Wiki: Fan cooling

[Andy Champ]

He's always been like that. Trouble is sometimes he says something useful, so I can't killfile him.

Andy

[ARWadsworth]

What a pity as I have just got a shot gun license.

Adam

[Steve Firth]

Threatening people with a shotgun is outside the terms of the licence. Your violent tendencies noted.

[meow2222]

its simply a means to avoid writing the same replies over and over and over, and the article creation process also works to gather every contributors knowledge and iron out many issues. Obviously its not perfect but its a handy resource for a lot of people.

I've never claimed any such thing, nor anything remotely like it, nor done anything like it. And no, I couldnt care less what mr firth thinks.

NT

[meow2222]

OK, theres a section called ==Experience== that documents what I've done so far.

1. the industrial fan experiment
2. a small system using a 12" fan in intake mode
3. another small system using a 5" fan in extract mode

Systems 2 and 3 have run for years with consistently good results. The cooling effect isnt as powerful as traditional a/c, but its generally able to keep the place at under 24C all day, which is as good as a basic a/c system, but with a tiny fraction of the operating energy and cost.

The article also mentions the fact that whole house versions of such systems are commonplace in hot countries. The term 'whole house fan' is well known in the US, and widely used for cooling, and describes exactly the system in this article.

There have been a few critical replies. If those people would like to point out what they think's wrong, please do. If unable to, or its just a personal thing, I'm not much interested in that.

In hindsight it would have been nice to include a couple of graphs in there, one describing the basic theory, and one showing the real world results. However I'm not sure I'm willing to slowly fry in order to provide the needed comparison of system operation with no cooling system! I'm grateful that I dont have to endure a coolingless house today :)

So in short, yes its a proven system widely used in America, known as a whole house cooling fan. What I've done is to apply the same method to a 1 room cooling fan, using exactly the same principles, making it easy and minimal cost to install to cool one room.

NT

[Tim S]

[e-mail] coughed up some electrons that declared:

OK - sorry I missed that. It might be more obvious to me when it's on a web page, but perhaps I might suggest moving the "howto" bit up a bit and the background theory down a bit. Just a suggestion. The fact it worked for you is the attention grabbing bit.

Well, I don't think you're bonkers. When I consider how hot it gets here and how well I can cool *some* rooms but opening a couple of windows *if* theirs a suitable wind in the right direction, adding some fans and smart control does seem to have merits worth exporting.

I never though of it and I am thinking of it now...

I need to read it again when I have more time, but it's bookmarked in my head to do so...

Cheers

Tim

[Tim S]

Tim S coughed up some electrons that declared:

And I have to apologise for the atrocious typing. It's the beer. That I'm about to have. English real ale - so much of a kick it travels back in time and messes with your head before you've opened a bottle...

[meow2222]

Right, good point, maybe I'll reorder things then. I did it that way initially because I realised most readers would be unfamiliar with the idea, but yes, I wouldnt claim to be especially good at getting ideas across. I think also a graph is needed, if I get time I'll do one.

Its stopped me frying in summer for years. What I always find odd is when people criticise something without showing any understanding of it.

NT

[ARWadsworth]

that is the best offer you will get apart from Mrs Palmer and her five daughters.

Adam

[The Natural Philosopher]

I do it without a fan at all.

Even less cost.

Simply by closing windows and curtains by day, and opening them by night.

Natural convection does the rest.,

The fan really does nothing at all to cool anything, unless its relatively dry heat, in which case it will cool by evaporative losses.

[JTM]

Yesterday I saw an ad on Ebay for gas detectors for caravanners referring to the advice from the Foreign + Commonwealth Office so it must be true.

I spent 30mins trawling the FCO site for a reference. Zilch. But people still peddle the rumours

John

[Onetap]

I haven't read it all, but......

It has been done on commercial systems, generally overcooling concrete floor and ceiling slabs overnight to reduce the peak cooling demand, i.e., reduce the size of the chillers (sized for peak demand) and the demand for high-cost electricity during peak times. There are also thermal store systems which are generally liquid based and there's some recent system (don't recall it's name) which has the air intake through buried concrete pipes, the earth being a heat sink at fairly constant low temperature.

The problems I anticipate are that houses don't have the thermal storage capacity of offices (not usually concrete upper floors) and the brick/block walls may be shared with adjoining buildings. The heat transfer to/from the walls or floors will be limited; I think U-values use a simplified factor for the transfer coefficient. I suspect that the heat transfer rate will be small, due to the limited temperature differential and the small surface area.

Some of the statements about limiting ventilation during the day seem to overlook the requirement for fresh air for the occupants.

'Sensor' usually means an electronic sesnsor, generally a NTC thermistor. A thermostat is generally an electro-mechanical switch. The terms aren't usually interchanged. Thermostats are crap, costly, unreliable crap as well. Radiation shields are available for outdoor air temperature sensors, but north-wall mounting is usually much preferable.

There is (used to be) an epic piece of work on the web about controlling humidity through ventilation control in museums and documents stores; similar princples. Worth a read if you're into the black arts of psychrometrics.

[Steve Firth]

Again, it speaks volumes about you.

[The Natural Philosopher]

Really quite small.

The *key* thing is you have to have thermal mass inside the insulation, and lots of insulation.

That's not common practice in many modern houses.

Having got that, the fan is completely irrelevant really. Unless you have a massive internal volume and very little window space, in which case summer solar gains are trivial anyway.

In short its the usual half baked 'read it somewhere and didn't understand it' nonsense from NT.

There is more than enough air throughput at night in any normal domestic dwelling to make a fan totally superfluous. There is no need to automate a dwelling as opposed to an office.

The key elements are insulation and some kind of thermal store.

Not fans.

[brass monkey]

So what's the best/easiest/cheapest way to cool down my South facing conservatory which hits >40C ? Other than pulling it down. It has double glazed sides and polysummatorother (Dibnah speak) roof.

[meow2222]

yes, its not really a new concept, just little known to domestic diy.

might be why a fair bit of air movement is needed, and the 24hr temp swing is a fair size.

really the 2 are unconnected. When the fans are off in day, the same fresh air supply thats always been there still operates. Fans on increases air exchange rate far beyond fresh air requirement.

1/2C accuracy is plenty

=A36 new, and lots of used ones about

reliable enough to have run nearly all central heating systems for the last 30 years. Electronic ones dont seem any better in practice.

right, I'll mention that ta

NT

[meow2222]

youre not grasping the core concept

NT

[geoff]

In message , Thomas Prufer writes

Well, its an absolutely irrefutable urban myth on Italian trains ...

BTW - habe ich etz eine enkel - a saupreisz

Allmaecht !

[Thomas Prufer]

Condolences, then!

Thomas Prufer

[The Medway Handyman]

Then why don't you use your vast knowledge to write a better piece about detergents then f****it?