CONFIDENTIAL NOTRE Annex 7 to Progress Report n.01 ANNEX 7 Simplified approach for refrigerated trucks CONFIDENTIAL NOTRE Annex 7 to Progress Report n.01 In the meeting in Paris, DIPTEM has discussed theoretical results obtained by means of a simulation program regarding the frost forming on cooling coils in trucks with tA about 5°C. The model solves the vapour mass balance of a refrigerated cell with the following assumptions: isothermal conditions, internal air recycle constant, perfect air mixing, fixed CC surface temperature. The scheme of the cell is depicted in fig 3 . R. A. C. C. - M VE1 . Fig. 3: Schematic cell mathematical model ( C.C. cooling coils; VE1 membrane contactor; M mass of product; R.A. renewal air) The ice forming process on CC is represented in fig. 4 on the psychometric chart; in it ts: coil surf. temp.; te: air temp. at the outlet of CC; tF: air temp. at the inlet of CC; E: air state at the outlet of CC; F’: air state at the inlet of CC. CONFIDENTIAL NOTRE Annex 7 to Progress Report n.01 ASHRAE PSYCROMETRIC CHART tS tE tF' 0 °C i F' E Fig. 4 Air dehumidification process on CC owing to the frost forming As example, ice forming on CC (ts = -5 °C, BF = 0.3) has been evaluated for a refrigerated cell having a volume of 100 m3, at a cell air temperature of 4°C and with a 7000 m3/h of total recycled air flow of which 700 m3/h are handled by the membrane contactor (8 m2). The desiccant solution is saturated CaCl2 at - 3°C inlet temperature. Fig. 5 Ice forming on CC as a function of time in presence and absence of membrane contactor Results reported in fig. 5 show that a significant reduction of frost formed on CC versus simulation time can be obtained, by dehumidificating only a part of the air flow recycled in the cell.