Measuring Heating Power at High Temperatures

In summary, the conversation discusses how to measure the heating power of a piece of brass material at high temperature (around 300 Celsius). It is suggested that for low temperatures, the heating power can be measured by circulating water and measuring its temperature change. However, for high temperatures, a different fluid like oil may be needed. The conversation also touches on the concept of heating power and how it can be calculated using the mass and specific heat of the metal. Suggestions are given for how to measure the heating power experimentally, including using a different fluid with a higher boiling point and starting with cold water.
  • #1
acoustic
11
0
Dear all,

I have a piece of brass material at high temperature (around 300 Celsius) and I would like to know how can I measure the heating power stored by this piece. the piece is designed in a way that we can flow a fluid through it.

For low temperatures ( below 100 Celsius) it is maybe possible to measure the heating power by circulating water and measuring the input and the output temperatures of it. but for high temperatures (above 100 Celsius boiling temperature of water) maybe the fluid should be changed to an oil or some other fluid. So what do you think of that.

Another question:

If the piece of brass is at 60 Celsius and I am using water to measure the heating power. Shall I flow water at around 60 degrees or is it ok to flow water at ambient temperature?Thank you in advance for your contributions
 
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  • #2
What exactly do you mean by "heating power"?
 
  • #3
I believe there is something somewhere that will give you the amount of heat contained within your brass pipe if you know the dimensions, composition, ETC. I just don't know where to find it.
 
  • #4
diazona said:
What exactly do you mean by "heating power"?

Thank you diazona for your interest.

I will try to explain you what I mean by heating power:

Let's consider that the temperature of my piece is equal to 50 °C. So there is an energy stored in this piece. If we circulate chilled water at 10 °C through the piece this water will come out at higher temperature let's say 30 °C. and hence the temperature of the brass piece will decrease to reach its equilibrum temperature.

The heating power in this case is the sensible heat recuperated by the water = water flow multiplied by the specific heat of water multiplied by the difference of temperature ( 20°C in our case).

but my question is how to measure the "heating power" at piece's temperature above 100 °C.
 
  • #5
Drakkith said:
I believe there is something somewhere that will give you the amount of heat contained within your brass pipe if you know the dimensions, composition, ETC. I just don't know where to find it.

Thank you Drakkith for your answer.
I liked very much " something somewhere" :smile:
but seriously, the problem here is that the dimensions of my piece are not regular I only know its weight.
I will try to look for this something :smile:

Thank you again for your contribution
 
  • #6
acoustic said:
Thank you diazona for your interest.

I will try to explain you what I mean by heating power:

Let's consider that the temperature of my piece is equal to 50 °C. So there is an energy stored in this piece. If we circulate chilled water at 10 °C through the piece this water will come out at higher temperature let's say 30 °C. and hence the temperature of the brass piece will decrease to reach its equilibrum temperature.

The heating power in this case is the sensible heat recuperated by the water = water flow multiplied by the specific heat of water multiplied by the difference of temperature ( 20°C in our case).

but my question is how to measure the "heating power" at piece's temperature above 100 °C.
Ah, so it sounds like what you're looking for is the amount of thermal energy lost by the metal as it comes to thermal equilibrium with a certain amount of water at a certain temperature. This quantity will, of course, depend on how much water you circulate and what temperature it enters at.

You can calculate the amount of thermal energy that a certain amount of metal loses as it goes through a given temperature change using the formula
[tex]\Delta Q = m C \Delta T[/tex]
where m is the mass of the piece of metal, C is the metal's specific heat capacity (you can look up the value for copper), and ΔT is of course the temperature change. So if you know the final temperature of the metal (or equivalently, of the water), you can just plug numbers into that equation.

If you don't know the final temperature, but you do know the initial temperature of the water, then it takes a bit of algebra. You can write
[tex]m_\text{water} C_\text{water} (T_f - T_{i\text{,water}) + m_\text{metal} C_\text{metal} (T_f - T_{i\text{,metal}) = 0[/tex]
which just says that the heat lost by the metal must equal the heat gained by the water. You can solve for [itex]T_f[/itex] given numerical values for all the other variables.

If you would rather make a physical measurement, consider these points: you can use water as long as the water is not in contact with the metal long enough to raise its temperature up to its boiling point. Using a large amount of water will extend the time it takes for the water to boil; also, keeping the water at high pressure in a sealed system of pipes would raise its boiling point. Alternatively, you could choose a different fluid with a large specific heat capacity and/or a higher boiling point. I'm sure there are many possibilities out there - 300°C is not a particularly high temperature.

There is no reason you would need to use water (or whatever fluid you choose) at any particular temperature like 60°C. It can start out at any temperature. In fact, if you are concerned about boiling, it's probably advantageous to start with the water as cold as possible without being frozen (so, just above 0°C), since that maximizes the amount of heat it can absorb without boiling.
 
Last edited:
  • #7
Thank you diazona for your reply.
Actually I want to measure experimentally the thermal energy. So I think I will try to find a kind of oil which boiling temperature is higher than 300 °C. I should also think about how to pump this oil through the brass piece (I don't have now any pump).

I used to measure the "cooling power" which is the heat supplied by an electric heater to the brass piece (which is at -40 °C) to increase its temperature to the thermal equilibrum temperature. but its my first time to measure the heating power.

Thank you once more
 
  • #8
acoustic said:
Thank you diazona for your reply.
Actually I want to measure experimentally the thermal energy. So I think I will try to find a kind of oil which boiling temperature is higher than 300 °C. I should also think about how to pump this oil through the brass piece (I don't have now any pump).

I used to measure the "cooling power" which is the heat supplied by an electric heater to the brass piece (which is at -40 °C) to increase its temperature to the thermal equilibrum temperature. but its my first time to measure the heating power.

Thank you once more

You can drop the brass in a 1KG of water, let the evaporation process to take it's place, wheigh the water and see how much of it has evaporated. So you get a value of energy by knowing how much energy was given by the brass to evaporate the grams of water plus the heat that the remaining water reached (usually below 100'C, as water boils locally around the brass and the rest just warms a bit)
 
  • #9
Lok said:
You can drop the brass in a 1KG of water, let the evaporation process to take it's place, wheigh the water and see how much of it has evaporated. So you get a value of energy by knowing how much energy was given by the brass to evaporate the grams of water plus the heat that the remaining water reached (usually below 100'C, as water boils locally around the brass and the rest just warms a bit)

Hi Lok

Thank you for your reply,
it seems that your idea is very interesting but unfortunately, in my experiments it's impossible to realize because my piece of brass is a part of an experimental device and can't be removed.

Thank you again for your idea
 
  • #10
acoustic said:
Thank you for your reply,
it seems that your idea is very interesting but unfortunately, in my experiments it's impossible to realize because my piece of brass is a part of an experimental device and can't be removed.

Most oils don't boil at 300 C, even vegetable oils. They just degrade a very tiny amount, and considering that it won't stay at that temperature for long I recommend the cheapest motor oil you can find, or only in case of last choice saturated vegetable oil ( as it might be in liquid form only at 50 or above).

Motor oil can be and has been used for temp of 800'C (and above) Steel quenching with ease so for a short duration 300'C it will be fine.
 

1. How do I measure the heating power of a system?

In order to measure the heating power of a system, you will need to use a device called a calorimeter. This device measures the amount of heat released or absorbed by a substance. You can use this information to calculate the heating power of the system.

2. What units are typically used to measure heating power?

The most commonly used unit to measure heating power is the watt (W). However, depending on the size and capacity of the system, other units such as kilowatts (kW) or British Thermal Units (BTUs) may also be used.

3. How do I calculate the heating power of a gas heating system?

To calculate the heating power of a gas heating system, you will need to know the rate of gas consumption (usually measured in cubic feet per hour) and the efficiency of the system. The formula for calculating heating power is: power = gas consumption rate x efficiency.

4. Can I measure heating power without using a device?

No, it is not possible to accurately measure heating power without using a device such as a calorimeter. This is because heat is an invisible form of energy and cannot be measured directly without specialized equipment.

5. How can I ensure accurate measurements of heating power?

To ensure accurate measurements of heating power, it is important to use high-quality equipment and follow proper measurement procedures. This includes calibrating the equipment regularly, controlling for external factors that may affect the measurements, and taking multiple readings to ensure consistency.

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