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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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