Compression/expansion process that allows temperature to vary independent of pressure

Abstract

Systems and methods are described herein to operate an air compression and / or expansion system in its most efficient regime, at a desired efficiency, and / or achieve a desired pressure ratio independent of discharge temperature, with little to no impact on thermal efficiency. For example, systems and methods are provided for controlling and operating hydraulic pumps / motors used within a hydraulically actuated device / system, such as, for example, a gas compression and / or expansion energy system, in its most efficient regime, continuously, substantially continuously, intermittently, or varied throughout an operating cycle or stroke of the system to achieve any desired pressure and temperature profile. Such systems and methods can achieve any desired pressure ratio independent of input or discharge temperature, and can also achieve any desired discharge temperature independent of pressure ratio, without altering any of the structural components of the device or system.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001]This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61 / 432,945, entitled “Compression / Expansion Process That Allows Temperature to Vary Independent of Pressure,” filed Jan. 14, 2011, the disclosure of which is hereby incorporated by reference herein in its entirety.BACKGROUND [0002]The invention relates generally to devices, systems and methods for the compression and / or expansion of a gas, such as air, and particularly to such a device that allows the temperature of the gas to be varied independently of its pressure during compression and / or expansion.[0003]Devices and systems used to compress and / or expand a gas, such as air, and / or to pressurize and / or pump a liquid, such as water, can generate heat during, for example, a compression process. Adiabatic compression assumes that no energy (heat) is transferred to or from the gas during the compression, and all supplied work is added to the ...

AI Technical Summary

Benefits of technology

[0012]Systems and methods are described herein to operate an air compression and/or expansion system in its most efficient regime, at a desired efficiency, and/or achieve a desired pressure ratio independent of discharge temperature, with little to no impact on thermal efficiency. For example, systems and methods are provided for controlling and operating hydraulic pumps/motors used within a hydraulically actuated device/system, such as, for example, a gas compression and/or expansion energy system, in its most efficient regime, continuously, substantially continuously, intermittently, or varied throughout an operating cycle or stroke of the system to achieve any desired pressure and t

Problems solved by technology

Adiabatic compression assumes that no energy (heat) is transferred to or from the gas during the compression, and all supplied work is added to the internal energy of the gas, resulting in increases of temperature and pressure.

Although adiabatic compression is less efficient, it is a very fast process for compressing a gas.

In practice, there will always be a certain amount of heat flow into the compressed gas, resulting in an increased temperature of the gas.

Since perfect isothermal compression is generally not attainable with conventional compression technologies, known compressor systems have a multi-stage compressor that may include intercoolers that cool air between stages of compression and / or after-coolers that cool air after compression.

In such a system, however, the air may still achieve substantial temperatures during each stage of compression, prior to being cooled, which will introduce inefficiencies in the system.

For example, unless an infinite number of compression stages with corresponding intercoolers are used, perfect isothermal compression cannot be achieved.

Since perfect adiabatic and isothermal compression are not practical, a polytropic model is used to measure real-world results.

For a given gas volume reduction (i.e., ratio of final volume to initial volume), an adiabatic compression process results in the highest final gas pressure, the highest final gas temperature, and the highest work consumption.

Processes that involve levels of heat flow intermediate to those in adiabatic (zero heat flow) and isothermal (maximum heat flow), result in intermediate values of gas pressure, gas temperature, and work consumption.

The reason for this design methodology is that conventional compression systems and processes are not capable of decoupling temperature from pressure.

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