Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculate work needed to evaporate water

  1. Oct 23, 2011 #1
    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 plzzzz
     
  2. jcsd
  3. Oct 23, 2011 #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."
     
  4. Oct 23, 2011 #3

    phinds

    User Avatar
    Gold Member
    2016 Award

    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.
     
  5. Oct 23, 2011 #4
    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
     
  6. Oct 23, 2011 #5
    thank you for the reply guys, see what im 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 wouldnt be the same amount of energy that the ac/heater has to apply to maintain the temperature at 75?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Calculate work needed to evaporate water
  1. Water Evaporation Rate (Replies: 3)

Loading...