Heat Pump?

Assuming this article


Some oddities

• It doesn’t specifically say Silverado, but all future Ultium platform autos, so presumably but not confirmed
• This is technically a scavenging system, which basically all EV’s have. Many share it between HVAC and battery, which is a problem if you’re trying to use the AC while fast charging (not uncommon). Better systems have a separate system for HVAC, and for battery conditioning.
• Maybe lost in translation, but the blurb says “Scavenges humidity” which is wrong. A head pump is simply a refrigeration unit which has variable control/servoing, and can run both ways. Either pulling or pushing heat. Humidity has nothing to do with it. But this doesn’t specifically say that it is an ambient HVAC heat pump - it’s simply a fancy scavenger/battery balancer, with access to the cabin HVAC.
• Which as mentioned above may not be a good thing. If this is it - which seems probable for cost savings, then you man not get your fancy 350 kW (peak) charging if you use the AC, as then this system would not have cooling capacity, unless it happens to have separated systems (which apparently it doesn’t).
• The Bolt uses a cooling plate, which is a great passive system for cooling the battery, transmission and motor. Watching OBD I see that it’s the motor that looks like generates the most heat (130-150F running temp). But for defog capability you probably still need a strip heater in there somewhere.

Possibly one clue is the humidity bit, perhaps what they mean by that is that this system can also provide dehumidifying/defogging capability but scavenging cabin heat, thereby avoiding the complications of a resistive heat strip. If so that’s great! However we might still be limited on cooling capability while fast charging.

The article above expands on this some more, but basically still says it’s a recovery system which as I say they all have. Still unknown if it pulls heat from ambient, if it has resistive elements, and what the capacity it relative to both HVAC and fast charging.

So I think the jury is out, but my engineering sense says this is somewhat encouraging.

Direct from GM:

"Today, GM announced a feature standard in its Ultium-based EVs that captures and repurposes waste energy from the battery. Through the Ultium Platform’s energy recovery system, this waste energy can increase a vehicle’s range, reduce battery energy needed for heating, increase charging speed and even enable sportier driving. "

GM Ultium heat pump press release

The heat recovery heat pump is "standard" on Ultium-based EVs. Everything from the $30K Equinox to the Hummer EV. E From what I've seen from some of the patents, the new heat pump is ingeniously-simple...probably is less expensive both in parts and labor than the Bolt's HVAC/EV thermal management system, with just one glycol loop, one expansion tank, and fewer pumps. They replace the Bolt's three independent glycol loops and two PTC-glycol heaters (one for cabin heat, one for battery heat) with a single PTC glycol heater for the entire glycol loop.The Bolt's cabin HVAC glycol-based heating coil is replaced with a refrigerant condensing coil. Per owners' manuals, the much-larger 100 kWh Ultium-based Lyriq only requires 11.4 qt. of glycol as compared to the Bolt's 13 qts. Lyriq has two pumps. The Bolt has three. Defogging, the most inefficient winter HVAC mode for all EV, (Bolt typically uses 7 kW or more) is extremely efficient, at extremely cold temperatures typically using 3 kW or less, as it recovers all the compressor heat + cabin humidity latent heat for re-heating the dried/dehumidified defogging supply air.