Help needed with heat loss calculation from a steam pipe please

In summary, the speaker is an entrepreneur in South Africa who has the rights to a new insulating coating. They have done test applications with promising results, but are struggling to determine the potential energy savings and complete a feasibility study. They are seeking help in understanding and calculating the formula for conductive heat loss and heat loss through radiation. They also mention the need to know the steam temperature and thermal conductivity of the coating in order to quantify the energy savings.
  • #1
physicsidiott
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I’m an entrepreneur in South Africa with the rights to a type of insulating coating. It’s new on the market here and no real research and development has been done on the coating to determine how much energy it can save. I’m a marketer and I don’t have the educational background to answer this question that I am faced with almost every day. I have done test applications for some large factories with promising results that show substantial decreases in surface temperatures for only a 1mm thick application. I was hoping that the engineers at these factories would be able to calculate the possible energy savings that the coating would give them but it seems that they are as inadequate as I am. This is particularly frustrating as this is paramount to completing a feasibility study so that these factories can place the orders for which I have been working so hard to achieve. I’m hoping that someone on the world wide web would be willing to help me speed up this process.

I believe that I can use the formula for conductive heat loss for a pipe or cylinder which is:
q = 2 π k (to - ti) / ln(ro/ri)
It’s a 6” diameter steel steam pipe with an uncoated surface temperature of 130 °C
After coating the pipe the temperature was reduced to 108 °C
I think the thermal conductivity of the steel pipe is 68 W/mK (should K be converted to °C?...and how would I do that?)
In South Africa we work in Watts and Kilowatts and °C and not Btu’s, °F or K.
I need to see how this formula works in a step-by-step calculation so that a ‘dumb ass’ like myself can understand it, explain it and use it again in future.

I’m also wondering how heat loss through radiation would come into the equation here?
This formula has caused me even bigger headaches which is:
P = ε б A (T⁴ - T⁴c)
It uses the Stefan Boltzmann constant which is: б = 5.6703 × 10⁻⁸ watt / m² K⁴
The emissivity of the steel pipe is 0.32 ...or is it 0.95? And what should the emissivity of the coating be...I would imagine, much closer to 0.1?
This formula will also require a step-by-step calculation in order for me to understand it.

If anybody on this forum is able to help and has the time to do so, the input will be greatly appreciated.
 
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  • #2
This really can't be quantified unless we have an idea of the steam temperature within the pipe and the thermal conductivity of the coating.
 

1. How do you calculate heat loss from a steam pipe?

To calculate heat loss from a steam pipe, you need to know the surface area of the pipe, the temperature difference between the steam inside the pipe and the environment, and the thermal conductivity of the pipe material. You can then use the following formula: Heat loss = Surface area x Temperature difference x Thermal conductivity.

2. What factors can affect heat loss from a steam pipe?

Several factors can affect heat loss from a steam pipe, including the surface area of the pipe, the temperature difference between the steam and the environment, the thermal conductivity of the pipe material, and the surrounding temperature and humidity. Insulation, pipe size, and pipe orientation can also play a role in heat loss.

3. How can you reduce heat loss from a steam pipe?

There are several ways to reduce heat loss from a steam pipe. One way is to insulate the pipe with materials that have low thermal conductivity. Another way is to reduce the surface area of the pipe by using smaller pipes or wrapping the pipe in a spiral pattern. You can also reduce heat loss by maintaining a higher temperature of the steam inside the pipe or by controlling the surrounding temperature and humidity.

4. What are the consequences of heat loss from a steam pipe?

Heat loss from a steam pipe can result in a decrease in the efficiency of the steam system, leading to higher energy costs. It can also cause condensation and corrosion on the pipe, leading to potential safety hazards and maintenance issues. In extreme cases, heat loss can result in a loss of pressure and flow within the steam system.

5. Can computer software be used to calculate heat loss from a steam pipe?

Yes, there are several computer software programs available that can help with calculating heat loss from a steam pipe. These programs take into account various factors such as pipe size, insulation, and environmental conditions to provide a more accurate calculation of heat loss. However, it is important to note that these programs should be used as a guide and the results should be verified through physical measurements.

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