Power by the Hour

THE ENGINEER’S WAY

Pence per minute; quarters per hour; that’s the information that we all need. Not just engineers. Let me tell you that nowadays, the designers and builders of engines for aircraft do not just sell the engines to the airlines. They sell them Power. The engine builder knows how much they cost to run and the airline likes to avoid the hassle. So the builder sticks a reasonable profit on top of the running and insurance costs; lends the airline the engines and charges them for however much power the airline uses. One builder at least calls it Power by the Hour.

That’s how we all need to think, not just the engineer’s family. Save the pounds or the dollar. Make it easier to save energy. Make it easier to save power. Make it easier to save money. It’s easy to help this to happen.

The Lad has been shouting this to himself today. His power bills are sky high and painful to pay. So are yours probably. In the modern household there are a multitude of electrical appliances. Some are power gluttons: they are mainly heaters of one sort or another. Some are only sipping at the meter: IT gadgets are such. Unless you are obsessed by the problem as is The Lad or any engineer, you will have little idea about how much power it takes to heat anything. An enginer can tell you, it’s enormous. In any flavour you want, it’s gigantic; be it kilowatthours, simply pedalling a bike or, if you prefer, horsepower.

Just running the hot water tap – especially running the hot water tap – costs a fortune over the month. The Lad’s old Physics master at school said to him that the specific heat of water [that is energy required to raise water by a degree or two of temperature] is higher than almost anything else except some gases. The Lad will dig out the figures for a future post.

Big Towel rail
Can you see it? At the right above the box. (c) The Lad 2011

Anyway, there was The Lad crawling around on the floor trying to find the Rating Plate of the various heaters in the house so that he could rant at the family. “Did you know it costs gold dust to run this thing for five minutes?

Small Towel rail
Another one lurking. On the left, behind this time! (c) The Lad 2011

But the Rating Plate was round the back or underneath or, better yet, inside. He cricked his neck looking up at the plate between the base of the appliance and the floor. Then the bifocals, joys of late-middle age, were the wrong way round. The distance reading area of the bifocal, intended for seeing the football or cricket ball a hundred metres away, were failing to assist him in reading the plate one centimetre from his nose.

Under the vacuum cleaner
This time it is underneath! You try turning a vacuum cleaner upside down! (c) The Lad 2011

No, No! Do it better. Help the Mother to harangue the family to do things better. Maybe in this day and age, it will be an ecologically conscious child. “Don’t waste money!”

We need a new label that the manufacturer of the appliance is required to supply. It will be applied prominently by the on/off switch. Or it could be one that we choose to make prominent. The most visible or even the only text would be a box into which the owner can write in a number which is a running cost, cash value and, after the box, will be printed the words ‘per minute’ or ‘per hour’.

The new owner will use her utility bill [which gives a cost of power per kilowatt hour] and the Instruction Leaflet or Rating Plate either of which will give the power absorbed by the appliance to help to calculate the cash cost. The Instruction Leaflet will also have a Table with a few lines with possible cash cost per kilowatt hour charged by the utility and, next to it the corresponding cash cost per hour or minute. Like this for a 1kW appliance:
                          Electricity                       Cost
                      pence per kWhr         pence per 15min
                                  20                                5
                                  30                               7.5
                              …………. and so on……………….

Easy, says the engineer! The new owner will consult this table and she can find the number to write in the label.

Published by

One thought on “Power by the Hour”

Leave a Reply

Your email address will not be published. Required fields are marked *