This idea is I admit a little esoteric, because it has a lot of requirements and assumptions.
The basic idea is to create an insulated extension on the sunny side of a house for multiple purposes.
Assume a house in a temperate climate, with a requirement for hot water or other low-grade heat.
Assume also that the resident(s) are eco-friendly enough to spend their time moving things round instead of using maximally labour-saving devices, and make an investment in this extension with its associated plumbing.
The extension itself is essentially a very well insulated, tall, narrow (and potentially tapering) conservatory, in direct sunlight as much as is possible. This can be used for drying stuff - for example clothing and/or wood for a wood-burning stove. As a utility/working space it will have a hardwearing floor; perhaps tiles.
Close to the top of the space there are a series of thermal connections to various house heating requirements - perhaps primarily the hot water system.
I suggest that there should be at least two different types - firstly, a passive system which pre-heats water entering the hot water system. This comprises a set of heat-pipes leading to a thermal reservoir 'block' - through which the water pipe passes.
Secondly, an active system which pumps refrigerant around a loop and dumps the heat into the house (potentially the bottom of the hot water tank). This can be used whenever there is a greater demand for heat.
The thermal transfer system is designed such that condensation is channelled away to either be discarded or perhaps for low-purity requirements, e.g. watering plants. The more moisture which can be driven out of stuff, the more efficient the energy transfer is. If there temporarily is no drying requirement and humidity of the space is not an issue, the water could be returned to the floor.
Thus, the solar energy can be used multiple times for complementary purposes. In the spring, firewood may be stacked against the wall.
The availability of a large drying capacity over summer may yield further uses. For example, some food waste (like orange peel) could be dried into useful fire-starting fuel instead of discarded as compost, with its embedded energy wasted.