Question

Your are tasked with providing a preliminary design of a solar system that is
to generate electricity at a rate of 10 kWe. Assume the generator is 95% effecient and
that the solar collector system operates at a temperature of 355K. The working fluid
will be R-134a. Assume that the cycle operates as an ideal Rankine cycle. The heat sink
temperature is 295K. Assume that the temperature difference between the collector and
the maximum working fluid temperature is 5K. Similarly, assume that at the condenserside

the temperature difference between the working fluid condensation temperature and
the available heat sink is 5K

You are tasked with:
1. Provide a Ts diagram for the working fluid, what are the critical temperature and
critical pressure?
2. Select the highest and lowest pressures in the cycle. Justify.
3. Draw the the cycle on Ts and ph diagrams. Use actual diagrams that show the
correct scales, not just schematics.
4. Compute all heat and work interactions (in all four processes).
5. Compute the cycle thermal efficiency (up to mechanical work).
6. If the collector is capable of delivering 200W=m2 to the working fluid, how muchcollector area will be needed?
7. How would your answers change if now the turbine has a isentropic efficiency of
0.9?
.

Answer 1