Evaporative Air Coolers

The reason I'm considering one at all is that we have a need to cool a number of rooms - particularly during this hot spell - but at different times of the day. An air cooler would operate in the office during the afternoon, a child's bedroom in the early evening and the parents' bedroom later in the evening. All of them can get incredibly hot. In the latter two cases the cooling could take place prior to the room being occupied, which fans wouldn't really do, then be switched off, eliminating the noise.

In an office environment, I'm a little worried about the idea of chucking a couple of litres of water per hour into the air near some computing equipment....do they actually cause dampness around the place, or does the existing hot air take care of that?

(I'm looking for a solution today rather than next year, so there won't be any planting of greenery outside the windows, installing an aircon system or anything like that)

C heers

Brian

Reply to
bigbria
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They don't work.

While they are quite capable of dropping the air temperature by

2-4C, in doing so they raise the relative humidity to close on 100%. This makes the room feel much hotter - high relative humidity is extremely uncomfortable, because your perspiration simply doesn't evaporate.

Look at ways of reducing the total heat input into the room. Presumably most of it is via light through south facing windows? If that's the case, then you need some highly reflective blinds (silvery-white). These will bounce a significant proportion of the visible spectrum back out. It's by no means a complete solution, but it will make a big difference.

Reply to
Grunff

Good point. (actually the one I looked at this morning advertsed a reduction of 6 degrees C, which is very noticeable but I personally hate humidity.

Brian

Reply to
bigbria

It depends where you live! They work(ed) very well indeed for us when we lived in Riyadh in Saudi Arabia but the RH there of course (at least in those days) was around 25% I think. Thus the evaprative coolers had dry air to work with and increasing the humidity was a 'good thing' comfort wise.

I agree that in the UK evaporative coolers are unlikely to be useful.

Reply to
usenet

Forget it - they don't work. The reason they don't work is that what you really want to do is reduce the humidity, and they do the opposite. Whilst an evaporative air cooler might manage to reduce the temperature a bit, the room will actually feel worse. They work in hot dry climates -- we never get those here.

For more details, see:

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Reply to
Andrew Gabriel

They dont work in a UK climate, they rely on the latent heat of evaporation of the water to cool the air...the evaporation doesnt occur in our high humidity heat so the cooling doesnt work.

We used them with much success in country NSW, 45degC in very low humidity and got a temperature drop of 7degC, but I wouldnt bother in the UK.

Ian

Reply to
Ian

Problem solved. I bought a floor fan that is sitting under my desk and, even as I speak, is cooling me to an almost uncomfortably cold degree...its lovely.

Of course, it hasn't solved the problem upstairs, but I'm all right jack :-)

Brian

Reply to
bigbria

Nope, cos its a floor fan. Its under the angle of the (L-shaped) desk, pointing up at me; papers blowing around is the very reason why I bought one like that, instead of a desk mounted or pedestal fan. Getting a lovely cold breeze up the shorts, and no papers going anywhere.

Brian

Reply to
bigbria

We still haven't had the worst the climate can throw at us. Plus the humidity has been plummeting all day.

You really can't beat a proper split air-con system. I've experimented with everything else and there's nothing to touch it.

Are your papers flying around the room yet?

Reply to
Simon Gardner

Are you not planning on connecting either the heat exchanger or the air con unit to the wall?

Reply to
bigbria

If you mena what I think you mean, at current humidities (just about

100%) evapiorative cooling simply won't work. Period.

Get proper refrigeration.

Reply to
The Natural Philosopher

Still, for comfort, you can't beat a nice 20 inside when it's 28.5 in the shade outside as it was today. And when it gets to 32 - as it certainly will within the next month or so - it will still be 20 indoors. I *love* my aircon.

Reply to
Simon Gardner

Was 32 today here in NE Kent - by two different thermometers, both in shade!

Reply to
Bob Eager

They are designed as free-standing units and have worked that way in one of my factories for more than a year. There is a provision for hanging the heat exchanger on the wall, which would presumably be required if I were not using them at ground level.

Colin Bignell

Reply to
<nightjar>

"sw" wrote | Grunff wrote: | > [blinds] | I will vouch for this. We've just fitted white blinds made of two | different reasonably open weave fabrics (I'll skip details of fabric | and design as it might be too girly) to all the upstairs windows on | the sw-facing front of the house. Leaving the blinds down all day | in hot weather has significantly reduced the temperature in the rooms.

I have pinoleum blinds at the windows and keep them down until the sun moves round from that side of the building (which usually coincides with about the time I'm dressed and able to open the blinds anyway).

They let the air (traffic fumes) through but do help keep out the heat.

Owain

Reply to
Owain

Ah, so (if Iunderstand you), its a portable (free standing) air con unit, installed at ground level, (and with the heat exchanger resting on the ground outside?). Which answers my next question about how you were going to wire the thing into the mains in your allotted 30 mins installation time :-)

Brian

Reply to
bigbria

I'm not sure that something that needs a 50mm hole in the wall and a spanner to disconnect the umbilical that passes through it really counts as portable. Transportable, perhaps. Apart from that, yes. There is a nice concrete slab, about 0.5m wide, down the whole side of that side of the house for the heat exchanger to stand on.

Using the 13 amp plug it is fitted with.

My point was really that effective air conditioning can be a quick fix, if you are using the right equipment. OTOH, the clean room I recently had done took three men about a week and it needed a fork lift truck to position the external heat exchanger.

Colin Bignell

Reply to
<nightjar>

I agree...but then I don't live in a Stephenson screen! It was just bloody hot for me!

Reply to
Bob Eager

I remember all that stuff...was responsible for the equipment at school for a year...but no doubt some of the technology was different in those long-ago days!

Reply to
Bob Eager

Certainly, it was - outside. The point of using Met Office criteria - which I do with my outdoors temperature kit is it gives you an accurate reference with respect to weather forecasts etc and a genuine comparative measure. Call me fussy, but if I give a temperature, I like it to be genuinely meaningful. (That's how I can state with certainty that there was a whole week with peak temperatures above 32 last year.) But you are right. It was bloody unpleasant today and Monday looks like being worse.

I'll just shuffle of to uk.sci.weather now, eh?

Reply to
Simon Gardner

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