Solvarme

Solvarme is a term used for systems and methods that convert sunlight into thermal energy for heating buildings, water, and processes. It encompasses both passive approaches that use building design and materials to collect and store heat, and active systems that employ solar collectors to heat a fluid for distribution.

Active solar heating relies on collectors, typically flat-plate or evacuated-tube types, which absorb solar radiation and transfer the heat to a heat-transfer fluid such as water or a glycol solution. The heated fluid is stored in insulated tanks and circulated to provide domestic hot water or space heating, often via heat exchangers and pumps. Passive solar heating uses architectural features, thermal mass, and proper orientation to capture and release heat with minimal mechanical equipment.

Storage and distribution are central to solvarme. Thermal storage can be short-term (daily) or seasonal, enabling heat to be retrieved during periods of low sun. Active systems are commonly integrated with backup heating and, in some cases, with heat pumps or district heating networks.

Applications include residential and commercial space heating, hot-water supply, and swimming pools, with industrial process heat as an expanding area in some regions. Performance depends on climate, collector area, storage, and heat losses; efficiency is influenced by collector type, insulation, and system design.

Advantages of solvarme include reduced fossil fuel use, lower operating costs, and potential emissions reductions. Limitations involve upfront costs, space requirements, maintenance needs, and variable performance in cloudy or low-sun conditions. Adoption is strongest in regions with favorable sunshine and supportive policies.