Understanding Tesla s Heat Pump System

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Hello, I'm Professor John Kelly, and this is  the Weber Auto YouTube channel in this video,   we are going to learn about the heat  pump systems used in Tesla vehicles   now if you're in the market for an electric  vehicle, and you live in an area where the   outside temperatures drop below 10 degrees  Celsius or 50 degrees Fahrenheit you really   should pay attention to the type of cabin heating  system that that electric vehicle has because it   can and will affect your driving range if you  want the heat turned on inside of your cabin,   so there are three different types of cabin  heating systems that I'm going to show you   that are still used today in new battery electric  vehicles, so the very first one I'm going to show   you are an old school really shouldn't be used  any more cabin heating system let's go look at it;   okay, on this cart, I have put together  the old-school cabin heating system   it includes what's called a heater core and the  heater core has been around for, uh, I don't know   I forgot to look up when it first started but I  suspect a hundred years it is basically a little   mini radiator that we pump hot coolant through  anti-freeze through inside of your passenger   compartment, your blower motor blows there through  it and the heat transfers from the coolant into   the air and warms the passenger compartment the  heat used to the source of the heat came from   the internal combustion engine but since electric  vehicles don't have internal combustion engines   somebody decided to invent an electric coolant  heater instead, so this part right here is the   high voltage cabin coolant heater and when you  turn the heat up all the way, this thing can   draw 7500 Watts or 7.5 kilowatts now we have a  coolant reservoir right here that we can use to   add coolant to the system, and then down below the  reservoir, we have a pump an electric pump, so we   put coolant in the reservoir, it goes down to the  pump through the hose comes up through the pump   hose to the heater goes from the electric heater  through a hose over to our old-school heater   core through the heater core and back to the  coolant reservoir so we basically just replaced   the internal combustion engine heat source with an  electric heat Source 7500 Watts on high now if you   want your windshield defogged or defrosted on a  cold morning then the air conditioning compressor   has to turn on and that can draw upwards of 2  000 more watts on a on a cold day if you drove   with your heat on high and the air conditioning  compressor was running for defrost purposes,   dehumidification of the cabin air, you would be  using 9500 Watts or 9.5 kilowatts if you drove   for one hour like that that's 9.5 kilowatt hours,  and if you could drive four miles per kilowatt   hour then that would be 38 miles of range lost  because of the energy used by these high voltage   components now if you count all the parts involved  in this old-fashioned cabin heating system that is   here on this bench the hoses the parts there are  11 pieces and what some manufacturers have done,   and this takes us to the second type of cabin  heating system is they have gone to an electric   air heater, so this part right here is called a  positive temperature coefficient PTC air heater   it has a orange cable it connects to high voltage,  and there's a controller built into the bottom   housing here and then we have these heat fins and  the controller electrically Heats these fins and   the blower motor blows air through it and we  get hot air inside the passenger compartment   of an electric vehicle this one piece replaces all  11 of these other pieces so there's fewer Parts,   there's virtually no maintenance on this electric  air heater on these ones still have coolant   running through a heater core you will still have  cooling system services at so many years or miles,   so this PTC air heater is a nice way to go as far  as reduction of Parts however it still can draw   almost exactly the same amount of electrical power  as the PTC coolant heater that we have right here   so we have a PTC coolant heater we have a PTC  air heater; they both use a lot of power the big   difference is the PTC air heater only has one  part one piece instead of the 11. so there are   Vehicles out there that have a heater core there  are Vehicles out there that have a PTC air heater,   and now let's look at the third method of heating  a passenger compartment, and that is with a heat   pump there are several vehicle manufacturers  that use heat pumps in their vehicles they are   not all the same the heat pump we are going to  look at today is used in Tesla vehicles. Now I  

have two Teslas here behind me. I have a Tesla  Model y right here, and I have a Tesla Model 3,   the purple one back there that model 3 was  made in 2018 and it uses the PTC air heater   for the passenger compartment heat and all the  way up through late 2020 Tesla still used the PTC   air heater in the model S X and three, but in late  2020, they switched everything over to a heat pump   and the heat pump system that Tesla uses is quite  remarkable and we're going to explore that today,   but they are not the only ones with a  heat pump. General Motors way back with   the ev1 electric vehicle had a heat pump a  Nissan Leaf is out of heat pump since 2013.   there are other vehicles that have heat pumps I  have a Kia Niro electric vehicle here in the shop   that has a heat pump I have a Subaru Crosstrek  plug-in hybrid that has a heat pump there's   several Toyotas that have heat pumps there's  differences between those heat pumps as far   as their efficiency and what temperature ranges  they will operate and so let's take a look at this   Tesla heat pump system the first thing you may  want to know is does your Tesla have a heat pump   so to find out if you'll get into your Tesla  touch the car icon in the bottom left corner   and then select software from the menu and  then select additional vehicle information look down to where it says cabin heater if it  says resistive is your cabin heater type then   you have the PTC air heater if it says heat pump  then you have the heat pump that we are going to   talk about in the rest of this video the advantage  of a heat pump is that it can be very efficient as   far as the use of electrical power so most  heat pump systems, regardless of the brand   use the electric air conditioning system  compressor as part of the heat pump system and   that is the only device under normal temperature  operating conditions that uses electrical power   and it typically only uses between 1000 watts  and maybe 2500 to 3000 watts of electrical power   and by comparison to the 7500 watts of the  PTC air heater and the PTC coolant heaters   that we just looked at, this is quite a  savings in energy usage which means you   will be able to drive farther down the road on  your existing battery power with a heat pump   as compared to the other methods of heating the  cabin that we looked at now Tesla heat pumps are   not rated by their efficiency instead, they  are rated by a coefficient of performance and   the reason for that is it is possible to  get more heat energy transferred into the   passenger compartment than the electrical energy  used to run the air conditioning compressor   so that would be more than 100 percent efficiency  which is not possible, so Tesla uses what's called   a coefficient of performance if all we get is  heat energy that equals the electrical energy   put into the air conditioning compressor then the  coefficient of performance is 1.0 if we get more   output in the passenger compartment more heat  energy output than we used in running the air   conditioning compressor, then we get a cop value  higher than one and on Teslas according to their   service information their cop can be as high as  5.6 which is very impressive the cop calculation  

is simply a ratio of the output energy divided by  the input energy now Tesla's heat pump system has   up to 30 different modes of operation and I'm  not going to take you through all 30 modes this   video would be extremely long, but I will show  you where it gets its heat and how it transfers   it into the passenger compartment or the cabin  as we've been calling it when the high-voltage   battery temperature is above 10 degrees Celsius or  50 degrees Fahrenheit we can transfer heat energy   from up to 16 different sources on the vehicle  into the passenger compartment which is quite   impressive, and of course the battery is one  of those okay so right here I have a 2022 Tesla   Model Y performance vehicle and I've removed the  luggage compartment and all the trim panels from   under the front lid here and looking inside of  here we have the air conditioning compressor and   a supermanifold and the radiator and some hoses  and pipes and other things these are just parts of   the heat pump. This is not the heat pump the heat  pump consists of all of these different pieces on   the vehicle that create heat energy including the  front and rear drive units the electric motors,   the entire high-voltage battery the radiator, the  hoses, pipes, valves, pumps, there are all kinds   of Parts involved in the heat pump system  so there is no part called the heat pump   so the heat pump system is intertwined throughout  the entire vehicle so let's get started by looking   at the individual components involved in the heat  pump system okay the first part of the heat pump   system I want to show you is actually inside  of the cabin of this vehicle and to understand   where it is if you look here under the front we  have five pipes, five aluminum pipes going into   the cap and the passenger compartment on this  vehicle, those pipes play an important role in the   heat pump system so I have built most of the heat  pump system on a workbench over here let's go take   a look at where those pipes go okay the five pipes  that we just looked at underneath the front lid   of that Model Y are right here and three of the  pipes are for heating the cabin two of them are   for cooling the cabin so let's follow these pipes  down the three pipes that are used for heating, go   to a special part called the cabin condenser and  there's a driver's side and a passenger side of   the condenser so you can have individual heating  controls so there's a cabin driver's side Inlet   and a passenger-side Inlet of hot refrigerant from  your air conditioning system and then there's a   single outlet where they both return now what  else do we have here we have a blower motor   that's going to blow air through your cabin  filters that are right here and they are in   front of the part that is used for cooling  your cabin which is called the evaporator and   it has the other two pipes that are here in this  five-pipe pentaport connection there, but when we   are heating the cabin; we can run just the cabin  condenser to allow air to be blown through it and   transfer heat energy from the hot refrigerant into  the air we are also running the air conditioning   compressor we can run a little bit of refrigerant  through the evaporator which gets it cold which   will cause more any moisture in the air to  condense on the outside of the evaporator   and drip out the bottom of the car and that's  for dehumidification of the air while heating   so that the inside of your windshield doesn't  get all frosted up or even Frozen on the inside   in some cases so all of the other parts that  are involved in the heat pump system operating   are there so that we can get heat energy into  the refrigerant and pumped inside the cabin here   to this inside condenser everything that's part  of the heat pump system is dedicated to getting   heat energy to this inside condenser  so the cabin condenser is the   source of heat that air is blown through to  heat the cabin now another source of heat energy   can be from the blower motor itself; this is  a three-phase 12 volt to 16 volt depending   on your low voltage system voltage a  blower motor controlled by the front   vehicle controller and I've taken the clip  out of it so I can remove the blades here   if I take the fan blades off and we look at the  back side of it here we have permanent magnets   right here and then over here we have the  stator coils those stator coils can get hot   and produce heat as part of normal operation  of the blower motor and so on the back of the   blower motor if you look really carefully  down in the edges here, it has a special set of fins kind of a spiral set of fins  on the other side of this, that help pull   air through the stator and that to help cool the  stator but that error transfers heat energy from   the stator into the air and then that comes into  the cabin and helps keep heat the cabin air also so although that is a minor source of heat it is  a source of heat all right now the third source of   heat might be surprising to you and it's actually  up in front of the vehicle and it's the vehicle   radiator so let's take a look at it here on my  bench all right on my workbench right here I have   the whole radiator assembly and I've unclipped  this upper cover that has the active shutter in   it that can close and block airflow from coming  in and of course it can open and allow airflow   under certain situations there's a little  motor that controls that right there but   let me get that out of the way so that we can  see the radiator right here is the radiator and   you might be thinking big deal radiator every car  has a radiator well this is a, this is a special   radiator this is a pretty big radiator compared  to uh some other electric vehicles and one unique   thing about this radiator is that we have the the  fan motor below it you can't see it here but the   fan motor is is below it here and that fan motor  can pull in what we call ambient error so we're   just going to pull air through the radiator not  for the purpose of cooling anything but for the   purpose of transferring the heat energy that's  in the air right here that we're blowing through   the radiator transferring that heat energy into  the coolant of the radiator and then that heat   energy from the coolant eventually Works its way  into the refrigerant and into our cabin condenser   so on this radiator the fan can be blowing at  high speed and you'll put your hand in near it   and it's cold air it feels cold to us but there's  still heat energy in cold air and so we can take   this is free energy it's just in the air itself we  take that free energy and put it into the coolant   that goes through the radiator now of course  this radiator can act like any other Radiator   on any other vehicle and that is if it's a hot  day and we want to get rid of some heat energy   then we can pump hot coolant through the radiator  turn the fan on and transfer the heat energy from   the coolant into the air so one more time this  radiator can transfer heat energy from the air   and put it into the coolant or it can transfer  heat energy from the coolant into the error   depending on the situation whether something's  too hot or something's too cold all right so   that is our third source of heat energy on this  vehicle okay our fourth source of heat energy is   the high voltage battery and if you look at this  photo of the high-voltage battery underneath our   model y right here you can see that it is very  large and it fills up the in almost the entire   underneath of this model y but in this photo here  you can see there are four coolant hose inlets   at the front of the battery and there are four  hose inlets at the back I'm not showing you but   we have coolant that runs through this battery  and the coolant going through the battery can   allow heat energy that's stored in the battery the  hardware itself the physical parts of the battery   to transfer into the coolant or if we need to  heat the battery we can transfer heat energy from   the coolant into the battery Hardware itself so it  can go both directions also the heat energy at the   high-voltage battery so that is our fourth heat  Source our fifth and sixth heat Source is built   into one big component that you can see here in  this Photograph called the power conversion system   or the PCS now on the passenger side of the power  conversion system is a high-voltage part called   the DC to DC converter and the job of the DC-to-DC  converter is to take high voltage from our high   voltage battery and step it down to a low voltage  so that we can run the rest of the vehicle either   on the 12 volt system or the 16-volt system that  Tesla has. to do that conversion, it produces heat   and so we can transfer heat energy from the  DC to DC converter into the cooling passages   into the coolant that runs through the cooling  plate at the bottom of the DC-to-DC converter   on the driver's side of the power conversion  system is the onboard charger the OBC and the   onboard charger is never used while you're driving  and so it does not produce heat while you're   driving however when you are charging your vehicle  with an AC level one or an AC level 2 charge cord   that charge cord is ac voltage and the battery  is DC and so we have to convert AC to DC and we   have to step the voltage up from whatever the wall  voltage is up to whatever the high-voltage battery   voltage is typically 400 so if you are using an AC  level one charge cord that's typically around 120   volts we need to charge a 400-volt battery with  that so we have to step up the voltage to 400   and convert it to DC if you're using an AC  level 2 charge cord, those are typically   around 240 volts but we still have to step up  that voltage to 400 volts and convert it to DC   that conversion creates heat, and that heat  energy is transferred into the coolant that   eventually gets transferred into the refrigerant  and then Works its way into the cabin condenser to   heat the passenger compartment so those were our  fifth and sixth sources of heat on a Tesla vehicle   so the seventh source of heat might surprise  you there is a liquid-cooled computer on this   car called the autopilot computer and it's just  over my shoulder I'm going to zoom in on it those   two hoses that go through the Bulkhead into the  passenger compartment have coolant going through   those and that goes into the autopilot computer  and the autopilot computer is the one that watches   all of the cameras and is used in Sentry mode  it's also used when you're driving down the   road and it generates a lot of heat while doing  that so this is a liquid-cooled computer inside   the vehicle okay if we look under the front  lid one more time right here in the front   we have over here on the driver's side the air  conditioning compressor and right next to that   we have What's called the super manifold and the  super manifold has many parts on it that we will   discuss later but one of the parts that we're  going to discuss is kind of hidden down below   there and it is called The Chiller okay so those  same two parts we just looked at under the hood   are right here here's our air conditioning  compressor here is our super manifold with   a whole bunch of other parts involved with  it if we look at the super manifold itself   here's here is the super manifold as far  as the refrigerant handling side of the   super manifold so any refrigerant routing that  needs to go anywhere goes through this super   manifold and we'll talk more about that later  but there's a piece bolded to the super manifold   right here called The Chiller and so here is the  chiller right here and the job of the chiller is   to transfer heat energy from the coolant into the  refrigerant so we have a coolant Inlet and Outlet   over here on the back side and then refrigerant  Inlet and outlet and this plugs right into   the super manifold right there and for the  refrigerant so we were just talking about the   radiator and how we could transfer heat energy  from the air into the coolant and then somehow   the heat energy transferred from the coolant  into the refrigerant; this is how we have that   coolant come into the chiller this is just  a heat exchanger and then that heat energy   gets transferred into the refrigerant that also  goes through here and so that allows the heat   energy into the refrigerant that then Works its  way into the cabin condenser to provide heat for   the passenger compartment this is another source  of heat although it doesn't produce heat it allows   heat transfer and so I consider that a critical  part of the heat pump system okay the 9th and 10th   sources of heat in the Tesla heat pump system are  the front Drive Unit inverter and the rear drive   unit inverter so right here on the wall behind me  I have the front inverter right up there and the   rear inverter right here and on the rear inverter  let me zoom in I've removed the cover this is the   cover right here for the coolant passages for the  rear inverter and you see all those little pins   in there coolant is going to come in on one of  these hoses go through all those little pins   transfer heat energy out of the high voltage  electronics and have the coolant come out   the other pipe there the heat energy comes from  all your high-voltage transistors and electronics   involved in running the three-phase motors in the  drive units so heat sources nine and ten are the   front and rear inverters not every vehicle has  a front inverter if it's rear wheel drive the   Plaid versions of the Tesla Model S and X will  have two inverters in the rear and one in the   front Okay heat sources 11 and 12 come from the  stator windings these copper wire copper wires   right here called the stator that goes around  the electric motor rotor right here so I have   a cutaway that I've created for the front motor  of our Tesla Model y the rotor rotates it rotates   because of a rotating magnetic field created in  the stator but we apply high voltage to these   stator windings and run a lot of current through  them they get hot there's a special transmission   fluid that an electric pump right here pumps  through and runs that transmission fluid over   these stator windings to transfer the heat energy  out of the stator windings into the transmission   fluid and then we have a special heat exchanger  it looks very much like that Chiller that we just   looked looked at but we have transmission fluid  coming in right here and out right here and that   transfers the heat energy from the transmission  fluid into coolant that comes in right here and   goes out right here and this just plugs in right  here on the side of the Drive Unit and there's   one for this is the front Drive Unit I've got  the rear drive unit right over here there is   a heat exchanger for the front drive unit and  another one for the rear drive unit to transfer   the heat energy from the transmission fluid that  it got from the Stators into coolant and then it   goes to the chiller where we transfer the heat  energy from the coolant into the refrigerant and   then into the passenger compartment condenser so  those were heat sources 11 and 12. okay the 13th  

source of heat on Tesla vehicles is actually the  cabin evaporator now the evaporator if you recall   from our earlier discussion is normally used to  remove heat energy from the passenger compartment   the cabin for cooling the air reducing the air  temperature, but think about this if we are trying   to add heat energy to the refrigerant that goes  to the cabin condenser if we already have somewhat   preheated air in the cabin and the cabin air is on  recirculation meaning we're not pulling in outside   air and heating it we're reheating the inside air  if that air can make a loop and come back through   the blower motor and then go through the cabin  evaporator as the air goes through the evaporator   if we allow for some refrigerant to go through  the evaporator the heat energy from the cabin air   can be transferred into the refrigerant that then  can go to the compressor that then can raise the   refrigerant pressure and temperature that sends  it back even hotter to the condenser to heat   the air the next source of heat is another part  on the super manifold okay so right here under   the frunk lid on our super manifold right on the  top is this box right here and I have another one   right here this is called the liquid-cooled  condenser so here's a liquid-cooled condenser on   the back of it we have a coolant Inlet and Outlet  we also have a refrigerant Inlet and Outlet so the   job of the liquid cooled condenser is to transfer  heat energy from the refrigerant into the coolant   now that's just the opposite of the chiller the  chiller's job was to transfer heat energy from   the coolant into the refrigerant so these two are  opposites of each other they're similar in size   but the liquid cooled condenser is larger the  liquid-cooled condenser plugs in on our super   manifold right here in the top just like this as  you can see right here now most Vehicles including   probably the one you are driving have a condenser  out in front of the radiator of the vehicle and   the job of the condenser on that vehicle was  to transfer heat energy from the refrigerant to   the outside air well this liquid-cooled condenser  instead of losing all of that heat energy energy   to the outside air we are transferring it into the  coolant and that way we can capture it we can save   that heat energy if we need to we can store it in  the high-voltage battery we can heat the passenger   compartment or the Power Electronics with it or  if we want to get rid of it then we already have   a radiator let's just move some switching Valves  and run that coolant right out to the radiator   where we can transfer the heat energy and the  coolant out to the air in the same manner that   a condenser would do so they've reduced a part in  front of the vehicle and replaced it with another   part inside the vehicle so they didn't really  reduce the number of Parts but they made it to   where we can capture that heat energy rather than  just lose it to the air and so that's a pretty   smart way of doing things and since we already  have a radiator whose job is to transfer heat   energy from the coolant to the air we don't need  two of those we don't need a condenser that does   that and a radiator that does that we can just use  the radiator so we've talked about a chiller and a   condenser the condenser liquid-cooled condenser  here is our 14th source of heat now the 15th   source of heat is actually the air conditioning  compressor this part right over here   so I have one of these compressors that I've  taken apart so here's part of it right here   inside of the air conditioning compressor is  a big three-phase stator assembly much like   the Drive Unit electric motors we connect high  voltage battery positive and negative DC to this,   it has its own built-in inverter where it drives  a three-phase permanent magnet electric motor and   it turns what's called a scroll compressor if  you look at these photos here it has a movable   scroll and a stationary scroll and if you watch  this video here you can see the movable scroll   doing its thing now this air conditioning  compressor stator coil can be a source of   heat so as it operates it gets hot just like  the transmission or Drive Unit Stators do   except now instead of transmission fluid going  across it we have refrigerant going across it   and it transfers the heat from these stator coils  into the refrigerant that it's compressing anyway   and by compressing the refrigerant it increases  its temperature by concentrating the Heat and   then pumps that to that inside condenser to  add heat to the cabin of the vehicle so the   air conditioning compressor itself can be a source  of heat so that's our 15th source of heat on the   vehicle the air conditioning compressor now  the 16th source of heat is really hard to see   but on this super manifold that we'll look at in  a little more detail here in a minute there are   four sets of passages that I've color  coded with a permanent marker here,   everything in blue is a low-pressure vapor;  everything in red is a high-pressure Vapor   everything in Black is a high-pressure liquid  and anything in green is a low-pressure liquid   or vapor they call it a dual State refrigerant now  if we take some of this high-pressure refrigerant   high pressure high-temperature refrigerant and we  run it back into the low-pressure low temperature   refrigerant side through a little part called a  mister just like a water Mister it just sprays   a fine Mist that additional heat energy from the  refrigerant will transfer into the low temperature   low-pressure refrigerant and add heat energy  to it, and that typically only happens at very   cold temperatures it's a way of it's basically  you're short-circuiting the refrigerant Loop   and adding the additional heat energy from  the compressor stator to it it's a quick way   of increasing the temperature of the refrigerant  and that is controlled with a special solenoid   over here called the recirculation solenoid that  screws into this passage and there are a bunch   of solenoids, we'll look at on here to control  the direction and flow of refrigerant in this   super manifold but as the 16th source of heat in  this heat pump system that is our final source   of heat and that is under normal operating  conditions which are defined by Tesla as 10   degrees Celsius 50 degrees Fahrenheit or above now  when the battery temperature drops below the 10   degrees Celsius or 50 degrees Fahrenheit there are  six other methods of producing heat that aren't   normally used in the regular operation of the heat  pump system so let's look at those six methods   the number one method we've mentioned already  but it has an extra Flair to it so let's come   back to our air conditioning compressor stator  here the air conditioning compressor stator   normally generates heat as part of normal  operation but in really cold temperatures   as the patent describes the inverter can control  these stator windings in what's called a lossy   manner l-o-s-s-y a lossy manner which means a very  inefficient manner and by being very inefficient   it will produce heat that we don't normally want  it to produce so if something in electronics isn't   very efficient it generally produces heat a lot  of heat with it and so by purposely making it   run inefficiently or in a lossy manner we can  convert more electrical energy into heat energy   in the stator windings to add additional heat to  the refrigerant that works its way to the cabin   condenser so this is cold extra cold temperature  this works clear down to a negative 40 degree   celsius which is also negative 40 Fahrenheit okay  so that's number one of six methods in super cold   temperatures the second method is back with our  blower motor assembly the blower motor stator   can also be operated in a lossy manner and cause  it to generate a lot of extra heat and that heat   is heat energy is transferred into the air and  blown across the evaporator and the condenser and   into the passenger compartment the cabin Okay the  third and fourth methods of generating extra heat   more heat than necessary is to run the front  and rear motor inverters in a lossy manner and   by running those in a lossy manner they generate  more heat than they normally would and that heat   gets transferred into the coolant that then gets  transferred to the chiller into the refrigerant   to the air conditioning compressor and then into  the cabin heater the fifth and sixth methods of   generating extra heat in really cold temperatures  is by using the stator windings of the front and   rear drive units and so we can operate the Staters  in a lossy manner much like we did with the air   conditioning compressor with the blower motor we  can run the Staters in the front and rear Motors   in a lossy manner a low power factor Manner and  they will generate extra heat I've done some   experimenting while charging and during battery  pre-conditioning as you can see in this screenshot   from an app the front drive unit was using  3.5 kilowatts of power the rear drive unit was   using 2.5 kilowatts of power with the car stopped  sitting still while pre-conditioning the battery   and what is that six kilowatts of power that's  very close to the 7.5 kilowatts of PTC heater   energy used to create heat on vehicles with a PTC  heater so on in really cold temperatures these six   methods I just showed you and described to you of  using the air conditioning compressor the blower   the front rear inverter and the front and rear uh  stator assemblies and any combination of those are   ways to create extra heat energy but they do it at  a cost and the electrical energy cost which can be   just as high as a PTC air heater or a PTC coolant  heater except these components can generate that   heat with the existing parts that are already  there we don't need an extra PTC heater   installed on the vehicle we don't need extra parts  installed to generate heat in low temperatures we   just use existing parts and can operate them  purposely in a lossy inefficient manner that   creates extra heat all that extra heat ends up in  the refrigerant compressed by the compressor heat   concentrated which raises the temperature  of the refrigerant which is then sent to   our cabin condenser and air blown through it  to keep you warm while you drive down the road   so a pretty amazing system and quite a wide  operating range there, which is quite impressive   this same heat pump system that we're looking  at here and describing here for the Model Y is   the exact same system on the Model 3 the Model S  and the Model X they all have the same heat pump   system they all have what appears to be the same  super manifold and air conditioning compressor   setup so it's a modular system that can bolt into  multiple vehicles and then just have the existing   parts coolant hoses hooked to it and then the  refrigerant lines transfer into the cabin as we   have discussed okay we have just looked at the  16 components of the Tesla heat pump system now   as far as overall operation of the system, there  is a refrigerant side of things and there is a   coolant side of things and the super manifold that  we took a quick look at has a coolant side and a   refrigerant side and if you go into service mode  on many Teslas you will be able to see the four   different modes of coolant flow on the vehicle  the series mode the series radiator bypass mode   the parallel mode and the ambient air mode and  their relationship to all of these 16 components   that we just looked at along with some additional  components that are part of the super manifold if   you look at this screenshot here from the Tesla  Service Mode you can see the different solenoids   that are part of the refrigerant side of the super  manifold along with the pressure and temperature   sensor readings that are also taken from pressure  temperature sensors on the super manifold so let's   go take a look at the Supermanifold in a little  more detail next okay here we have the cast   aluminum piece of the supermanifold that handles  refrigerant distribution to understand the super   manifold you must have a good idea of how the  refrigerant Loop works on a traditional vehicle   so if you look at this Photograph here of the  refrigerant Loop of just about any vehicle on the   road we start with the air conditioning compressor  and it pulls in a low-pressure low temperature   vapor and compresses it and concentrates the Heat  and makes it a high-pressure high temperature   vapor it then is pumped out to the condenser in  front of the radiator where it condenses into a   liquid as the error passes through the radiator  and it gives off heat leaving the condenser we   have a high-pressure, high-temperature liquid  that goes into a receiver dryer where moisture   is removed through the use of a desiccant bag  and then it goes to a thermostatic expansion   valve or TXV on most Vehicles; there are other  methods out there but a TXV is pretty common   thermostatic expansion valve has a small opening  where as the high-pressure, high-temperature fluid   goes through it it is allowed to expand and as  it expand its temperature decreases and now it   becomes a low-temperature, low-pressure  liquid that goes into the evaporator and   as cabin air passes through the evaporator this  low temperature low pressure liquid accepts heat   energy from the cabin air and begins to boil  and it boils into a vapor which is then sent   back to the air conditioning compressor and so we  have a complete Loop so there are four different   states of refrigerant in this Loop well the super  manifold cast aluminum piece here has to handle   all four of those States so in blue we have the  low pressure Vapor return that goes back to the   air conditioning compressor in red we have the  compressed high pressure Vapor that leaves the   air conditioning compressor in Black we have the  liquid high pressure refrigerant that after it's   gone through the liquid-cooled condenser and  condensed into a liquid then in green we have   the refrigerant that can be inside the evaporator  that could be liquid or vapor now that translates   to the front here so at the front of this  manifold pretty much everything at the bottom here   is the low pressure Vapor system everything at  the top is the high pressure Vapor system we have   as part of the supermanifold here we have three  what are called pressure temperature sensors   so here is a temperature sensor that also  is a pressure sensor built into one unit and   this is for the suction side or the low  pressure side of the refrigerant system   so that's just going to screw in to the  super manifold right here on the top then   we have another pressure temperature sensor  this is for the liquid high pressure line   and it screws in right here and  measures the pressure and temperature of the high pressure liquid then we have  another pressure temperature sensor which is   for the high pressure Vapor side leaving the  compressor and so that screws in right here   all right so we've got three temperature pressure  sensors so this part protruding out of the   manifold portion of the supermanifold is  called the receiver dryer and accumulator   and the accumulator's job is to allow any liquid  refrigerant to boil off into a vapor before it   goes back to the air conditioning compressor  so that we don't break the air conditioning   compressor so that's the job of the accumulator  but there's also a drying portion where we absorb   any moisture in the refrigerant through what's  called a desiccant bag the desk and bag itself is   inside of this black cartridge you may have seen  desiccant bags in like a bag of jerky, there's a   little pouch in there with these little beads  this has those beads in it and so this fits in   a Groove and slides down into the receiver dryer  portion of the super manifold here then it has   a plug with two O-rings on it and  these O-rings like to get stuck   in the snap ring Groove that goes right here so  this plug goes in, and then a snap ring goes in   on top of it and then there's a cap that screws  on to that plug that keeps dirt from getting into   that area where the snap ring is and so this  is a serviceable item and on Teslas, I think   it's every six years the desiccant bag needs to be  replaced on other vehicles, I've seen it as low as   three years and the air conditioning compressor is  running almost always on these vehicles not just   Teslas but anybody with a liquid cooled battery  in hot weather that air conditioning compressor   is going to be running to remove heat energy  from the battery as you drive or as you charge   and that does it through the air conditioning  compressor okay um that plug is very difficult   to get out it just shows in the Tesla Service  information grabbing a pair of pliers and lifting   this out yeah good luck it doesn't come out that  easy at all it's very difficult to get out all   right now other parts that are here we have three  one-way check valves three check valves and so   let me bring in a check valve here there are two  places for check valves right here on the front   and one place for a check valve on the back and  a check valve is just a spring-loaded plug that   prevents refrigerant from going One Direction but  allows it to go the other direction and so we have   a cover for the check valve and then  the valve and a spring and a snap ring   and so the check valve is this  little rounded piece right here   that sits down inside of a plastic housing  and that fits down inside of this hole there's a spring that sits on top of that check  valve and holds it in the closed position and then   there's a plug that comes in on the top with the  snap ring that holds it in place and so there are   three of these we have one for the evaporator so  that refrigerant can only come from the evaporator   and not go backward into the evaporator through  this passage we have another one for the liquid   cooled condenser so that it will only go one  direction through the liquid-cooled condenser and   then we have another one for the cabin condenser  so that the refrigerant comes from the cabin   condenser can only come in this direction and  not try to go in the outlet side of the condenser   pipes all right, then we have six solenoids  six solenoids these solenoids are all identical   they have a plunger with a spring-loaded plunger  it is a normally closed plunger there's a coil of   wire that fits over the top of that plunger and  all of these little normally closed solenoids   screw in here on this super manifold these  solenoids are not serviceable the check valves   are not serviceable the temperature sensors  are but these solenoid plungers are not let   me get all six of these installed they all  have the same part number on the end of them   they're all the same there we go so this is this  solenoid mechanical portion the plunger portion   of these solenoids and these six solenoids are we  have one that controls the refrigerant going into   the chiller, we have another one that controls  the refrigerant going into the evaporator another   one that controls the refrigerant going into the  driver's side of the condenser inside the vehicle   we have another one that controls the refrigerant  going into the passenger side of the condenser   inside the vehicle, we have another one that  controls the refrigerant going through the liquid   cooled condenser and the last one over here is  the one that controls the amount of recirculation   refrigerant that goes through that little Mister  during really cold temperatures to try to boost   the heat content of the refrigerant each one of  these mechanical plungers have an identical coil   of wire that fits down over the top of it they  have a seal that fits up inside here to keep   moisture out and those slide down I'm going to  take the seal off because they're really hard to   put on and take off and I need to keep this apart  for demonstration for my classes but this is   solenoid coil is just going to sit down there's a  little Groove in the super manifold that it Clips   over right there and now it won't come off and so  we have a four-wire solenoid connector for every   for each of the six solenoids so this one  is for the evaporator this one is for the   chiller this one is for the left cabin condenser  there this one is for the right cabin condenser   right there this one is for  our liquid cooled condenser   right there and the last one is our recirculation  solenoid so now we have six solenoids installed   to control the amount of refrigerant that goes  through these ports these solenoids can be just on   or off allow a lot of fluid or no fluid they can  also be pulse-with modulated to act as a variable   orifice and so those are the solenoids now we  have an additional Port right here for a larger   solenoid this solenoid here is called the shut  off solenoid valve for the liquid-cooled condenser   and basically, it's a big pressure regulator  valve it's to prevent over pressurizing of this   manifold here so all four of these solenoids  these four black solenoids here are on the   high side high-pressure, high-temperature Vapor  side of the refrigerant Loop if we are cooling   the passenger compartment these two are off  for the driver's side and passenger side of   the condenser this one is off because that's  only used in cold cold temperatures to boost   the Heat and so we have the cabin condenser I'm  sorry the liquid cooled condenser solenoid that   controls how much refrigerant goes through the  liquid cooled condenser if for some reason that   gets stuck or fails all of these could be  stuck in the off position which would cause   the high side pressure in the air conditioning  system to Skyrocket this will open it will blow   open I believe it will blow open it has a little  spring-loaded plunger and it has a solenoid valve   or solenoid coil of copper wire right there that  screws on and sits on the top of there to control   over pressurizing of the high pressure system  okay I'm going to bring in the chiller now it   just plugs in to these two holes right here and we  have the chiller inlet at the top from the chiller   electronic expansion valve and the outlet at the  bottom that goes over to the receiver dryer it   just has a couple of O-rings and some bolts  that hold it in place AC loot oil on those   O-rings there we go goes right in there is our  chiller installed as part of our super manifold   at the top of the supermanifold we have two holes  for the liquid cooled condenser so the liquid cool   condenser is right here it's going to plug in  other than the three check valves that I did not   install the two on the front and the one on the  back the refrigerant portion of the super manifold   is assembled nothing is torqued or bolted down  but I use this for demonstration in my classes   um the two holes that you see right here the red  and the blue is the suction side that comes from   our air conditioning compressor and the red is  the discharge side from the air conditioning   compressor so those two pipes that you see under  the front over there from the air conditioning   compressor they just plug in right there so that  is the front of our super manifold but there's a   back portion that is used for coolant okay let's  look at the coolant part of the super manifold   so there's this big plastic coolant  manifold right here so this manifold has   a place for two electric water pumps  and then it has a three places for   coolant hose connections we have one coming from  the high voltage battery one coming from the   high voltage powertrain and one going to the high  voltage battery and then on the front here we have   the coolant connections to the chiller coolant  connections to the liquid cooled condenser and   then three more coolant connections one to the  radiator down the bottom center here one from the   radiator and one from the high voltage powertrain  okay so on the back side here I'm going to get our   coolant pumps here they are there are two of them  there's one coolant pump for the battery which   is this one and one coolant pump for the high  voltage powertrain these are both the same part   number these can these are three feet three phase  16 volt Motors they max out at 6000 RPM and draw   15 amps a piece when they're at that speed the  battery coolant pump goes at the bottom down here   and so we will plug that in it matters its  orientation it'll I think it only goes one way   but these pumps are serviceable screws  in it to keep them from falling out   and then we have the powertrain pump also  and it only bolts in in One Direction okay so now we've got our two coolant pumps  installed powertrain pump at the top high voltage   battery pump at the bottom now there's another  component that goes here and it's called the   Octo valve the octal valve octal meaning eight  this is an eight-way coolant switching valve   and if you look right here in this plastic  manifold there are eight ports right here   these ports can be connected together up and down  like this or even side to side depending on the   five different positions of the octal valve on it  has five positions but only four of them are used   so there is an electric motor and a position  sensor on the bottom of the Octo valve it just   has a big like a canister that it spins inside or  there rotates it doesn't spin uh inside to give   us the different positions for the four different  coolant modes actually there's five coolant modes   if you count off on the Tesla vehicles so we'll  get that at sensor and motor Drew down here   there we go okay if you look at these drawings  of the four different modes of operation   the first mode which is full counterclockwise  rotation of the Octo valve as viewed from   underneath the octave valve we connect Port 5  to Port one so the coolant goes straight up we   connect Point Port two to point Port six so the  coolant comes down and then we connect port 4 to   Port three so the coolant goes in a loop from four  to three and then also from seven to eight so that   is one of the four octal valve usable positions  all right now the next octal valve position   uh we just moved the octal valve clockwise  one position and by doing that we switch to   this series radiator bypass position the first  position by the way was called parallel mode   so now now we're doing this series radiator bypass  we connect Port 5 to Port one Port 2 to Port 3 Port 6 and 7 are connected together  and then we connect Port 4 to Port 8.   and allow coolant to flow there all right then  the next position we just slide everything over   one is called ambient source and as you can see  we connect Port 2 to Port 1 Port 5 to Port six   Port 7 to Port 3 and Port 4 to Port 8. so  there's our third mode out of four and our  

fourth mode is called series mode and in series  mode the coolant just goes straight up or down   so we connect Port 5 to Port one Port 2 to Port  6. Port 7 to Port 3 and then Port 4 to Port 8.   so these are the four different operational  modes of the octal valve we are switching coolant   on eight different Passages at once with this  octal valve assembly so the octal valve bolts in   right here the octave valve is serviceable  you can replace the octal valve if necessary   okay so now we have assembled the  back half of the plastic portion of   the super manifold that controls the flow of  coolant in the system and what's beautiful about   this design is that instead of having a pump  that's remotely mounted with hoses that would   connect to it and then hook hook to something  else they got rid of the hoses and just moved   the pump into here the same thing with the octo  valve here this is really two four-way switching   valves that would have been remotely mounted  somewhere else on some of the other somebody   else's vehicle including the older Tesla Model S  and X and then they moved it to this manifold got   rid of the hoses and hose clamps and it all became  part one part of this super manifold assembly so   they were able to reduce the number of Parts on  the vehicle now this plastic portion bolts to the aluminum portion here so I'm  going to lay the aluminum portion down   put the plastic portion in  its proper location here it's like that there are some  seals that are underneath it   that allows the ceiling of the aluminum Chiller  to the plastic portion of the super manifold here   there's also seals where it goes from the liquid  cooled condenser to the plastic it has to seal and   have no coolant leaks there this plastic portion  and the aluminum portion are not serviceable   here's to replace the entire super manifold  assembly if either one of these get broken okay now we have the entire  super manifold assembled   the only other thing that we could bolt to  it would be the coolant reservoir and what's   neat about this super manifold is it's  Universal this can bolt into a model y   it can bolt into a model three I believe  it can bolt into the model S and X also   but you just change the coolant reservoir so this  Reservoir plugs in right here and there's a Bolt from the other side that holds it in place there's  two of these and it seems like the other one is on   the back let me see yes it is right there  okay there is the complete super manifold   we control the flow and direction and volume  of refrigerant in the cast aluminum piece   and the same thing on the back in the plastic  except for the flow of coolant there is a set of   the five pipes right here that's going to bolt in  to the back of the super manifold right here and   go into the cabin as we saw under the front lid of  our model y over there a series of five pipes and   then of course there is a wiring harness that  plugs into all of those solenoids and pressure   temperature sensors and the the pumps and the  octave valve and the fluid level sensor and so on   um this is a very impressive system in my opinion  there's a lot of heat pump systems out there if   you look under the hood of our Kia Nero over  here it has a heat pump with a PTC air heater   it doesn't have the operational range that this  heat pump does but it isn't as refined it has   aluminum pipes going everywhere it has a bank  of solenoids up underneath the hood as you can   see here on the passenger side inner fender  it's just pipes and pipes and pipes and it's a   I think it's an evolutionary process where Tesla  I think has really thought this system out well   and brought everything into one modular piece  that can be moved from vehicle to vehicle or   installed from vehicle to vehicle all right so  wrapping up this video it's been a long video   the big advantage to a heat pump system for cabin  heating if you live somewhere where you use cabin   heating is it only uses heat energy from the  air conditioning compressor under most operating   conditions the Teslas I've driven that have heat  pumps are very impressive in very cold weather   and I have no complaints at all with them only  uses a small amount of electrical energy unless   the temperatures are really really cold and in  that case then it uses existing parts to create   heat rather than additional bolt-on Parts  like some other vehicle manufacturers have   so if you're in a market for an electric  vehicle I would recommend you seriously   consider one with a heat pump all heat pumps are  not the same do your homework do some research   find out customer reviews Tesla has had some  problems with this heat pump when it first   came out with no heat at all occurring  and they figured out that there was a   solenoid that was not believing off pressure at a  certain time when it should have been and they've   released a software update to fix that all right  well thank you for watching as always if you think   you benefited from this video please feel free to  donate to the Weber State automotive department   there's a link in the video text shown below  this video here until next time have a good day

2023-05-25

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