Airships only make sense in a world in which the economy takes into account ecodestruction. Kind of like wind-powered ships. If we didn’t know what GHGs do environmentally, which offset any short-term efficiency gains provided by burning hydrocarons, nobody would ever dream of abandoning these miracle fuels. So you can only examine the efficiency of airships with hydrocarbons off the table entirely.
They do plenty of ecodestruction. If we had them now, they’d be fueled by hydrocarbons. That could hypothetically be batteries in the future, but batteries good enough for that could do equally well in airplanes.
The material used in making them rigid also has a carbon cost.
It wouldn’t be light enough. Panels weight about 19kg each for a 1x1.7m panel. This can probably be slimmed down for the application, but probably not by enough. Perovskite promises a lighter weight panel, but they still have longevity issues that are being worked out in the lab.
Why not put those panels on a boat instead? Or in a field and power a train?
Your 1 panel at less than 2 sqm weighs as much as more than 6 square meters of thin film. The 40 or 50% better relative efficiency doesn’t make up for the increased square footage. What kind of wattage would we even need?
Hindenburg used 4x 735kW diesel engines which need to be powered constantly (almost 3MW overall). That is the output at the shaft, which means we need electric motors that match that. Fortunately, electric motors are pretty efficient.
Thin-film can do 80-120W per m^2. That’s the rating when the sun is shining directly on them. We’ll assume it’s flying above the cloud layer and don’t need to worry about that.
At the top end, it will take 24,500m^2 of panels. Hindenburg had a length of 245.3m and diameter of 41.2m. If it were a cylinder (because I don’t feel like doing the math on its actual shape), it would have a surface area of 35,000m^2, but that includes the underside. It’ll probably pick up some power being reflected off the clouds or the earth’s surface, but you’re probably only getting 60% of the full power averaged over the entire surface.
Which is closer than I thought it would be, but not quite enough to power the motors if they were 100% efficient, and dropping it to the real world 85-90% won’t help. Neither will accounting for its actual shape.
Hindenburg had a cruising speed of 131km/h, so solar electric would just be pegged to a lower top speed assuming we didn’t touch any other parts of the design.
I think efficiency gains in propeller tech, changes in crew and gear requirements, structural materials, and the rest of it would make it feasible.
Airships only make sense in a world in which the economy takes into account ecodestruction. Kind of like wind-powered ships. If we didn’t know what GHGs do environmentally, which offset any short-term efficiency gains provided by burning hydrocarons, nobody would ever dream of abandoning these miracle fuels. So you can only examine the efficiency of airships with hydrocarbons off the table entirely.
They do plenty of ecodestruction. If we had them now, they’d be fueled by hydrocarbons. That could hypothetically be batteries in the future, but batteries good enough for that could do equally well in airplanes.
The material used in making them rigid also has a carbon cost.
Don’t forget that they are huge, you could fit a lot of solar power on them, given that it would be light enough
It wouldn’t be light enough. Panels weight about 19kg each for a 1x1.7m panel. This can probably be slimmed down for the application, but probably not by enough. Perovskite promises a lighter weight panel, but they still have longevity issues that are being worked out in the lab.
Why not put those panels on a boat instead? Or in a field and power a train?
"Thin film solar is light weight at 7-10 ounces per square foot. "
https://en.m.wikipedia.org/wiki/Thin-film_solar_cell
Your 1 panel at less than 2 sqm weighs as much as more than 6 square meters of thin film. The 40 or 50% better relative efficiency doesn’t make up for the increased square footage. What kind of wattage would we even need?
Hindenburg used 4x 735kW diesel engines which need to be powered constantly (almost 3MW overall). That is the output at the shaft, which means we need electric motors that match that. Fortunately, electric motors are pretty efficient.
Thin-film can do 80-120W per m^2. That’s the rating when the sun is shining directly on them. We’ll assume it’s flying above the cloud layer and don’t need to worry about that.
At the top end, it will take 24,500m^2 of panels. Hindenburg had a length of 245.3m and diameter of 41.2m. If it were a cylinder (because I don’t feel like doing the math on its actual shape), it would have a surface area of 35,000m^2, but that includes the underside. It’ll probably pick up some power being reflected off the clouds or the earth’s surface, but you’re probably only getting 60% of the full power averaged over the entire surface.
Which is closer than I thought it would be, but not quite enough to power the motors if they were 100% efficient, and dropping it to the real world 85-90% won’t help. Neither will accounting for its actual shape.
Hindenburg had a cruising speed of 131km/h, so solar electric would just be pegged to a lower top speed assuming we didn’t touch any other parts of the design.
I think efficiency gains in propeller tech, changes in crew and gear requirements, structural materials, and the rest of it would make it feasible.