26-06-2013, 03:55 PM
Heat Operated vapor Compression Refrigeration Cycle
[attachment=56067]
Principles of vapor jet refrigeration systems
Vapor jet refrigeration is other type of vapor compression refrigeration cycle driven by heat source of high temperature.
As the same as the mechanical vapor compression refrigeration cycle, the vapor jet refrigeration cycle can accomplish the removal of heat through the evaporation of a refrigerant at a low pressure and the rejection of heat through the condensation of the refrigerant at a higher pressure.
The pressure difference in the system is created by a high pressure vapor or steam ejector, as shown in Fig.5-15.
An analysis for a basic steam jet refrigeration system
The basic steam jet refrigeration system, seen in Fig.5-16, consists of the following components:
an evaporator;
refrigerated object;
boiler;
nozzle, a mixing chamber;
diffuser;
condenser;
an expansion valve;
pumps.
In the steam jet system the vapor power cycle (1-2-3-3'-4-1) and the refrigeration cycle (6-7-8-3-9-6) are realized simultaneously.
This can be explained by the progressive, independent observation that the state of the motive steam and refrigerant vapor changes.
Motive steam is expanded in the nozzle from point 1 to point 5, but after mixing with refrigerant vapor it is compressed from 5 to 2, or in the mixture from a to b.
[attachment=56067]
Principles of vapor jet refrigeration systems
Vapor jet refrigeration is other type of vapor compression refrigeration cycle driven by heat source of high temperature.
As the same as the mechanical vapor compression refrigeration cycle, the vapor jet refrigeration cycle can accomplish the removal of heat through the evaporation of a refrigerant at a low pressure and the rejection of heat through the condensation of the refrigerant at a higher pressure.
The pressure difference in the system is created by a high pressure vapor or steam ejector, as shown in Fig.5-15.
An analysis for a basic steam jet refrigeration system
The basic steam jet refrigeration system, seen in Fig.5-16, consists of the following components:
an evaporator;
refrigerated object;
boiler;
nozzle, a mixing chamber;
diffuser;
condenser;
an expansion valve;
pumps.
In the steam jet system the vapor power cycle (1-2-3-3'-4-1) and the refrigeration cycle (6-7-8-3-9-6) are realized simultaneously.
This can be explained by the progressive, independent observation that the state of the motive steam and refrigerant vapor changes.
Motive steam is expanded in the nozzle from point 1 to point 5, but after mixing with refrigerant vapor it is compressed from 5 to 2, or in the mixture from a to b.