Non-tracking East-West XCPC solar thermal collector for 200 celsius applications

The design and development of a commercial-ready medium-temperature solar thermal collector, the external compound parabolic concentrator (XCPC), is presented in which a nonimaging reflector is paired with an evacuated tube absorber for efficient and low-cost heat collection between 100 and 250 degrees C. The absorber geometry is optimized under the constraint of being assembled with an ultrasonic welding machine, with a final pentagon-shaped absorber selected. The modified absorber shape, gap loss, and truncated reflector result in a geometric efficiency of 93% compared to an ideal CPC. The final prototype has a 4.56 m(2) aperture and simulations predict an optical efficiency of 71% and thermal efficiency of 50% at 200 degrees C. Experimental test results (optical, thermal, stagnation) have confirmed an optical efficiency of 62% and a thermal efficiency near 50% at 200 degrees C with a final stagnation temperature of 333 degrees C. A detailed economic analysis reveals the technology can be installed for $0.58/watt and deliver a levelized cost of heat at 3.01 cents per kWh over a 20 year lifetime. This is equivalent to the current cost of natural gas in the United States, which underscores the potential of this technology to assist in decarbonizing the thermal energy sector.