B4-FV-12-A PAO oil H Provided for synthetic low temperature Bevel-helical speed reduction gearboxes B4

Flender/Flender Gear Units/Bevel-helical speed reduction gearboxes B4

y does not vary by more than 1 during the year for any given location ( if taken at depth at which soil temperature is nearly constant. This depth varies with geographical region and can range from 2 to 9 (. The water can be used as heat sink to cool produce if circulated through some type of heat exchanger. 3.5.3 High-Altitude Cooling The temperature of air drops about 1 for every 1- increase in altitude (. This can be useful for cooling produce if the situation warrants. For example, produce that must be transported into nearby mountainous area, either to be distributed or to reach its nal destination, may be stored in that area to take advantage of the lower temperature. 3.5.4 Underground Storage Underground storage is good for keeping produce cool but not for removing eld heat. Soils have low thermal conductivity, which limits the rate of transfer away from thestorage. This problem can be solved partially by installing network of pipes in the soil through which air can be pumped to transfer heat away from the soil. greater soil volume can then be used to cool the produce. 3.5.5 Thermoelectric Cooling (Peltier Effect) The Peltier effect is the heat absorbed or evolved when current is passed across junction between two dissimilar metals (. Dissimilar thermoelectric metals are those that have different available electron energy levels. When electrons ow from one such material to another, the electrons must change energy levels and thus absorb or release heat. Thedirection of the ow of electrons determines whether the heat is absorbed or evolved. Theelectrons are forced to ow by applying voltage difference across the two dissimilar Cooling and Storage 5 materials. circuit that consists of two dissimilar thermoelectric materials and voltage source is known as Peltier thermoelectric couple . The principles described can be used to produce refrigeration system that acts much as heat pump. Thermoelectric cooling has advantages over mechanical re