Evaporative Cooling

[trinidefender]

I have to wonder if using the method of evaporative cooling could work in an F1 car. At work so don't really have time to do an explanation of it but would like to hear what others have to say about it. I suggest those who don't know what it is do some reading. To me it sounds like a viable concept, a bit heavier than a traditional water/glycol radiator but can be used to remove most of the cooling inlets and outlets.

[beelsebob]

I have to wonder if using the method of evaporative cooling could work in an F1 car. At work so don't really have time to do an explanation of it but would like to hear what others have to say about it. I suggest those who don't know what it is do some reading. To me it sounds like a viable concept, a bit heavier than a traditional water/glycol radiator but can be used to remove most of the cooling inlets and outlets.

The issue would be that you would have to finish on the weight limit. So you'd have to carry around all the fluid you're going to evaporate for the whole race. That's a big weight penalty.

[langwadt]

I have to wonder if using the method of evaporative cooling could work in an F1 car. At work so don't really have time to do an explanation of it but would like to hear what others have to say about it. I suggest those who don't know what it is do some reading. To me it sounds like a viable concept, a bit heavier than a traditional water/glycol radiator but can be used to remove most of the cooling inlets and outlets.

The issue would be that you would have to finish on the weight limit. So you'd have to carry around all the fluid you're going to evaporate for the whole race. That's a big weight penalty.

and illegal.

7.6 Cooling systems :
The cooling systems of the power unit, including that of the charge air, must not intentionally
make use of the latent heat of vaporisation of any fluid with the exception of fuel for the
normal purpose of combustion in the engine as described in Article 5.14.

[trinidefender]

beelsebob evaporative cooling is by no means a total loss system when used in engines. The steam is recycled and put under pressure raising it's boiling point and hence it is turned back into a liquid.

langwadt thats a shame, I wish designers were given more freedom when it comes to things like this. If they were able to perfect this science in F1 then maybe it could have been applied to road cars to reduce fuel consumption and pollution, so much for F1 driving automobile technology. This is assuming the system would provide a net efficiency gain over normal radiators of course.

[Lycoming]

I wish designers were given more freedom when it comes to things like this. If they were able to perfect this science in F1 then maybe it could have been applied to road cars to reduce fuel consumption and pollution, so much for F1 driving automobile technology. This is assuming the system would provide a net efficiency gain over normal radiators of course.

But then... why not develop the technology for road cars using road cars? Automakers face no regulation prohibiting this and have the budget to do so. Why use F1 to perfect the technology when automakers have much, much more freedom to road test cars?

beelsebob evaporative cooling is by no means a total loss system when used in engines. The steam is recycled and put under pressure raising it's boiling point and hence it is turned back into a liquid.

If you do that, then what's the advantage over a conventional system?

[trinidefender]

I wish designers were given more freedom when it comes to things like this. If they were able to perfect this science in F1 then maybe it could have been applied to road cars to reduce fuel consumption and pollution, so much for F1 driving automobile technology. This is assuming the system would provide a net efficiency gain over normal radiators of course.

But then... why not develop the technology for road cars using road cars? Automakers face no regulation prohibiting this and have the budget to do so. Why use F1 to perfect the technology when automakers have much, much more freedom to road test cars?

beelsebob evaporative cooling is by no means a total loss system when used in engines. The steam is recycled and put under pressure raising it's boiling point and hence it is turned back into a liquid.

If you do that, then what's the advantage over a conventional system?

The question shouldn't be why do it in F1 when road car manufacturers should use their budget. The question should be, why don't we give F1 engineers more freedom to design while making the fuel efficiency demands higher. That way it forces teams to be innovative instead of just spending massive budgets on small gains. F1 used to be a driving force behind technology for road cars, for everybody out there who is about to say no they weren't, many road cars had them first, I don't mean F1 cars had them first but I mean in many cases F1 cars pushed the development of these technologies. Things like turbocharging, electronic fuel injection, aerodynamics, fuel compounds, material research, especially the application and development of carbon fibre. The list is exhaustive.

To answer your second question is that evaporative cooling uses no or very small radiators therefore teams would be able to get rid much of the large inlet and outlet ducts allowing airflow to be used for downforce instead.

[gruntguru]

Do you have any more details of what you are proposing. To my mind if you are re-condensing the steam you will still need similar sized heat exchangers to cool the steam down.

[trinidefender]

Do you have any more details of what you are proposing. To my mind if you are re-condensing the steam you will still need similar sized heat exchangers to cool the steam down.

I'll try digging up some more info. Many designers were looking at them for fighter aircraft before and during the WWII period but the idea was largely dropped because the amount of piping needed made it vulnerable to enemy fire.

If you want to do your own research try googling engine evaporative cooling.

[trinidefender]

Here is a good link to read. http://www.freepatentsonline.com/5255635.html

Traditional head exchangers are not needed because the heat energy gets used as the water turns to steam.

[Lycoming]

But when you turn water to steam, you're not "using up" the energy because it still remains in the system. When you condense the steam back to water as you will inevitably need to do for a closed cycle system, all that heat you "used up" comes back into play. So I don't get how you can use smaller heat exchangers, because the power you need to dissipate doesn't change and as far as I can tell, the efficiency of dissipation into the free stream has in no way improved.

[trinidefender]

But when you turn water to steam, you're not "using up" the energy because it still remains in the system. When you condense the steam back to water as you will inevitably need to do for a closed cycle system, all that heat you "used up" comes back into play. So I don't get how you can use smaller heat exchangers, because the power you need to dissipate doesn't change and as far as I can tell, the efficiency of dissipation into the free stream has in no way improved.

Yes a condenser is needed however due to design the condenser can be much smaller than today's radiators and requiring less airflow therefore allowing for smaller entrance and exit cooling ducts.

[Lycoming]

But a condenser is just a type of heat exchanger, so why can't those features be built into radiators? Better yet, do you have a source or a more detailed explanation as to why a condenser can be smaller than a radiator?

[trinidefender]

But a condenser is just a type of heat exchanger, so why can't those features be built into radiators? Better yet, do you have a source or a more detailed explanation as to why a condenser can be smaller than a radiator?

It can be smaller because of what it is trying to do. In a normal water to air heat exchanger you are trying to directly cool the liquid for it to be heated back up again in the engine then cooled again.

In an evaporative cooling system the major transfer of energy comes when the pressure is released from the coolant as it runs into an open chamber or what have you. This then becomes steam. The steam is then passed through a condenser which lowers the water temp by just enough for it to be liquified. The water is then passed through pressure pumps, raising the boiling point again then put back into the engine.

It seems that while the ducting may be smaller and less airflow needed it might have a weight penalty with the additional piping and slightly higher power usage from the engine to run the pumps as they will have to 'work harder' than in a conventional system.

[Dragonfly]

Isn't this the 'heat pipe" principle?
One application I know is in computer CPU cooling, especially laptops. The aim is to extract as much as possible heat from a source with small area and quickly transfer it to a suitable place and means to effectively dissipate it into the surrounding air.

[Tommy Cookers]

in principle evaporative cooling requires far less coolant (due to the large latent heat)
so would be relatively valuable with water coolant and unpressurised (as envisaged by RR pre WW2)
but then higher BP coolant and pressurisation allowed somewhat less coolant and smaller radiators anyway

current F1 limits cooling system pressure but not temperature as such ?
maybe these engines can stand a high coolant temperature