|Acquisition Program: || Objective: ||The objective of this topic is development of a technology that will enable small tactical operations to take advantage of renewable energy, thereby reducing fuel consumption, reducing operational costs, and reducing the need for logistics fuel resupply.
Concentrated Solar Thermal (CST) solar-to-electric conversion is particularly efficient with a net average annual yield rate ranging between 18 and 23%, higher than any other solar energy system.  Accordingly, this is the technology of interest for this topic.
|| Description: ||The focus of this topic is development of a tactically-mobile, deployable/stowable solar concentrator for use with solar thermal conversion devices (Stirling, Brayton, TPV, etc.) Given the desire for transportability, ruggedization is a critical part of this topic, potentially spurring the requirement for more robust glass/ceramic materials, or higher UV resistance in polymeric materials.
There are many types of solar collectors (flat plate, parabolic trough, parabolic dish, heliostats, etc.)  These collectors are being used world-wide at fixed sites, and their use is expanding. For mobile, tactical military units to capitalize on the advantages of solar thermal energy, development is required to understand the potential for concentrators to operate predictably and efficiently after repeated deployments in a demanding environment. The military environment involves temperature, altitude, and humidity extremes , but also includes airborne contaminants (engine emissions and others) that could foul reflective surfaces of a solar collector.
Automated two-axis control for solar tracking is desired for maximum solar energy capture. Automated deployment and stowage of the concentrator is preferred. Alternatively, deployment and stowage may be accomplished by 2 personnel within 15 minutes (objective) or 30 minutes (threshold). Proper alignment and focal accuracy is important for maximizing solar energy capture.
|| ||PHASE I: Investigate tactical solar concentrator approaches for a 3-5 kW electric power requirement. A system-level approach should be taken such that various types of collectors and thermal-to-electric converter combinations are considered. Identify the most promising combinations of collectors and thermal-to-electric converters for the intended application herein, and provide supporting data. As appropriate, modeling and simulation to guide this research is very strongly encouraged. The target military platform for the solar collector, thermal-to-electrical converter, and auxiliaries involves mounting onto a Light Tactical Trailer (LTT) and towing by a HMMWV.
|| ||PHASE II: Develop and demonstrate technology approaches in a lab environment, and with an industry partner capable of providing hardware to enable meaningful system-level demonstrations of one or more solar collector configurations. Characterize the concentrator’s ability to provide the thermal input necessary for power generation, optical accuracy & repeatability, deployment times, size, weight, volume, etc. Develop a technology transition and/or insertion plan for future systems and commercial ventures.
|| ||PHASE III: Integrate the most promising solar concentrator technology with a thermal-to-electrical converter and mount on the targeted Light Tactical Trailer or similar platform. Demonstrate the ability to produce 3-5 kW electrical output under peak sunlight conditions in a variety of selected geographical locations. Convert the technologies to a marketable product via licensing or well established relationships with system supplier(s).
PRIVATE SECTOR COMMERCIAL POTENTIAL/|| ||DUAL-USE APPLICATIONS: This technology can be utilized by the mobile construction industry to save fuel costs and reduce emissions. State and local governments could also benefit from this technology for various applications.
|| References: ||
1. Cavallaro F., Renewable Energy 34 (2009) 1678–1685
2. Kalogirou S. A., Progress in Energy and Combustion Science 30 (2004) 231–295
3. Army Regulation 70-38
4. Shuai Y., et al., Solar Energy 82 (2008) 13–21
5. Grimmer, Derrick P., A comparison of compound parabolic and simple parabolic concentrating solar collectors , Solar Energy, Volume 22, Issue 1, 1979, Pages 21-25
6. D.E. Prapas, B. Norton, S.D. Probert, Optics of parabolic-trough, solar-energy collectors, possessing small concentration ratios, Solar Energy, Volume 39, Issue 6, 1987, Pages 541-550
7. Solar Energy Vol. 57, No. 4, pp. 317-321, 1996
8. Kribus A., et al., Energy Conversion and Management 47 (2006) 3582–3590|
|Keywords: ||Renewables, Solar thermal power, Solar concentrator, Solar collector, Power generation, Alternative energy|
Questions and Answers:
Q: Is this solicitation limited exclusively to concentrating solar thermal/solar-to-electric conversion, or will competing alternatives (e.g. concentrating solar photovoltaic) also be considered?
A: As the topic notes, "Concentrated Solar Thermal (CST) solar-to-electric conversion ... is the technology of interest for this topic." Competing alternatives will not be considered under this topic unless the alternative includes CST technology wholly or in part.
Q: 1. Is the goal of this topic to figure out how to put over 20 square meters of mirrors that would fit onto a military trailer?
2. Are you requesting that we also design and build a stirling engine?
3. What criteria will you evaluate each proposal on for this topic.
4. Is this topic considered high priority?
5. Is this Topic suggested by a third party?
A: 1. As noted in the topic, the objective of the SBIR is the "...development of a technology that will enable small tactical operations to take advantage of renewable energy, thereby reducing fuel consumption, reducing operational costs, and reducing the need for logistics fuel resupply. Concentrated Solar Thermal (CST) solar-to-electric conversion ... is the technology of interest for this topic." The concentrator must be transported by the trailer, but could be deployed on or off the trailer.
2. Phase III involves integrating "...the most promising solar concentrator technology with a thermal-to-electrical converter...". The converter need not be Stirling-based. Any thermal-to-electric converter technology having potential to meet topic objectives will be considered. The converter can be designed and built as part of the SBIR, or an existing converter design can be selected/adapted.
3. Section 4 of SBIR Solicitation 10.2 covers selection and evaluation criteria.
4. SBIR topics are not assigned priorities.
5. This topic was not suggested by a third party.
Q: 1. Can we go over the 3-5kw ?
2. Is the assembly time critical? What is it took 40 minutes to build?
3. Can we design the solar collector to heat up water or cooking as well as electricity generation?
A: 1. Approaches that provide more than 3-5kW are acceptable.
2. The assembly time is critical due to the expeditionary nature of the topic. A 40 minute setup period would not be responsive to the SBIR topic requirements.
3. As long as the basic objectives of the topic are addressed, adding additional functionality is acceptable.
Q: 1. Can We build a model for phase I?
A: For phase I, modeling and simulation is very strongly encouraged. Presumably the question refers to building a physical model, however. Building a physical model in phase I is acceptable provided that the this effort does not displace the technology development objectives of the SBIR topic.