Systems and methods for generating electricity via a pumped thermal energy storage system

A generation system in a pumped thermal energy storage (“PTES”) system, comprising:

• a fluid circuit for the circulation of a working fluid therethrough, the working fluid comprising a first portion and a second portion comingled together, the fluid circuit comprising:
• a pump to circulate the working fluid within the fluid circuit, wherein the working fluid enters the pump at a first pressure, and the working fluid exits the pump at a second pressure,
• a first heat exchanger through which the working fluid circulates in use;
• a second heat exchanger through which the working fluid circulates in use;
• a first turbine positioned between the first heat exchanger and the second heat exchanger and wherein the first turbine is for expanding the working fluid to a third pressure, the third pressure greater than the first pressure and less than the second pressure;
• a separation location where the working fluid is separated into the first portion and the second portion,
• a second turbine positioned between the first heat exchanger and the second heat exchanger and wherein the second turbine is for expanding the first portion of the working fluid to the first pressure;
• an auxiliary line through which the second portion of the working fluid circulates between the first turbine and the first heat exchanger;
• a third heat exchanger through which the working fluid circulates in use positioned between an outlet of the first turbine and an inlet of a heat rejection heat exchanger, and in fluid communication with the auxiliary line, wherein the third heat exchanger removes thermal energy from the second portion of the working fluid;
• and
• the heat rejection heat exchanger positioned between an outlet of the third heat exchanger and an inlet of the first heat exchanger, and in fluid communication with the auxiliary line, wherein the heat rejection heat exchanger removes thermal energy from the second portion of the working fluid;
• a high temperature reservoir connected to the first heat exchanger for transferring thermal energy to and from the working fluid;
• a low temperature reservoir connected to the second heat exchanger for transferring thermal energy to and from the working fluid;
• and
• a waste heat reservoir connected to the third heat exchanger for transferring thermal energy to and from the working fluid.

A method for charging a pumped thermal energy system, comprising:

• circulating a working fluid through a fluid circuit, wherein the fluid circuit comprises a first heat exchanger, a second heat exchanger, a third heat exchanger, and a recuperator positioned between the second heat exchanger and the third heat exchanger connected thereto;
• circulating the working fluid through the second heat exchanger, the working fluid entering the second heat exchanger at a first temperature and the working fluid exiting the second heat exchanger at a second temperature;
• providing thermal energy from the second heat exchanger to the working fluid;
• circulating the working fluid through the recuperator;
• circulating the working fluid through the third heat exchanger, wherein:
• a waste heat reservoir storing waste heat transfers thermal energy to the working fluid to increase its temperature;
• and
• the working fluid enters the third heat exchanger at a third temperature and the working fluid exits the third heat exchanger at a fourth temperature;
• circulating the working fluid through a compressor, the working fluid entering the compressor at the fourth temperature and a first pressure and the working fluid exits the compressor at a fifth temperature and a second pressure;
• and
• circulating the working fluid through the first heat exchanger to transfer thermal energy from the working fluid to a high temperature reservoir connected to the first heat exchanger.