Thursday, September 17, 2009

PROF'S POSER - Stone cold

Here's one for the thermodynamicists.

And/or anyone in one of the UK's many older homes, where certain insulation options are not exactly on the table. 3' thick stone walls and no gaps, for one.

After a not bad summer, with doors opened to the outside to air the place out, or opened to the conservatory to warm up the interior for most evenings, now we have hit September it's starting to get a wee bitty nippy.

Certainly for my Eastern blossom missus. And while her going around like a hood ornament for Dr. Zhivago is a fashion treat, the neighbours are talking.

My poser is (and a memory lurks that I might have done so before)... when is the right point at which to fire up the central heating?

Because one thing we have noticed, if empirically, is that if you leave it late and allow the cold to bite, the walls seem to keep it that way no matter what.

However, for good eco and plain money reasons, I don't want to be running the boiler until I have to.


Dave said...

You should start by calculating the thermal mass capacity of the walls and then ...... errrrrr ...

Peter said...

When I saw you had commented, I thought 'Goodie... an engineering solution'.

So if you don't know... :(

Makes you wonder, though, how much energy might be saved if that calculation was done, such that the optimal result was inspired from Lands End to John O'Groats.

Dave said...

It would be a massively complex calculation, as there are so many variables involved - type and style of wall construction, its material(s!) of construction, local weather conditions, efficiencies of space heating systems, degree of airtightness plus many, many more.
But.... there ought to be someone, somewhere, out there, who could have a stab at it.

Peter said...

Many, many tx.

All your points noted and appreciated.


I think it may well be worth it.

Not like HMG and her quango spawn have not lobbed bazillions at equally tricky stuff in the name of green.

Even a rough chart with ballpark results to get folk thinking that could be used in awareness PR might be a start.

Have you ever tried the limitless, all competing, mostly funded carbon calculators out there? I do better using alchemy to arrive at a sensible result.

Or even such as USwitch on energy providers.

Somewhere... out there... beneath the pale moonlight... my prince will come... bearing a slide rule.

Dave said...

Your prince will probably need a super-computer rather than a slde rule!
One thing I would suggest is posing the question on the Green Building Forum - there are lots of clever, highly knowledgeable people hanging around there - it can be a source of very good advice (and stimulating debate!) sometimes.



Peter said...

Your wisdom, sir, is exceeded only by your good looks:)

And priceless fonts of linkage.