R134a refrigeration cycle
Learning Goal: I’m working on a mechanical engineering presentation and need a sample draft to help me learn.
Please improve my presentation using the following points mentioned.
My first impression on viewing this presentation is surprise at the use of imperial units. In the lecture and the lab we used SI units only. In your dialogue, it sounds like you may be using a pointer on the screen, unfortunately I can not see this in the recording. Some description is given to how the refrigerant changes state around the circuit. More detail could have been provided here for example how heat is given off from the refrigerant in the condenser and absorbed in the evaporator and also how the pressure and temperature change around the circuit. The enthalpy values on the chart are inconsistent with the values in your table. From the chart h3=h4=260 kJ/kg which is different from the values in the table. This will of course impact the calculation for refrigeration effect and CoP. The second slide appears to focus totally on the pressure enthalpy chart itself rather than the refrigeration cycle represented on the pressure enthalpy chart. We need to look at the cycle in combination with the chart in order to gain a complete understanding of the changes that are happening to the refrigerant and the refrigeration effect of the cycle. Subcooling and superheating are not discussed. Values for the superheating degree and subcooling degree have been provided. However, according to the pressure enthalpy diagram, very little superheating is shown – this is the difference in temperature of measurement point 1 from the saturated vapour line at that pressure.