The aim of this study is investigate in using refrigerants mixtures as substitute to
R134a in a testing compression refrigeration cycle designed to work with a mass of 100g
of R134a without make changing or modification in the cycle. The new mixtur
e that made
it is ozone-friendly, safe for using and consists of R134a, propane R290, butane R600, we
use three various types of this mixture and the coefficient of performance (COP) and other
properties was compared with R134a on the same conditions and on different evaporation
temperature. The results shows the refrigerant mixture (M40) has higher coefficient of
performance (COP) than that of R134a by about 7.77% and increasing the refrigeration
effect about 30% and decreasing the discharge temperature from compressor 3.2%
compared with R134a.
This study support possibility of using refrigerant mixtures in refrigeration cycle that
designed to work with pure refrigerant (single component) without making any change in
the cycle also it support the possibility of using refrigerant that have an excellent
thermodynamic properties and environmentally friendly like Propane and butane but there
are some warning from using it because their flaming.
In this study، a traditional air source heat pump was modified by adding secondary
evaporator within hot water tank which acted as a water heat source of the heat pump. We
made the heat pump to run alternatively either using surrounding air heat or
water heat
gained from solar power.
We have done experiments during five months starting in December of 2014 until
April 2015. Temperature and pressure were measured at specific points of the cycle. Then
we defined the enthalpy at each point for both cycles using EES software (which is a
software to simulate thermodynamic elements)، and calculated the amounts of heat gained
in the evaporator، heat charged from the condenser، compressor work، coefficient of
performance ، and electrical power consumed by the compressor.
Then we made a compare between the two cycles and found that the improvement
ratio in of the modified cycle to the traditional cycle was 77.07%، and the reduction
ratio in electrical power consumed by the compressor of the modified cycle was 33.54%.
