Search results
Results from the WOW.Com Content Network
Evaporative cooling is an atomic physics technique to achieve high phase space densities which optical cooling techniques alone typically can not reach. [1]Atoms trapped in optical or magnetic traps can be evaporatively cooled via two primary mechanisms, usually specific to the type of trap in question: in magnetic traps, radiofrequency (RF) fields are used to selectively drive warm atoms from ...
Evaporative cooling is also the last cooling step in order to reach the ultra-low temperatures required for Bose–Einstein condensation (BEC). Here, so-called forced evaporative cooling is used to selectively remove high-energetic ("hot") atoms from an atom cloud until the remaining cloud is cooled below the BEC transition temperature.
Demonstration of evaporative cooling. When the sensor is dipped in ethanol and then taken out to evaporate, the instrument shows progressively lower temperature as the ethanol evaporates. Rain evaporating after falling on hot pavement. Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. [1]
Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and non-toxic; however, it can contain impurities and cause corrosion. Water cooling is commonly used for cooling automobile internal combustion engines and power ...
The law holds well for forced air and pumped liquid cooling, where the fluid velocity does not rise with increasing temperature difference. Newton's law is most closely obeyed in purely conduction-type cooling. However, the heat transfer coefficient is a function of the temperature difference in natural convective (buoyancy driven) heat transfer.
There is evidence that evaporative cooling may have been used in North Africa as early as the Old Kingdom of Egypt, circa 2500 BC. Frescoes show slaves fanning water jars, which would increase air flow around porous jars to aid evaporation and cooling the contents. [3] These jars exist even today. They are called zeer, hence the name of the pot ...
The measurements range from under 30 to over 120 inches per year. Formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool. [5] [6] In some countries, the evaporation rate far exceeds the precipitation rate. Evaporative cooling is restricted by atmospheric conditions.
Evaporation: The evaporation of the warmer water reduces the mass of the water to be frozen. [22] Evaporation is endothermic, meaning that the water mass is cooled by vapor carrying away the heat, but this alone probably does not account for the entirety of the effect. [5]