There are several solar thermal technologies available, all work by using sunlight to heat a fluid.
Due to the seasonal variation in daylight hours this technology is best suited to heating hot water rather than space heating. This is usually achieved with a roof mounted panel that heats a primary fluid to over 100°C this is then used to heat a thermal store.
Solar walls have been used for space heating by directly heating air, but in the UK the short winter daylight hours mean that there is the least amount of sunlight when heating is needed the most.
Solar thermal heat can also be combined with absorption chilling to provide solar cooling.