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Hello... first post here so take it easy on me.

From the Book: "Aquatic Systems Engineering: Devices and How They Function, Selection Installation Operation" by P.R. Escobal

In the section about heat loss (section 12.9) the author gives the basic conductivity equation in the form:

Q = (A * 2.54) * k * T * time/d

Where:

Q = calories

A = Area in square inches (using 2.54 to convert to centimeters)

k = cal cm/sec in Celcius

T = Temperature differential between Hot and Cold side of panel in degrees Celcius

d = thickness in inches

So using an example of

A = 3505 square inches

k = .002 (thermal conductivity of glass)

T = 4.44 degress celcious (8 degrees F)

t = 1 second

d = .375 inches

Q = 3505 * 2.54 * .002 * 4.44 * (1/.375)

Q = 251.85

So far so good. The result is consistent with any other form of the conductivity equation I find. I tried a few different variation and got the same result.

So here is where I am confused. The equation outputs 251.85 calories. I presume that because I chose 1 second as the TIME, then thermal loss to the aquarium is 251.84 calories/sec?

1 Watt = 4.184 calories/sec

So 251.84 calories/sec = ~1054 Watts

HOWEVER:

The author indicates that to convert the result to Watts, you must multiply Q by 0.23889, giving a result of 60.16 Watts!

If I use the conductivity equation in the form found here:

http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/heatcond.html

I get the result of 1055.5 Watts or 3601.62 btu/h There is no "time" input. I would assume that it is an HOUR based on the BTU/h form fields.

That exactly matches the results from the authors equation before his conversion to Watts.

What am I missing here? Where is the authors multiplier to get Watts coming from?

Oddly, if I divide the BTU/h result by 60 I get the authors Wattage number. But I don't understand where the factor of 60 is coming from. The authors equation is in calories/sec and the reference equation from the website is in btu/h both give the same answer that is a factor of 60 from the authors Wattage.

Somebody please enlighten me!

From the Book: "Aquatic Systems Engineering: Devices and How They Function, Selection Installation Operation" by P.R. Escobal

In the section about heat loss (section 12.9) the author gives the basic conductivity equation in the form:

Q = (A * 2.54) * k * T * time/d

Where:

Q = calories

A = Area in square inches (using 2.54 to convert to centimeters)

k = cal cm/sec in Celcius

T = Temperature differential between Hot and Cold side of panel in degrees Celcius

d = thickness in inches

So using an example of

A = 3505 square inches

k = .002 (thermal conductivity of glass)

T = 4.44 degress celcious (8 degrees F)

t = 1 second

d = .375 inches

Q = 3505 * 2.54 * .002 * 4.44 * (1/.375)

Q = 251.85

So far so good. The result is consistent with any other form of the conductivity equation I find. I tried a few different variation and got the same result.

So here is where I am confused. The equation outputs 251.85 calories. I presume that because I chose 1 second as the TIME, then thermal loss to the aquarium is 251.84 calories/sec?

1 Watt = 4.184 calories/sec

So 251.84 calories/sec = ~1054 Watts

HOWEVER:

The author indicates that to convert the result to Watts, you must multiply Q by 0.23889, giving a result of 60.16 Watts!

If I use the conductivity equation in the form found here:

http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/heatcond.html

I get the result of 1055.5 Watts or 3601.62 btu/h There is no "time" input. I would assume that it is an HOUR based on the BTU/h form fields.

That exactly matches the results from the authors equation before his conversion to Watts.

What am I missing here? Where is the authors multiplier to get Watts coming from?

Oddly, if I divide the BTU/h result by 60 I get the authors Wattage number. But I don't understand where the factor of 60 is coming from. The authors equation is in calories/sec and the reference equation from the website is in btu/h both give the same answer that is a factor of 60 from the authors Wattage.

Somebody please enlighten me!

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