Exhausted: How we can stop lithium mining from draining water, draining wetlands and endangering communities in South America
‘Home of the Future’ – Solar Home Equipped with Electric Ford F-150 Lightning Backup Power (Video)
Astute readers will recall that we already reported on this new Ultium technology when we first announced it late last month, but I think it’s something to look back on, as it’s a big part of the big efficiency issues that plague everyone’s cars: Get some benefits from waste heat.
Before I go any further, it’s important to note that EVs generate far less waste heat than ICE vehicles.For an average gasoline car, about 25 percent of the chemical energy in a gallon of gasoline is used to actually drive the car to its destination.The rest is used for waste heat and seeps through the radiator, exhaust and heat in the engine bay.Ordinary friction brakes for non-electric vehicles also generate waste heat, literally absorbing kinetic energy in the car and converting it into heat to slow the vehicle down.
benefit?Gasoline and diesel cars can absorb some of the waste heat and use it to keep the cabin warm.The heater core is basically a small radiator that gets hot as coolant is pumped from the engine, and a fan blows air through it to give you heat.Thus, a small fraction of wasted energy is fully utilized.
By contrast, electric vehicles convert only a fraction of their energy into waste heat, using most of that energy to actually get the car on the road.When you factor in regenerative braking (producing some electrical energy instead of waste heat like friction brakes), the overall efficiency of an EV can be closer to 90%.This is an amazing feat.You can’t use waste heat to run the vehicle’s heat the way you can with a gasoline car, but you also don’t waste a lot of energy and dump it into the atmosphere.
But that doesn’t mean EVs don’t need to deal with waste heat.Decent EVs have liquid battery cooling systems that extract this waste heat from the battery pack and dissipate it through a radiator, just like burning a car.However, there is a lot less waste heat, so there is no need for a large radiator and the front of the vehicle is more aerodynamically efficient.
Tesla and other companies that make electric cars do try to harness the waste heat from battery packs.Tesla has a multi-way valve that can pump some heated coolant into the heater core, or conversely, heat the coolant and pump it into the battery pack to heat the battery and improve cold-weather performance.
In a GM press release, it said: “The Ultium platform can recover and store waste heat from the Ultium propulsion system. In addition, it can capture and utilize moisture inside and outside the vehicle, including the body temperature of passengers.”
I have to admit, at first, I was a complete nerd and reminded me of The Matrix (in which AI robots use human body heat to power their civilization).However, I’m reasonably sure the GM isn’t plugging us into the virtual world and stealing our body temperature, so they may be using other methods.
When I was trying to figure out what GM was doing to achieve energy recovery, I couldn’t find the details.A YouTube channel interviewed a GM engineer who barely told viewers that it had little to do with it other than recycling waste heat and putting it to work.Other sources speculate a bit, but otherwise just regurgitate the press release, which gives us an idea of ​​what the energy recovery system does, but not how it happens.
The only clue I can find is here where an engineer says what makes the system special is not the novel parts, but how the existing parts fit together and work together.So now I can actually make some educated guesses instead of making random guesses.
Without novel parts, we can rule out the idea of ​​something really cool in the system, like a thermoelectric generator.Instead, we have to assume that components commonly found on electric vehicles are already functioning as GM says are the new system for the Ultium car.Because they mention cabin heat, that means we need to look at not only the battery cooling system, but also the HVAC system.
This leaves us with a liquid cooling/heating system for the battery pack and liquid connections to the HVAC components.We can also assume a heat pump is involved, as this is the most efficient way to cool and heat the cabin, unless resistance heating is required in extremely cold conditions.But I think GM uses its heat pump more like a geothermal heat pump.
Geothermal heat pumps exchange heat or cooling with the earth, thereby maintaining a constant temperature.This is more efficient than exchanging heat or cold with air, which varies widely throughout the year, so the heat pump itself doesn’t have to work as hard to heat or cool a home or business.
Through heat exchange between the battery pack, power electronics (including regenerative braking waste heat), the radiator, and the interior of the vehicle (which may be hot or cold), the computer can decide which way to pump the heat.If the cabin gets too hot, the heat pump can work as an air conditioner, taking heat from the cabin air and depositing it in the cooling system to pretreat the battery pack.It can do the opposite if the cabin is cold.
If both the cabin and the battery are hot, a pump can help remove the heat from both.It can act as a more efficient battery preconditioning system (rather than resistive heat) if both are too cold.In this way, the system can theoretically use as little energy as possible in all situations.
But how does it use our body temperature?Well, that’s not much, but when the cabin is too hot, so are you!As it cools the cabin, your body heat is drawn into the system along with other heat.
Finally, if you can’t use the excess heat to generate electricity for the battery pack, how do you store that energy?GM may be using the same trick to store heat as the Toyota Prius: basically a large thermos.If there is too much heat in the battery/cabin cooling system and it cannot be used now, the system may be putting some hot coolant into the insulated chamber.Then, if hot coolant is needed to heat the cabin or the battery, they can release the heat instead of using the battery’s energy to cool it.
GM will come out later and tell us all about how the Ultium heat pump system works, and it may differ from what I wrote here.But I don’t see normal HVAC and cooling systems doing what they claim to do in any other way (Editor’s note: a quick Google search shows that back in 2016, a company called Evonik demonstrated a thermoelectric generator , whose website states that General Motors is one of its end customers).However, GM can’t go around telling everyone else how to make a more efficient system, otherwise everyone would do it.If you work for an EV company, don’t just do what I say in this article, because GM probably owns some of these patents.
Either way, it’s great to see that more and more manufacturers are taking efficiency seriously.Hope more companies follow.
Jennifer Sensiba is a longtime efficient car enthusiast, writer and photographer.She grew up in a transmission shop and has been experimenting with vehicle efficiency since she was 16, driving a Pontiac Fiero.She enjoys exploring the American Southwest with her partner, children and animals.Follow her on Twitter for the latest articles and other random things: https://twitter.com/JenniferSensiba
While the U.S. Postal Service is fiddling with gasoline vehicles, Ford Motor Co. has launched its new E-Transit electric vehicle in the delivery van market.
GM CEO Mary Barra told Yahoo!The company plans to sell more electric vehicles in the U.S. than any other automaker, including Tesla, finance said,…
Copyright © 2021 CleanTechnica.Content produced on this site is for entertainment purposes only.The opinions and comments posted on this site may not be endorsed by, and do not necessarily represent, CleanTechnica, its owners, sponsors, affiliates or subsidiaries.