How does the heat pump work in a Toyota Prius Prime plug-in hybrid?

Discussion in 'Prime Technical Discussion' started by priuscatprimeguy, May 24, 2017.

  1. lech auto air conditionin

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    Nothing special this is old technology been around for decades automotive air-conditioning is my specialty for the last 30+ years I also have a commercial HVAC business we only install heat pumps and heat recovery systems that make the new Toyota heat pump look like a Mattel toy . The problem is there is no training on the system for mechanics to work on it or even understand it the misdiagnosis for repairs is definitely going to skyrocket at the cost of the customers pocketbook. The biggest percentage of our electric compressor failure is we see coming from customers are DIYs and autobody shops after a collision repair improperly recharging the electric compressor is contaminated refrigerant is another problem in proper oil contaminating the oil hi moisture content from collision repair with the pipes left open today atmosphere for days or weeks well being repaired improper charging a couple ounces to much a couple ounces to low both cause damage to the efficiency in the life of the electric compressor. The damage is not immediate usually except in severe cases it’s more like a ticking time bomb usually seen a compressor failure between nine months to 18 months after a vehicle lease a collision repair center or a do it yourself or tries to go down to the auto parts store with one of those little cans with the little hose in gauge on it and fill it up themselves or with the aid of a friend . As discussed above heat pumps are very efficient compared to using electricity to heat a electric resistive element . Using refrigerant to cool the compressor is ancient technology been around for a long time in the commercial heat pumps produced by Daikon, Mitsubishi, LG, Samsung, FUJITSU, amongst 20+ other manufacturers around the world, I just got to work on my first one from a collision repair was called in to do the recovery of refrigerant so they can take it apart . Condenser was replaced due to damage I was called back in to recharge the system . Looks like in operates very much like the heat pump installed on my house and some of the commercial systems I sell and install. One of the biggest problems were going to see in the future as these cars get into accidents the condenser is being replaced with cheap inexpensive aftermarket condensers that raise the head pressure and lower the efficiency of the system. The reason most aftermarket condensers are cheaper if you actually count the cooling refrigerant tubes for flow of refrigerant you usually find that there are fewer on the aftermarket condenser and you count the fins for cooling per inch you also find there’s fewer fins per inch in combination this lowers the cooling efficiency for the heat rejection of the condenser . And on a heat pump system it will make the heating less efficient in either case gas mileage goes down and the life of the compressor decreases due to the extra load of work it has to perform and On very hot days the extra amp draw for the electric compressor draws down they electric drive battery causing the battery to constantly be in a state of charging and discharging shortening the life of the drive battery . For those of you with experience mechanics more technically inclined you’ll notice sometimes on very hot days when a Prius has a cheap aftermarket condenser the cars engine stays on almost 100% duty cycle to compensate to charge the high voltage battery. Customers bring their cars into shops complaining of poor gas mileage and just because of a condenser unnecessary so called tuneups are performed diagnosis that leaves a mechanic nowhere and the customer losing money. That’s just a short synopsis of the story .
     
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  2. schja01

    schja01 One of very few in Chicagoland

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    An ASHRAE Engineer once told me it's much more efficient to move something from one place to another than building it from scratch at the destination. Exactly what a Heat Pump does vs a Heating Element.
     
  3. Longhood

    Longhood Junior Member

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    The heater core is NOT hot in most cars all the time. Coolant is throttled to zero when heat control or thermostat is set to cool.

     
  4. allenbrown

    allenbrown New Member

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    Thanks for sharing....
     
  5. drash

    drash Senior Member

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    The A/C and heat all work off of the heat pump, so it’ll work in EV or any mode. The only difference is the Heat Pump doesn’t work at less than 14F, so the engine would kick on and run in Hybrid mode to meet whatever temperature is set. If you force the Prime to use the Front Defroster by pressing that button, then it’ll run the engine until the Front Defroster button gets turned off just like a regular Prius.


    Unsupervised!
     
  6. Rose02218

    Rose02218 New Member

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    really quite interesting technology. Very informative
     
  7. Old Bear

    Old Bear Senior Member

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    I've had my Prime for two years and think that the heat pump is a vast improvement over the cabin comfort provisions in earlier cars:

    winter-comfort.jpg

    Not only that, but he Prime's heat pump came with the car and did not have to be purchased as an after-market accessory!
     
  8. schja01

    schja01 One of very few in Chicagoland

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    Yep. Back in the day radio, heater and whitewalls were all separately orderable accessories on automobiles.
     
  9. ChapmanF

    ChapmanF Senior Member

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    I owned a car once that worked that way. And I remember a friend had one like that.

    But most that I've owned, including Prii, have had the always-hot heater core and the temperature control by a door that shunts airflow through or around it.

    I suspect part of the reason is that it responds faster, and people are all about "hey I moved the control, why doesn't it feel different yet?"
     
  10. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    The Prime also has a coolant core that is always hot if the gasoline engine has been running, that has a damper to control its use. It also has a hot A/C condenser coil on the inside of the car that has a damper for "heat pump" heating; this coil always hot when the A/C is on, but if the damper is closed, no air flows over it and it doesn't have any effect. In heat pump mode, air flows over the inside condenser coil to heat the cabin, and the coil in the engine compartment is used as the cold "evaporator". When cooling, the A/C uses the coil in the engine compartment as the hot condenser coil, and an evaporator coil in the cabin to cool the cabin. It is an incredibly sophisticated and efficient system.
     
  11. lech auto air conditionin

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    Comparing a Prius prime to a commercial heat pump package unit on a building




     
  12. srivenkat

    srivenkat Active Member

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    Curious to know if the compressor in the Prime Heat Pump is an inverter-driven variable speed compressor that can modulate its output. Or is the the on/off type.
     
  13. ChapmanF

    ChapmanF Senior Member

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    Prius compressors have been inverter-driven variable speed since 2004. :)
     
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  14. lech auto air conditionin

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    If they were not inverter driven gas mileage would really suck power consumption would go up battery life would go down electronica components life of the compressor would go down.
    It’s a lose lose situation all the way around when commanding a electric motor to switch off and on to control a air conditioning circuit.

    You definitely lose dehumidifier mode because when you turn off the Compressor refrigerant flow stops the evaporator coil gets warmer has your airflow go through the evaporator it reevaporate the moisture out of the coil Fins and put it back into your cabin air steam.
     
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  15. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Here is a new interesting video on the Prime's heat pump.

     
  16. lech auto air conditionin

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    If you thought that was complicated you got another thing coming wait until you see the Audi SUV with the heat pump system. In the volts wagon and a Mercedes.

    On top of that they have a CO2 version where you’re using pressures upwards of 1400 psi 1700 psi

    I already worked on a few of them and release some videos about them.

    The Prius prime accumulator assembly is $2600 .
    On the Audi if you have to purchase that AC system you might as well purchase a whole brand new Prius prime .

    The CO2 version is offered in Germany . Unfortunately for me I wish they offered the CO2 version here in the United States.
    I’m ready to work on it easy Childs play.

    We are already using CO2 in our commercial refrigeration systems especially in supermarkets. Like your Safeway or Albertson’s or QFI or Vons

    And this exact same system similar to the Prius prime has been used on residential units for the last decade,
    It’s a heat pump system for your house residential you also incorporate a hot water tank to it for your house.

    So at the same time in the summertime when you’re using all that energy and spending money to cool your house instead of wasting that heat through the fans rejecting it out into the atmosphere.

    You take all that energy in the form of heat that you just paid to remove from your house and injected into a plate heat exchanger to heat water for your hot water for your house to do laundry take a shower etc.

    And it’s for free because you already paid to remove that heat all you did was transferred into water instead of the air outside in the back of your house.

    This technology will put a lot of radiator air conditioning shops out of business because of lack of education and tools.

    And if they introduced CO2 with the high pressures that will put a whole new category and group of regular mechanical general service repair shops out of the air conditioning business in that sector.
     
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  17. Banksy

    Banksy Active Member

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    That guy is awesome! He's got some of the most detailed videos I've ever seen on toyotas hybrid systems and the way they work

    He did a awesome video on what toyota needed to do to make the prime a EV and explained what they did

    Really really good channel
     
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