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Airflow through front grill questions
- Thread starter JPinzolo
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- Driving Dynamics Model S
JPP
Active Member
There are various radiators/coolers behind the front grille for the battery and drive unit as well as the HVAC system. Note that there are louvers/dampers that open and close to modulate the air flow and also to optimize aerodynamic efficiency.
The radiators on the left and right front (the ones with the louvers) cool the drive system as necessary. They have fans mounted on the back of each radiator and the air from them exhausts into the front wheelwells. You can see the openings that the air exhausts through inside the wheelwells in front of the tires. The center cooler is the A/C condenser. There are two electric fans mounted in a case behind it that exhaust air around the "frunk" liner and then under the car.
Otmar
EV Modder
I think you have that a bit reversed. I am intimately familiar with the setup since it is all clearly visible on my car and this is what I've seen.
The center radiator carries coolant in a loop with the motor, controller, charger(s) and the battery when it is in series plumbing mode. The center radiator has control flaps on either side where the air exits, this air feeds in front of the two outboard AC condensers. The condensers can also get air directly from the front when their shutters are open. Each AC condenser has a fan pulling air through it and exiting in the the wheel wells, those fans also pull the air through the center radiator when in that mode.
The battery coolant can be cooled with the main ambient coolant loop, or switched into a parallel mode for more temperature control allowing the battery coolant to be cooled by the AC chiller, or heated by the battery heater.
I find it's a pretty interesting system.
aaroninsan
90D
Question: When should I see the louvers open vs closed? I was washing the car (2017 S 90D) when I noticed that they were open. It is the first time that I have ever seen them open.
Thank you;
Aaron
Thank you;
Aaron
I'm also curious about this. I have never seen mine close. Admittedly I've only had the car a week or two but I was curious when they do close.
The louvers will open or close based on the amount of air the car needs to pull past the freon condensing coils (Otmar is correct in this placement).
As the Freon chilling system provides cooling for both the battery pack/drive-unit loop, and cabin Air conditioning, there are a number of circumstances where the car will command them open based on the needs of either.
The car will close them for better aero efficiency at speed if it doesn't need the airflow past the condenser coils. One example is that the ambient outside flow/temp is sufficient to provide "passive" battery cooling via center radiator, and there's no need for cabin A/C.
As the Freon chilling system provides cooling for both the battery pack/drive-unit loop, and cabin Air conditioning, there are a number of circumstances where the car will command them open based on the needs of either.
The car will close them for better aero efficiency at speed if it doesn't need the airflow past the condenser coils. One example is that the ambient outside flow/temp is sufficient to provide "passive" battery cooling via center radiator, and there's no need for cabin A/C.
Could you post pictures I think my is busted... out of warranty. A/C blows warm intermittently and fan runs really loud.
dark cloud
Active Member
The center radiator is for the normal coolant loop. Behind it is a duct that splits up and goes to the two 'radiators' in front of the wheels. They are technically condensers for the AC system. There is no coolant going through those. Those run the freon of the AC.
When the cooling needs are low, the air goes through the center radiator, then through the duct and then through the two condensers into the wheel well. The louvers that you see under the head lights are closed in that case to support the airflow through the center radiator. If more cooling is needed, the fans behind the condensers will start sucking air and help get more air through the center radiator. The louvers are still closed in that case. The fans might run quite strong. If more cooling is needed (battery, cabin, power train) the AC will kick in. Now the louvers open and the fans will suck in air directly. When switching from fan only to AC, the fans might actually spin slower which can be confusing to the owner. The AC can use up to 6 kW.
There is another set of louvers hidden in the duct from the center radiator to the side radiators/condensers. This will prevent the airflow through the center radiator for the most part. I'm not 100% sure when this happens. You can't see them and what they do unless you have the whole front off.
The cooling system has several valves to direct the coolant. It can totally bypass the radiator to avoid any cooling, for example in cold temperatures in winter.
When the cooling needs are low, the air goes through the center radiator, then through the duct and then through the two condensers into the wheel well. The louvers that you see under the head lights are closed in that case to support the airflow through the center radiator. If more cooling is needed, the fans behind the condensers will start sucking air and help get more air through the center radiator. The louvers are still closed in that case. The fans might run quite strong. If more cooling is needed (battery, cabin, power train) the AC will kick in. Now the louvers open and the fans will suck in air directly. When switching from fan only to AC, the fans might actually spin slower which can be confusing to the owner. The AC can use up to 6 kW.
There is another set of louvers hidden in the duct from the center radiator to the side radiators/condensers. This will prevent the airflow through the center radiator for the most part. I'm not 100% sure when this happens. You can't see them and what they do unless you have the whole front off.
The cooling system has several valves to direct the coolant. It can totally bypass the radiator to avoid any cooling, for example in cold temperatures in winter.
I have had my Tesla in Alaska for a month, since August. I’m concerned about keeping my charge when it’s 0, 10, or 20 degrees. Otmar mentioned “switching to parallel mode” to maybe heat the batteries. Is this “switch” something that’s fone automatically by the Tesla kr is it something I should know how to do to keep my batteries charged longer?
Gridlok
Member
The temperature here has just dropped to about 12c. At this point my regeneration is not as strong because of the cold battery. As far as I know, the cabin heat control is the only option. Does it preheat the battery as well? I do love one pedal driving!
dark cloud
Active Member
Cabin resistive heater is independent of battery coolant heating. The latter will do automatically as needed; but turning climate on before driving car will preheat the battery, which is essential in sub zero temperatures if you want regen to work. You will see a red battery icon in the app about 30 seconds after preconditioning in cold weather. I assume it will still be there with the latest app version.
Hi David,
Can you explain how the louvres under the headlights work in the winter time. I find it strange that they are open even when it is -20C (4F). This also allows snow and ice getting where the condensers are.
Good question. Tesla has adjusted the cooling system a bit over the years. Especially once they added the heat pump, things changed. I don't know each scenario in which they open. I assume they open any time the chiller is needed. It sounds odd that the car would run the compressor for the chiller when it's that cold outside. But keep in mind there is no way to cool some of the car's system from the air directly.
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