Understanding Tesla's Heat Pump System
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 00:43
