BTU calculator?

[Frick]

Is there one out there for volumes of water?

It would have to have water volume size obviously, and how many degrees you would need to drop. What other varibles are nessiccary?

And how are BTUs converted to horsepower? I guess what i am asking is how are chillers rating themselves for aquariums size?

 

[disc1]

I do know this much. Pure water takes 4184 J / L to change 1 degree. That equates to 3.966 BTU / L.

Horsepower and BTU's aren't convertable. BTU is energy and HP is power. So we have to introduce a time unit on BTU.

1 HP = 2544.43 BTU / hr.

So a 1 HP chiller can take up 2544 BTU's per hour. That's assuming 100% efficiency, which we won't have, so the actual number will be a bit less.

Let's round these numbers off and do the calculation. Efficiency calulates in, so an estimate is the best we can do anyway.


Changing 1 degree per hour takes 4 BTU / L. A 1 HP chiller gives 2500 BTU / hr.

(2500 BTU / hr) / (4 BTU / L / degree) = 625 degrees / hr / L.

So theoretically, we could drop 625 L by 1 degree in 1 hour with a 1 horse chiller.

In reality, we don't need to account for the temperature change, but the amount of heat that is added by the things adding heat. If you only have 10 gallons of water and take 100 BTU / hr out, but also put in 120 BTU / hr, then the temperature is still going to go up.

 

[BeanAnimal]

Liters

Usually when we do BTU calcs we use Imperial measurements such as Gallons and Defgrees F. Simply because by definition, a BTU is amount of energy needed to raise or lower (without phase change) the temperature of one pound of water by one degree F. (I did not check the math, but assume disc was using L and degrees C)

Pure water weighs 8.34540444 pounds so therefore, it takes 8.34540444 BTUs to raise or lower 1 gallon of water 1 degree F.

There are 3.78541178 liters in a gallon so therefore, it take 2.20462262 BTUs to raise or lower 1 Liter of water 1d F. (not that we want to mix liters with BTUs and HP)

I will leave the rest of the math to the reader

 

[disc1]

Ha. I'm converting stuff because I don't know jack about imperial units. Would have been a lot easier if I had known that BTU is to pound and F as Joule is to g and C.

It would make life so much easier if we could all get over to the metric system.

 

[BeanAnimal]

One more thing i am not a fan of. I have spent 40 years wrapping my head around imperial units and am do justr fine without the metric system. Ohh I see the utility but have no desire to spend the mental effort to reprogram my brain

 

[disc1]

I would agree if the rest of the world would use them. But there's nothing like tryig to spec out a part with a european supplier when all of your engineers speak imperial and all the German guys speak metric. Hell, I end up having to sit and translate the math more than the language.

I guess it all depends what you grow up with.

 

[Frick]

1 HP = 2544.43 BTU / hr.

(2500 BTU / hr) / (4 BTU / L / degree) = 625 degrees / hr / L.

So theoretically, we could drop 625 L by 1 degree in 1 hour with a 1 horse chiller.

In a nut shell this is what i was looking for. Thank you.

Liters

Usually when we do BTU calcs we use Imperial measurements such as Gallons and Defgrees F.

Pure water weighs 8.34540444 pounds so therefore, it takes 8.34540444 BTUs to raise or lower 1 gallon of water 1 degree F.

There are 3.78541178 liters in a gallon so therefore, it take 2.20462262 BTUs to raise or lower 1 Liter of water 1d F. (not that we want to mix liters with BTUs and HP)

I will leave the rest of the math to the reader

Also good to know, thank you.

It would make life so much easier if we could all get over to the metric system.

But what would i do with all that extra time? :reading: