Image Credits and References:
Photo above shows solar concentrators heating Stirling generators at Sandia National Laboratories, February 2008, https://share.sandia.gov/news/resources/releases/2008/solargrid.html
Interesting V-twin alpha Stirling engine
Solar-powered alpha-style Stirling engine by Dan Rojas at Green Power Science,
The task is to design and build an alpha-style Stirling engine powered by the sun. Solar power will be concentrated on the high-temperature cylinder by a set of mirrors or a large Fresnel lens. The output power from the engine will be used to turn a DC generator to produce electric power. The DC power will be converted to 120 volts AC using a single-phase inverter.
Level of Difficulty: High
Stirling Cycle, pressure-volume diagram, specific heat, regenerator, thermal conductivity, mass flow rate, flywheel, permanent magnet generator, DC link capacitor, insulated gate bipolar transistor (IGBT), pulse-width modulation, power piston eccentric
Brief history of the Stirling Engine, MIT, Mechanical Engineering Department, http://web.mit.edu/2.670/home/s10/html/Stirl/stirl.html
Electrical Engineer (2) – Electrical Engineers on the project are responsible for converting the engine’s mechanical motion to electric power. The task includes selecting a DC generator that matches the predicted output power of the Stirling engine. Converting the DC power to 120-V AC power is accomplished by designing and building a single-phase, IGBT-switched inverter. The Electrical Engineers must work closely with designers and MEs to tightly integrate the generator.
Mechanical Engineer (2) – The Mechanical Engineers on the project are responsible for the design and construction of an alpha Stirling engine. The task includes calculations and simulations of the machine’s available power, taking frictional loss into account. The design may include closed loop liquid cooling to increase power and enhance the regenerator. The Mechanical Engineers must work closely with the EEs and Physicists to integrate the generator and optical system.
Physicist (2) – The Physicists on the project are responsible for the solar collection system. The optical design may include a large Fresnel lens to capture sunlight and a reflector assembly to capture scattered light and redirect it to the target. The task includes measuring the temperature of a solar-illuminated collection surface to be used in the Stirling engine’s design.
Computer Scientist (2) – The Computer Scientists on the project are responsible for the engine diagnostics that include pressure and temperature sensors to tune the engine’s efficiency. Data from the engine will be collected and displayed using LabView. A data illustration will include an active p-v diagram.
Designer (2) – Designers on the project will integrate the engine, optical, and power systems into a package that is safe to demonstrate to the public. For example, special care must be taken to mount the engine on a non-reflective, non-flammable surface so that the public is not endangered by intense sunlight reflections or fire.
Journalist (1) – The Journalist documents the project’s progress on the website, communicates with the local media, and is responsible for a final report to the principal sponsors and Power Mountain Engineering. The Journalist also works closely with the Multimedia Artist to provide video and graphic art displays for demonstrations that explain the project to the public. The whole project is your project.
Multimedia Artist (1) – The Artist also documents the project’s progress on the website and works with the Journalist to maintain the project’s presence on social media. Additionally, the Artist designs and organizes all public relations events to assure spectator safety and to enhance the community’s awareness of science and technology. In this case, high intensity solar power is the principal risk to spectators. The whole project is your project.
Business Manager (1) – The Business Manager is responsible for reporting the project’s progress against a predetermined schedule, determines critical path items to completion, and tracks project spending to assure that costs remain within a fixed budget. The Manager works with all team members to identify problems early and resolve them quickly. The whole project is your project.