The HarperLake solar farm is located in Mojave Desert close to Daggett, CA. The solar radiation in Daggett is provided by the following table from:
The HarperLake solar farm is form of 1-Axis horizontal concentrators oriented North-South of 464,340 m2.
a. Select the correct line in the table above that represents the solar radiation received by the concentrators over the year.
It is the second line: 1-Axis North-South Horizontal Axis
b. Calculate the total radiation received by the concentrators through a year, in MWh/year.
c. The average annual production of the solar farm between 1998 and 2002 was 138GWh/year, calculate the conversion rate of the plant.
d. The oil temperature in the concentrators is 391oC, calculate the theoretical Carnot's efficiency of the system, considering the cold source temperature is 35oC.
e. How does the actual conversion rate compare to the theoretical Carnot's efficiency?
The actual conversion rate is much lower that the Carnot conversion rate.
f. What are the major factors of the difference?
The major factors of the difference are:
- The mirrors are not perfect (reflectivity of about 94%)
- The movement of the collectors requires some energy
- The pipes lose a part of their heat to the environment
- Energy is required to circulate the oil through the extensivenetwork of solar collectors
- The steam turbine follow a Rankine cycle
- The turbine is not perfect
- The generator is not perfect