Model Y Heat Pump

Model Y is the first Tesla with a heat pump. Here’s why that’s a big deal.

An inconvenient fact all electric vehicle drivers must learn to contend with during their first winter is range reduction. The 250-mile range of Model 3 Standard Range Plus sounds great, but that range is for ideal conditions. Drive your EV on a cold winter’s day and you won’t make it the full 250.

Heating the cabin for passenger comfort is actually one of the biggest factors in winter range reduction. Most EVs still use a resistive heating element, like in an electric space heater. The problem is that this method of heating uses a lot of electricity, and every electron pulled from the battery pack to heat the cabin is an electron not being used to power the car forward.

While it’s actually fairly easy to cope with winter range reduction with a little planning, it still diminishes the capabilities of electric vehicles—and most EV owners would prefer to eliminate or mitigate the problem, if at all possible.

Between heating the cabin and the reduced efficiency of the Lithium-ion battery in cold weather, some EV drivers are looking at up to 40 percent less range, according to one AAA study.

Thankfully, there’s an available technology that’s more efficient than these traditional electric resistance heaters: heat pumps.

Heat pumps operate similar to refrigerator compressors by moving heat from one place to another. A refrigerator pumps warm air (heat energy) out of its interior into its surroundings, while a heat pump in an EV pumps energy from its surroundings into the car. You can also think of it like an air conditioner running in reverse.

Nissan Leaf Heat Pump Diagram

Diagram of a Nissan Leaf heat pump. | Image source: Nissan

Heat pumps are already on the road in several electric vehicles—sometimes as standard equipment, sometimes as a higher-trim feature, and sometimes as part of a cold-weather package.

Heat pumps appear in the Volkswagen e-Golf, Kia Soul EV, and were first adopted by the Nissan Leaf.

In an article about its first heat pump design, Nissan said “a more efficient air-conditioning system is achieved through optimization of the heat exchanger design that implements low power consumption, along with heating and cooling according to set temperatures, and temperature control when switching between cooler and heater that optimally adjust the compressor rotation.”

Volkswagen claims that e-Golfs equipped with the heat pump regain about 30 percent range in the right conditions, which is around 25 to 35 degrees Fahrenheit outside. If it gets much colder than that, the heat pump is less effective and the cars will use their resistive heaters instead.

German technology company MAHLE is working on its own heat pump to sell to automakers. It claims its technology can improve cold-weather cruising range by between 7 and 20 percent.

“In field tests with a compact electric car, MAHLE has demonstrated that its ITS [Integrated Thermal System] reduces the loss of cruising range substantially, especially at cold ambient temperatures,” MAHLE said in a press release. “The original vehicle equipped with conventional electric heating started with a cruising range of 100 kilometers. When the vehicle was equipped with the ITS, the cruising range increased to 116 kilometers.”

Heat pumps are one of those rare areas where Tesla has lagged behind the competition. All of its cars have relied solely on a traditional resistive heater—none have used a heat pump—until now. Its Model Y is the first of the bunch to come with one.

This upgrade has gone unannounced by Tesla. The news only broke when one of the earliest Model Y owners made a video where they dug beneath the frunk to see what was below. To everyone’s surprise, they found a heat pump.

Heat Pump

Close up of the Model Y Heat Pump. | Image Source: Daerik, YouTube.

Tesla’s long range and strong Supercharging infrastructure likely made the inefficient heating system a lower priority. After all, when cars have 250 miles of range or more, the winter reduction matters less.

That said, this new technology is sure to help Model Y. Its larger size and stance makes it less efficient than Model 3. While its range is close (just 5 to 7 miles off), a Model Y needs more help to ensure it achieves the highest possible range in all conditions—including cold weather.

Given the higher range of a Tesla, the potential 7 to 30 percent range a heat pump can save from being lost during cold weather driving is a much higher number of miles than what you’d see with a lower range car. If a 250-mile Model 3 Standard Range Plus had this technology, it could potentially gain 20 miles or more depending on conditions.

Whether or not heat pumps will reach the rest of the Tesla fleet is yet to be seen. While the company will normally roll out upgrades to all cars as soon as they can enter production, the heat pump in the video looks like it was sized and fit for the space underneath the hoods of Model Ys, so it may not be a simple plug-and-play solution.

Either way, heat pumps are a nice addition to EVs that have them, and they would serve a useful role on all of Tesla’s vehicles.

Posted in Electric Vehicle News March 25th, 2020 by