I did a quick check on our house (a 4-bedroom
detached house built of brick in 1972, typical of many UK houses of the
era). My finding was
Gas consumption - 72GJ/y
Electricity consumption - 22GJ/y
Total - 92GJ/y
----- Original Message -----
Sent: Friday, February 03, 2006 7:11
PM
Subject: [USMA:35947] Re: When was the
joule introduced to SI?
Stan, I agree it's difficult to upgrade an old
house, however from experience, we had an energy efficient house built in
Illinois (not a warm place in winter) with 150 mm thick walls, 25 mm
isocyanurate outside that, plastic lining before the drywall installed, no
holes or wires thru the upstairs ceiling. The average gas bill was $29 month.
I moved to Maryland, similar size if not slightly smaller house and it jumped
to $112. I'll have to see if I have the records on how much energy we actually
used in the Illinois house. You have to design the efficiency in to the
house.
Mike Payne
----- Original Message -----
Sent: Thursday, 02 February, 2006
16:02
Subject: Re: [USMA:35936] Re: When was
the joule introduced to SI?
Too much emphasis is placed on the insulation
and other such tricks in the energy consumption in my experience.
Lowering the thermostat (and putting on the
ugly xmas-present sweater) or limiting the hot water usage (showers,
dishwashers) is far more effective.
Our New England colonial household (of the
usual 150 GJ/y for a generation) recorded zero improvement
(statistical averaging) in adding attic insulation, zero improvement in
replacing a 60 years old oil-heating system with a new boiler, natural gas
fired (a few years later), etc.
On the other hand, when another person
moved in to live with us, the prior year's 145 GJ jumped promptly to
165 GJ, all else equal. A colder weather (and do not believe that year's
weather was colder) cannot account for the difference. Shower, Jacuzzi,
cloth washer and dryer, dishwasher and other appliances do.
As a matter of fact, if the heating were to
predominate, the house should use less energy for the additional 100 W of
heat every person generates. Doing nothing, that is.
Stan Jakuba
----- Original Message -----
Sent: 06 Feb 01, Wednesday
10:58
Subject: [USMA:35936] Re: When was
the joule introduced to SI?
I keep a record of our household energy use,
last year we used 186 GJ of energy for the whole year, combined natural
gas and electric, (Pat said the average was 150 GJ) mostly due
to the poor insulation of the house we live in. The highest use was in
winter. Average $20,23/GJ. Another reason I'd like to build a well
insulated solar powered house.
----- Original Message -----
Sent: Sunday, 08 January, 2006
23:25
Subject: [USMA:35609] Re: When was
the joule introduced to SI?
This was my original note. I have collated the
responses below.
Dear All,
Can anyone give me the definitive date
that the joule was introduced into the SI as the unit for
energy. I suspect that it was at the same time as the newton,
but Im having trouble finding the right reference.
I
have searched the BIPM web site but with no
luck.
Dear
All,
Many thanks to everyone who contributed to my request for
information about the joule. Thanks for your help in tracing the
official origins of the joule as the unit for energy.
It seems
that the chronology goes something like this.
1818
James
Prescott Joule (1818/1889) was born into a wealthy brewing family in
Salford, England.
1840
Joule stated a physical law, now
called Joule's Law, that heat is produced in an electrical
conductor.
1845
Joule was the first person to measure
the equivalence of work and heat, by having falling weights rotate
paddles in water.
At about this time, Joule shared in
discovering the law of the conservation of energy, which says that
energy used up in one form reappears in another form and is never lost.
His co-workers were Hermann von Helmholtz, Julius von Mayer, and William
Thomson (1824/1907) (later Lord Kelvin) and he worked with Lord Kelvin
to develop the absolute scale of temperature. Joule never claimed to
have formulated a general Law of Conservation of Energy but his
experiments were certainly fundamental in bringing about that
formulation.
1881
At the First International Electrical
Congress (IEC) in Paris, five 'practical' electrical units were defined;
they were: the ohm, farad, volt, ampere, and coulomb. This decision was
based on the recommendations of a British Association for the
Advancement of Science and their recommendations were largely based on
Joule's researches on electrical energy. See an excellent article by
Robert A. Nelson at: http://www.aticourses.com/international_system_units.htm
on these and some other metric issues.
1889
In 1889, the year
of Joule's death, it seems likely that the British Association for the
Advancement of Science (BAAS) suggested the name for the energy unit to
honor the name of James Prescott Joule for his pioneering work on
electricity and energy. The BAAS promoted this idea actively and the
Second Congress of the International Electrical Conference (IEC) added
the joule, watt, and a unit of inductance that was later given the name
henry.
The joule was adopted by the IEC as the unit for
energy and work. The Oxford Dictionary of Weights and Measures quotes
'Le Système International d'Unités (Sevres; France: Bureau International
de Poids et Mesures, 1985)' as its source.
1946
The
joule was defined by the CIPM. (SI brochure, Appendix 1, Section 2.4
(Electric current)), which shows CIPM resolution 2 giving the definition
of the joule,
1948
The joule and its definition were
ratified by the CGPM as the official SI unit for energy. This made the
joule the official world unit for energy. Resolution 3 of the CGPM
(1948) said:
3. The unit of quantity of heat is the
joule.
They then went on to say in a
footnote:
Note: It is requested that the results of
calorimetric experiments be as far as possible expressed in joules. If
the experiments are made by comparison with the rise of temperature of
water (and that, for some reason, it is not possible to avoid using
the calorie), the information necessary for conversion to joules must
be provided. The CIPM, advised by the CCTC, should prepare a table
giving, in joules per degree, the most accurate values that can be
obtained from experiments on the specific heat of
water.
It seems that the CGPM felt troubled by the
promoters of the calorie (or is that Calorie) even then. (This footnote
has a decidedly grumpy tone in my opinion!)
1960
When the CGPM
first defined SI, in 1960, it included the joule as the derived unit for
energy. This reconfirmed the joule as the official SI metric unit for
energy.
1998
The joule is listed in 'The International
System of Units (SI) in 'Table 3. SI derived units with special names
and symbols' as the SI derived unit for the 'Derived quantity' of
'energy, work, quantity of heat'.
2006
Question: Why am I
researching the origin of the joule?
Answer: Recently, I
was rewriting my web page on why we should move more quickly towards the
metric system (See http://metricationmatters.com/why_metrication
), when I realised that a lack of knowledge about energy, and
particularly about how to measure it using joules, kilojoules, and
megajoules etc., was seriously hampering a great deal of public debate
on extremely important energy issues.
I
wrote:
Energy and power
This lack of ability
of old measures to lead to understanding can lead to very serious
problems in the world. Consider the world's pressing need to understand
how we use our limited energy supplies and how quickly we use them.
These questions directly relate to global
warming.
Fundamental concepts such as energy and power are
essentially simple in concept but they often confuse politicians because
of the numerous ways they are measured with so many unrelated units.
This complexity makes it difficult, if not impossible, for politicians
to understand even basic quantitative information about the physical
world around them. To understand the total world energy issue using old
measures is quite difficult (even for scientists and engineers) and
almost completely impossible for politicians and the rest of
us.
If you want to begin to comprehend global warming, you
need to have a working knowledge of most of these 68 old pre-metric
energy measures because in the year 2006 they are all still in
use:
Atomic energy unit, barrel oil equivalent, billion
electron volts, British thermal unit (16 °C), British thermal unit (4
°C), British thermal unit (international), British thermal unit (ISO),
British thermal unit (IT), British thermal unit (mean), British thermal
unit (thermal), British thermal unit (thermochemical), calorie, calorie
(16 °C), calorie (20 °C), calorie (4 °C), calorie (diet kilocalorie),
calorie (int.), calorie (IT) (International Steam Table), calorie
(mean), calorie (thermochemical), Celsius heat unit (int.), coulomb
volt, cubic centimetre atmospheres, cubic foot atmospheres, cubic metre
atmospheres, dutys, dyne centimetres, electron volt, erg, foot-grains,
foot-pound force, foot-poundal, gigaelectronvolt, gram calorie, gram
calories (mean), hartree, horsepower hours, horsepower hours (metric),
inch pound force, Kayser, kilocalorie (16 °C), kilocalorie (4 °C),
kilocalorie (int.), kiloelectronvolt, kilogram calories (int.), kilogram
force metre, kilojoule, kiloton TNT equivalent, kilowatt hour, kilowatt
minute, kilowatt second, megaelectronvolt, megajoule, megaton TNT
equivalent, megawatt hours, newton metres, Q unit, quadrillion, quad,
Rydberg, therm (EC), therm (US), thermie (16 °C), ton TNT equivalent,
tonne coal equivalent, tonne oil equivalent, watt hour, and watt
second.
In contrast, using the metric system to consider
energy is relatively easy. We know that energy is measured in joules and
that we will probably need to use some large prefixes to understand our
energy use on a global scale. Here are some figures to
consider.
If you are an average teenager you will need 11
000 kilojoules or 11 megajoules of food energy each day. This is 77
megajoules each week 330 MJ each month and about 4000 MJ of energy
for a whole year.
You might even like to think of this as four
gigajoules per annum (4 GJ/a) as there are 1000 megajoules in a
gigajoule. Even a hardworking construction worker only needs about 5
gigajoules per annum (5 GJ/a).
In a temperate climate, an
average family household uses a bit over 100 gigajoules of energy in a
year. This might go up to 150 GJ in a cold climate.
In
2003, the USA used 112 exajoules of energy that was made up
from:
42 exajoules from petroleum,
26 exajoules
from natural gas,
26 exajoules from coal,
11 exajoules from
nuclear energy, and
7 exajoules from renewable
energy.
See: http://metricationmatters.com/why_metrication
for more details about why we should move more rapidly to the metric
units expressed as 'The International System of Units
(SI).
Cheers,
Pat Naughtin ASM (NSAA), LCAMS (USMA)*
PO
Box 305, Belmont, Geelong, Australia
Phone 61 3 5241
2008
Pat
Naughtin is the editor of the free online monthly newsletter,
'Metrication matters'.
You can subscribe by going to http://www.metricationmatters.com/newsletter
*
Pat is the editor of the 'Numbers and measurement' chapter of the
Australian Government Publishing Service 'Style manual for writers,
editors and printers', he is an Accredited Speaking Member (ASM) with
the National Speakers Association of Australia, and a Lifetime Certified
Advanced Metrication Specialist (LCAMS) with the United States Metric
Association. For more information go to: http://metricationmatters.com
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