Heating a car with a combustion engine is a simple problem to solve. But what about electric vehicles, which do not have a thermal energy source? Let’s take a look.
Conventional vehicles use a combustion engine to drive themselves by generating thermal energy. But the energy efficiency of such machines is, at best, 50%, the rest being lost as heat.
It is this heat that a car with a combustion engine uses to heat the passenger compartment and ensure the well-being of the occupants.
But, in the case of an electric car, such a system is impossible because the heat generated by the system is insufficient (we are talking about energy efficiency values above 85%).
“Heating the passenger compartment on cold winter days can become a serious drawback for autonomy.”
There is no shortage of systems, in any case, to generate heat in the passenger compartment of an electric vehicle.
The problem is that almost all of them consume energy from the batteries and, therefore, the range of the car will be affected.
The range is one of the biggest problems of today’s electric vehicles, so having to do without part of it to heat the passenger compartment on cold winter days in areas with extreme temperatures can become a severe drawback.
Heating systems in electric cars
How do manufacturers currently deal with this issue? Below we will look at the present and future methods, some more effective than others.
Electric heaters or heat pumps
This is the most conventional system and generates heat by heating electrical resistors, which, in turn, heat the liquid in the heating circuit.
Vehicles such as the Nissan Leaf or the Renault Zoe already use another variant: the heat pump, which is much more energy efficient.
In any case, both systems require energy from the battery and therefore reduce the vehicle’s range.
Recharging as an ally
One of the systems that some manufacturers use is to take advantage of the vehicle’s battery recharging process.
Using a programmer, the vehicle uses part of the energy received through the recharging point to heat the passenger compartment using electric emitters so that the autonomy is not affected and the occupant gets into the car at a previously set temperature.
The charging points are used by some vehicles to preheat the passenger compartment.
This makes it much easier to maintain a pleasant atmosphere in the passenger compartment once the car is underway and requires significantly less battery energy.
Obviously, for this system to be effective, the vehicle must be well insulated, and the occupants must cooperate, as opening the windows or doors will ruin the energy savings previously achieved.
Volvo initially developed this system, the electric C30. It used ethanol or ethyl alcohol as fuel through burners that heat the passenger compartment and other vehicle systems.
Ethanol is cheap and has high energetic power; a sink of about 25 liters can be enough to heat a passenger compartment for a month in cold climates.
Another advantage is that it is a system that is entirely independent of the car’s electrical system, so it will not reduce autonomy. However, the disadvantage is that it is a tank to be controlled and refilled by the user.
This project, launched in 2014 and funded by the European Union, aims to reduce the drawback of the lower autonomy of electric vehicles to make them more attractive and competitive than thermal engine cars.
The first results, unveiled in 2019, speak of savings of up to 57% of the energy used by heating systems in electric vehicles and seek to take advantage of radiant heat.
The system focuses on radiating heat in the areas near the occupants through the Joules effect, which consists of heating a metal through electric currents.
But since vehicle interiors are mostly made of plastic materials, conductive nanoparticles are added to make this possible.
Thanks to such plastic panels, doors, floors, roofs, seats, etc., can be heated. According to studies by organizations such as Durplastics or the Galician Automotive Technology Center, comfort is superior to that of the traditional system, and energy savings are 30%.
Keeping the interior of a vehicle warm in winter can require a lot of energy.
But there is an additional 27% energy savings through data analysis provided by measurement sensors installed in the vehicle that allows optimizing consumption or more advanced materials.
Examples of this are the system’s eco-driving recommendations or the lighter glazing in transparent plastic with particles that reflect solar radiation when the passenger compartment needs to be cooled.
How much does the heating of an electric car cost?
The answer to this question depends on the circumstances and the individual vehicle. It is not the same to heat a large passenger compartment as a small one or to heat it in the morning after a winter frost as on a cool autumn or spring morning.
In any case, heating an electric car equipped with a conventional system in winter will require a reduction in range of between 6 and 10% under normal conditions.