victor e
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- Southern Cali
is this a trick question? or... does anyone know how many watts are a BTU?
stupid question
- Thread starter victor e
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A
a.wayne3@verizon.net
Guest
Re: stupid question
Actually it is not a trick question . As it is there are 3 btu`s/watt this is from a conversion table i found after reading your post
Actually it is not a trick question . As it is there are 3 btu`s/watt this is from a conversion table i found after reading your post
goldstar
Senior Member
- Location
- New Jersey
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- Electrical Contractor
Re: stupid question
That's interesting. Where did you find the table ? (Just curious).
That's interesting. Where did you find the table ? (Just curious).
- Location
- Massachusetts
pierre
Senior Member
- Location
- Westchester County, New York
Re: stupid question
1 watt= 3.412 Btu/hr
From Delmar's Standard Textbook of Electricity, 3rd edition
Pierre
1 watt= 3.412 Btu/hr
From Delmar's Standard Textbook of Electricity, 3rd edition
Pierre
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: stupid question
Victor
Energy can be converted to any other energy (with loss) it is just a way of doing the math of how much is required to convert it. and most is based on the electrical conversion. like 1 HP= 746 watts.
If we learn these little formulas we can understand how much energy a appliance might use and be able to convert it to how much power we might need for a given circuit.
Victor
Energy can be converted to any other energy (with loss) it is just a way of doing the math of how much is required to convert it. and most is based on the electrical conversion. like 1 HP= 746 watts.
If we learn these little formulas we can understand how much energy a appliance might use and be able to convert it to how much power we might need for a given circuit.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: stupid question
A word of caution on using 1HP=746W. - Do not use this for determing the incoming power requirements for horsepower rated motors. However you can use it to convert between KW and HP sized motors.
This formula is for a 100% efficient 100% power factor motor. Motors are rated based on output power, so without knowing the losses of the motor you can not calculate input power.
A word of caution on using 1HP=746W. - Do not use this for determing the incoming power requirements for horsepower rated motors. However you can use it to convert between KW and HP sized motors.
This formula is for a 100% efficient 100% power factor motor. Motors are rated based on output power, so without knowing the losses of the motor you can not calculate input power.
- Location
- Illinois
- Occupation
- retired electrician
G
Guest
Guest
Re: stupid question
There a several neat calculators on www.electrician.com
The calculators are Java linked so I can't post the links here. Go to that page and click on the Java button link for "CALCULATORS".
There a several neat calculators on www.electrician.com
The calculators are Java linked so I can't post the links here. Go to that page and click on the Java button link for "CALCULATORS".
Re: stupid question
"A ton of cooling", I wonder how many people understand this terminology and where it came from. I can imagine back in the old days some butcher going down to the ice house and having them deliver him a "ton of ice". What he was doing in reality was ordering what we refer to today as a "ton of refrigeration". 2000 lbs (1 ton). of pure water cooled to 32 degrees F. and then frozen solid will release 288,000 BTU of latent heat. As the ice re-absorbs the heat(melts) Divide this by 24hrs/day and you come to our present terminology of 12000 BTU/HR/24HR = 1 ton cooling . 12000 BTU per hr. for 24 hrs is equal to the amount of heat a ton of ice can absorbe. The ice temperature will start at 32 degrees F. and the final water temp (after the ice is melted) will be 32 degrees F.
1 BTU will raise (or lower) the temperature of 1 pound of pure water 1 degree F. (from and at 62degrees F.) The heat added to raise the water temp or to lower it is known as apparent heat (you can see it happening with a thermometer). You can see that where boiling starts (212F/100C) or freezing occurs (32F/0C) the thermometer will stop showing temperature rise or fall although heat transfer is still occuring. This is known as latent heat transfer. Latent heat is all that is considered in refrigeration or (non resistive) heating calculations. All other applied and consumed energy required to produce it is wasted and applies directly to the efficiency of the producing machine.
"A ton of cooling", I wonder how many people understand this terminology and where it came from. I can imagine back in the old days some butcher going down to the ice house and having them deliver him a "ton of ice". What he was doing in reality was ordering what we refer to today as a "ton of refrigeration". 2000 lbs (1 ton). of pure water cooled to 32 degrees F. and then frozen solid will release 288,000 BTU of latent heat. As the ice re-absorbs the heat(melts) Divide this by 24hrs/day and you come to our present terminology of 12000 BTU/HR/24HR = 1 ton cooling . 12000 BTU per hr. for 24 hrs is equal to the amount of heat a ton of ice can absorbe. The ice temperature will start at 32 degrees F. and the final water temp (after the ice is melted) will be 32 degrees F.
1 BTU will raise (or lower) the temperature of 1 pound of pure water 1 degree F. (from and at 62degrees F.) The heat added to raise the water temp or to lower it is known as apparent heat (you can see it happening with a thermometer). You can see that where boiling starts (212F/100C) or freezing occurs (32F/0C) the thermometer will stop showing temperature rise or fall although heat transfer is still occuring. This is known as latent heat transfer. Latent heat is all that is considered in refrigeration or (non resistive) heating calculations. All other applied and consumed energy required to produce it is wasted and applies directly to the efficiency of the producing machine.
Re: stupid question
THANKS GUYS,
AFTER I POSTED MY REQUEST,I,TOO, DID FURTHER RESEARCH. PIERRE WAS RIGHT ON THE MONEY WITH 3.413
FOR THE WATTS TO BTU RATIO.THIS IS BEING APPLIED TO AN ELECTRIC HOT WATER FORCED AIR SYSTEM.HOWEVER
THE WATTS/BTU WILL BE BASED ON THE TEMPATURE OF THE RETURNING WATER.BASED ON A 21 GALLON PER GALLON PER HOUR WITH COLD WATER AS THE SUPPLY,IT WOULD FOR 45OO WATTS,IT WOULD APROX. BE 18,000 BTU'S PER HOUR.
THANKS AGAIN,
RICK
THANKS GUYS,
AFTER I POSTED MY REQUEST,I,TOO, DID FURTHER RESEARCH. PIERRE WAS RIGHT ON THE MONEY WITH 3.413
FOR THE WATTS TO BTU RATIO.THIS IS BEING APPLIED TO AN ELECTRIC HOT WATER FORCED AIR SYSTEM.HOWEVER
THE WATTS/BTU WILL BE BASED ON THE TEMPATURE OF THE RETURNING WATER.BASED ON A 21 GALLON PER GALLON PER HOUR WITH COLD WATER AS THE SUPPLY,IT WOULD FOR 45OO WATTS,IT WOULD APROX. BE 18,000 BTU'S PER HOUR.
THANKS AGAIN,
RICK
Re: stupid question
Hillbilly;
I have often been perplexed by that "ton" designation in HVAC. Now that you spelled it out it simply makes sense. There are a lot of units, methods, terms used today that have a very clear, understandable basis. I find it enlightning to read of such things. Jim's caution about HP of motors is often hard for customers to accept. Thanks to each.
Chris
Hillbilly;
I have often been perplexed by that "ton" designation in HVAC. Now that you spelled it out it simply makes sense. There are a lot of units, methods, terms used today that have a very clear, understandable basis. I find it enlightning to read of such things. Jim's caution about HP of motors is often hard for customers to accept. Thanks to each.
Chris
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: stupid question
Assuming you meant that ?The conversion factor for Watts to (BTU/hr) will be based on the temperature of the returning water, I repeat that it will not. That is like saying that converting the distance your car traveled on a recent trip from units of ?miles? to units of ?kilometers? is based on the speed that the car was moving. But a mile is 1.61 km, no matter how fast the car moves. I think you mean to say one of two things, and both are true: (1) The amount of time it takes for a 4500 watt water heater to bring the temperature to the desired level will depend on the temperature of the returning water, or (2) The temperature that can be achieved by a 4500 watt water heater, with the water entering at a continuous flow rate of 21 gallons per hour, will depend on the temperature of the returning water.
No it won?t. But let?s start by being more careful with units of measure. Pierre?s answer was correct, but it did not correctly answer the original questions. The correct answer to the original questions (there were two) are, (1) ?Yes, it?s a trick question,? and (2) ?You cannot convert Watts to BTUs.? You can convert Watts to ?BTUs per hour,? and the conversion factor is as Pierre reported.
Assuming you meant that ?The conversion factor for Watts to (BTU/hr) will be based on the temperature of the returning water, I repeat that it will not. That is like saying that converting the distance your car traveled on a recent trip from units of ?miles? to units of ?kilometers? is based on the speed that the car was moving. But a mile is 1.61 km, no matter how fast the car moves. I think you mean to say one of two things, and both are true: (1) The amount of time it takes for a 4500 watt water heater to bring the temperature to the desired level will depend on the temperature of the returning water, or (2) The temperature that can be achieved by a 4500 watt water heater, with the water entering at a continuous flow rate of 21 gallons per hour, will depend on the temperature of the returning water.
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