Analysis, Fabrication, and Testing of a Liquid Piston Compressor Prototype for an Ocean Compressed Air Energy Storage (OCAES) System

Abstract

Previous work concerning ocean compressed air energy storage (OCAES) systems has revealed the need for an efficient means for compressing air that minimizes the energy lost to heat during the compression process. In this paper, we present analysis, simulation, and testing of a tabletop proof-of-concept experiment of a liquid piston compression system coupled with a simulated OCAES system, with special attention given to heat transfer issues. An experimental model of a liquid piston system was built and tested with two different materials, polycarbonate and aluminum alloy, used for the compression chamber. This tabletop liquid piston system was tested in conjunction with a simulated OCAES system, which consisted of a hydrostatic tank connected to a compressed-air source from the wall to mimic the constant hydrostatic pressure at ocean depth experienced by the air stored in an actual OCAES system. Good agreement was found between the experimental and numerical studies and demonstrated that the heat transfer characteristics of a liquid piston compression process are effective in reducing the increase in air temperature that occurs during the compression process. The results also suggest that it may be possible to achieve a near-isothermal process with a fully optimized liquid piston compression system.

Various methodologies to improve the energy efficiency of a compressed air energy storage system

“…This system uses underwater structure to store the compressed air (refer Figure 6). 28,89 Generally, it uses a flexible fabric bag for underwater air storage. 29,90 Hydrostatic pressure in the deep ocean is used in OCAES system for storing the compressed air at fixed high pressure.…”

“…26,27 Moreover, to enhance the efficiency and increase the area of its application, the researchers presented several modifications on the CAES system. The modified CAES systems are as OCAES system, 28,29 Micro-CAES, 30,31 LP-CAES, 32,33 PH-CAES system, 34,35 LAES system, 6,36 SC-CAES 6,37 etc.…”

Experimental study of heat transfer enhancement in a liquid piston compressor/expander using porous media inserts

“…However, since the instrumentation was limited, only limited qualitative inferences could be made. Recently, a liquid piston compressor was also demonstrated in a benchtop ocean compressed air energy storage (OCAES) system [27].…”

Effect of Integrating Metal Wire Mesh with Spray Injection for Liquid Piston Gas Compression

“…This concept was further studied in [12], which presents a control strategy for an open accumulator CAES. Ocean compressed air energy storage (OCAES) where the storage vessel is placed on the seabed was designed and studied [8,[17][18][19]. Placing the storage tank underwater lessens safety and environmental concerns.…”