Project Name: Oil-Free, High-Temperature Heat Transfer Fluid Circulator
Funding Opportunity: Generation 3 Concentrating Solar Power Systems
SETO Subprogram: Concentrating Solar Power
Location: Albany, NY
SETO Award Amount: $1,678,243
Awardee Cost Share: $539,904
Principal Investigator: Hooshang Heshmat

This project will develop a high-temperature, high-pressure, gas heat-transfer fluid (HTF) circulator to integrate with a heat-transfer and thermal energy storage (TES) system. Applying the HTF flow and pressure requirements for the Gen3 CSP Gas Pathway prototype plant design, the team will perform technical and economic trade-off assessments to establish the design of an oil-free HTF circulator subsystem capable of integrating with the CSP Gen3 Gas Pathway heat transfer and TES loop. Under Topic 2a of this funding program, the circulator will enable CSP Gas Pathway systems in Topic 1 projects to achieve power, efficiency, economic, and life cycle goals.

High-temperature circulator hardware

Precursor high-temperature, variable-speed, motor-driven-circulator hardware. Photo courtesy of Mohawk Innovative Technology.


Mohawk will use its high-temperature turbine technologies in the HTF circulator, which collects heat from the sun and delivers it to a thermal storage system. These technologies include Mohawk’s foil gas bearings, Korolon™ thermal/environmental barrier coating, and system integration technologies that address thermal management and vibration. The variable-speed circulator will be able to respond to changes in the amount of sunlight and therefore readily accommodate changes in flow demand for the heat-transfer loop, depending upon the amount of solar energy in the system.


The HTF circulator does not require the HTF to cool before use, which increases the efficiency of the heat-transfer loop. The foil bearings will use the gas produced by the supercritical carbon dioxide process as a lubricant instead of the oil and sealants normally required for the bearings to reduce friction and support the turbine shaft. A new thermal barrier module will allow for a simpler, compact construction, resulting in a reliable, low-cost system.