Calculate work needed to evaporate water

In summary, the energy required to evaporate water from clothes is the mass of water multiplied by the latent heat of vaporization, and sensible heat can be included.
  • #1
pikiche
3
0
how would you calculate the work needed to evaporate water from washed clothes, if the clothes r in a well isolated room with temperature of 75F
help pleasezzz
 
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  • #2
The energy required is the mass of water multiplied by the laten heat of vaporization:

Q = m [itex]h_{fg}[/itex]

Q = energy required
m = mass of water
[itex]h_{fg}[/itex] = latent heat of vaporization

If you want to estimate how long it will take to evaporate naturally, search for "swimming pool evaporation equation."
 
  • #3
edgepflow said:
The energy required is the mass of water multiplied by the laten heat of vaporization:

Q = m [itex]h_{fg}[/itex]

Q = energy required
m = mass of water
[itex]h_{fg}[/itex] = latent heat of vaporization

If you want to estimate how long it will take to evaporate naturally, search for "swimming pool evaporation equation."

No, he said it starts off at 75 degrees. Surely that has to be taken into account. I mean, it CAN'T take the same amount of energy to evaporate water at 1 degree above freezing as to do it to water at 1 degree below boiling.
 
  • #4
phinds said:
No, he said it starts off at 75 degrees. Surely that has to be taken into account. I mean, it CAN'T take the same amount of energy to evaporate water at 1 degree above freezing as to do it to water at 1 degree below boiling.
The sensible heat can be included as follows:

q = m [itex]h_{fg}[/itex] + m [itex]c_{p}[/itex][itex] \Delta[/itex]T

cp = specific heat
[itex]\Delta[/itex]T = temperature change = 212 F - 75F
 
  • #5
thank you for the reply guys, see what I am trying to do is actually calculate how much money would u save from line drying clothes vs using an electric dryer. knowing that u have an ac/ heater at the houseto keep the temperature at 75. so i was thinking that after calculating the heat to evaporate the water from the clothes wouldn't be the same amount of energy that the ac/heater has to apply to maintain the temperature at 75?
 

What is the definition of work in this context?

In this context, work is defined as the amount of energy required to change the state of water from liquid to gas, also known as evaporation.

What is the formula for calculating the work needed to evaporate water?

The formula for calculating work needed to evaporate water is W = m * L, where W is the work in joules, m is the mass of water in kilograms, and L is the latent heat of vaporization in joules per kilogram.

How do I determine the mass of water for this calculation?

The mass of water can be determined by measuring the volume of the water in milliliters and using the density of water, which is 1 g/mL, to convert to mass in kilograms.

What is the latent heat of vaporization for water?

The latent heat of vaporization for water is 2,260 joules per gram, or 2,260,000 joules per kilogram.

Can this calculation be applied to other liquids?

Yes, this calculation can be applied to other liquids as long as the specific latent heat of vaporization for that liquid is known.

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