Varying compression ratios in energy storage and retrieval systems

Patent metadata

Field	Value
Publication number	US-10458283-B2
Application number	US-201715440295-A
Country	US
Kind code	B2
Filing date	Feb 23, 2017
Priority date	Sep 27, 2012
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

In the present disclosure, an example method is provided. The example method may comprise operating a pumped thermal system in a charging cycle at a first compression ratio, wherein the pumped thermal system comprises a working fluid circulating through, in sequence, a compressor system, a hot side heat exchanger, a turbine system, and a cold side heat exchanger, wherein the working fluid is in thermal contact with a hot thermal storage (“HTS”) medium in the hot side heat exchanger and the working fluid is in thermal contact with a cold thermal storage (“CTS”) medium in the cold side heat exchanger. The example method may also comprise operating the pumped thermal system in a discharging cycle at a second compression ratio different than the first compression ratio.

First claim

What is claimed is:

1. A method comprising:
operating a pumped thermal system in a charging cycle at a first compression ratio, wherein the pumped thermal system comprises a working fluid circulating through, in sequence, a compressor system, a hot side heat exchanger, a turbine system, and a cold side heat exchanger, wherein the working fluid is in thermal contact with a hot thermal storage (“HTS”) medium in the hot side heat exchanger and the working fluid is in thermal contact with a cold thermal storage (“CTS”) medium in the cold side heat exchanger; and
operating the pumped thermal system in a discharging cycle at a second compression ratio different than the first compression ratio,
wherein the pumped thermal system is configured to circulate the working fluid through, in sequence and in the same direction, the compressor system, the hot side heat exchanger, the turbine system, and the cold side heat exchanger when the pumped thermal system operates in the charging cycle and when the pumped thermal system operates in the discharging cycle.

2. The method of claim 1 , wherein the compressor system comprises at least a first compressor and a second compressor.

3. The method of claim 2 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first compressor and the second compressor in parallel, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the first compressor and the second compressor in series.

4. The method of claim 2 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first compressor and not the second compressor, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the second compressor and not the first compressor.

5. The method of claim 2 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first compressor and not the second compressor, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the first compressor and the second compressor.

6. The method of claim 1 , wherein the turbine system comprises at least a first turbine and a second turbine.

7. The method of claim 6 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first turbine and the second turbine in parallel, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the first turbine and the second turbine in series.

8. The method of claim 6 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first turbine and not the second turbine, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the second turbine and not the first turbine.

9. The method of claim 6 , wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first turbine and the second turbine, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the first turbine and not the second turbine.

10. The method of claim 1 , wherein the compressor system comprises a compressor, wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises operating the compressor at a first rotation speed, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises operating the compressor at a second rotation speed different than the first rotation speed.

11. The method of claim 1 , wherein the turbine system comprises a turbine, wherein operating the pumped thermal system in the charging cycle at the first compression ratio further comprises operating the turbine at a first rotation speed, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio further comprises operating the turbine at a second rotation speed different than the first rotation speed.

12. The method of claim 1 , wherein the compressor system comprises at least a first compressor and a second compressor, wherein the turbine system comprises at least a first turbine and a second turbine, wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises circulating the working fluid through the first compressor and the first turbine and not circulating the working fluid through the second compressor and the second turbine, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises circulating the working fluid through the second compressor and the second turbine and not circulating the working fluid through the first compressor and the first turbine.

13. The method of claim 1 , wherein the compressor system comprises a compressor comprising a variable pressure stator, wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises tuning the variable pressure stator to operate the compressor at a third compression ratio across the compressor, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises tuning the variable pressure stator to operate the compressor at a fourth compression ratio across the compressor.

14. The method of claim 1 , wherein the turbine system comprises a turbine comprising a variable pressure stator, wherein operating the pumped thermal system in the charging cycle at the first compression ratio comprises tuning the variable pressure stator to operate the turbine at a third compression ratio across the turbine, and wherein operating the pumped thermal system in the discharging cycle at the second compression ratio comprises tuning the variable pressure stator to operate the turbine at a fourth compression ratio across the turbine.

15. The method of claim 1 , wherein the first compression ratio is a value such that

T
1
+

T
1

=

ψ
C

1
/

η
cp

,

wherein η cp is a polytropic efficiency associated with the compressor system, T 1 is a temperature at which the working fluid enters the compressor system, T 1 + is a temperature at which the working fluid exits the compressor system, and

Assignees

• Malta Inc

Inventors

• Laughlin Robert B
• Larochelle Philippe
• Cizek Nicholas

Classifications

• F28D15/00

  Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls {; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies (F28D17/00, F28D19/00, F28D20/00 take precedence)} · CPC title

• Y02E20/14

  Combined heat and power generation [CHP] · CPC title

• F01K3/12

  having two or more accumulators · CPC title

• F01K3/00 Primary

  Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein (regenerating exhaust steam F01K19/00) · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title