Plotting and Reading P-h Diagrams

[weighman2210]

Hi all,

I'm having a slight problem with a laboratory exercise that I'm doing as part of my degree course. I am trying to plot the results of various refrigeration cyles on a P-h diagram. We experimented with various evaporator pressures and were asked to plot the cycles on the diagrams and comment on why in reality the throttling process was not isenthalpic. From the experiment we recorded the evaporator and condenser pressures and the temperatures at each point in the cycle. I have managed to plot 3 of the points for each cycle and hence find the enthalpy but am struggling to find the enthalpy at the evaporator inlet after the expansion valve. How do you calculate where on the horizontal isotherm to read the enthalpy from? From the data we were given i don't think there is a way of calculating teh quality of the mixture.

Thanks

[Toosh]

Hi all,

I'm having a slight problem with a laboratory exercise that I'm doing as part of my degree course. I am trying to plot the results of various refrigeration cyles on a P-h diagram. We experimented with various evaporator pressures and were asked to plot the cycles on the diagrams and comment on why in reality the throttling process was not isenthalpic. From the experiment we recorded the evaporator and condenser pressures and the temperatures at each point in the cycle. I have managed to plot 3 of the points for each cycle and hence find the enthalpy but am struggling to find the enthalpy at the evaporator inlet after the expansion valve. How do you calculate where on the horizontal isotherm to read the enthalpy from? From the data we were given i don't think there is a way of calculating teh quality of the mixture.

Thanks

Hi Try this
http://www.jsrae.or.jp/jsrae/stady/Eng%20saikuru.htm

Norm

[nicolacozma]

Try to use this software. Maybe it can help to solve your problem.

[Dial666]

hello toosh
good link very usefull
will keep a copy thanks

[phamvuong146]

thank for your post, good link