In the car, driver comfort is essential. The air-conditioning system is made of an air circuit and a closed refrigerant circuit (air-conditioning loop) and is mandatory to create cabin comfort, but can absorb 5% to 12% of a thermal engine power and up to 50% of the power of an electric engine. Highly aware of environmental issues and forthcoming regulations, Valeo is looking for innovative ways to improve energy efficiency and avoid losses, not just for vehicles with thermal engines (which run on fossil fuels – oil) but also for hybrid and electric vehicles.
The components of an air-conditioning loop are:
Compressor: This compresses the refrigerant in a gaseous state (under high pressure, at a high temperature, in the form of vapor) and sends it to the condenser.
Condenser: located in the front-end of the vehicle, it cools the vapor which returns to its liquid state.
Receiver dryer: this prevents the formation of water (humidification) in the refrigerant.
Expension valve: this cools the refrigerant before it enters the evaporator by reducing its pressure (bringing it to the same level as the evaporator pressure).
HVAC unit: located bellow the dashboard and attached to the bulkhead (on the engine hood side), it adjusts the temperature and air distribution in the cabin according to the user’s requirements. When it crosses the evaporator, the refrigerant evaporates at a low temperature and low pressure. Then the air passes away the evaporator is cooled, before being blown into the cabin. The radiator heats the air that crosses it, raising the cabin temperature in cold weather.
For electric vehicles, it is possible to mount a heat pump system which operates like a reversible air-conditioning system. This system captures calories from the exterior air, delivering them to the vehicle interior in heating mode and, conversely, evacuates calories from the cabin air to the outside in air-conditioning mode. This system generates significant energy efficiencies and therefore improves battery autonomy.
Find out more
The air-conditioning loop is a closed circuit that contains refrigerant only. The refrigerant currently used is R134A. It will soon be replaced by 1234yf.
This refrigerant leaves the compressor in a gaseous state under high pressure, and at a high temperature due to the pressure. It is sent to the condenser, where heat is exchanged between the cold exterior air and the hot fluid. As it cools, the refrigerant condenses and converts from a gaseous to a liquid state. It leaves the condenser as a warm liquid, under a lower pressure. The refrigerant passes through the receiver dryer which captures the water created by condensation. Then it crosses the expansion valve, which reduces the pressure of the refrigerant, thereby cooling it. The decompressed refrigerant then passes through the evaporator, where heat is exchanged between the air flowing into the cabin and the cold refrigerant circulating in the evaporator.When it leaves the evaporator, the refrigerant is warm and does not have enough pressure to travel through the air-conditioning loop, so it is redirected towards the compressor, which repressurizes it again so it can circulate around the loop.
When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. These cookies do not store any personally identifiable information.
These cookies allow us to measure visits and traffic sources so we can improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and your personal data will not be identified by these cookies as they collect anonymous information. Some other sites may call these “performance or analytics cookies”. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
These cookies enable us to personalise your experience on our site with things like relevant content (e.g. videos) or products you might be interested in (e.g. based on what you previously viewed). These cookies may be set by us or by third party providers who add services/features to our sites (e.g. videos). If you would like the site to be more tailored to you, please turn these cookies on.