| General > General Technical Chat |
| Window screens |
| << < (12/18) > >> |
| james_s:
--- Quote from: Zero999 on June 08, 2023, 09:26:12 pm ---You've put the decimal point in the wrong place. Global temperatures have risen by 0.08°C per decade. https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature --- End quote --- Whoops, thanks, I thought something looked wrong when I went back to read it. At any rate I didn't intend for this to turn into a global warming debate, I was merely curious how widespread window screens are, and the answer seems to be a lot less so than I had assumed. They're such a universal thing in my part of the world, and so simple, the technology having existed in some form for thousands of years, I just assumed they were everywhere. Sounds like outside of North America they are not really a thing except in Australia which is not too surprising given what I've heard about insects and other nasty critters there. |
| james_s:
--- Quote from: IanB on June 08, 2023, 09:57:04 pm ---In principle, if you could use outer space as your heat sink, where the temperature is about 4 K, then you could have quite a nice temperature differential of 300 K or so. Not huge, but plenty good enough for heat pumps. Unfortunately, it would require some kind of very efficient radiator with access to clear skies at night. It's a shame there is unlikely to be a way to engineer such a thing. --- End quote --- Even if you ignore the distance, using outer space as a heat sink is is easier said than done. Dissipating heat from spacecraft is a significant challenge due to the fact that conduction and convection are not available, so all you have at your disposal is radiation. It's challenging enough to dissipate more than a few tens of watts here on earth without forced air cooling. |
| james_s:
--- Quote from: Circlotron on June 08, 2023, 01:03:22 am ---Unusual that the traffic would be backed up in both directions at the same time. Generally everyone is either going to work or coming home. Not impossible of course, just unusual. --- End quote --- That's certainly not unusual here. Try driving from Woodinville, Redmond, Kirkland, etc to Seattle or Everett and through much of the day it will be backed up both ways. It's typically worse in one direction than the other, but a shocking number of people live in the big city and work in the suburbs while another group lives in the suburbs and works in the big city. Beats me why anyone would want to live in an urban city other than for convenient access to a downtown job but some people do seem to love those crowded dirty dumps. |
| james_s:
--- Quote from: IanB on June 08, 2023, 03:14:37 am ---Your friend is correct about screens not being a thing. Firstly, your friend is a wuss. There are a few people who jump up and down and scream: "Ooh, a little flying insect, oh no, how scary!" Most people just shrug and ignore them. --- End quote --- I don't think he's jumping and screaming and scared of them, like me he just finds them to be a nuisance. I certainly don't want bugs in my house, not because I'm afraid of them but because it's extremely distracting and annoying to have a fly buzzing around or a moth attracted to the light of the TV or computer screen or flitting around a light, and flies carry disease (they crawl around on piles of animal shit) so I don't want them crawling around on my food. Also here where I am we have a large number of mosquitoes which love my blood and eat me alive given the chance, and wasps which I'm mildly allergic to which causes a very painful sting with lots of swelling. |
| coppice:
--- Quote from: james_s on June 08, 2023, 11:55:23 pm --- --- Quote from: IanB on June 08, 2023, 09:57:04 pm ---In principle, if you could use outer space as your heat sink, where the temperature is about 4 K, then you could have quite a nice temperature differential of 300 K or so. Not huge, but plenty good enough for heat pumps. Unfortunately, it would require some kind of very efficient radiator with access to clear skies at night. It's a shame there is unlikely to be a way to engineer such a thing. --- End quote --- Even if you ignore the distance, using outer space as a heat sink is is easier said than done. Dissipating heat from spacecraft is a significant challenge due to the fact that conduction and convection are not available, so all you have at your disposal is radiation. It's challenging enough to dissipate more than a few tens of watts here on earth without forced air cooling. --- End quote --- There are a bunch of videos on YouTube where people have experimented with various coatings on a shaded surface to radiate upwards to space as an air con. They are interesting experiments, but get too small a result to be useful. |
| Navigation |
| Message Index |
| Next page |
| Previous page |