skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Flexible Rotary Pipe Interconnection

Abstract

The Brayton Helical Pipe Coil (HPC) intends to support development of molten salt parabolic trough (MSPT) concentrating solar power (CSP) systems by reducing the risks associated with heat transfer fluid (HTF) interconnection pipes connecting plant manifolds to rotating solar receiver tubes. Molten salt HTF allows higher-temperature operation and thus greater efficiency than current oil-based heat transfer fluids, while reducing thermal storage system costs. Current interconnection technologies are proven unreliable when used with molten salt, which presents a barrier to industry acceptance of MSPT systems. Brayton’s HPC system uses a continuous all metal conduit formed into a helix to connect static supply piping to the rotating and expanding receiver. The helix acts as a mechanical spring, allowing for diurnal angular and axial displacement. Brayton has worked closely with the leaders of the industry to identify challenges of operating trough based CSP systems with molten salt and directly address them with design, analysis, and rigorous laboratory testing. It is designed to be a price competitive and scalable product that conforms to applicable codes, and is comprised of standard components allowing for a competitive supply chain. There are no commercial MSPT systems presently in operation. Without extensive operational experience on which to basemore » a design specification, a comprehensive effort was needed to identify operating conditions and system requirements. Brayton worked with SkyFuel, Abengoa, and Solar Dynamics to identify system operating conditions as basis for design. The configuration basis for the HPC is the SkyFuel DSP trough system, with four solar collector assemblies (SCA) in a U-Loop configuration. NREL’s System Advisory Model was used to obtain plant characteristics for a 140 MWe system in Arizona. Design of the fluid conduit is guided by ASME Power Piping Code B31.1 to determine allowable stress levels. Material choice has been guided by Sandia National Lab’s experience with Solar Salt in the Solar 2 molten salt power tower demonstration. Parasitic pumping power ranges between 0.2% and 1.0% of the system electrical power, and heat loss ranges from 1.3% to 1.9% of plant thermal power, depending on configuration. The present configuration demonstrated over 8,600 requisite angular and axial cycles at a maximum temperature of 550°C, though it has not yet been tested with molten salt. The total system cost for a representative loop (four-SCA U-loop) is estimated to range from $59/kWe - $94/kWe. The OPEX of the HPC system are competitive when considering 30-year life with no maintenance downtime. Parabolic trough technology is the most mature of CSP systems, and remains the most widely implemented. However, lack of advanced development has bound the system to lower operating temperatures, and thus efficiency. Brayton views reliable MSPT interconnections as an enabling technology for more efficient and less costly CSP systems, with greater market penetration. Brayton is prepared to fulfill orders for the HPC system and will continue to demonstrate its capabilities to gain industry acceptance.« less

Authors:
 [1]
  1. Brayton Energy, LLC
Publication Date:
Research Org.:
Brayton Energy, LLC
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1479462
Report Number(s):
FinalReport_BraytonEnergy_11965_2018-07-13
7744544580
DOE Contract Number:  
SC0011965
Type / Phase:
SBIR (Phase II)
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; Molten salt; Nitrate Salt; Parabolic Trough; CSP; Abengoa; Sky Fuel

Citation Formats

Caruso, William R. Flexible Rotary Pipe Interconnection. United States: N. p., 2018. Web.
Caruso, William R. Flexible Rotary Pipe Interconnection. United States.
Caruso, William R. Sun . "Flexible Rotary Pipe Interconnection". United States.
@article{osti_1479462,
title = {Flexible Rotary Pipe Interconnection},
author = {Caruso, William R},
abstractNote = {The Brayton Helical Pipe Coil (HPC) intends to support development of molten salt parabolic trough (MSPT) concentrating solar power (CSP) systems by reducing the risks associated with heat transfer fluid (HTF) interconnection pipes connecting plant manifolds to rotating solar receiver tubes. Molten salt HTF allows higher-temperature operation and thus greater efficiency than current oil-based heat transfer fluids, while reducing thermal storage system costs. Current interconnection technologies are proven unreliable when used with molten salt, which presents a barrier to industry acceptance of MSPT systems. Brayton’s HPC system uses a continuous all metal conduit formed into a helix to connect static supply piping to the rotating and expanding receiver. The helix acts as a mechanical spring, allowing for diurnal angular and axial displacement. Brayton has worked closely with the leaders of the industry to identify challenges of operating trough based CSP systems with molten salt and directly address them with design, analysis, and rigorous laboratory testing. It is designed to be a price competitive and scalable product that conforms to applicable codes, and is comprised of standard components allowing for a competitive supply chain. There are no commercial MSPT systems presently in operation. Without extensive operational experience on which to base a design specification, a comprehensive effort was needed to identify operating conditions and system requirements. Brayton worked with SkyFuel, Abengoa, and Solar Dynamics to identify system operating conditions as basis for design. The configuration basis for the HPC is the SkyFuel DSP trough system, with four solar collector assemblies (SCA) in a U-Loop configuration. NREL’s System Advisory Model was used to obtain plant characteristics for a 140 MWe system in Arizona. Design of the fluid conduit is guided by ASME Power Piping Code B31.1 to determine allowable stress levels. Material choice has been guided by Sandia National Lab’s experience with Solar Salt in the Solar 2 molten salt power tower demonstration. Parasitic pumping power ranges between 0.2% and 1.0% of the system electrical power, and heat loss ranges from 1.3% to 1.9% of plant thermal power, depending on configuration. The present configuration demonstrated over 8,600 requisite angular and axial cycles at a maximum temperature of 550°C, though it has not yet been tested with molten salt. The total system cost for a representative loop (four-SCA U-loop) is estimated to range from $59/kWe - $94/kWe. The OPEX of the HPC system are competitive when considering 30-year life with no maintenance downtime. Parabolic trough technology is the most mature of CSP systems, and remains the most widely implemented. However, lack of advanced development has bound the system to lower operating temperatures, and thus efficiency. Brayton views reliable MSPT interconnections as an enabling technology for more efficient and less costly CSP systems, with greater market penetration. Brayton is prepared to fulfill orders for the HPC system and will continue to demonstrate its capabilities to gain industry acceptance.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {7}
}

Technical Report:
This technical report may be released as soon as October 29, 2022
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item. Keep in mind that many technical reports are not cataloged in WorldCat.

Save / Share: