HVAC EFFICIENCY AND EFFECTIVENESS

Updated: May 1, 2019

It's 12°F outside at 6:00 am and you're just about to hit the road, but getting into a stone cold vehicle isn't the most motivating idea to start your day. Some fossil fuel pickups have remote start capabilities - if you remember to do it and if you're not parked in a garage, but they take a long time to heat up. Idling isn't an effective way to warm an engine.

Most electric vehicles (EVs) provide a little more capability, allowing scheduling of pre-conditioning, faster heat-up of the cabin, with no concerns around starting inside a garage. Your 6:00 am trek is no longer so intimidating. However, as EV owners who live in northern states know well, one of the largest power draws on an electric vehicle outside of the traction motors is the heating, ventilation, air conditioning (HVAC) system. Warming the cabin in cold weather while driving (not plugged in), is one of the most significant items that reduce winter range.

At Atlis Motor Vehicles, we believe this is one area of overall vehicle efficiency that can be greatly improved upon, and we have filed a number of provisional patents around these technologies. We also believe that the customer experience should be as seamless as possible - we want to provide a comfortable environment without the customer having to jump through excessive hoops. So with regard to the HVAC system, here are a few things we're doing to provide the best experience possible.

Seat heaters will be integrated to the HVAC system settings, which will be especially useful for cabin preconditioning. Right now many vehicles are capable of automatically pre-heating the air of the cabin, but not the seats. With our system, if the interior of the cab is cold and the vehicle is preconditioned via schedule or remotely “started”, both the cabin heater and seat heaters will turn on automatically until a comfortable temperature is achieved. We see no reason the user should take extra steps or have to push extra buttons to make the cabin comfortable.

Some EVs have a “driver only” mode where you can press a button to tell the HVAC system that there are no passengers, and it will shut off the second zone to focus the heating or air conditioning just to the driver's area to reduce the total power draw. That's a great concept, but again we think it should be automatic. Utilizing pressure sensors in the passenger seats we will be able to tell where people are seated in the vehicle and automatically focus the system only to those areas. If a driver is alone in the vehicle, power won't be wasted heating the passenger side or rear of the cab and will instead be focused solely on the driver's area, automatically.



Overall efficiency of vehicle heating systems are pretty low - because of poor insulation, poor airflow control, and the fact that the vehicle can be travelling at 70 mph through cold ambient conditions. It makes for a difficult environment to keep comfortable, especially with so much glass. With fossil fuel vehicles, the heating efficiency was never a concern because the engine already creates a tremendous amount of excess heat which is relatively easy to redirect to the cabin. But EVs have a very efficient drivetrain with little wasted energy.

To combat this, Atlis will use heat pumps and heat scavenging from the motors and controllers in order to use as little energy as possible while still providing a comfortable cabin.

Atlis is focusing on sealing the cab as tight as possible while providing just the right amount of external airflow for fresh air and moisture control. Any external-to-internal air flow channels are designed such that they aren't dumping air directly on any passengers. Cabin panels will be insulated as well, using techniques from the aerospace industry to provide thin but effective insulation. All of this is aimed at maintaining a comfortable cabin environment with a minimum electrical draw from the batteries.

While cold-weather situations are the harshest, we're also taking into account extreme heat and sun. The airflow controls and insulation described above will be beneficial in both cold and hot weather, but we're also examining technology to auto-tint the windows when parked in hot weather to reduce the wear and heat levels in the interior. That, coupled with an automatic ventilation system in hot conditions, will keep the cabin at more reasonable temperatures even in the extreme heat and direct sun of Arizona where we're based.

All of these efforts are to provide as much range as possible, delivered efficiently, while providing maximum passenger comfort and convenience.

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