Refrigerated Cybertruck Frunk?

[JBee]

Do you mean condenser?

What got me thinking about this was the observation of an 15° F rise in the R1T frunk after a couple of hours. As Sandy Munro had just done a video on that part of the truck I had some idea of what the geometry is. The condener is exposed to the airstream and a fan sucks air through it and blows it onto the frunk around which it flows before being channeled out to the bottom of the space. There is no ducting (other than what it provided by the confines of the body) and no insulation.

I would think so but I don't see the comparison. You can't have a frunk in an ICE car (unless it's mid or rear engine).

Well technically isn't there a radiator and a condenser in the front of a EVTesla? Or do Teslas only have a condenser and all of the heat, from motors, battery pack and cabin all runs through the condenser and heat pump?

My comment regarding "cooler" was more about how much heat is even being generated in a EV/Tesla (in comparison to a ICE) and how much heat would actually be coming in contact with the frunk and warming it up. In a ICE you can't have any type of storage under the hood simply because of the temperature under there alone, regardless of how much space there was.

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[ajdelange]

I've never seen a post complaining about Tesla's A/C.

Try a search on "tesla A/C weak"

 

[ajdelange]

Well technically isn't there a radiator and a condenser in the front of a EVTesla? Or do Teslas only have a condenser and all of the heat, from motors, battery pack and cabin all runs through the condenser and heat pump?

I think it depends on the model in question. I can say that there are heat exchangers up front and that at least one of them is refrigerant to air and that may blow hot air over the frunk as it does in the R1T. There may be coolant to air ones as well and they also could blow hot air over the frunk tub.

 

[charliemagpie]

Try a search on "tesla A/C weak"

Seems to be a problem which can be resolved.

 

[HaulingAss]

The part that counts (the condenser) is mounted up front with the radiator so the effective temperature the system is exposed to is the ambient. ICE engineers are not stupid. The vapor line would need to be better insulated in an ICE vehicle though as it runs through the engine compartment.

I've seen lots of posts about how ineffective Tesla A/C is in hot weather and even in not so terribly hot weather but under tough driving conditions (positive grade, high speed). This is because much of the compressors capacity is allocated to keeping the battery/inverters cool leaving less than sufficient capacity for the cabin.

I was going to ignore this but then I realized some readers may not know any better and actually believe it.

Insulating the AC lines and compressor in an ICE car can only do so much. And often these items are not insulated at all or not very effectively. It helps but does not solve the fact that engine compartments get brutally hot in stop and go traffic on a hot summer day. There is no single part that "counts" in an air conditioning system, it's a system and all parts must work together to achieve good performance. Even the heat-soaked compressor is affected very negatively by the brutal temperatures in the engine compartment of an ICE car. The net result of the brutal heat found in an ICE cars engine compartment is a drastic reduction in cooling power which is especially noticeable when stuck in traffic because that will test the thermal capacity of any AC system (but especially ICE because the engine keeps producing heat even though it's not doing any real work as it idles away).

Tesla continually improves their products, the cooling system when the Model 3 was released was found to be greatly improved over the Model S and X which would find themselves thermally limited when driven hard in hot weather. In normal driving the Model 3 has plenty of cooling capacity to keep the cabin cool and I assume the Model Y is at least as good. I expect the Cybertruck will be at least as good also. The refreshed Models S and X were also improved in this area.

You can find Tesla complaints on every subject under the sun including silly stuff like rapid brake pad wear, ineffective headlights, crappy sounding stereo ond other made-up stuff. It's important to understand just how many other industries a disruptive company like Tesla threatens and the lengths they will go to try to dissuade people from trying a Tesla.

These same people incessantly claim Tesla has a demand problem (or will very shortly) but nothing could be further from the truth. But reality doesn't stop these slimeballs from trying to make their predictions come true by trying to scare off potential customers with bogus reports. They are all over the Internet. Their tactics actually work on some people but demand for Tesla's is so high it doesn't matter. Tesla has a customer waiting list longer than Santa's "naughty" list.

I don't know if the reports you put so much trust in are simply FUD driven reports or if they refer to early Tesla's that had much more limited capacity to reject heat (and were not as efficient so they created more heat that needed rejecting). In either case, realize that modern Tesla have no problem keeping the cabins cool in typical sweltering summer situations.

The trickiest situation for an ICE car to keep the occupants cool is child's play for a modern Tesla. Specifically, running errands in hot summer weather with multiple stops that cause the engine bay to become an inferno. This does not happen on a Tesla. Perhaps at a race track where the motors are driven to the thermal limits one might wish for more cooling (I don't know, have not tracked either of my Model 3's) but these are not the concerns of typical Tesla owners who experience the superior cabin comfort in hot, sweltering weather. And they all have the capability to pre-cool the cabin a couple of minutes before you get in.

Yes, you can find FUD reports that claim otherwise but Jimi said it best: "As you well know, you just can't believe everything you see and hear, can you?"

Now if you'll excuse me, I must be on my way.

 

[JBee]

Do you happen to know what the temperature delta is for battery and motor coolant? How cool do you need to keep batteries, is ambient cool enough when it is >100F outside? I know keeping them warm, when it's cool outside requires active heating of the cells, either resistive or through the heat pump, but I haven't really looked out the heat removal side, which is actually more relevant for my neck of the woods.

 

[HaulingAss]

Do you happen to know what the temperature delta is for battery and motor coolant? How cool do you need to keep batteries, is ambient cool enough when it is >100F outside? I know keeping them warm, when it's cool outside requires active heating of the cells, either resistive or through the heat pump, but I haven't really looked out the heat removal side, which is actually more relevant for my neck of the woods.

Ideal battery temperatures are 70-90 degrees F. Most of the heat produced by an EV is in the motors because they are only around 92% efficient. The batteries are over 99% efficient so, while they do produce a small amount of heat as they charge/discharge, it is a very small amount. When an ICE car idles it is 100% inefficient, ie, all the energy produced is wasted (except the small amount used to turn the compressor and alternator) and that energy manifests as heat that soaks the cabin and A/C system. In traffic this extreme heat can even backdraft right into the condenser that relies upon a flow of cooler ambient air to cool the cabin.

All this talk of heat blowing on the frunk is misguided. That's what insulation is for. True, you don't want to put ice directly in the uninsulated frunk liner unless you don't care if it rapidly melts. But that's what insulation is for. And a Tesla has much less waste heat than a Rivian because they are more efficient. I get very long life out of the ice packs I put in my frunk soft cooler. Over two days on a high speed trip to Montana through hot deserts and over multiple mountain ranges at high speeds in the late summer. The area surrounding my soft cooler was always cold when I would open the frunk because it was lined with a single thin layer of bubble/foil insulation.

 

[JBee]

I was going to ignore this but then I realized some readers may not know any better and actually believe it.

Insulating the AC in an ICE car can only do so much. It helps but does not solve the fact that engine compartments get brutally hot in stop and go traffic on a hot summer day. There is no single part that "counts" in an air conditioning system, it's a system and all parts must work together to achieve good performance. Even the heat-soaked compressor is affected very negatively by the brutal temperatures in the engine compartment of an ICE car. The net result of the brutal heat found in an ICE cars engine compartment is a drastic reduction in cooling power which is especially noticeable when stuck in traffic because that will test the thermal capacity of any AC system (but especially ICE because the engine keeps producing heat even though it's not doing any real work as it idles away).

Tesla continually improves their products, the cooling system when the Model 3 was released was found to be greatly improved over the Model S and X which would find themselves thermally limited when driven hard in hot weather. In normal driving the Model 3 has plenty of cooling capacity to keep the cabin cool and I assume the Model Y is at least as good. I expect the Cybertruck will be at least as good also. The refreshed Models S and X were also improved in this area.

You can find Tesla complaints on every subject under the sun including silly stuff like rapid brake pad wear, ineffective headlights, crappy sounding stereo ond other made-up stuff. It's important to understand just how many other industries a disruptive company like Tesla threatens and the lengths they will go to try to dissuade people from trying a Tesla.

These same people incessantly claim Tesla has a demand problem (or will very shortly) but nothing could be further from the truth. But reality doesn't stop these slimeballs from trying to make their predictions come true by trying to scare off potential customers with bogus reports. They are all over the Internet. Their tactics actually work on some people but demand for Tesla's is so high it doesn't matter. Tesla has a customer waiting list longer than Santa's "naughty" list.

I don't know if the reports you put so much trust in are simply FUD driven reports or if they refer to early Tesla's that had much more limited capacity to reject heat (and were not as efficient so they created more heat that needed rejecting). In either case, realize that modern Tesla have no problem keeping the cabins cool in typical sweltering summer situations.

The trickiest situation for an ICE car to keep the occupants cool is child's play for a modern Tesla. Specifically, running errands in hot summer weather with multiple stops that cause the engine bay to become an inferno. This does not happen on a Tesla. Perhaps at a race track where the motors are driven to the thermal limits one might wish for more cooling (I don't know, have not tracked either of my Model 3's) but these are not the concerns of typical Tesla owners who experience the superior cabin comfort in hot, sweltering weather. And they all have the capability to pre-cool the cabin a couple of minutes before you get in.

Yes, you can find FUD reports that claim otherwise but Jimi said it best: "As you well know, you just can't believe everything you see and hear, can you?"

Now if you'll excuse me, I must be on my way.

I seriously don't think ajdelange needed to know anything of what you wrote, but your post has a couple of assumptions that are just not technically correct and I have to correct it just in case anybody else might read your post and get completely the wrong idea....you never know, you know, right?

There is no difference between the engineering of a "adequately sized" ICE or EV air conditioning system. Yeah sure, ICE might have higher temperature engine bays, but that doesn't stop you from putting in even bigger condensers to compensate. Let alone every single condenser in a ICE, like in every EV, gets fresh ambient temperature air straight from the outside without being pre-heated by the car in any way at all. So no reason to spread technical FUD buddy!

 

[HaulingAss]

Do you happen to know what the temperature delta is for battery and motor coolant? How cool do you need to keep batteries, is ambient cool enough when it is >100F outside? I know keeping them warm, when it's cool outside requires active heating of the cells, either resistive or through the heat pump, but I haven't really looked out the heat removal side, which is actually more relevant for my neck of the woods.

In cold weather, Tesla's use the waste heat from the computers and drive motors and inverters to warm the battery. If it's super frigid they will also use resistance to create additional warmth but it has to be pretty damn cold to need much of that. Even cars with heat pumps will use a bit of resistive heat in temps that cold.

 

[HaulingAss]

I seriously don't think ajdelange needed to know anything of what you wrote, but your post has a couple of assumptions that are just not technically correct and I have to correct it just in case anybody else might read your post and get completely the wrong idea....you never know, you know, right?

There is no difference between the engineering of a "adequately sized" ICE or EV air conditioning system. Yeah sure, ICE might have higher temperature engine bays, but that doesn't stop you from putting in even bigger condensers to compensate. Let alone every single condenser in a ICE, like in every EV, gets fresh ambient temperature air straight from the outside without being pre-heated by the car in any way at all. So no reason to spread technical FUD buddy!

It's not technical FUD. Heat soaking the A/C components drastically reduces the amount of cooling that can be supplied to the cabin - it's not different from saying hard driving on a racetrack reduces the amount of cool air that can be supplied to the cabin of a Tesla. In both cases the cooling systems are sized to deal with the expected loads but that doesn't mean challenging conditions can't make you wish for more cooling capacity.

Ever since my 2010 F-150 was brand new it has had trouble keeping my northern genetics cool enough, even on a day that is sunny and not much over 80 degrees. Especially after multiple stops with a heat-soaked engine bay. I have noted this problem on every ICE car I've ever driven.

There is a difference in the engineering of an ICE cooling system and an EV's cooling system because they operate in drastically different environments and the cabin of the ICE car has a much higher cooling load to deal with.

 

[firsttruck]

It's not technical FUD. Heat soaking the A/C components drastically reduces the amount of cooling that can be supplied to the cabin - it's not different from saying hard driving on a racetrack reduces the amount of cool air that can be supplied to the cabin of a Tesla. In both cases the cooling systems are sized to deal with the expected loads but that doesn't mean challenging conditions can't make you wish for more cooling capacity.

Ever since my 2010 F-150 was brand new it has had trouble keeping my northern genetics cool enough, even on a day that is sunny and not much over 80 degrees. Especially after multiple stops with a heat-soaked engine bay. I have noted this problem on every ICE car I've ever driven.

There is a difference in the engineering of an ICE cooling system and an EV's cooling system because they operate in drastically different environments and the cabin of the ICE car has a much higher cooling load to deal with.

Yup.

Also with ICE it is not just the engine bay but you also have the exhaust system & catalytic converter adding heat to cabin & trunk.

 

[HaulingAss]

Yup.

Also with ICE it is not just the engine bay but you also have the exhaust system & catalytic converter adding heat to cabin & trunk.

That shit is hot, especially the catalytic converter! And it heats the steel that surrounds the occupants. The catalytic converter is famous for starting grass fires so ICE car companies try to tuck them up high in a cavity of the underbody, away from the dry grass, which puts them right up against the cabin. And, yes, heat rises! The entire exhaust system is like one big radiative cabin heater that the A/C system must overcome.

 

[JBee]

It's not technical FUD. Heat soaking the A/C components drastically reduces the amount of cooling that can be supplied to the cabin - it's not different from saying hard driving on a racetrack reduces the amount of cool air that can be supplied to the cabin of a Tesla. In both cases the cooling systems are sized to deal with the expected loads but that doesn't mean challenging conditions can't make you wish for more cooling capacity.

Ever since my 2010 F-150 was brand new it has had trouble keeping my northern genetics cool enough, even on a day that is sunny and not much over 80 degrees. Especially after multiple stops with a heat-soaked engine bay. I have noted this problem on every ICE car I've ever driven.

There is a difference in the engineering of an ICE cooling system and an EV's cooling system because they operate in drastically different environments and the cabin of the ICE car has a much higher cooling load to deal with.

Dude whats the inlet air temperature difference between a condenser on a ICE and a EV?

 

[ajdelange]

Seems to be a problem which can be resolved.

It is a problem nevertheless.

Most problems can be resolved eventually. Some take nothing more than a reboot. Some require redesign and ultimately recall.

I'm just noting people complaining about inadequacy in the R1T A/C and note that the first thing Sandy Munro said when he took the frunk tub out of one was that the compressor looked very small. It seems these BEV use as small a compressor as they think they can get away with to save Wh thus extending range.

 

[ajdelange]

your post has a couple of assumptions that are just not technically correct and I have to correct it just in case anybody else might read your post and get completely the wrong idea.

Why thank you! Now I don't have to do it!

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