A kind of carbon dioxide thermoelectric energy storage device and control method thereof

Abstract

The invention discloses a carbon dioxide thermoelectric energy storage device and a control method thereof, comprising: an energy storage part and an energy release part. The present invention is equipped with a plurality of energy storage throttling expansion valves for throttling and expansion of the working medium to achieve temperature reduction and pressure reduction; the use of throttling valves instead of expansion turbines without work requirements can reduce the entropy loss of the system, thereby improving the efficiency of the carbon dioxide cycle. Thermoelectric storage efficiency; add a vapor-liquid separator to the cycle and change the cycle structure, so that the outlet of the power turbine does not reach the two-phase area, but enters the two-phase area after condensation of the normal temperature medium and expansion of the throttle valve, realizing energy release during the cycle The working fluid can be condensed by the medium at normal temperature, stripping the cold storage components, reducing the system cost, and at the same time ensuring that the system efficiency does not decrease during the process.

Description

technical field [0001] The invention belongs to the technical field of peak regulation energy storage devices and control, and in particular relates to a carbon dioxide thermoelectric energy storage device and a control method thereof. Background technique [0002] Energy storage technology is one of the key research directions in the future energy field. Existing energy storage technologies include pumped hydro storage, compressed air energy storage and electrochemical energy storage, etc., but pumped hydro storage has problems such as terrain restrictions; compressed air energy storage There are problems such as low energy storage efficiency and low energy density; electrochemical energy storage has problems such as scale and grade restrictions. In response to these problems, thermoelectric energy storage systems based on carbon dioxide cycles have gradually developed, but there are still some problems: [0003] 1) The current system uses an expander to reduce the pressur...

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Problems solved by technology

[0003] 1) The current system uses an expander to reduce the pressure and temperature of the working fluid during the energy storage process and complete the cycle of the working medium. The expander has problems such as high entropy loss, which will lead to a decrease in the energy storage efficiency of the system

[0004] 2) In the current system, if the turbine back pressure is too low and the working fluid enters the two-phase region, it cannot be condensed by normal temperature water during the energy release process, and must use a lower temperature cold medium such as ice-water mixture to condense, so that the thermal power storage The energy system must have a cold storage medium, which will increase the operating cost; if the turbine back pressure is too high and the working fluid does not enter the two-phase region, the thermal efficiency of the system will be reduced

In summary, both of these situations will reduce the economic benefits of the system

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