Enhanced Solar Energy Harvest for Power Generation From Brayton CycleEPA Grant Number: SU836032
Title: Enhanced Solar Energy Harvest for Power Generation From Brayton Cycle
Investigators: Lee, Hohyun , Daley, Brian , Neber, Matthew
Current Investigators: Lee, Hohyun , Barker, Laughlin , Marumoto, Darcy , Neber, Matthew , Olaes, Criselle , Valdez, Joe , Zabalegui, Aitor
Institution: Santa Clara University
EPA Project Officer: Lank, Gregory
Project Period: August 15, 2011 through August 14, 2012
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2011) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Energy , P3 Awards , Sustainability
Solar energy is considered to be the most abundant and easily accessible renewable energy source. Yet high costs and low yields prevent effective deployment of existing technology to the end user. Solar photovoltaic cells are the most expensive renewable energy technology and are the only available option at the home use level. In order for more people to use solar energy, the cost of end user systems must decrease significantly. Moreover, the space needed to implement an energy system in urban areas should be sufficiently small. The objective of this project is to develop a solar absorber to be used for a small scale modular dish-brayton solar power generator. This system aims to be one-third the size of an equivalent photovoltaic system, at half of the total cost.
Silicon carbide ceramic is used to fabricate a blackbody cavity solar absorber integrated with a direct contact heat exchanger. The receiver will be comprised of two main ceramic parts—one as a cylindrical blackbody solar receiver, the other as an outer shell to create an air passage around the absorber to transfer heat into the working fluid. The high thermal conductivity of silicon carbide allows for a compact heat exchanger, while the high absorptivity allows for a cylindrical part that closely approximates a blackbody cavity. The cylindrical geometry allows the parts manufactured by a simple casting and sintering process resulting in a lower manufacturing cost than existing absorbers.
The design is expected to achieve air temperatures near 1500 K, and thereby higher thermal efficiency than existing systems, which operate below 1200 K. For a single household, 2.5 kWe of energy will be generated from a 15 m2 reflective dish, whereas typical solar photovoltaics require roughly 25 m2 to generate the same amount of energy. Wasted heat can be further extracted to provide domestic hot water. As such, the new solar receiver design augments the energy density of CSP systems and increases the practicality of tapping solar power from smaller collector areas.