. Commercial cooling of fruits and vegetables. Fruit; Fruit; Vegetables. 44 42 ^40 LU <r 3 <38 LU Q. 36 34 32 Water returning to ice Effective water temperature on load Water leaving ice. Water contacting ice Fig. 31. Diagram of water temperature cycles in hydrocoolers. Water cooled by ice or by mechanically refrigerated surfaces at 32°F. Water flow in relation to refrigeration load: ample water flow: te -10 = 1°F; marginal water flow: te-t0 = 2°F. Contact of water with ice or refrigerated surfaces: water well cooled: (to - 32) (t0 - 32) (to - 32) = 1; water fairly well cooled: = 2; wate
. Commercial cooling of fruits and vegetables. Fruit; Fruit; Vegetables. 44 42 ^40 LU <r 3 <38 LU Q. 36 34 32 Water returning to ice Effective water temperature on load Water leaving ice. Water contacting ice Fig. 31. Diagram of water temperature cycles in hydrocoolers. Water cooled by ice or by mechanically refrigerated surfaces at 32°F. Water flow in relation to refrigeration load: ample water flow: te -10 = 1°F; marginal water flow: te-t0 = 2°F. Contact of water with ice or refrigerated surfaces: water well cooled: (to - 32) (t0 - 32) (to - 32) = 1; water fairly well cooled: = 2; water poorly cooled: = 4. (t. - to) (t, - to) If containers are run through a hydrocooler, about two-thirds of the weight of wood or one- fourth the weight of aluminum or one-eighth the weight of steel should be added to the weight of the produce for calculations. These calculations assume te to be midway between the temperatures of the water leaving the cooling surfaces and returning to them. Air channel dimensions in forced-air coolers Static pressure losses in air channels beside stacks of produce being cooled by forced-air may result in uneven cooling if the channels are not wide enough (Guillou, 1963; Haerter, 1963). Figure 32 shows friction and velocity pressure losses in a forced-air cooler. • Friction loss in a forced-air cooler supply channel is reduced by "peeling off" of air as it enters the load, and may be roughly estimated as equal to one-half of the velocity pressure. Maximum reduction in effective static pressure in this channel is usually at the open end, where the reduction is equal to the velocity pressure. • Friction loss in a return channel is increased by the blocking effect of the air as it leaves (te-to) the load and may be roughly estimated as equal to one and one-half times the velocity pressure at the open end. Friction loss and velocity pressure at the open end combine to raise the effective static pressure at the closed end of this chan
Size: 1815px × 1377px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, bookpublisherberkeley, booksubjectvegetables
