Heavy cooling under extreme hot weather

[Ashburn]

Hello everyone!

We've been experiencing an intense heat wave over my area, and AC units are working overtime everywhere since apparently they are running overcapacity. Moreover, I enjoy lower temperatures in my bedroom (around 12°C/53°F). Out of curiosity, that led me into thinking how people deal with it under more extreme conditions.

Those online air conditioning capacity calculators don't seem to take into account extreme weather, so how do I calculate the amount of cooling power it would take to cool down a room to 12°C/53°F assuming both outside and inside temps reach, hypothetically, 50°C/120°F?

Someone suggested me a room that can be cooled by 10°C using a 10.000 BTUs unit can therefore be cooled down by 40°C if 40.000 BTUs worth of power is installed, but empirically I don't believe cooling requirement grows linearly like that.

How to do the math in this case? Thank you! ;)

[eggs]

There must be a lot of 'lovin going down in your bedroom if you need 12 deg c :D

Eggs

[chemi-cool]

I have never seen an AC unit that can go down to 12 C.

Every room load should be calculated so outdoor temp will not affect the temp.
The problem can be the outdoor unit, is it designed for hot ambient?
I live in a hot climate [around 40C in summer] and never had problems.Units are designed for that.

[Ashburn]

There must be a lot of 'lovin going down in your bedroom if you need 12 deg c :D

Eggs

HAHA not sweating makes up a great excuse for not taking a shower afterwards, you know! :D lol


I have never seen an AC unit that can go down to 12 C.

Every room load should be calculated so outdoor temp will not affect the temp.
The problem can be the outdoor unit, is it designed for hot ambient?
I live in a hot climate [around 40C in summer] and never had problems.Units are designed for that.

Thanks! My unit can't be set to anything under 17°C, and it is not able to go under 25°C these days (and I don't expect it to). That makes me wonder it would take a huge amount of cooling capacity to achieve my desired 12°C. Maybe I'd be better off fitting my bed into a fridge... :)

I've never experienced that hypothetical 50°C, but 40°C+ is quite common around here.

I'm not sure if my unit is designed for that kind of payload, but it doesn't seem to be going go fail anytime soon.

So, taking into account houses over here are mostly built out of bricks and concrete, the greatest challenge in the event of an extreme 50°C is going all the way down to the 12°C instead of surviving the external climate? What would it take after all?

Thanks a lot!

[install monkey]

you need a celler cooler- good for 10 deg!-fans are a bit noisy though!

[mikeref]

Air-conditioners are not designed to run lower than, say 17 deg C as the average requirement is 23 C.
As return air drops, the heat transfer through the evaporator is less and the a/c runs longer with no off cycles and ices up.
Sizing an a/c depends on heat load. Room size, roof insulation, wall insulation, window area and radiation from direct sunlight + humidity etc
My bedroom is 12 ft by 12 ft. with timber walls and bugger all insulation in the roof. :o (That will change with a new roof fitted soon.) Used 75 Btu / square foot floor space and came up with 10,800. Fitted 12,000 or 3.5 KW split for 22 C overnight, and Bobs your uncle.

For 12 C, you need a coldroom.;) (Magoo, yeah i know... still using Imperial with Metric.):eek:

[monkey spanners]

Fit air con above bed, then put curtains round bed lik four poster. Be a bit draughty though.

Or a water bed and chill the water but be careful you don't get hypothermia!

[gwm121]

All comfort cooling splits cool to a minimum of 16 or 18 degrees.

You can obtain "cellar coolers" which will cool to 10 degrees, however these will be noisy and ugly. (google cellar coolers for suppliers)

There is ONE company ony in uk which will supply a modern neat unobtrusive spit system cooling down to 10 degrees (and they will do the heat load calc for you), they do this by stripping out all electronics from a daikin outdoor, and fujitsu indoor and rebuilding it as a bespoke unit with their own control circuitry and custom built wired remote controller. This will be EXTREMELY expensive. google for details.

If eventually you decide 16 degrees is adequate, thus saving muliples of the price, any good installer will be able to carry out a heat gain calculation either for comfort cooling. OR to take account of the hhottest day, midday, no cloud, all lights equipment on etc etc.

[Ashburn]

Thank you, everyone! This has been very helpful!

I knew cooling a room all the way down to 12C wouldn't be a piece of cake, but I thought it would be a common practice in countries where people are adapted to cold weather and electricity is affordable like US and Canada. It seems like this would set me back way more than an one-way ticket to Alaska! :p

Anyway, I never specified a room size, roof properties and insulation since this is just hypothetical, but I'm glad to find out this is possible with those cellar coolers some of you mentioned. I'm looking at the model "J5LC28C" unit, and presumably it might be able to the job in an ambient as large as 72m3 (not taking into account heat generated by human and devices).

I think I could get around with all the noise by attaching the internal unit into the central air conditioning ducts (which would involve simple, yet custom controls), or maybe I could even build a "Z" shaped box out of soundproof foam so it wouldn't affect cooling capacity. Maybe?

I'd never heard of these cellar coolers to this date and I'm surprised why there are not several off-the-shelf solutions for the fans of cold weather all year long out there, so it feels like I've got a lot of reading to do! ;)

[back2space]

One question why would you want to cool a room down to 12C in the first place? That is not normal temperature to be comfortable at. I think your existing unit is not cooling the room properly and so therefore you think you need it to be colder. At 20C I am starting to feel chilly in the bedroom if I am getting ready to go out and to sleep I like about 20C but any lower and its rediculous.

[back2space]

All comfort cooling splits cool to a minimum of 16 or 18 degrees.

You can obtain "cellar coolers" which will cool to 10 degrees, however these will be noisy and ugly. (google cellar coolers for suppliers)

There is ONE company ony in uk which will supply a modern neat unobtrusive spit system cooling down to 10 degrees (and they will do the heat load calc for you), they do this by stripping out all electronics from a daikin outdoor, and fujitsu indoor and rebuilding it as a bespoke unit with their own control circuitry and custom built wired remote controller. This will be EXTREMELY expensive. google for details.

If eventually you decide 16 degrees is adequate, thus saving muliples of the price, any good installer will be able to carry out a heat gain calculation either for comfort cooling. OR to take account of the hhottest day, midday, no cloud, all lights equipment on etc etc.

What is the name of this company? Cant find them anywhere.

[Simeonx1]

IF you removed thermostat so it runs longer .. this will course icing up and what other problems ? anything bellow 18c is to cold and you will feel sick when you go out to the heat.