter long pendulum to determine star transit times to tie it all together.
 

drcampbell

Senior Member
... The Metric System ... has created nothing but time wasting-problems ...
People at large need to get that some few are tired of having this thing forced on them. ...
OK, Gramps.

What's your suggestion? Quit doing business with everybody in the world except Myanmar and Liberia?

In case you're not payin' attention, nobody's "forcing" anything on you. You don't want to use it, don't use it. But that also means not using imported machinery, vehicles or parts. And not doing business with people or corporations that do. That's a pretty big sacrifice for the privilege of clinging to the past, but you're free to do so.

The problem isn't the metric (Système Internationale d’Unités) system; it's trying to use two systems simultaneously. Or more than two, if you count all the variations in the British system. (short tons, long tons, refrigeration tons, BTU/hour, registry tons (100 feet[SUP]3[/SUP]), tons of energy (tons of TNT equivalent), ... ) And the solution isn't eliminating SI; it's finally eliminating the archaic & provincial British system.
 

gadfly56

Senior Member
Did not meter of today start with French revolution?

Have also seen theories that prehistoric henge builders used the meter, determined by using strings, sticks, an artificial horizon, the movement of stars, and using a meter long pendulum to determine star transit times to tie it all together.
Yes, we can blame the French for this one. ;) It was originally supposed to be one ten millionth the distance from the equator to the North Pole along a Great Circle through Paris.
 

kwired

Electron manager
Yes, we can blame the French for this one. ;) It was originally supposed to be one ten millionth the distance from the equator to the North Pole along a Great Circle through Paris.
I believe all SI units are based on Earth constants in one way or another. Many reference a property of water I believe. A kilogram of water is 1 cubic decimeter of water I believe (at a certain temp).

I also seem to recall a gram of water has a volume of one milliliter which is also one cubic centimeter.

Units of force and mass are pretty much same numbers in Earth's gravity, and terminology is wrongly used at times, but we get away with it because they are usually the same numerical values on Earth
 

Besoeker3

Senior Member
The problem isn't the metric (Système Internationale d’Unités) system; it's trying to use two systems simultaneously. Or more than two, if you count all the variations in the British system. (short tons, long tons, refrigeration tons, BTU/hour, registry tons (100 feet[SUP]3[/SUP]), tons of energy (tons of TNT equivalent), ... ) And the solution isn't eliminating SI; it's finally eliminating the archaic & provincial British system.
It pretty much is in Britain. But we still stick with pints and miles per hour.
 

kwired

Electron manager
It pretty much is in Britain. But we still stick with pints and miles per hour.
But most your shorter linear measurements are commonly in meters, centimeters or millimeters, right? Or is yards,feet and inches still pretty common?
 

Besoeker3

Senior Member
But most your shorter linear measurements are commonly in meters, centimeters or millimeters, right? Or is yards,feet and inches still pretty common?
I think most people know what they are but if you buy, say a piece of furniture dimensions are in centimetres. Meds are in mg. Bottled water in in litres or ml. Carrots are in kg.
 

kwired

Electron manager
I think most people know what they are but if you buy, say a piece of furniture dimensions are in centimetres. Meds are in mg. Bottled water in in litres or ml. Carrots are in kg.
So "everyday" linear measurements for most people are done in SI units. Meaning a common tape measure is marked in SI units, here it is kind of rare to find a tape measure that is marked in SI units only. Not that you can't buy one, just not many have one and those that do have one probably don't use it very often.
 

Besoeker3

Senior Member
So "everyday" linear measurements for most people are done in SI units. Meaning a common tape measure is marked in SI units, here it is kind of rare to find a tape measure that is marked in SI units only. Not that you can't buy one, just not many have one and those that do have one probably don't use it very often.
I can't speak for most people. Might be an age/generation thing.
The steel tapes I have are dual marked.

 
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Frank DuVal

Senior Member
One more example of a good reason to ditch the British system of weights & measures and use metric.

In the metric system, there are only seven base units to learn and just ONE unit of refrigeration capacity, the Watt, (or kilowatt, megawatt, et at.) No confusion and no need for unit conversion.
No confusion??????????????:?

You must be young!:p

SO, I get a cooling system rated in killowatts. How does that help me wire it? DIvide KW by system voltage to get amps? I thought so, it is still read the nameplate! Now I have a product with TWO killowatt ratings. That is not confusing?:?

Much clearer with Killowatts being the amount of electricity consumed and the cooling ability in BTU or tons.

Same with motors/engines rated in horsepower. I know what a 300 HP engine does in a car. I have to convert to use KW of engine.

Cubic inch to liters is not too hard, a factor of 60.8. After 35 years most have learned what size engines are in liters.

Maybe in another 35 years when we are gone young guys will speak of KW in cars, but not yet here!:thumbsup:

By then cars will be electric and KW will seem so more applicable anyway.

In the mean time, I need some device boxes to fit those 50.8 x 101.6 studs. Easier, right!:lol:
 
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