Project Name: Loop Thermosyphon Enhanced Solar Collector
Funding Opportunity: Solar Desalination
SETO Subprogram: Concentrating Solar Power
Location: Lancaster, PA
SETO Award Amount: $1,500,000
Awardee Cost Share: $375,000
Principal Investigator: Fangyu Cao

Advanced Cooling Technologies, Inc. and the University of Maryland at College Park will develop an innovative loop thermosyphon solar collection system for efficient, low-cost solar-thermal desalination. The design features graphene-oxide-based nanofluids and high-power thermosyphon technology that will acquire and transfer heat from sunlight to steam without moving parts, keeping installation, operation, and maintenance costs low. The team will build a prototype and test it using an indoor heat source and a heat sink to collect the excess heat.

A schematic of the proposed loop thermosyphon solar collection system.
A schematic of the proposed loop thermosyphon solar collection system. Graphic courtesy of Advanced Cooling Technologies, Inc.


A glass tube solar receiver attached to the loop thermosyphon will absorb sunlight directly into the fluid and generate steam. The steam will flow into a thermal desalination system and return to the receiver without the use of a pump. A graphene-oxide-based nanofluid will be used in the loop thermosyphon to absorb the concentrated solar light.


The loop thermosyphon solar collection system will convert solar energy to saturated steam at a high rate with low thermal resistance and exergy loss. It will use nanofluids that have higher solar absorptivity, which will improve the system’s efficiency and simplify the collection of solar-thermal energy in desalination processes. The heat transfer method will be passive and driven by gravity, which will lower thermal desalination costs by eliminating the need for active system operation and maintenance.