humidity?

it's been hot, humid, and otherwise disgusting around here lately. the car does perform a little differently in these conditions. i can still get it to glide once it's been running for a bit- usually my final stretches between work and home are gliding. don't know if you can attribute it to the temp or the humidity.

 

I have access to the Prius Simulator beta and increasing the humidity as an independent variable has a small effect on the MPG but it is quite minor tenths and hundredths of a MPG. The Barometric pressure is a larger variable. I don't know how these may influence each other. As an aside I get quite cranky in humid weather and that is why I no longer live in Ohio. Here is the Web site : http://privatenrg.com/#Nomograph

 

Are you asking an aerodynamics question or an electronics question?

If it is aerodynamics: YES.
Temperature and humidity affect air density. At a given altitude, the <strike>higher</strike> lower the humidity, the higher the air density, the higher the drag.
Drag = 0.5 x (air density) x (speed^3) x (frontal area of car) x (drag coefficient)

If it is an electronics question: I doubt it . . .
Anything short of arcing and sparking from excessive humidity, there really are no electrical/humidity problems except the possibility of problems associated with corrosion - which can be exacerbated by high humidity.
The cooling effect, or lack thereof, in which humidity plays on batteries and consequently if the battery charge is affected would also be minuscule in a Prius.


EDITED for <strike>higher</strike> lower mistake.

 

Actually, humid air is less dense than dry air. Water molecules are lighter than nitrogen or oxygen. Water molecules are made of hydrogen and oxygen. Dry air is 79% nitrogen which is significantly more dense. Each water molecule displaces a nitrogen molecule or oxygen molecule from a given volume of air.

 

<div class='quotetop'>QUOTE(Sufferin' Prius Envy @ Jun 1 2006, 02:22 PM) [snapback]263883[/snapback]</div>

Where does "the higher the humidity, the higher the air density" come from?

My assumption is...
N2=28g/mol, O2=32g/mol, therefore dry air=28.8g/mol. And H2O=1*2+16=18g/mol.
If the air does include more H2O, it becomes low density.

Ken@Japan

 

OOPS :mellow: My bad.
I wrote "density" twice, but when I changed the first density to humidity I failed to change the corosponding high to low.
Glad to see we have some smart people here on PriusChat who don't believe everything they read.

Isn't that how NASA crashed a couple of space probes? Failing to insert a negative sign on one and not converting all the numbers to metric on the other.