Is the heat pump, more and more present on electric cars, really useful? This is what journalists from the Automobile Propre website wanted to know. And the result is not necessarily obvious.
The autonomy of electric cars is still a barrier to purchase for many motorists. And this even if the network of fast charging stations is developing and it is no longer necessary to have a vehicle that can travel very long distances without the slightest stop. Contrary to what some manufacturers like Lucid or Zeekr think.
An increasingly popular system
The brands are still keen to offer long ranges, in order to seduce the most reluctant customers, such as Tesla with its Model S that can travel up to 723 kilometers on a single charge according to the WLTP cycle. If the value announced by the manufacturer is intended to be close to reality, it is a little different in winter, since the cold has an impact on consumption. Particularly due to the use of heating.
This is why many electric cars are now equipped with a heat pump. This is for example the case of the Hyundai Ioniq 6, Kia EV6 and other Renault Mégane E-Tech and Audi Q4 e-tron, which had to do without it due to the shortage of semiconductors. Unlike resistance heating, this system reduces the electrical consumption of the heater.
For that, it uses the calories present in the air to make it warmer or colder according to requirements and ambient temperature. This reduces consumption by 3 to 4 times compared to a conventional system, which requires between 2,000 to 3,000 watts. To compare, the heat pump requires less than 500 watts.
However, this system has limits and is far from being a miracle solution, as the site’s journalists point out. Clean Automotive. They wanted to know if this system, which generally represents an additional cost when purchasing, as an option, is actually useful and relevant. And you will see that this is not always the case.
Useful in certain situations
For this, they used a Hyundai Ioniq 6 equipped with a heat pump and which accurately displays the consumption of the various on-board systems, including air conditioning. The journalists then left the vehicle parked outside overnight in the shade so that the sun would not affect the sensors. They then turned on the heating and set the temperature to 20 degrees.
There, power soars, displayed at 5.92 kW before dropping to 4 kW then to 1.5 kW while the temperature in the cabin was 22.5 degrees. Less than fifteen minutes later, the power was below 1.0 kW, beforeoscillate between 0.6 and 0.5 kW after 45 minutes. Once the car started, the power picked up slightly before dropping again.
These figures prove that during the first kilometers traveled in winter, the heat pump does not manage to heat the passenger compartment quickly enough on its own. It is then assisted by a resistor… which consumes a lot of energy. But beware, this test was carried out with an outside temperature of 0°C. A particular situation, since it is around this temperature that most heat pumps no longer manage to operate on their own and need a resistor.
With a slightly milder outside temperature, the results would undoubtedly have been different. In fact, as soon as the heat pump can operate on its own, we see that consumption drops drastically: from around 6,000 watts to 1,000 or even 500 watts.
According to calculations by Automobile Propre, the heating system of a Hyundai Ioniq 6 equipped with a heat pump consumes an average of 1.7 kWh for 30 minutes with freezing outside temperature. A figure that then drops over time. The results are therefore unequivocal: the heat pump is really interesting in terms of consumption, but only for long journeys. If you drive less than half an hour, it is not necessarily necessary to opt for this option.
If this system makes it possible to draw less on the car battery, and therefore to reduce consumption and the cost of recharging, it takes several years to make it profitable. It will therefore only be relevant in certain cases, especially since motorists on long journeys often already have a large battery. The heat pump will therefore have a negligible impact, especially since it is also heavier than conventional heating. And weight is the enemy of autonomy.
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