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The USDOE Reflux Receiver Development Program

Conference ·
OSTI ID:7006459
; ;  [1];  [2]
  1. Sandia National Labs., Albuquerque, NM (United States)
  2. National Renewable Energy Lab., Golden, CO (United States)

The US DOE's Solar Thermal Electric Program, through its Sandia and Renewable Energy National Laboratories, has been actively developing liquid metal reflux receivers for application to modular parabolic dish concentrator/Stirling cycle converter solar energy systems. These systems are intended for use in high-value remote and grid-connected utility applications. The liquid-metal reflux-receiver concept was selected because this type of solar receiver (1) can optically mate a given dish with a given engine, and (2) can provide an isothermal environment for the high-temperature heat-input portion of the l engine, thus enhancing reliability. The Program is investigating two types of reflux receivers: heat pipes and pool boilers. Sintered-nickel-wick sodium heat-pipe receivers rated at 30 kW[sub t] have been extensively tested as part of DOE/Cummins cooperative commercialization programs. One recent test article was tested at rated and power temperature for 500 hours. This same receiver demonstrated a 40 kW[sub t] throughput, believed to be the most ever for a solar heated heat-pipe receiver. Another 30-kW[sub t] sodium heat-pipe receiver, this one using a stainless-steel-screen wick design, was also tested as part of these cooperative programs. Much of experimental reflux receiver work conducted at the program's laboratories involves the pool-boiler concept. During nearly 50 hours of solar testing, the Sandia 75-kW[sub t] pool-boiler receiver demonstrated stable sodium boiling over a wide range of temperatures. Hot restarts after simulated cloud passages were investigated using various quantities of added non-condensible gases. Novel x-ray techniques provided information on instantaneous void fractions in the receiver. Present work is focusing on longer lived designs having low-cost, high-strength boiling surface enhancements and using eutectic NaK as the working fluid. The paper will summarize the developments leading to the present and describe future plans.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
7006459
Report Number(s):
SAND-92-0300C; CONF-920938--4; ON: DE93003244
Country of Publication:
United States
Language:
English