Cold last night

[Oldgreybeard]

First real frost here this winter. Also first time we've opened the blinds to see frost on the windows (on the outside):

Frosty windows.jpg (65.59 KiB) Viewed 3098 times

Nice to have 52mm thick triple glazing, though!

[openspaceman]

Nice to have 52mm thick triple glazing, though!

I wish

Went to -4 outside and 14 inside overnight, ramping up at 2 degrees an hour currently.

I did notice an extra 1+GW of nuclear contributing to electricity demand, where did that come from?

[nowty]

I did notice an extra 1+GW of nuclear contributing to electricity demand, where did that come from?

We have had 3 reactors offline due to off load refuelling and inspections for a few weeks. Two are now back, we still have Reactor 1 from Hartlepool still being refuelled, it should be back in a couple of days.

[Oldgreybeard]

I'd forgotten this thread, accidentally started another one (now deleted)! A better illustration of triple glazing effectiveness this morning.

Coldest night of the year, got down to -4°C last night. Bedroom still at 21°C this morning (there's no heating in our bedrooms or first floor). Opened the bedroom blinds this morning to see this (the ice is on the outside). Hard to beat 52mm thick triple glazing units:

Ice on window.jpg (71.77 KiB) Viewed 3020 times

Put a contact thermometer on the inside pane of glass (IR thermometers massively misread on glass due to the reflectivity being way outside their calibrated value) and the inside pane was at 18°C. Not been outside to measure the surface of the outer pane, but it will probably be slightly lower than air temperature, due to the additional overnight radiative heat loss, I think (the reason things like cars show frost overnight when the air temperature is still slightly above freezing - they radiate heat out into the deep cold of space on a clear night)

[Moxi]

Lets hope nothing goes ping while they are ramping up through the xenon dead time (or poison threshold to some), like most big kit the reactors and the turbines like it best when they are left to churn out the power at a steady constant they do not like the constant interference of control mechanisms checking and balancing their natural rhythm. lets not forget those cracked control rod channels in the moderators - it needs only a little movement before a Rod cannot be inserted due to miss-alignment of debris blockage and then we are off line and back to figuring out how to correct the issue of if the reactor has met its end.

After 48 hours we should be clear of the significant risks as the Xenon will have been scrubbed and transmuted away to trace quantities and no longer a contributory constituent to the overall reaction.

One of the reasons that the AGR's were all designed to fuel on load but for various reasons this never came to fruition and we were left with the same situation as first perceived in the magnox fleet.

Moxi

[Moxi]

OGB,

Is the absence of frosting around the edges of the outside pain due to the proximity of the frame ?

I've never owned windows that frost over on the outside but I have lived in two houses where ice formed on the inside! once in the 1970's and at my current address in 2010 when we first lived here and there was no heating upstairs just a knackered old WBS downstairs that was woefully inefficient.

Moxi

[Oldgreybeard]

OGB,

Is the absence of frosting around the edges of the outside pain due to the proximity of the frame ?

I've never owned windows that frost over on the outside but I have lived in two houses where ice formed on the inside! once in the 1970's and at my current address in 2010 when we first lived here and there was no heating upstairs just a knackered old WBS downstairs that was woefully inefficient.

Moxi

The heat loss through the edges of the glazing units is a lot greater than that through the centre, because of the bonded spacers between the glass panes that keep them apart. In our case those spacers are 20mm thick hollow aluminium tubes, with perforations on the inner edge, and the centre of them filled with desiccant. The frames are well-insulated, they are a sandwich of timber inside, rigid plastic foam in the centre and aluminium skins bonded to the foam. The weak points are the glazing edge spacers, not much can be done about them, really, but they do always conduct more heat than the centre of each pane.

Best mitigation for this is to design the glazing to not have any small panes of glass. Small glass panes are a lot less thermally efficient than large ones, because they have a longer length of edge than an equivalent area single pane.

I grew up in a house with steel framed windows (Crittal ones that were popular 70 to 80 years ago). They used to ice up on the inside. I well remember being told off as a small boy for scraping rude pictures on the inside of my bedroom window . . .

[dan_b]

-2C in SW London overnight/this morning. Great to have the pre-heat function on the Tesla! Still haven't turned on my central heating...

[Moxi]

I don't have a tesla but your comment reminds me of the times I used to take a hot water bottle to and from the office, I would use it or loan it out to others in the office through the day as needed and at 4pm I would fill it up and stick it inside the car on the drivers seat and cover it over with a blanket.

Then when I drive home I would pop it in the passenger foot well and crank up the hot air on that side of the car all the way home.

At home (caravan as I worked away at the time) I would rap the still hot hot water bottle in the blanket again and pop it on the dash board.

It was rare for me to have to defrost the windscreen on the drivers side and when I did it was a weak ice covering.

The other useful memory is those re-usable two phase hand warmer pouches - I still have around 6 of them and they are brilliant, click the metal clack to precipitate crystal growth and release the heat.

I use those all over the place as they are so convenient and easy to recharge as they go into a pan of water with a cloth in the bottom (to stop them sticking) the pan sits on the WBS for an hour while they change phase again and then off the stove and on to the trivet to cool ready to go again.

When at clients offices or places of work I recharge them in a cup of boiling water in much the same manner so that I have them to hand in the evening.

Moxi

[Oldgreybeard]

The other useful memory is those re-usable two phase hand warmer pouches - I still have around 6 of them and they are brilliant, click the metal clack to precipitate crystal growth and release the heat.

I use those all over the place as they are so convenient and easy to recharge as they go into a pan of water with a cloth in the bottom (to stop them sticking) the pan sits on the WBS for an hour while they change phase again and then off the stove and on to the trivet to cool ready to go again.

When at clients offices or places of work I recharge them in a cup of boiling water in much the same manner so that I have them to hand in the evening.

Moxi

We have about 150kg of that stuff (super saturated sodium acetate trihydrate solution) in a big thermal battery that heats our hot water. Works faultlessly. Either heated up by excess PV generation (like today and yesterday) or by cheap rate electricity if there's not enough sun. The pack sits there as a "charged" liquid, losing no heat, until it self-nucleates and starts to change phase to a solid, releasing a lot of heat (at around 56°C), when a hot tap is opened (the inrush of cold water to the heat exchanger initiates nucleation).

The really cool thing is that the phase change can be stopped when the nucleation event stops and when the temperature in the thermal battery equalises, so again it sits there, not losing heat, until nucleation is triggered the next time a tap is opened.

It will happily store heat for a very long time if just left, unlike a hot water tank that loses heat all the time. Big advantage for us with such a low heating demand house was that the old hot water tank we had, even with a lot of extra insulation, made the small room adjacent to our spare bedroom very hot, over 40°C in summer) and also made the spare bedroom to hot.