[inference-lord]

If India is building more power plants, which I'm assuming are coal? Isn't that going to mess them up worse than before? I mean, having air-con is nice, it's not possible for the whole of India to be inside with air-conditioning on for 3+ months of the year.

Even in places like Tokyo, they have to limit their use of A/C because it' so energy intensive due to the crazy amount of heat from the urban heat island effect.

[logifail]

> Even in places like Tokyo, they have to limit their use of A/C because it' so energy intensive due to the crazy amount of heat from the urban heat island effect.

I was in Singapore on Friday, for one day.

There's air-conditioning in the MRT (metro) stations, but (at least from what I experienced during my brief stay) the stations are not typically closed off from the outside.

You approach a station at street level and it's perhaps 33°C (91F) w/ humidity outside. Around midday my phone reported the weather as '33°C feels like 38°C (104F)'.

You go down an open set of stairs/escalators, and it gets progressively cooler and then you're in the metro and it's pleasantly cool. I was very quickly wondering whether this wasn't a mind-blowingly wasteful use of energy.

Anyone care to comment?

[paulmd]

heat rises and cold falls, so the cold air will stay in the subway system. there is no real need for doors/etc at the entrances as long as you're going down.

the subways themselves put off a substantial amount of heat (from friction, motor loss, etc - all inefficiency eventually becomes heat) and for example in london they have problems with heat buildup in the tube system. so air-conditioning the platforms is generally desirable and probably necessary (especially in a more equatorial climate than england).

[inference-lord]

What about the waste heat from the a/c units heating the surrounding areas?