Hey, thanks for fulfilling my video request. The video is comprehensive and the illustrations make it very understandable. I paused for a second when you explained the formula for Q_dot but that's because I was only familiar with the second "in practice" one. Looking forward to your next video. Have a nice weekend!
Very interesting video. I had no ideo that the cooling requirements for hydrogen fuel cell vehicles was they high. That is a major drawback compared to BEV.
Two questions I have, if you could help I’d appreciate it. I’m trying to figure out a ball park number for heat lost within a rotary engines cooling system. If you would know a estimate percentage, let me know, currently trying to come up with sizing for a radiator on a side project. The other question is about the difference in efficiency or k value of micro tube radiators in comparison to normal ones. Recently watched the video about them and was fascinated. Any answers are really appreciated!
Rotary engines are combustion engines too but with slightly lower thermal efficiency than piston engines. So you would need slightly more cooling than a comparable piston engine. Also, they produce the same power in a smaller engine, so there should be a good cooling system to avoid overheating of components. Micro tube radiators have a much higher k factor than normal fin radiators. Like I described, you only use the radiator net area in the formula but the real surface area of these micro tube radiators is much larger. Additionally, heat rejection is better because of the flow behaviour within these radiators. But they are complex, tend to leak and expensive.
It is a very rough approach, but, I like how you simplified the cooling power requirement for each system. Maybe, I miss something in the video, but, I do not understand how you are supposed to simply double the radiator size just to overcome the difficulty for BEV and FCEV just because they have lower coolant temperature levels. Would it be possible for you to get into the details of that? Keep up the good work!
That's a topic lots of people don't know about or get confused by. The reason for this are the different operating temperatures of the systems. I could do a future video specifically about this.
This is a great channel. I wonder though, this crazy pursuit of electric transport... I recently listened to a podcast featuring Paddy Lowe, yes, ex Williams/McLaren/Mercedes/Williams engineer and founder of Zero Petroleum, a TRUE sustainable powersource it seems. Perhaps you have thoughts on this and could comment on the short-lived craze of electric automobiles? (Which I think is running out of steam before it can really start, and is in any case not sustainable - the power grid and battery system are a toxic combination...).. thoughts please!
I'd like to see these 3 drivetrains in a 24h race with the only rules being: all use the same allocation of energy for the whole race, all use the road car facilities to replenish the energy storage (i.e. regular pumps, public fast chargers etc.).
Good idea, Same energy allocation in kWh. And you find the answer in the video already. You see the power you need to input to drive the same constant speed for all 3 drivetrains.
And I have one question - when the fuel cell car makes some water in process of making electricity, is there any chance to use it for a bit of an "exhaust" thermal collection? Or is there too little water made to be effective?
If you take a common consumption of a fuel cell vehicle 0.8kg H2/100 km then you will end up with 13.2 kg of water after driving the 100 km. Let's take a velocity of 100km/h then it will take you one hour to emmit the 13.2kg of water. Toyota Mirai for exaple uses a Polymer Electrolyte Fuel Cell with relatively low exhaust temperatures (max. 80°C) . With an estimated delta of 60°K to ambient temperatures and the thermal capacity of water you can calculate the thermal losses through the exhaust to be roughly equivalent to 1 KW in this scenario. So i would say maybe you can take that heat for passenger cabin ventilation like with an ice, but that is not be enough to start thinking about solutions to convert it back into electricity.
Great explanation. To harvest this energy you would need to add complexity and to heat a cabin you usually need 3 - 4kW, to keep cabin temperature around 1kW. Keeping in mind that this harvesting would have some losses too, it wouldn't be worth it. Converting this into electricity would add more losses.
Electric cars with heat pump systems do that already. They don't need their radiators in certain weather and driving conditions. But there are always situations with high ambient air temperatures where they still need the radiator. There is research in phase change thermal storages but it's not easy for manufacturers to make this bullet proof for customer use.
Hey, thanks for fulfilling my video request. The video is comprehensive and the illustrations make it very understandable. I paused for a second when you explained the formula for Q_dot but that's because I was only familiar with the second "in practice" one. Looking forward to your next video. Have a nice weekend!
Thanks for the idea!
Wonderful explanation, good to see this comparison with efficiency equations. Cheers!!!
Glad you liked it!
I have to say it again. Amazing stuff. Thanks so much for this insight. I had no idea, why was the first mirai so hideous. And now i know!
the smartest youtuber on my subscriber list. thanks for the video
Wow, thanks!
Absolutely amazing video
Thank you very much!
Very interesting video. I had no ideo that the cooling requirements for hydrogen fuel cell vehicles was they high. That is a major drawback compared to BEV.
Awesome channel. Thank you so much for this kind of stuff.
Glad you enjoy it!
Two questions I have, if you could help I’d appreciate it. I’m trying to figure out a ball park number for heat lost within a rotary engines cooling system. If you would know a estimate percentage, let me know, currently trying to come up with sizing for a radiator on a side project. The other question is about the difference in efficiency or k value of micro tube radiators in comparison to normal ones. Recently watched the video about them and was fascinated. Any answers are really appreciated!
Rotary engines are combustion engines too but with slightly lower thermal efficiency than piston engines. So you would need slightly more cooling than a comparable piston engine. Also, they produce the same power in a smaller engine, so there should be a good cooling system to avoid overheating of components.
Micro tube radiators have a much higher k factor than normal fin radiators. Like I described, you only use the radiator net area in the formula but the real surface area of these micro tube radiators is much larger. Additionally, heat rejection is better because of the flow behaviour within these radiators.
But they are complex, tend to leak and expensive.
Super interesting like always!
Thank you! Cheers!
Great video
It is a very rough approach, but, I like how you simplified the cooling power requirement for each system. Maybe, I miss something in the video, but, I do not understand how you are supposed to simply double the radiator size just to overcome the difficulty for BEV and FCEV just because they have lower coolant temperature levels. Would it be possible for you to get into the details of that?
Keep up the good work!
That's a topic lots of people don't know about or get confused by. The reason for this are the different operating temperatures of the systems. I could do a future video specifically about this.
@@BSport320 Yes, I would totally look forward to watching such a video. Thanks!
This is a great channel. I wonder though, this crazy pursuit of electric transport... I recently listened to a podcast featuring Paddy Lowe, yes, ex Williams/McLaren/Mercedes/Williams engineer and founder of Zero Petroleum, a TRUE sustainable powersource it seems. Perhaps you have thoughts on this and could comment on the short-lived craze of electric automobiles? (Which I think is running out of steam before it can really start, and is in any case not sustainable - the power grid and battery system are a toxic combination...).. thoughts please!
How effective are fuel cell cooling solutions? Are there any major inefficiencies in cooling due to the actual structure of the fuel cells?
The problem is not the cooling within the fuel cell stack, it's the low efficiency of the fuel cell itself.
I'd like to see these 3 drivetrains in a 24h race with the only rules being: all use the same allocation of energy for the whole race, all use the road car facilities to replenish the energy storage (i.e. regular pumps, public fast chargers etc.).
Good idea, Same energy allocation in kWh.
And you find the answer in the video already. You see the power you need to input to drive the same constant speed for all 3 drivetrains.
@@BSport320 The video is mostly about thermal efficiency. It doesn't cover the proverbial elephant in the room - the recharging.
And I have one question - when the fuel cell car makes some water in process of making electricity, is there any chance to use it for a bit of an "exhaust" thermal collection? Or is there too little water made to be effective?
If you take a common consumption of a fuel cell vehicle 0.8kg H2/100 km then you will end up with 13.2 kg of water after driving the 100 km. Let's take a velocity of 100km/h then it will take you one hour to emmit the 13.2kg of water. Toyota Mirai for exaple uses a Polymer Electrolyte Fuel Cell with relatively low exhaust temperatures (max. 80°C) . With an estimated delta of 60°K to ambient temperatures and the thermal capacity of water you can calculate the thermal losses through the exhaust to be roughly equivalent to 1 KW in this scenario. So i would say maybe you can take that heat for passenger cabin ventilation like with an ice, but that is not be enough to start thinking about solutions to convert it back into electricity.
Great explanation. To harvest this energy you would need to add complexity and to heat a cabin you usually need 3 - 4kW, to keep cabin temperature around 1kW. Keeping in mind that this harvesting would have some losses too, it wouldn't be worth it. Converting this into electricity would add more losses.
Thanks guys for an explanation! I thought so, it is not enough to help, but had to ask. :)
Do you know if someone's doing R&D into harvesting heat energy of drive trains to replace radiators?
Electric cars with heat pump systems do that already. They don't need their radiators in certain weather and driving conditions. But there are always situations with high ambient air temperatures where they still need the radiator.
There is research in phase change thermal storages but it's not easy for manufacturers to make this bullet proof for customer use.
And the most demanding operation for a BEV to cool is under charging.
Сheck out the new BR 03!
Are you German ?
yes
@@BSport320 oh so basically everything you say about cars is right