1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B KWh versus kW times Time

  1. Mar 16, 2017 #1
    Say I have a 60W device.

    I know running for one hour it uses 60 W x 3600 s = 216 kJ of energy.

    Does that mean it uses 216 kWh of energy?

    Or does kWh means 60 W x 1 hour = 60 kWh?

    I am confused because the units in 60 kWh is not in their simplified terms.

    More specifically, this pertains to a project that I am working on.
    From experimental values, I found that with X kg/s of water flowing through the heat exchanger and some temperature increase, I can find the power of the heat exchanger in kW.
    I would like to provide the values in BTU since that is just what people still use in the States.
    I realized BTU is an energy unit, not power, and 1 kWh = 3412 BTU.
    So I need to convert kW to kWh.
     
  2. jcsd
  3. Mar 16, 2017 #2

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    you have a k in there that you shouldn't

    60 W x 1 hour = 60 Wh

    so going from what I wrote above

    a 1kW heater running for 1 hour = 1kWh
     
  4. Mar 16, 2017 #3
    Alright, thanks! I thought kWh is basically kJ. I guess kWh needs to convert by a factor of 3600 before it becomes kJ then.
     
  5. Mar 16, 2017 #4

    CWatters

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes that's possible/correct.

    I believe they actually use BTU/h (BTU per hour) but the "h" is sometimes omitted (bad practice).

    So you just need to use..

    1 kW = 3412 BTU/hr
     
  6. Mar 17, 2017 #5
    One thing worth remembering: a Joule is a Wattsecond.
    So 3600 J = 3600 W s = 1 W h = 0.001 kW h .
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: KWh versus kW times Time
  1. KW and kWh (Replies: 11)

Loading...