Using heat pump air conditioners for Electric Vehicles

Context of Transport Climate Action

Transport is a large contributor in global CO2 emissions, and cars produce around 12% of EU’s CO2 emissions (1). Therefore European Union created the CO2 emission Regulation that sets car fleet CO2 emission performance targets for 2015 and 2021. A large variety of existing or developing technological solutions must be utilized in order to achieve this target. Electric Vehicles (EV) can play an important role in the overall vehicle product mix to achieve these targets at an affordable cost for the consumer.

However, the short range (distance on one charge) of electric vehicles has limited their popularity. DENSO has recently developed a solution that vastly extends their cruising range. This heat-pump air conditioner, the world’s first for automobiles, was made possible by advanced DENSO heat-energy management technology. Heat-pump air conditioners deliver both passenger comfort and eco-friendly performance.




Conventional heating currently consumes 50 percent of an EV’s energy.

Eco-friendly vehicles like EVs and hybrid vehicles (HVs) are good for the environment, but the comfort of passengers is important as well. In the winter, vehicles powered by gasoline and diesel engines warm their interiors using heat from the engine. But EVs need to use electricity as the engine does not produce as much heat, taking power from the drive motor. In fact, over half of the stored electricity can end up being used to warm the car interior, reducing the driving range of the car.


When an EV’s electric heater is replaced with a heat-pump air conditioner, its interior can be heated in winter using dramatically less electricity. So the EV can retain more of its charge for driving.


When developing the heat-pump air conditioner, we first focused on achieving efficient heat control and secondly we made sure it kept all passengers comfortable in a simulated interior, testing weather extremes. And finally, we made sure the compressor ran quietly with minimal vibration to match the silent performance of EVs. Using our comprehensive expertise, we have developed an entire system (including control and adjustment features) that satisfies the requirements of our automotive customers. The commercialization of this device has started and we expect that within a period of 10 years our heat-pump air conditioner to become the world standard.


Besides the extended cruising range and comfort during the winter season mentioned above, there are several other benefits.

Upstream CO2 savings from electricity

The CO2 emitted from electric vehicles is dependent on the grid profile. The EU electric energy mix has carbon intensity of 540 g CO2eq/kWh (2).

As EVs become more efficient this also contributes in reducing the upstream CO2.

Electricity grid network

It is expected that there will be a growth in renewable energies which brings challenges in grid stability. EVs and managing when they are charged can be one of options in balancing the demand and supply of electricity.

Resource use

Increasing the EV electric efficiency avoids using larger battery and therefore saves rare materials.

(2) WELL-TO-WHEELS Report Version 4.a (2014). JEC WELL-TO-WHEELS ANALYSIS. JRC technical reports. European Commission

Potential for scaling up

EVs can play an important role in curbing CO2 emissions from transport. But currently the market uptake of EVs is slow. By focusing on the customer needs and by exceeding the customer expectations for comfort and convenience, DENSO’s approach is helping to accelerate the market uptake of EVs.

Additionally, incentive policies such as Eco-Innovations, the EU’s CO2 credit scheme under Cars CO2 emission Regulation, can also act as a stimulus to market takeup. Comfort related functions (heating/cooling) are excluded from its scope today. However, they are important to improve comfort in the cabin and their efficiency improvement is also important to reduce global CO2 emissions when the cars are actually being driven (real world). Therefore expanding the Eco-Innovations scope, so that Heating and Cooling technologies are also eligible for CO2 savings, would be one of ideas to facilitate the uptake of EVs further.

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Global, mitigation, passenger car, technology, innovation




Toshio Hirata

“We hope DENSO’s heat-pump air conditioner becomes the next-generation automotive standard."

Name: Peter Flanker
Role: Regulatory Affairs