M. Anderson, A. Bond and B. Beachnau
Icarus RT, Inc.,
Keywords: energy storage, solar plus storage, thermal energy storage
Summary:Icarus RT, Inc. offers a novel photovoltaic/thermal (PV/T) solar plus storage cogeneration system for commercial and utility scale applications. The hybrid system cools PV panels by extracting waste heat, collecting and storing thermal energy, and converting thermal energy into hot water and/or additional power on demand (i.e., after sunset) using Organic Rankine Cycle (ORC). Icarus’ proprietary heat extractors attach to the back of PV panels and reduce panel temperature while heating the fluid flowing through the heat extractor. Stored thermal energy produces hot water and/or power by vaporizing organic fluid and expanding it through a micro-turbine. Current PV technology is inefficient, converting only about 21% of solar energy into usable power typically rated at the ideal temperature of 25 °C. Panels often reach temperatures of 65–75 °C significantly reducing production. The mismatch between daily solar energy output and utility peak energy demand periods compounds the problem. The California “Duck” Curve illustrates this concept – solar energy production decreases in the afternoon as demand increases, straining energy resources and the grid. Despite technology and economic advances, high battery cost plus panel inefficiencies deters commercial business owners from purchasing solar plus storage systems. Still, commercial and industrial PV plus storage is expected to grow from $8.6 billion in 2020 to $30.1 billion in 2030. Many have tried and failed to develop hybrid PV/T technologies. Icarus offers an effective alternative that overcomes the shortcomings of previous attempts of PV/T systems with a solar plus storage system that improves panel efficiency and provides affordable and environmentally safe thermal energy storage. A new Icarus solar plus storage system has 50% the expected lifetime cost of a new PV plus lithium-ion (Li-ion) battery system. A primary factor for the cost reduction is that Icarus boosts PV array daytime output while charging the thermal battery without consuming PV production. Traditional battery systems consume PV output to charge, reducing the power available during the day. Overall, Icarus provides improved panel efficiency, increased power output, energy storage for power and/or hot water, and continuous grid reliability at a lower cost without the environmental downsides of Li-ion batteries. In 2018, Icarus built a 2.5-kW solar lab at the University of California, San Diego Englekirk Structural Engineering Facility. The array was upgraded in 2020, as part of Icarus 2019 CalSEED Concept Award. Updates to the array included prototyping and testing the heat extractors and energy storage tank, with engineering support from the National Renewable Energy Lab (NREL) provided by the Shell Gamechanger Program. Additionally, Icarus’ proprietary control system was developed to collect system data, and manage flow rate, cooling, power production and storage. This proof of concept demonstrates Icarus is a viable, cleaner, lower-cost alternative to traditional battery systems for reducing burden on the grid during peak demand and minimizing the “duck curve.” The successful completion of the CalSEED Concept Award led to follow up funding in February 2021 by the California Energy Commission through the CalSEED Prototype Award.