Is the Y heat pump air conditioner blown by Musk really black technology?

Many people, obviously with air conditioning at home, use electric heaters to keep warm in winter. Why don't they turn on the air conditioner?

Answer that air conditioning costs electricity.

In fact, this is a long-debated topic:

Who saves more electricity, 2kW air conditioner or 2kW electric heater?

Many people choose the latter, because the electric energy consumed by the external air conditioner is converted into mechanical energy, while the electric heater converts electric energy into heat energy by almost 100%, so there is no energy waste, so the electric heater saves more electricity.

But I want to tell you clearly, as long as the temperature is not lower than-10℃, the air conditioner saves more electricity.

Because of their different heating methods, air conditioners press external heat into the room through heat exchange (that is, heat pump) and pump away indoor cold air, which is just the opposite of summer refrigeration; And the electric heater is through PTC (positive? Temperature? Thermistors directly heat cold air.

Simply put, the electric energy consumed by air conditioners is mainly used to drive compressors and fans to exchange heat with the outside world. In a unit time, two horses' air conditioners can even exchange 6kW of heat, with an efficiency as high as 300%. A 2kW electric heater can only generate 2kW heat, and the efficiency is 100%.

Let's talk about the air conditioning and heating mode of pure electric vehicles.

Similarly, at present, air conditioners for pure electric vehicles also have two heating methods: heat pump and PTC.

But PTC is still the mainstream. Low-end electric vehicles and some high-end electric vehicles are in use, and they are electrically heated by battery packs.

For example, Weilai ES8 even installed two PTC heaters with rated power of 5.5kW in the front row and 3.7kW in the back row. Assuming that the power of two PTC's working at the same time is 7kW (the PTC of an ordinary electric vehicle is 6kW), then heating for one hour will consume 7 kWh of electricity.

Use ES8? If the battery pack is 70kWh and the battery life is 355km, the air conditioner consumes 10% per hour, which means that the battery life is reduced by 35km.

This is also the reason why ES8 consumes electricity faster than ES6 in winter, because ES6 uses heat pump air conditioning.

Some people may want to ask, can the power of PTC be designed to be smaller, so as to save electricity?

I can't. Because there are some standards and specifications for mass production vehicles in China, for example, the main driving view area of the front windshield should be thawed to 80% within 20 minutes. Under this standard, it is difficult to meet the requirements when the PTC power is less than 3kW, especially for a large space vehicle like the ES8, which needs more PTC power.

Since heat pump air conditioning is so good, why not adopt mainstream electric vehicles?

Although PTC consumes a lot of electricity, it has obvious advantages, simple structure, low cost and fast heat output. In winter, electric vehicles can generate hot air as soon as they are turned on, which is also the place where many people like electric vehicles, while fuel vehicles generally have to wait until the engine temperature comes up in winter.

Of course, the advantage of PTC is the disadvantage of heat pump.

Such as cost. The earliest heat pump air conditioner in China is SAIC Roewe. According to SAIC engineers, the cost of heat pump air conditioning in Roewe Ei5 was as high as 1 10,000 yuan earlier.

Even though the price of heat pump air conditioner has dropped to about 3 thousand yuan now, it is still about 1 thousand yuan more expensive than PTC, which is not a small cost. ?

In addition, heat pump air conditioning is also restricted by temperature. Generally speaking, when the outside temperature is lower than-10℃ (it is not excluded that some central air conditioners obtain heat from lower temperature through enthalpy-increasing technology), the efficiency of heat pump obtaining heat from the outside is obviously reduced. At this time, air conditioning heating mainly relies on electricity to assist heating, which is PTC mode.

So in the northeast, it is not cost-effective to turn on the air conditioner in winter. Heating is preferred, followed by electric heating.

So Tesla model? What's the difference between Y's heat pump technology?

Before Tesla went from Roadster to the latest model? 3. The passenger compartment and battery basically adopt PTC electric heating scheme, so why do we need to model it? Y will change the heat pump scheme?

There is a podcast on Youtube that Tesla's early main market was in California, with the coldest winter above 0℃, and the cruising range changed little in winter and summer. But now Tesla is sold all over the world, especially in northern Europe, where environmental awareness is high. The cold weather and PTC heating have a very obvious impact on the battery life of electric vehicles.

2065438+February 2009 American consumer report shows that in outdoor weather around -20 degrees Celsius, Model? 3 Actually run 64 miles, and the power is cut off 12 1 mile. In other words, in this climate, the battery life will be damaged by nearly half.

So Tesla has to consider adopting heat pump technology with higher thermal efficiency.

In addition, there is another reason. The application of each technology is the result of the balance between cost and function. In the past, the cost of heat pump was high and the structure was complex, so PTC was naturally a cost-effective choice. But with a model? 3. For example, in the aspect of liquid cooling system, Tesla has some experiences and solutions to solve some complex integrated systems.

In fact, this is also a model? Compared with BMW i3, Jaguar I-PACE and Audi? Roewe Marvel Comics? For X, Weilai ES6 and other heat pump models, models? In the combination of heat pump and automobile, Y may go further.

What do you mean?

As mentioned above, the efficiency of heat pump will decrease or even fail at low temperature, but Model? Y's heat pump system will absorb more heat energy.

Simply put, when the outside temperature is lower than the threshold, Model? Y may only need PTC to heat the battery before starting, and PTC is not needed after the vehicle runs. At this time, the heat pump will absorb heat from the main heating components such as motor, electronic control and battery pack and transport it to the passenger compartment, and still heat efficiently.

This is a very complicated combination, which requires the computer to accurately judge when PTC and heat pump work at the same time and when they work independently. At the same time, different working modes require different piping systems and models. Y controls the heat transfer path in various modes through an 8-way reversing valve.

It is said that Tesla even intends to replace the traditional resistance speed regulation with PWM (alternating voltage) stepless speed regulation, which is similar to controlling the motor because the fan will generate heat and consume electricity.

In short, Tesla just wants to build a detailed "heat energy generation and recovery system" through all-digital hardware means, and basically produce and sell energy without venting. This is the evolution direction of smart cars.

Then it can be imagined that when Tesla overcomes the low-temperature efficiency of heat pump air conditioners, more and more pure electric vehicle companies will follow suit, and PTC will be eliminated in the future. It doesn't matter if you buy an electric car now and use it in the south. If you are in the north, you should focus on air conditioning technology, which is an important factor affecting battery life.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.