jimmyhackers said:
just wondering if this is a thing? with energy prices going up in the uk/world i wondered how cost effective this could be? you could paint only the sides of your house that face the sunlight to reduce paint usage....or limit it to walls that wont offend your neighbours. anyone done this or knows what kind of benefit it could have?
Jimmy,
From my experience: I have a Firebird automobile with glass T-tops. The glass "roof panels" are very dark, with a black perforated metal screen embedded. On any warm sunny day, the glass was too hot to touch. At freezing air temperatures, this was okay, but in the summer, even the air conditioning struggled to cool the car inside. Being an RC airplane guy, I decided to coat the T-tops outside with silver (chrome) Mylar film (by Monokote). It is applied to the glass with a clothing iron, wrapped in a towel. It is heat-shrink material, so compound curves are no problem. In strong summer sunlight, with the chrome film applied, the T-tops are cool to the touch inside. I peel and discard the Mylar film each Autumn, get my solar heating back for Winter driving.
So, I have a suggestion. There are lots of options, but some solar mods to the house may be offensive to the neighbors. Certainly the Trombe wall is a nice start, but you can double the sunlight (heat) applied if you lay out "chrome" reflective panels flat on the ground at the base of the window wall. The sun-angle at your location will dictate the best placement (and width) of these reflective panels. At sundown, you would want to roll down full-cover window shades inside your glass, using white or reflective materials. If the window shades travel down in channels on each edge of the glass, and the bottom edge seals by weight, your window shades will prevent a lot of heat from escaping back into the atmosphere. Quite possibly, the neighbors may not shoot you for creating an eyesore, because they can't see the reflective panels.
The Trombe wall inside your house does not support anything, it is just a heat sink. You can paint it a dark color. Dark green is better than black, for solar heating; you have never seen a black tree growing. If you use (cheaper) cinder blocks for the Trombe wall inside the house, you can fill the big voids in the blocks with rock salt, because salt retains heat like mad, even better than solid blocks. Regulate the heat you will capture by adjusting the reflective panels and window shades. A ceiling fan near the Trombe wall can help to distribute the heat inside the house. HTH.