Passive solar systems integrate solar air heating technologies
into a building’s design. Buildings are designed with
materials that absorb or reflect solar energy to maintain
comfortable indoor air temperatures and provide natural
daylight. Floors and walls can be designed to absorb and
retain heat during warm days and release it during cool
evenings. Sunspaces operate like greenhouses and capture
solar heat that can be circulated throughout a building.
Trombe walls are thick walls that are painted black and
made of a material that absorbs heat, which is stored during
the day and released at night. Passive solar designs can
also cool buildings, using vents, towers, window overhangs,
and other approaches to keep buildings cool in warm climates.
technologies can be used for
residential, commercial, and industrial applications. Commercial
and industrial applications can include air preheating for
commercial ventilation systems, solar process heating, and
solar cooling. A solar ventilation system can preheat the
air before it enters a conventional furnace, reducing fuel
consumption. Solar process heat systems provide large quantities
of hot water or space heating for industrial applications.
A typical system includes solar collectors that work with
a pump, a heat exchanger, and one or more large storage
tanks. Heat from a solar collector can also be used for
commercial and industrial cooling of buildings, much like
an air conditioner but with more complex technology.
solar power systems
focus sunlight on collectors that serve as a heat source
to produce steam that drives a turbine and electricity generator.
Concentrating solar power systems include parabolic-trough,
dish-engine, and power tower technologies. Parabolic-trough
systems concentrate the sun’s energy through long
rectangular, u-shaped mirrors, which are tilted toward the
sun and focus sunlight on a pipe, heating the oil in the
pipe and then using it in a conventional steam generator
to produce electricity.
systems use a mirrored dish similar to a satellite dish,
which collects and concentrates the sun’s heat onto
a receiver, which in turn absorbs the heat and transfers
it to fluid within the engine. The heat causes the fluid
to expand against a piston or turbine to produce mechanical
power, which is then used to run a generator to produce
electricity. Power tower systems use a large field of mirrors
to concentrate sunlight onto the top of a tower, where molten
salt is heated and flows through a receiver. The salt’s
heat is used to generate electricity through a conventional
steam generator. Because molten salt efficiently retains
heat, it can be stored for days before being converted into
electricity and ensures power production on cloudy days
and after the sun has set.