MBH vs. BTU

eric_2

Can someone tell me this difference between a MBH and a BTU?

Alan(CaliforniaRadiant)Forbes

Shorthand

MBH means thousands of BTU per hour; so, 100 MBH is 100,000 BTU's.

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Mike T., Swampeast MO

BTU is heat energy required to raise one pound of water one degree Fahrenheit. (It's actually more finicky, but this is close.)

MBTU is 1,000 BTUs.

"M" seems to come from old Roman numerals. Also common in printing when specifying quantity.

eric_2

Thanks

Many thanks on a Friday morning. Hope you guys have a good weekend.

Brad White_2

Not to be pedantic but

when I teach engineering (to architects) I dock them half a point for the "raise" by one degree answer. I give full credit for "change" temperature because when one gets, the other loses. Handy in cooling too.

My students both love me and hate me :^)>

DanHolohan

A good page to bookmark:

Acronyms of the Industry

Brad White_2

That was ASAP!

:^)>

And PDQ, too.

Ed_13

WOPAC Boilers

Dan,

Good list. I like “BER” which stands for Beyond Economic Repair.

Reminds me of one that I used to use on invoices, so I did not offend the homeowner.

They thought that their boiler was like a cat, with 9 lives. I thought it was a WOPAC.

W.O.P.A.C. = Worn Out Piece Of Crap. )

Regards

Ed Carey

Ed_13

WOPAC Boilers

Dan,

Good list. I like “BER” which stands for Beyond Economic Repair.

Reminds me of one that I used to use on invoices, so I did not offend the homeowner.

They thought that their boiler was like a cat, with 9 lives. I thought it was a WOPAC boiler.

W.O.P.A.C. = Worn Out Piece Of Crap. )

Regards

Ed Carey

jerry scharf_2

units, units, units

Come on guys, I can't believe none of you got this. He asked the difference between BTU and MBH.

BTU is a measure of energy, and Mike gave you the derivation. A BTU is comparable to a Joule in the metric system.

MBH is thousands of BTUs per hour (we especially love compound TLAs.) It is a measure of power (energy per unit time,) and it's comparable metric unit is Watts.

I may not have learned much in my physics, but I still always check the units.

jerry

Brad White_2

Mike T. actually did

answer that one early-on (MBH=1,000 BTU's per hour). After that, were just delving into the finer points of BTU's and Abbreviations, that's all. What I like about this forum is a rational circumnavigation of any topic posted. Sort of the difference between a college and a university :^)>

kf_2

Brad White

Brad,

Not sure that that is an accurate statement.

Cooling can't actually be added to an object or space. What makes an object or space seem cooler is actually the removal of heat.

In an air conditioning or refrigeration system heat is actually moved from one space to another space. Such as; in a house, heat or BTU's are actually moved from inside the space to outside, essentially raising the temperature outside. This is noticed when your hand is placed on top of a condenser fan (the air will be warm).

So a BTU can only raise the temperature. You actually have to remove BTU's to make something SEEM cooler.


Not to be a wise A*#,
just sounded like a fun argument.
And I felt bad for the architects.

kf

Brad White_2

Ah, Grasshoppa...

A Btu indeed IS defined as the amount of heat required to change a pound of water one degree Fahrenheit. As stated, by definition. That it is moved in one direction or the other makes no difference. One fluid loses, the other gains. When water is chilled for AC, it is BTU's removed. Still change.

The vector (direction of heat flow and means) matters not.

I never stated anything about "adding cooling", just the definition of BTU.

p.s. Do not feel bad for the Architects. At least one of them switched to engineering!

eric_2

And to think

All this started due to a lack of coffee braincramp. Gotta' love this place!

R. Kalia_2

heat is \"required\" to cool?

> A Btu indeed IS defined as the amount of heat

> required to change a pound of water one degree

> Fahrenheit. As stated, by definition. That it is

> moved in one direction or the other makes no

> difference.


But heat is not "required" to cool something, although one can correctly say that heat is moved; or one can say that negative heat is required.

The direction certainly makes a difference; try running the AC backwards!

The use of language in science is very precise; it can't be used in any way one wants to, unlike general conversation.

Brad White_2

Indeed.

Moving heat is required to cool. Move heat from one point to another and the first point (object, fluid, what have you) will be cooled. The BTU is simply a measurement of heat quantity. It has no direction.
Yes, you can run AC backwards as in a heat pump. It moves (and generates by heat of compression) what is measured in BTU's. Simply.

Christian Egli

It's Friday again, and I've got plenty of coffee

> All this started due to a lack of coffee

> braincramp. Gotta' love this place!



I'll side with Mike T. and kf on that one. I think you can get away talking only about a change but it gives no detail about how the heat transfer occurs. I know it does not matter to the test question, but a student who gives you the detail should get extra points. To increase the temperature of your pound of water, you need to add the BTU, to lower the temperature, you need to remove the BTU.

So requiring a BTU to raise the temperature is not only correct, it gives the additional information. It thus warrants a bonus. What would also be correct is to say a BTU is released when lowering the temperature of the water.

But saying that a BTU is required to lower the temperature would not be correct, you need to get rid of the BTU, not keep it, and you are certainly not going to want to buy a BTU that you need removed, neither would you want to give a bonus point.

I agree that all of this is only a matter of convention, we generally regard the BTU going into the water as a positive value. What is important is to all be on the same page at the same time. It is the same thing that happens when you sit down with your loan officer, you define by convention which way the money will flow between the two of you and who will be the debtor and who will be the creditor, and I don't think your banker will agree that it does not matter at all which way the money goes.

Do you give bonus points for semantics?

The BTU is a unit for a bucket of energy. Count how many buckets you burn in an hour and you get a rate, the BTU per hour, which is confusingly abbreviated in many ways, from just BTU to BTUH, BTUHR, BTU/h, BTU/hr, BH... If you have a 1000 of these, you add the M in front and MM for a million. Bankers use these abbreviations also, but watch out, in the metric system, the lone capital M stands for mega, like a million. In metric, for a thousand you would add a non capitalized k, for kilo. Who wants to be a MMillionaire?

Confusing? well, I prefer by far the BTU/h abbreviation, because it makes it clear we are talking about a rate: a total quantity of BTU clearly divided by a total number of hours.

In the original question, did you mean BTU as a rate or as a quantity? Any how, MBH is clearly a rate.

Am I still helping?

It all gets very confusing when talking about electric power, because a kilowatthour, kWh, is not at all a measure of rate but a measure of quantity. You'll notice that it is not abbreviated as kW/h nor is it ever spoken of as a kilowatt per hour, this would make no sense whatsoever since the watt itself is already a unit of rate ( one watt is the rate at which a joule is consumed in a second 1 W = 1 J/s joule per second)

To get a unit of quantity in order to establish your electric bill, you'll need to de-rate the W unit by multiplying it by a unit of time, the hour. As such, a 100 W light bulb, if left on for 10 hour will have burned 100Wx10h or 1000Wh, AKA 1kWh. For the same difference, light bulb manufacturers could rate their bulbs in BTU per hour. Our 100 W bulb would now be about a 340 BTU/h bulb. If it had been left on for 10 hours, it would have burned 3400 BTU or 3.4 MBTU and it would be so easy to compare electric rates with gas rates.

Actually, there would be an argument for converting everything to joules because it fits so nicely in the SI units, without conversion factors, 1 J = 1 Nm (the newton*meter, the same unit for torque) Oooh, I can see the single equation that controls the whole universe... It's the brain cramp you mentioned, Eric.

Thanks for reading.

Christian Egli

It's Friday again, and I've got plenty of coffee

I'll side with Mike T. and kf on that one. I think you can get away talking only about a change but it gives no detail about how the heat transfer occurs. I know it does not matter to the test question, but a student who gives you the detail should get extra points. To increase the temperature of your pound of water, you need to add the BTU, to lower the temperature, you need to remove the BTU.

So requiring a BTU to raise the temperature is not only correct, it gives the additional information. It thus warrants a bonus. What would also be correct is to say a BTU is released when lowering the temperature of the water.

But saying that a BTU is required to lower the temperature would not be correct, you need to get rid of the BTU, not keep it, and you are certainly not going to want to buy a BTU that you need removed, neither would you want to give a bonus point.

I agree that all of this is only a matter of convention, we generally regard the BTU going into the water as a positive value. What is important is to all be on the same page at the same time. It is the same thing that happens when you sit down with your loan officer, you define by convention which way the money will flow between the two of you and who will be the debtor and who will be the creditor, and I don't think your banker will agree that it does not matter at all which way the money goes.

Do you give bonus points for semantics?

The BTU is a unit for a bucket of energy. Count how many buckets you burn in an hour and you get a rate, the BTU per hour, which is confusingly abbreviated in many ways, from just BTU to BTUH, BTUHR, BTU/h, BTU/hr, BH... If you have a 1000 of these, you add the M in front and MM for a million. Bankers use these abbreviations also, but watch out, in the metric system, the lone capital M stands for mega, like a million. In metric, for a thousand you would add a non capitalized k, for kilo. Who wants to be a MMillionaire?

Confusing? well, I prefer by far the BTU/h abbreviation, because it makes it clear we are talking about a rate: a total quantity of BTU clearly divided by a total number of hours.

In the original question, did you mean BTU as a rate or as a quantity? Any how, MBH is clearly a rate.

Am I still helping?

It all gets very confusing when talking about electric power, because a kilowatthour, kWh, is not at all a measure of rate but a measure of quantity. You'll notice that it is not abbreviated as kW/h nor is it ever spoken of as a kilowatt per hour, this would make no sense whatsoever since the watt itself is already a unit of rate ( one watt is the rate at which a joule is consumed in a second 1 W = 1 J/s joule per second)

To get a unit of quantity in order to establish your electric bill, you'll need to de-rate the W unit by multiplying it by a unit of time, the hour. As such, a 100 W light bulb, if left on for 10 hour will have burned 100Wx10h or 1000Wh, AKA 1kWh. For the same difference, light bulb manufacturers could rate their bulbs in BTU per hour. Our 100 W bulb would now be about a 340 BTU/h bulb. If it had been left on for 10 hours, it would have burned 3400 BTU or 3.4 MBTU and it would be so easy to compare electric rates with gas rates.

Actually, there would be an argument for converting everything to joules because it fits so nicely in the SI units, without conversion factors, 1 J = 1 Nm (the newton*meter, the same unit for torque) Oooh, I can see the single equation that controls the whole universe... It's the brain cramp you mentioned, Eric.

Thanks for reading.

Brad White_2

Thank you

Professor! Well explained. BTU is a bucket, BTU/h is a rate. Life does not get better than that.