"significant increase in the range of 10.7-42.2% for lightweight and aerodynamic efficient vehicles" shout out to aptera motors https://aptera.us/vehicle/ that's currently vapor ware "Designed with ~700 watts of integrated solar cells, drive up to 40 miles per day completely off the grid and enjoy 400 miles of range per full charge"
I have seen repeated claims of heat pump CoPs improving over decades. Can anyone summarize or provide links to what improvements are being made? Compressor technology? refrigerants? Fans to move heat? all of the above? Where is the path from here?
I can provide a likely incomplete summary of the improvements.
Compressors themselves have gotten much more energy efficient, although I'm not sure the impact on CoP is all that great since and waste heat from the compressor is being deposited in the home anyway. Variable speed compressors are the most efficient you can get pretty much.
Refrigerants have improved in someways, but not really in others. Since heat pumps could be running with exterior temperatures that are quite low, with the system under pressure, some refrigerant blends would have less than desirable vapor pressures leading to problems running in very low temperature conditions. For the most part, the changes to refrigerant blends have been related to their Global Warming Potential (GWP).
Expansion valves are a very important piece of a refrigerant loop, these used to be fixed orifaces. Nowadays these are dynamic, meaning they can increase efficiency of the system by metering the flow based on system load and other characteristics. These are called TXVs or Thermostatic Expansion Valves. Electronically controlled expansion valves are now hitting the market further increasing efficiency.
Finally there is the design of the interior and exterior coils. I dont think materials have changed much, but the surface area has changed. You may noticed a 2 ton unit from 1997 is about 1/4th the size of a 2 ton unit from 2022. More surface area on the coil for the exterior unit lets you extract more heat from the air without burning a ton of energy running the fan super hard.
Interior air handlers have probably improved some as well, variable speed motors, etc. Variable speed really is nice because you can get much more consistent temperatures in the home and wont get blasted in the face with heat from vents when a regular system cycles on and off.
refrigerants (though some regulations have negative impact on this),
Optimizing (DC motors and computers with sensors figuring out what is the best setting),
Absorbing waste heat from the process,
Insulation,
Materials that stay more clean or self clean.
There might be an additional benefit for fossil fuel trains. Point source capture is usually more efficient than direct air capture.
This isn't necessarily directly point source, but if the diesel exhaust is partially directed into the capture train, the CO2 concentration should be higher, and could have a more efficient CO2 capture.
From my armchair-research, there are scale challenges with plants.
Algae is commonly the go-to for CO2 scrubbing for it's relative efficiencies. Algae might scrub 1-3 grams of CO2 per liter per day (https://www.osti.gov/servlets/purl/1485133).
Humans exhale approximately 1kg CO2 per day.
I consider 300-1000 L of algae scrubber tanks per person a lot of volume.
I think there are large room diy heat pumps. "diy mini split heat" found me this [0] for example.
Also, depending on your hackerness, you could adapt window air conditioners.
From what I've seen, solar PV for heat only really makes sense if you're using a heat pump. But solar thermal for heat can be good, though. http://builditsolar.com has a number of DIY heating projects for X,000 USD in materials.
