Selective Inverted Sink
Encyclopedia
The selective inverted sink or SIS is a device used by farmer
s to protect plants from frost
, developed by Uruguay
an Rafael Guarga in the late 1990s.
The sink is actually a large fan
housed in a chimney-like
structure, and works by defeating surface temperature inversion. Cold air is denser
than warm air, and will pool at ground level during calm weather. This lowers the surface temperature, even if the ambient temperature is higher. Vents near the base of the chimney allow cold surface air to be pulled up through the chimney, creating a suction effect that draws warmer air down to surface level.
The SIS is more efficient than typical ground-heaters, and is widely used to combat frost.
Farmer
A farmer is a person engaged in agriculture, who raises living organisms for food or raw materials, generally including livestock husbandry and growing crops, such as produce and grain...
s to protect plants from frost
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
, developed by Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
an Rafael Guarga in the late 1990s.
The sink is actually a large fan
Fan (mechanical)
A mechanical fan is a machine used to create flow within a fluid, typically a gas such as air.A fan consists of a rotating arrangement of vanes or blades which act on the air. Usually, it is contained within some form of housing or case. This may direct the airflow or increase safety by preventing...
housed in a chimney-like
Chimney
A chimney is a structure for venting hot flue gases or smoke from a boiler, stove, furnace or fireplace to the outside atmosphere. Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the...
structure, and works by defeating surface temperature inversion. Cold air is denser
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
than warm air, and will pool at ground level during calm weather. This lowers the surface temperature, even if the ambient temperature is higher. Vents near the base of the chimney allow cold surface air to be pulled up through the chimney, creating a suction effect that draws warmer air down to surface level.
The SIS is more efficient than typical ground-heaters, and is widely used to combat frost.