Figuring out the split for power dissipated?

In summary, the conversation is about building a humidifier and determining the amount of energy being dissipated into vaporizing the liquid and how much is being lost into the surrounding air. The speakers discuss using a heat balance equation and conducting experiments to find this information.
  • #1
Valkarie
1,100
0
Hello everyone!

This is my first post, I've done a bunch of searching on this forum which has yielded me quite positive results, so thank you for all of your posts which are a bloody gold mine of information.

Although I've gotten quite a lot of information that has been useful, I'm still having a problem with understanding what I have to do and was wondering if anyone could offer any input for this problem so I could wrap it together.

Basically, I am attempting to build a humidifier, which works by evaporating a liquid and releasing it into the room. The problem I am having is attempting to build an open loop model whose input (voltage -> power) can be related to the amount of mass of liquid which is being evaporated.

I am investigating how the power dissipated though a heating element relates to how the energy lost is split amongst different sources of losses. The heating element will boil some of the liquid it is in contact with, it will heat up some of the air around it, it will lose some energy via radiation. Its internal energy will also heat up and it will itself heat up as power is provided to it.

Lets assume we have a heating element made from a simple resistive metal, this heating element has a constant layer of a fluid on its surface (thin layer). The element will boil the layer of liquid and this will be carried away by a constant stream of air moving away from the element. Thus we can assume that the humidity, pressure and temperature of the air are constant within the control volume.

As the resistor dissipates energy, how do I know how much energy is being disspiated into vaporizing the liquid and how much will be lost into the surrounding air?

So far I have set up an experiment to find the temperature of the resistor in the operating conditions, and compare this with the theoretical temperature assuming no energy is dissipated and all energy goes into raising the internal energy of the resistor, then comparing the two to find the energy lost to the combination of the surroundings. But it all seems very shambles to me.

Can anyone point me in the right direction?
 
Engineering news on Phys.org
  • #2


Hi there,

Thank you for sharing your project with us on the forum. Building a humidifier can be a challenging task, but it sounds like you have done a lot of research and have a good understanding of the principles involved.

One approach you could take to determine the amount of energy being dissipated into vaporizing the liquid and how much is being lost into the surrounding air is to use a heat balance equation. This equation takes into account all the sources of energy (input) and losses (output) in a system. By setting up a control volume around your heating element and considering all the sources and losses of energy, you can use the heat balance equation to calculate the amount of energy being dissipated into vaporizing the liquid and the amount being lost into the surrounding air.

Another approach you could take is to conduct experiments using different input voltages and measuring the resulting temperature of the resistor and the amount of liquid being evaporated. By varying the input voltage and measuring the resulting changes, you can create a relationship between the input voltage (power) and the amount of liquid being evaporated. This can then be used to determine the amount of energy being dissipated into vaporizing the liquid.

I hope these suggestions are helpful to you. Good luck with your project!
 

1. How do you calculate the power dissipated in a circuit?

The power dissipated in a circuit can be calculated using the formula P = VI, where P is the power in watts, V is the voltage in volts, and I is the current in amperes.

2. What is the difference between power dissipated and power supplied in a circuit?

Power dissipated refers to the amount of energy that is converted to heat or other forms of energy in a circuit, while power supplied refers to the amount of energy that is provided by the source or battery in the circuit.

3. How can you determine the split of power dissipated among components in a circuit?

The split of power dissipated among components can be determined by calculating the power dissipated in each component using the formula P = VI, and then dividing it by the total power dissipated in the circuit and multiplying by 100% to get the percentage of power dissipated by each component.

4. What factors can affect the split of power dissipated in a circuit?

The split of power dissipated in a circuit can be affected by the resistance of the components, the voltage and current in the circuit, and the arrangement of the components (e.g. series or parallel).

5. How can you increase the power dissipated in a circuit?

The power dissipated in a circuit can be increased by increasing the voltage or current in the circuit, or by decreasing the resistance of the components in the circuit.

Similar threads

  • Materials and Chemical Engineering
Replies
23
Views
2K
Replies
15
Views
1K
Replies
14
Views
934
Replies
18
Views
3K
  • Thermodynamics
Replies
33
Views
1K
  • General Engineering
Replies
10
Views
3K
  • Introductory Physics Homework Help
Replies
8
Views
974
  • Electrical Engineering
Replies
23
Views
6K
Replies
32
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
22
Views
1K
Back
Top