January 15 news, Tesla Model 3/Y multiple owners previously complained that Tesla in a low temperature environment, there is a heat pump "rest" problem, the vehicle in an extremely cold environment can not use the heat pump heat.
Although Tesla previously updated the sensor with defects, there are still problems with some Of the Model 3 and Model Y produced in 2020-2021.
The reason for this problem is that the air inlet of the heat pump is frozen, resulting in abnormal sensor data and the entire system shut down. According to mspoweruser, Tesla today pushed the 2021.44.30.7 OTA update for the vehicle, which solved this problem.
The changelog indicates that this version of the system allows the heat pump to start smoothly at lower temperatures. Users can turn on the heating function of the vehicle through the mobile app 30-60 minutes before departure to warm up.
However, this update also has a hidden problem, if the environment of -15 ° C, heat pump heating may still fail. Tesla advises car owners to park their cars in warm places as much as possible to heat up the vehicle to solve this problem.
In fact, after canceling the PTC heating heating, only the heat pump heating is used, and Tesla's poor heating efficiency in the low temperature environment is also a matter of certainty, which is because the working principle of the heat pump is determined.
According to reports, the main components of the heat pump are 1: condenser (exothermic), 2: throttle valve (pressure reduction), 3: low temperature (heat absorption), 4: compressor (pressurization).
In the above process, the low boiling point liquid (such as Freon in the air conditioner) is evaporated after the throttle valve is decompressed, absorbs heat from a lower temperature (such as outdoor), and then compresses the steam through the compressor to increase the temperature.
After liquefying the absorbed heat as it passes through the condenser, it is returned to the throttle valve. This cycle continuously transfers heat from a lower temperature place to a higher temperature (where heat is needed).
PTC can be said to convert electrical energy into heat energy, is to create heat, in the extreme case, can only achieve 100% energy conversion. Consumes 1 joule of energy and can only provide 1 joule of heat at most.
The heat pump, on the other hand, is to transport heat, can use the energy of 1 joule, from a colder place to move more than 1 joule of energy, so in the power consumption to be greatly saved.
However, in the low temperature environment, the external heat is low, the heat pump is difficult to carry heat, in the outdoor environment close to -18 ° C, consume 1 joule of energy, but also probably only transport 1 joule of heat.
In addition, when the heat pump obtains heat from the outdoor low temperature air, the moisture in the air condenses and freezes on the outdoor exchanger, and the system must remove these frosts in stages.
At the same time, when the outside air is extremely cold, the heat pump heating may not be as good as PTC heating, or the heat pump system will not start. Therefore, Tesla's practice of only equipping vehicles in the cold regions of the north with heat pump systems is worthy of scrutiny in itself.