چكيده به لاتين
Abstract:
Due to the destructive effect of refrigerants on the environment, R22 refrigerant is being replaced with new environment friendly gases such as R410a. In the current work we have analyzed and compared vapor compression cycle of R22 and R410a using theoretical calculations and computer simulations to find the overall thermodynamic cycle of these gases.
The simulations are based on thermodynamic formulas and results have been simulated and illustrated using EES software.
Compression work, refrigerant effect, co-efficient of performance, compressor temperature, effect of evaporator and condenser temperature changes on cycle performance, effect of superheating and sub-coldness on refrigerant, rate of heat exchange in condenser, pressure ratio, and thermal conductivity for both R410a and R22 gases have been simulated and compared for a state of constant heat capacitance.
Results show that the overall COP for R410a is lower than that of R22 and a more powerful compressor is needed for refrigeration using this gas. R410a also has a higher cooling capacity and higher compressing temperature than R22. In hot environment temperatures, where load is equal to that of R22, R410a reaches the critical region faster than R22 because of its lower critical temperature and loses its efficiency. Loss of efficiency in higher condenser temperature is made even worse due to lower heat conductivity during saturation vapor state and the need for more heat exchange. In cooler temperatures just above room temperature, R410a needs lower mass flow but as the temperature increases it needs a higher mass flow and its performance degrades at a higher rate. R410a can have the same refrigerating capacity of R22 with a lower mass flow and can operate in refrigerating devices that are smaller in size than those using R22.
Keywords: Refrigerant,COP,R22,R410a,vapour compression
