BTU's

[LarryN 4106]

I am going to pull my factory heat system out of my 4106. I have already bought one 30,000 auxilary heater with fan and am going to buy another. That would be 60,000 btu's plus the heat output of the defroster coil which, of course, I ain't touching. I am wondering if I really need three of the auxiliary units mainly due to my floor layout, but I am curious as to the physics of just how many btuh's can be removed from a 8v71 rolling down the highway. The factory heat is fine, so obviously, the engine creates enough heat to heat the innards of the coach. I am planning on using 3/4" pipe, btw.

[buswarrior]

In calculating these things, remember that the stock HVAC was drawing in large quantities of outside air, and having to heat it.

It takes a lot less BTU to keep it warm inside if you ony heat the inside air.

Who remembers the heat rejection of an 8V71?

happy coahing!
buswarrior

[Nick Badame Refrig/ACC]

Hi BW,

Who remembers the heat rejection of an 8V71?

A little less then a 8V92....


Larry, BW is correct, you may not need that much but, you can never have too much heat unless it's summertime!

Looks like you are on the right track.

Good Luck
Nick-

[LarryN 4106]

Yes, I did forget about the O.A. component. Thanks.

[TomC]

To give you an idea of the difference-heaters and air conditioners are rated at BTU's per hour.  Heat rejection for engines through the radiator and transmission heat outputs are rated at BTU's per minute!  For instance, an Allison transmission at stall (full throttle standing still in gear) is putting out something like 22,000btu's per minute.  Going down the road only maybe 2500btu's per minute (that's still 150,000btu's per hour!).  I wouldn't worry too much about those small heat exchangers for heating the interior of the bus.  They are quite small compared to the original heating coils.  Good Luck, TomC