tailieunhanh - Advanced Vehicle Technology Episode 3 Part 10

Tham khảo tài liệu 'advanced vehicle technology episode 3 part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Fig. Heavy duty diesel engine shaft driven compressor refrigeration unit Sensible heat Refrigerant begins to boil vaporize Refrigerant absorbs heat converting to vapour Refrigerant rejecting heat converting to liquid Latent heat of evaporation Super heat Saturated temperature Refrigerant completely boiled to a saturated vapour 5 5 g Heat increase J Fig. Illustrative relationship between the refrigerant s temperature and heat content during a change of state 572 Latent heat of evaporation Fig. This is the heat needed to completely convert a liquid to a vapour and takes place without any temperature rise. Superheated vapour Fig. This is a vapour heated to a temperature above the saturated temperature boiling point superheating can only occur once the liquid has been completely vaporized. Principles of a vapour-compression cycle refrigeration system Fig. 1 High pressure subcooled liquid refrigerant at a typical temperature and pressure of 30 C and 10 bar respectively flows from the receiver to the expansion valve via the sight glass and drier. The refrigerant then rapidly expands and reduces its pressure as it passes out from the valve restriction and in the process converts the liquid into a vapour flow. 2 The refrigerant now passes into the evaporator as a mixture of liquid and vapour its temperature being lowered to something like 10 C with a corresponding pressure of 2 bar under these conditions the refrigerant will boil in the evaporator . The heat latent heat of evaporation necessary to cause this change of state will come from the surrounding frozen compartment in which the evaporator is exposed. Compressor Receiver Sight glass Liquid line Refrigerant rejects heat to surrounding atmosphere Superheated vapour 8 C 2 bar low pressure Refrigerant absorbs heat from surrounding frozen storage space Oil separator Suction Evaporator line coil low pressure Saturated vapour -10 C 2 bar low pressure Discharge line Superheated Condenser line .