20-07-2016, 02:30 PM
Ejector Expansion Refrigeration Systems
ABSTRACT : Refrigeration forms the basic essence of living comfort. Ejector Expansion Refrigeration Cycle
(EERC) is a not so commonly used method of refrigeration. The use of this method is quite understated. It
increases the efficiency of the normal refrigeration cycle by almost 16% over the basic cycle by utilising the
energy wasted otherwise in the expansion valve in form of expansion process losses. EERC system has high
potential which if harnessed properly could prove to be a very efficient method of refrigeration. This paper aims
to showcase the real features of this method in a hope that it finds its way out in the commercial industry today.
I.INTRODUCTION
Refrigeration is one of the leading uses of electric power across the globe. The term "refrigeration"
refers to air-conditioning for homes, businesses, and industry and the operation of refrigerators, freezers, and
heat pumps. The technology most often in use today for refrigeration purpose is the vapour compression cycle
which is 100 years old, inefficient, and environmentally unsound. Since the 1980’s, the refrigeration industry
has faced pressure to improve efficiency and reduce the emission of the chlorofluorocarbons (CFC) compounds
which pose a serious threat to the environment. Attempts to decrease CFC emissions by using alternate
compounds have typically made refrigeration devices less efficient.
Theoretically, in a refrigeration cycle, the pressure drop is considered as an isenthalpic process where the
enthalpy remains constant. However, isenthalpic process causes a decrease in the evaporator cooling capacity
due to energy loss in the throttling process. An efficiency-enhancing alternative was proposed to recover this
energy loss, which uses an ejector that can be used to generate isentropic condition where the entropy remains
constant in the throttling process. Such a cycle is called as ejector expansion refrigeration cycle. The ejector
expansion refrigeration cycle is a variant of the standard vapour compression cycle in which an ejector is used to
recover part of the work that would otherwise be lost in the expansion valve.
This method uses a two-phase ejector as an expansion device while the conventional refrigeration cycle uses an
expansion valve. A typical ejector consists of a motive nozzle, a suction nozzle or receiving chamber, a mixing
section and a diffuser. High pressure motive stream expands in the motive nozzle and its internal energy
converts to kinetic energy. The high speed motive stream entrains low pressure suction stream into the mixing
section. Both streams exchange momentum, kinetic and internal energies in the mixing section and become one
stream with almost uniform pressure and speed. The stream converts its kinetic energy into internal energy in
the diffuser to reach a pressure higher than the suction stream inlet pressure.
more reference;
http://www.researchinventypapers/v5i2/D52025029.pdf
ABSTRACT : Refrigeration forms the basic essence of living comfort. Ejector Expansion Refrigeration Cycle
(EERC) is a not so commonly used method of refrigeration. The use of this method is quite understated. It
increases the efficiency of the normal refrigeration cycle by almost 16% over the basic cycle by utilising the
energy wasted otherwise in the expansion valve in form of expansion process losses. EERC system has high
potential which if harnessed properly could prove to be a very efficient method of refrigeration. This paper aims
to showcase the real features of this method in a hope that it finds its way out in the commercial industry today.
I.INTRODUCTION
Refrigeration is one of the leading uses of electric power across the globe. The term "refrigeration"
refers to air-conditioning for homes, businesses, and industry and the operation of refrigerators, freezers, and
heat pumps. The technology most often in use today for refrigeration purpose is the vapour compression cycle
which is 100 years old, inefficient, and environmentally unsound. Since the 1980’s, the refrigeration industry
has faced pressure to improve efficiency and reduce the emission of the chlorofluorocarbons (CFC) compounds
which pose a serious threat to the environment. Attempts to decrease CFC emissions by using alternate
compounds have typically made refrigeration devices less efficient.
Theoretically, in a refrigeration cycle, the pressure drop is considered as an isenthalpic process where the
enthalpy remains constant. However, isenthalpic process causes a decrease in the evaporator cooling capacity
due to energy loss in the throttling process. An efficiency-enhancing alternative was proposed to recover this
energy loss, which uses an ejector that can be used to generate isentropic condition where the entropy remains
constant in the throttling process. Such a cycle is called as ejector expansion refrigeration cycle. The ejector
expansion refrigeration cycle is a variant of the standard vapour compression cycle in which an ejector is used to
recover part of the work that would otherwise be lost in the expansion valve.
This method uses a two-phase ejector as an expansion device while the conventional refrigeration cycle uses an
expansion valve. A typical ejector consists of a motive nozzle, a suction nozzle or receiving chamber, a mixing
section and a diffuser. High pressure motive stream expands in the motive nozzle and its internal energy
converts to kinetic energy. The high speed motive stream entrains low pressure suction stream into the mixing
section. Both streams exchange momentum, kinetic and internal energies in the mixing section and become one
stream with almost uniform pressure and speed. The stream converts its kinetic energy into internal energy in
the diffuser to reach a pressure higher than the suction stream inlet pressure.
more reference;
http://www.researchinventypapers/v5i2/D52025029.pdf