While what you're bringing up is worth discussing, it's not the topic that was brought up. @Stealthflanker was talking about the cooling needs for power consumption (DEW, radar, etc.), which is what @tphuang was replying to and IMO he's right that tech developed for EVs can indeed be applied there. You're now talking about the cooling needs for power generation, which is an entirely different topic. Many PHEVs use the engine to recharge the battery, but obviously that's not nearly as applicable to electricity generation with a turbofan.
Chengdu next gen combat aircraft (?J-36) thread
- Thread starter Blitzo
- Start date
superdog
Junior Member
I'm pretty sure the distinction you made between heat engine and battery is incorrect.
If you're talking about transforming the mechanical energy at the accessory gearbox of a turbofan into electricity, the efficiency can be fairly high at >90%, heat dissipation for this part would be fairly manageable even at 1MW (requires about 100kw of cooling capacity). Even the cooling system from a regular car would be able to handle that.
If you're talking about the jet engine generating an extra 1MW of power from fuel, and the cooling implication for that......well that's just a small part of what the WS-15 typically generates (most of it becomes thrust), the cooling needs for a turbofan engine is an already solved problem.
If you're talking about cooling for the electronic components (e.g. radar) that eventually used up that 1MW, yes you need increased cooling when you fire up more power hungry electronic devices. But this has nothing to do with whether that power came from a battery, from utility poles, or from a so called heat engine. The source of the electricity makes zero difference here.
Cooling at the component end is also not a difficult problem to solve as long as you have space (a big fuselage). Just like tphuang mentioned, modern cars (regardless of EV or ICE) can easily achieve hundreds of kw in cooling capacity, and 1MW is just 1000kw. 6th gen designers may try to minimize their system size/weight while achieving the needed cooling capacity, but this is just a matter of how compact they could make it, not a question of whether it is achievable.
An advanced NEV tech tree would also help in minimizing efficiency loss (waste heat) in the storage, transmission and distribution of this 1MW.
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Wait NEVs really have that much cooling capacity in the hundreds? Thats more than an F-35, either something is off or F-35 is an utter joke lol. Do we mean hundreds of watts of heat that they are able dissipate?
Could be wrong, but would that be the decision to use fuel for coolant?
Pretty much all modern fighters do but the main bottleneck is usually your heat dissipators and engine. Fuel volume mostly delays how long it takes to saturate with heat, which is useful for short bursts of very high energy consumption but dosent increase cooling capacity in and of itself.
superdog
Junior Member
Regular EV may not need that much cooling capacity because electric motors are very high efficiency, only high performance EV needs increased cooling. ICE cars (at least those with higher horsepower) do have hundreds of kw in cooling capacity, but you don't need high tech for that, just your typical coolant pump, radiator, intercooler stuff, make them bigger as needed.
And yes it is in kw not watts. Gas engine in cars are only about 30-40% efficient, that means when you generate 200kw in power, you're also generating 300-400kw in heat that you'll need to dissipate. Fortunately we don't use full throttle all the time so the cooling system usually handles a fraction of that load.
Cooling is only difficult when you don't have space and weight quota for it, such as when you want to cramp in higher power electronics into a compact fuselage not designed for such wattage.
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I think there's something more going on here if your average ICE car is capable of dissipating/cooling hundreds of Kw and an F-35 cant. Something about what/how we are measuring things and perhaps certain conditions are off or being ignored.
Bit tangential to the thread but, its not as complicated as you make it out to be, like most systems fighter jets can only dissipate as much heat as it was originally designed for. From the little reading I've done, the F-35 electronics cooling system was initially estimated and subsequently designed for a 14kw load, but in reality Block 3F were putting out upwards of 30kw of heat. That's twice the original design. They're estimating future upgrades will get the load up to 80kw, that's over 5x the original design estimate. With the rest of the jet already "solidified" so to speak, it's difficult to integrate a beefier system. Especially when there are crucial space, structural integrity and weight constraints, and more importantly there are loads of jets that would need to be torn down to upgrade those systems.
Its more down to design oversight than any inherent difficulty of cooling a few hundred kilowatts.
Someone posted this as a reply to me and I think this is helpful just showing how tempest project plans to generate electricity through rolls royce
notice that it has starter motor and energy storage (battery I assume). All things China got really good with NEVs. I have posted what they have done here in other threads.
China should be really good with this stuff.
notice that it has starter motor and energy storage (battery I assume). All things China got really good with NEVs. I have posted what they have done here in other threads.
China should be really good with this stuff.
It just was never developed with the piping needed for that. NEVs are designed from day 1 to handle certain level of output. Even with that, I know BYD did serious work to get sustained high power output going through thermal management system improvements. The cooling work they did is no joke.