Measuring heat/energy injected into an asphalt storage tank

[hcw]

thread391-125441
We are trying to come up with a way to accurately measure the amount of heat/energy that is expended in heating asphalt tanks within our bulk terminal, so that we can account and bill our various customers for heat. We are heating the tanks with a thermoil system consisting of one hot oil heater connected to circulation pipeline loops in each tank. Has anyone had experience with this, or can possibly direct me to a company that provides a solution. We are thinking that we can meter the flow through each tank as well as the input and outflow temperatures which would be sent to and recorded by a computing device that would also calculate the heat (loss?)to arrive at a consumption amount. We thank you in advance for your ideas and input!

 

[IRstuff]

What more would you need beyond:

flow*density*heat_capacity*temperature_change = power

TTFN

FAQ731-376

 

[CH5OH]

since you're intrested in distributing the cost,you don't need to calculate the heat,you just intrested in the distribution rate
since the thermal oil is heated by means of burning fuel(I assume),and the outlet from the boiler goes to all the different billing points, you only need to know the flows.
For a billing point, the cost can be calculated:
(installation cost + running cost + fuel cost)/invoice billing point = sum off all billing points thermal oil flow / one billing point thermal oil flow

 

[hcw]

Thank you! But I beleive we need to account for the heat as well due to the fact that the temperature in an individual tank affects how much heat is absorbed from that particular circuit, and in addition, when you are heating several cold tanks, and perhaps a hot one (maintenence heat) the heat plant may not be able to keep up and so the hetar output temps can vary, which affects the downstream circuits as well. I believe your idea would work if all circuits would have the same heat absorbtion rate, and where the heater were able to always maintain its out flow to the same point. Thanks!

 

[IRstuff]

Then, you simply need to measure the inlet and outlet temperatures of the fluid, and do the above calculation in real-time.

The integral of that calculation over time will be the heating provided by your system.

TTFN

FAQ731-376

 

[chicopee]

IR Stuff, your equation should have the "mass rate" not "density"--power is the rate of doing work.

 

[IRstuff]

flow*density is mass rate, is it not?

TTFN

FAQ731-376

 

[ione]

hcw,

If I have understood your problem, you are not trying to evaluate the efficiency of your asphalt heating process, so you don't need to calculate the heat loss involved.
You know the flow and the temperature your hot oil must have to reach your goal (asphalt heated), so what matters here is how much you spend (fuel, electric energy) to obtain the required conditions for hot oil.