BTU and KW

[Abe]

Someone said he got a 12000 Btu ac.
I only work in metric, am wondering how many Kw that is

Thank you

[al]

Abe

12 000 Btu/hour [I.T.] = 3.516 852 84 kilowatt

From http://www.onlineconversion.com/power.htm

Very useful site!!

Al

[Jase]

Approximately 3.5 KW.

Jase

[Abe]

Thanking you both for your help

Regards

[lana]

Hi Abe,

I am sure you know this but I say it anyway.
BTU is energy but kW is Power (energy/time).
BTU/hr can be converted to kW.

1 kW = 3412.14 Btu/hr

Cheers

[Abe]

Thank you Lana
As ever youre very informative and helpful

[lana]

Thank you Abe,

You are very welcome. Glad to help.

Cheers

[airconadam]

hey fellas thos websites are great thanks alot adam

[BigJon3475]

This may be off subject but what are you guys opinions on using the formula:

(Volts x amps) x 3.413/TD x 1.08=CFM

Where the 1.08 is a variable based on what your conditions on the psychrometric chart are.

1CFMx60 Minutes=60CFM/Hrx .075 (lbs per cubic foot standard conditions)=4.5 x .024(specific heat of air)=1.08 *this is the variable obviously where your plot on the psychrometic chart would vary for your ft³ per lb of air.

This formula is given by at least one manufacturer to find the CFM on a Air Handling Unit with resistive heat strips. I ask this in this thread because of the obvious conversion for Btu's to Kilowatts. If anyone can chime in I am curious. I see this as reliable as what is used in cars for mass air flow systems since it's basically the same idea but I would like some opinions from some of you. Thanks in advance.

[Argus]

.

It's an old formula that's been around for years. As a quick check it is OK but can be inherently inaccurate.
I first encountered it in Carrier manuals in the 60’s and they stressed that you need at least 3 duct diameters of clear, straight, unobstructed duct, before and aft of your thermometer and both sides of the machine. Then you need to average a series of readings, just as you would with a Pitot tube.

It is easy to get accurate temperature and electrical readings these days, but its main practical drawback and barrier to accuracy is obtaining even air flows at your measuring point at your site. At least, that’s my experience.

Any inaccuracy here will throw your figures wildly out.

As you probably know, finding this configuration at site is almost impossible and if you have such a straight piece of duct why not do a conventional traverse with a manometer?

Great for a QLS, but I wouldn’t stand up in court on that evidence.

.

[BigJon3475]

Thanks. I am looking for basics of trying to figure out if I had an airflow problem or not. I will eventually get the TSI velocicalc. So many tools so little money.

http://www.geotechenv.com/newfiles/velocicalc.html

[Argus]

.

Well, This test is as basic as it gets.

To determine if you have an air flow problem before you buy expensive software, look at your installation and try this simple visual check list:

• Tight duct angles with few straight lengths
• Blocked filters,
• Long lengths of ribbed, flexible ducts.
• Long distances in the room between the supply and return grilles.
• Dusty coils.
• Ineffective fan.
• Etc

It's a graded check, so if you can check any of those you have an air flow problem - the more you can check, the more expensive your problem.

.

[frank]

You could always install a Wilson Flow Grid.

http://airflowinstruments.co.uk/prod...x?Cid=1&Pid=40

[Brian_UK]

You could always install a Wilson Flow Grid.

Been there, done that, can't afford the tee shirt now

Have you noticed that the price is missing from the shopping basket?

Got to admit that Airflow have done and still do some good kit.

[BigJon3475]

Thanks for the info sorry to go off topic somewhat.

[sinewave]

Someone said he got a 12000 Btu ac.
I only work in metric, am wondering how many Kw that is

Thank you

Your just joking Abe, right?


A site moderator with 1700+ posts not knowing basics such as this?


Nah!

Not having it, sorry!

[The MG Pony]

I live in a metric country yet some how only ended up learning BTUs! Any thing is possible.

Starting to get the handle between them though.

[BigJon3475]

http://www.megaconverter.com/mega2/

For any conversion problems I have found so far this can pretty much do anything I have seen.