Heat pipe solar receiver development activities at Sandia National Laboratories
Over the past decade, Sandia National Laboratories has been involved in the development of receivers to transfer energy from the focus of a parabolic dish concentrator to the heater tubes of a Stirling engine. Through the isothermal evaporation and condensation of sodium, a heat-pipe receiver can efficiently transfer energy to an engine's working fluid and compensate for irregularities in the flux distribution that is delivered by the concentrator. The operation of the heat pipe is completely passive because the liquid sodium is distributed over the solar-heated surface by capillary pumping provided by a wick structure. Tests have shown that using a heat pipe can boost the system performance by twenty percent when compared to directly illuminating the engine heater tubes. Designing heat pipe solar receivers has presented several challenges. The relatively large area ({approximately}0.2 m{sup 2}) of the receiver surface makes it difficult to design a wick that can continuously provide liquid sodium to all regions of the heated surface. Selecting a wick structure with smaller pores will improve capillary pumping capabilities of the wick, but the small pores will restrict the flow of liquid and generate high pressure drops. Selecting a wick that is comprised of very fine filaments can increase the permeability of the wick and thereby reduce flow losses, however, the fine wick structure is more susceptible to corrosion and mechanical damage. This paper provides a comprehensive review of the issues encountered in the design of heat pipe solar receivers and solutions to problems that have arisen. Topics include: flow characterization in the receiver, the design of wick systems, the minimization of corrosion and dissolution of metals in sodium systems, and the prevention of mechanical failure in high porosity wick structures.
- Research Organization:
- Sandia National Laboratories, Albuquerque, NM (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 20026756
- Resource Relation:
- Conference: Renewable and advanced energy systems for the 21st Century, Maui, HI (US), 04/11/1999--04/15/1999; Other Information: 1 CD-ROM. Operating system required: Windows i386(tm), i486(tm), Pentium (R) or Pentium Pro, MS Windows 3.1, 95, or NT 3.51, 8 MB RAM; MacIntosh and Power MacIntosh with a 68020 or greater processor, System software version 7.1, 3.5 MB RAM (5 MB for PowerMac) 6 MB available hard-disk space; UNIX; PBD: 1999; Related Information: In: Renewable and advanced energy systems for the 21st century, RAES'99 proceedings, by Hogan, R.; Kim, Y.; Kleis, S.; O'Neal, D.; Tanaka, T. [eds.], [1125] pages.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Design considerations for heat-pipe solar receivers
Design considerations for heat-pipe solar receivers