Heat Transfer Fluid
Heat can be stored for later use in a heat transfer fluid. This can overcome the intermittency of solar energy to some extent. Heat from biomass can also be stored in a heat bank, allowing for "cascading" use (example: waste heat from cooking is captured in a chimney and later used to heat up water). Examples of heat transfer fluids are water, molten metals/salts and oils.
Molten Salts and Metals
used in (fast) breeder nuclear reactors sodium (Na), potassium (P) or an alloy of these (NaK, pronounced "nack").
molten salts: Sodium nitrate - used as heat transfer fluid for large solar thermal installations
Oils
Vegetable oils can be used as heat transfer fluids. They have high thermal capacity, are often very liquid at high temperature, but may degrade over time and are expensive.
Product Ecology
- heat sources: solar energy from a heliostat; also biomass energy
- Solar Combined Heat Power System