No thermostat?

[SPYDERLK]

Does it work the same with a heater core. Although the air is cooler on high speed,does it heat the car quicker or does the low air flow which is warmer heat the car faster. And how about the air conditioner on max and low speed.

Thats a hard one because some, and usually most, of the air coming thru the coil is fresh air. Already warmed air is leaving the car to make room for it. See the, at least partial, trade off? You are adding more heat [calories or BTU] per unit time to your space, but it is in the form of lower temperature at higher volume. When the air in the car is cold the hi fan is extemely more effective - and, i would think, less and less more effective than lo fan as the car warms.
larry
ps. missed AC part. It has some special considerations too. Later. gotta do something else right now.

 

[3RRL]

woodchuckie,
lol ... You have not been paying attention! You will have to stay after school and retake the final exam. I don't know about you guys, but I haven't done any calculus integrals or derivatives since like 1968.

 

[tallyho8]

Anyone who has ever been caught up in a traffic jam in bumper to bumper traffic on a hot day and has watched their temperature guage move to the red line as they wait almost motionless, knows that if they turn their heater on max temp and max fan speed, and open their windows, that it will cool their engine down fast at the expense of their own discomfort. It is worth the discomfort to avoid burning up your motor. Upon resuming normal speed you can turn off your heater and turn your a/c back on. If you try this with your heater on low fan speed, your temp guage may not even stop rising as I have had occasion to try this many times, so I say high air flow with less heat transfer will transfer more heat than low air flow with more heat transfer over a given period of time.

(Works for me)

 

[patrick_g]

On the water jacket/evaporation cooling system I am not too familiar but whats new?

Now for radiators should we be thinking crossflow or vertical tubes? ehh

Egon, cross flow or vertical means less and less as flow velocity increases. Thermal siphon aids low velocity vertical if the flow is bottom to top. High velocity water swamps out the differences.

Woodchuckie, If you are running your car's climate control in recirc mode then the fastest fan speed will give the best heating and cooling (with a proviso.) You will heat the car faster with max air flow but the high velocity air flow before the air coming out of the heater gets up to a satisfactory temp will not feel as comfortable as slower velocity air even though the temp in the car will rise faster. Good air flow supports evaporation of perspiration and aids the cooling effect of the A/C. A thermometer will show a faster drop if the fan is on high rather than low even though the air coming out of the vent is not as cold. In extremely humid circumstances slower air movement gives better dehumidification (per pass through the evaporator.) Humidity control is an important part of comfort.

If I missed anything my assistant, SPYDERLK will fill in the gaps.

If you are running in flow through ventilation mode then low fan speed can be a better deal as you will dehumidify better and lower the air temp more on the single pass than if you used hight fan. Even in recirc mode there is leakage (infiltration) and intentional makeup air so the air doesn't get stale (assuming no cigars.) In general for heating or cooling, recirc is way better performance. Flow though is good when the temp in the car is comfortable in flow though mode with little or no added heat or cooling and if you are having a tough time with fogging windows.

Pat

 

[tallyho8]

PS
This is also equivalent to the fan blade on your car going faster or slower while you are in that traffic jam. A slow moving blade pulls less air through the radiator but transfers more heat per cfm while a fan blade going faster moves more air through the radiator but transfering less heat per cfm, but I'll go with the faster moving fan blade to cool my motor off in this case anyday. No calculus integrals or derivatives, just plain ole fashioned experience.

 

[patrick_g]

When results are easily and correctly predicted by a casual observer it is not beneficial to invoke higher math. If concrete examples and simple thought experiments can lead someone to enlightenment, again higher math is not useful.

Pat

 

[Egon]

again higher math is not useful.

So now you tell me! Just after I got my shoes and socks off!

Just thinking of cooling systems brings back those memories of poplar fuzz and plugged radiators or frost and plugged radiators.

 

[3RRL]

How about those days when we drove around with water sacks hanging from our hoods for any long trip. At least out here in California. I can remember my Dad with his '49 Pontiac and the water sack when going on vacations. I didn't have to do that. I had a '55 and it ran pretty cool most of the time.

 

[woodchuckie]

Was the water sack for adding water to the radiator or what. I've never heard of that. Why was it hanging from the hood instead of being in the trunk or something.

 

[Egon]

They was for keeping the drinking water cool! cool