Calculating Heat Loss in a Home Heating System

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Discussion Overview

The discussion revolves around calculating heat loss in a home heating system, specifically focusing on a closed loop pipe system where hot water circulates. Participants explore the relationship between temperature change, flow rate, and heat loss, considering both theoretical and practical aspects of the calculation.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant seeks to calculate heat loss based on initial and final temperatures of water in a pipe, along with the flow rate.
  • Another participant suggests using the formula for power, indicating that the temperature change and mass flow rate are essential for determining the power delivered to the house.
  • A different participant mentions the formula for Btu, emphasizing the importance of accurate flow and temperature measurements, and provides a conversion for flow rates from gallons per minute to pounds per hour.
  • There is a light-hearted exchange regarding the use of imperial versus metric units, with participants sharing their experiences with different measurement systems.

Areas of Agreement / Disagreement

Participants express varying approaches to the calculation, with some focusing on different units and methods. There is no consensus on a single method or formula to use, and the discussion remains unresolved regarding the best approach to calculate heat loss.

Contextual Notes

Participants highlight the need for accurate measurements of flow and temperature, as well as the potential complexity in converting between different units of measurement. The discussion does not resolve the mathematical steps required for the calculations.

Who May Find This Useful

Individuals interested in home heating systems, engineers, and those studying thermodynamics or fluid mechanics may find this discussion relevant.

marmulak
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Hi every body
This question came to my mind when I was looking at a Home Heating System.
The system is a closed loop. In this closed loop of pipe hot water is flowing.
I know the temperature of the pipe in the beginning and at the end of the pipe.
I also know the flow rate of water in the pipe.
I want to calculate the heat loss in this circulating system.
For example at the beginning of the pipe I have the temperature of 50 centigrade degree, and at the end of the pipe this temperature becomes 40 degrees, if the water flows at the rate of 8 ft/m, then how much is the heat loss in this system.
I am an electronics engineer and I don't know how to calculate this.
Thanks for your help.
 
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This takes me back to the Callender and Barnes experiment we did in the V1 form. If you know the temperature change and the rate of mass flow then that will tell you the Power being delivered to the house.

Power (in Watts) = Temperature Change X Specific Heat of Water X kg of water flow per second

Nots: it's not the speed of the water that counts - it's how many kg per second are going through. You will need to get out a bucket and a stopwatch! Actually, if you know the speed and the diameter of the pipe, you could work out the volume per second - which gives the mass etc. etc. Is the speed you refer to the speed of water in the main output of the boiler?

You can substitute imperial units and still get the answer. (SI rules in UK and most of Science and you would need an answer in kW, in the end. no?)
 
Your answer lies in the formula for Btu. 1 degree F x 1Lb of water= 1 btu.
T1-T2 x flow in Lbs/ hr will yield Btuh.
The tough part is 1) accurate flow measurement and 2) accurate temp measurement.
Remember to convert Gpm to Gph by multiplying by 8.33 ( Lbs/ gallons)
Sorry for the imperical units, its how I learned it and I'm too old to change.
 
All that remains is to count the cost in Pounds Shillings and Pence.
Can you really be that much older than I?
I did the Imperial thing at School - 32 ft/sec/sec and all that but it was more than 50 years ago.
 

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