Recent content by insightful

  1. I

    Why not use electricity directly instead of hydrogen

    I drive a Honda Insight and average 50 mpg...what's your point?
  2. I

    Why not use electricity directly instead of hydrogen

    No "range anxiety."
  3. I

    Why not use electricity directly instead of hydrogen

    What keeps H2 alive as a fuel is that 10 pounds can propel a fuel cell car 300 miles.
  4. I

    Pressure Loss in Parallel Pipes

    Yeah, I think if we had a defined system it would be clear. Say two atmospheric tanks, one with a water level 10m below the other. All parallel pipes between these tanks (with submerged entrances and exits) would have a head loss of 10m regardless of how many pipes you put in.
  5. I

    Pressure Loss in Parallel Pipes

    This seems to say that adding a resistor reduces the voltage (rather than the resistance).
  6. I

    Pressure Loss in Parallel Pipes

    Well, you're agreeing with #1 which is treating head losses the same as electrical resistances. Is that your contention?
  7. I

    Pressure Loss in Parallel Pipes

    But isn't head loss analogous to voltage drop? Parallel resistors have the same voltage drop. This assumes the parallel pipes have entrances that are all in the same vessel at the same elevation to each other, and the exits are all in another vessel at the same elevation to each other. I'd...
  8. I

    Is it practical to generate all US power by solar PV?

    Obviously, you meant per watt.
  9. I

    What is the function of a car muffler and how does it work?

    Many (most?) mufflers do not have packing: http://www.paraglidingteam.nl/PPGTechnics/sound%20and%20noise/Mufflers/1155795969.pdf
  10. I

    How Does a Heat Engine's Efficiency Affect Final Temperature and Work Output?

    First, clearly define variables: TA, TB, Tf, C=mc as above. Ta = variable temperature of tank A. Tb = variable temperature of tank B. QA = variable heat leaving tank A and entering engine. QB = variable heat leaving engine and entering tank B. W = variable work produced by engine. We know the...
  11. I

    How Does a Heat Engine's Efficiency Affect Final Temperature and Work Output?

    I, as I think you do, believe the final temperature for Part (b) is less than (TA+TB)/2. Have you solved Parts (b) and (c)?
  12. I

    Temperature change of Water after dropping a ball into it

    We assume that the ball and the water have the same initial temperature, right?
  13. I

    Steam produced heat transfer heat exchangers

    Use these numbers. How long would a single tube bundle be to give the required surface area?
  14. I

    Steam produced heat transfer heat exchangers

    A note on the "10% loss." Since we don't know exactly where the heat loss occurs, it is prudent to consider it to occur after the heat is transferred through the tubes. (Prudent because it results in 10% greater surface area and is thus more conservative.) That is why I would not incorporate...
  15. I

    Steam produced heat transfer heat exchangers

    Should this be kJ/hr??