Fair enough. In what I was thinking about, there would be no long ducts. Just directly thru the wall. So the fan power and noise would be much less, if convection wouldn't do enough.My house came with a "solar air heater" installed on the outside. It consisted of a layer translucent fiberglass with an air gap, then corrugated and stippled aluminum painted black with an air gap, and then some 6"x8" ducts in both of the upstairs bedrooms. Those ducts ran down to the slab, then joined in a channel running under the floor to a blower under the stairs. We tried to use it and didn't really think much of it. The blower is loud and the exterior treatments are hideous. I'll try and find a picture taken before we removed it. I covered the ducts coming out of the slab and sealed them. The large 12" round duct coming out of the floor under my stairs is also closed in. This system probably worked better in the summer to cool the house since the intake for the slab duct was facing the front door, which also faces North and has loads of shade. We never got to find out since we started tearing the solar wall down before it got hot. Before destroying all of that work the builder put into the house I asked some folks on this site and around town, most everyone, besides our home inspector, said it is not very effective.
Edit: Our house also has a solar water heater on the roof, but the way it was integrated into the house (completed 1976) did not work well. This means we have a 1975 SWH on the roof that has had water run through it once by me as a test for leaks and probably once by the builders. Eventually I'd like to repurpose it to use a heat exchanger and glycol to assist our current DHW system, which is a 40 gallon tank heated by my cookstove with a on demand electric heater for backup.
I did remove the registers from the bedroom ducts and put my hand against the panel during our first winter and it was almost too hot to touch on a clear day. How much of that heat made it into the bedroom is questionable. Whatever heat gain we had in the house was offset by how hideous the solar air heater was.Fair enough. In what I was thinking about, there would be no long ducts. Just directly thru the wall. So the fan power and noise would be much less, if convection wouldn't do enough.
Meh. Azobenzenes get used in all kinds of 'magic trick' experiments with light, but they are not very efficient or durable. And the energy stored per mass of the material is likely rather low.I'm not sure if it will pan out, but this branch of research is intriguing in its potential for solar heating.
As we move away from fossil fuels and shift to renewable energy to tackle climate change, the need for new ways to capture and store energy becomes increasingly important.www.lancaster.ac.uk