UC Merced

With the recent IPCC report, the time to de-carbonize the energy sector and provide cost-competitive renewable technology is now! Using the most abundant source of energy, the sun, solar irradiance can be captured (through materials and optics) and converted to renewable energy in the form of low carbon emitting electricity or useable heat. The Integrated Compound Parabolic Concentrator (ICPC) is a simple, wide-angle, nonimaging optic that negates the need for tracking. The solar design process of module and array scale results of the ICPC are outlined containing the 3 fundamental steps: develop a system design, estimate system cost, and estimate system performance. Multiple design prototypes of the ICPC coupled with low cost aluminum minichannel absorbers were fabricated including: a low temperature, hybrid photovoltaic/thermal (PV/T) design for residential and commercial buildings, and a high temperature ICPC with vacuum insulation for solar heat industrial processes (SHIP) and solar thermal desalination. With solar PV’s low cost and wide adoption into the electricity grid, the PV/T design does not seem to be ideal for low temperature applications in these end-use heat sectors based on modular performance and cost. Therefore, the thermal only collector solar design processes of the ICPC is highlighted with modular performance, and fabrication of a 12 kW array is analyzed to incorporate additional system losses that modular performance neglects. The ICPC, thermal only, module collector demonstrated instantaneous solar-to-thermal efficiencies of 72% ±4% at 43˚C, 60% ±4% at 120˚C, and 55% ±5% at 140˚C. The ICPC’s 26.25 m2 array averaged daily efficiencies of 38%, and generated an average 65 kWh of thermal energy over an average span of 6.4 hours of active solar each day (producing average 2.5 kWh/m2-day at 38%). The array’s annual thermal generation estimation of 784 kWh/m2-year estimates the cost of ICPC’s delivered heat over operating temperatures of 120˚ at $0.0168/kWh. The array experienced 11% vacuum tube failure and about 5% solder connection failure. With further improvements in the thermal and manufacturing stages, the ICPC cost of levelized heat has the potential to be reduced to $0.015/kWh; making the ICPC a top cost-competitive challenger to high carbon-emitting fossil fuels. The ICPC has been submitted to the DOE’s solar initiative contest called “American-Made Solar Desal Prize: round 2”, and won the first stage of prize ($50,000) and accepted to move on for stage 2 submission teaming phase. The four-stage competition was designed to accelerate the development of low cost desalination systems that use solar-thermal power to produce clean water from salt water. The phase 2 application has been submitted and awaits announcements (expected late April 2022).