Refrigerant 134a enters a well-insulated nozzle at 14 bar, 60°C,
with a
velocity of 37 m/s and exits at 1.2 bar with a velocity of 460 m/s.
For steady-state
operation, and neglecting potential energy effects, determine the
exit
temperature, in °C.
A commercial refrigerant that uses R-134a as the refrigerant is
used for cooling, to keep the condition at -35o, throws heat into
the cooling water that has been in the condenser at 18oC and 0.25kg
/ s and has been formed since 26o. The refrigerant enters the
condenser at 1.2 MPa and 50o ° and exits by cooling 5o C more than
the saturation temperature at the same pressure. If the compressor
consumes 3.3 kW (Answer: 0.0498 kg / s,...
How do you determine the
properties of steam or refrigerant 134a from the properties if you
know only specific internal energy and specific volume (or specific
enthalpy and specific entropy) at the thermodynamic
state?
refrigerant 134a enters the evaporator of a
refrigeration system operating at steady state at -12°C and a
quality of 20% at a velocity of 7 m/s. At the exit, the refrigerant
is a saturated vapor at -12°C. The evaporator flow channel has
constant diameter of 1.7cm.
Determine the mass flow rate of the refrigerant in
kg/s
Determine the velocity at the exit in m/s
Refrigerant 134a enters an air conditioner compressor at 4 bar,
20°C, and is compressed at steady state to 12 bar, 80°C. The
volumetric flow rate of the refrigerant entering is 7.5 m3/min. The
work input to the compressor is 112.5 kJ per kg of refrigerant
flowing. Neglecting kinetic and potential energy effects, determine
the magnitude of the heat transfer rate from the compressor, in
kW.
Refrigerant 134a enters a horizontal pipe operating at steady
state at 40°C, 300 kPa, and a velocity of 25 m/s. At the exit, the
temperature is 70°C and the pressure is 240 kPa. The pipe diameter
is 0.01 m. Determine: (a) the mass flow rate of the refrigerant, in
kg/s, (b) the velocity at the exit, in m/s, and (c) the rate of
heat transfer between the pipe and its surroundings, in kW.
A piston–cylinder device contains 0.85 kg of refrigerant-134a at
-10°C. The piston that is free to move has a mass of 12 kg and a
diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now,
heat is transferred to refrigerant-134a until the temperature is
10°C. Determine (a) the final pressure, (b) the change in the
volume of the cylinder, and (c) the change in the enthalpy of the
refrigerant-134a.
Consider a vapour
compression refrigeration cycle
that uses R-134a as
refrigerant. The R-134a
enters the compressor
as a saturated
vapour at 200 kPa,
and exits the
condenser as a
saturated liquid at
900 kPa. The rate
of refrigeration of
the cycle is to
be 6.0 tons of
refrigeration (1 ton
of refrigeration =
3.517 kW). The
compressor isentropic
efficiency is 80%.
Determine: a) The temperature
of evaporation and
condensation of the
refrigerant; b) Mass flow
of the refrigerant
R-134a, in ...
One kilogram of Refrigerant 134a vapor initially at 2 bar and
20°C fills a rigid vessel. The vapor is cooled until the
temperature becomes -24°C. There is no work during the
process.
Let To = 20°C, po = 0.1 MPa and ignore the
effects of motion and gravity.
2. For the refrigerant, determine the change in exergy, in
kJ.
Note: for part 1: q=-98.086kj please find part two- the change
in exergy in kj