% superceded by heating, lighting, information.tex
What are the chief ways in which we use electricity?
In the home, there's the refrigerator, the lights,
and appliances like kettles, electric cookers,
computers, and TVs.
Outside, society has street-lights, traffic lights,
and some electric transportation (trains and trams).
Industry uses electricity for production of metals
and to hoik stuff around.
\begin{table}\figuremargin{
\begin{tabular}{l*{3}{r@{\,}l}} \toprule
Device & \multicolumn{2}{c}{Power} & \multicolumn{2}{c}{Time per day} & \multicolumn{2}{c}{Energy per day} \\
\midrule
Kettle & 3&kW & 1/3&h & 1&kWh \\
Television & 0.1&kW & 4&h & 0.4&kWh \\
Digital set-top box & 0.1&kW & 24&h & 2.4&kWh \\
Computer & 0.1&kW & 24&h & 2.4&kWh \\
Laser printer (sitting idle) & 17&W & 24&h & 0.4&kWh \\
Refrigerator & 0.1&kW & 24&h & 2.4&kWh \\
10 incandescent lights & 1&kW & 5&h & 5&kWh \\
10 low-energy lights & 0.1&kW & 5&h & 0.5&kWh \\
Microwave & 1&kW & 1/3&h & 1/3&kWh \\
Electric cooker & 2&kW & 1/2&h & 1&kWh \\
Electric oven & 5&kW & 1/2&h & 2.5&kWh \\
Tumble dryer & 2.5&kW & 1/2&h & 1.25&kWh \\
Vacuum cleaner & 1.6&kW & 1/8&h & 0.2&kWh \\ %% measured by me
\begin{tabular}{@{}l@{}} Washing machine\\ with electric water heater\end{tabular} &
2.5&kW & 1/3&h & 0.8&kWh \\
\begin{tabular}{@{}l@{}}
Dishwasher \\ with electric water heater\end{tabular} &
2.5&kW & 2/3&h & 1.6&kWh \\
\bottomrule
\end{tabular}
}{
\caption[a]{Electric consumption (domestic).
A plausible total is 24\,kWh per home per day; perhaps
12\,kWh per person per day.}
%% I've got mine down to 4 kWh/d
\label{tab.domestic.elec}
}
\end{table}
\begin{table}\figuremargin{
\begin{tabular}{cccc} \toprule
`Primary units' (the first 2\,kWh/d) & 10.73\,p/kWh \\
`Secondary units' (the rest) & \ 8.13\,p/kWh \\
\bottomrule
\end{tabular}
}{
\caption[a]{Domestic electricity charges (2006) for
Powergen customers in Cambridge, including tax.
%% My elec bill is 240 pounds per year. About 4 units per day.
}
\label{tab.domestic.elec}
}
\end{table}
Street-lights:
one per ten people,
% five houses,
each with a power of 100\,W, switched on
for 10\,h/d. That's 0.1\,kWh per person per day.
Traffic lights: each intersection has
8 bulbs lit, perpetually, 250\,W per bulb.
That's 2\,kW per intersection, 48\,kWh/d.
How many controlled intersections are there?
One per 1000 people?
That's 0.05\,kWh per person per day.
Producing metals.
Aluminium cans:
if you throw away four cans a day,
the energy wasted is 6\,\kWhd.
In the workplace, comparable heating and electricity
to the home.
\newpage
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.28}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Domestic electricity -- 12\,units per day per person;
workplace electricity, heating and cooling --
about 24\,units per day per person.
}
}
% \end{figure}
\section{My actual consumption}
Actually I use about 4\,units per day at home.
I don't have a TV, VCR, tumble-dryer, or computer.
My main appliances are probably my refrigerator,
microwave, mobile-phone chargers, and lightbulbs.
I also have a stereo and two bedside clock-radios.
As for gas, the condensing boiler is a 35\,kW system supplying
central heating and hot water.
% installed 8 march 2004
Electricity
Costs at 1 March 2006: Eastern electricity: 16.972p (first tier) then 8.817p.
Costs at 1 March 2006: Eastern electricity with payment discount: 15.037p
(first tier) then 8.817p.
Gas prices: 3.441p, then 2.553p. per kWh.
My gas consumption is 42 kWh/d.
% Sat 20/1/07 UNITS on Meter at house:
% https://www.house.co.uk/cgi-bin/house/house/general/personalHome.jsp?BV_SessionID=HHHH1805147926.1169332344HHHH&BV_EngineID=ccdcaddjmdifghlcefecfngdfhidfln.0&_txtJourneyKey=standard_login&_txtStep=1
your gas details and consumption
reading date reading type reading
08 Dec 2005 Meter Reader 4548
28 Feb 2006 Price change estimate 4660
units for period 08 Dec 2005 to 28 Feb 2006 112
converted to 3519 kWh
reading date reading type reading
28 Feb 2006 Price change estimate 4660
09 Mar 2006 Meter Reader 4676
units for period 28 Feb 2006 to 09 Mar 2006 16
converted to 502 kWh
When we work out your bill, we convert your gas units into kilowatt hours as follows:
% * units used (cubic ft)
% * x 2.83 (for metric conversion - omit if your meter measures cubic metres)
% * x 1.02264 [vol conversion factor]
% * x 40.2 [calorific value]
% * รท 3.6 -> kWh
% see ../data/gas
%
%# unit of Measure is Cubic Ft
%
% average 2.97 1.45 0.33 1.01 1.24 1.4 0.26 0.8 1.41
%date (mm/yy) 03/04 05/04 08/04 11/04 02/05 06/05 09/05 12/05 03/06
% WINTER SUMMER WINTER WINTER SUMMER WINTER (AIMS)