Apparatus and methods for the storage of energy as heat

A method of transferring thermal storage me a from a media store to a heat exchange chamber, or vice versa, across a pressure differential, in an apparatus comprising a working fluid circulation pathway, the working fluid circulation pathway comprising a heat exchanger which comprises the heat exchange chamber, wherein the apparatus is a pumped heat energy storage apparatus, the thermal storage media is a solid and the working fluid, as a gas, is brought into direct contact with the thermal storage media in the heat exchange chamber and thereby transfers heat to or from the thermal storage material, the method comprising:

• receiving thermal storage media into at least one transfer chamber in the presence of gaseous working fluid,
• decreasing or increasing the volume of at least one working chamber to thereby compress or expand working fluid in least one transfer chamber while the at least one transfer chamber is fluidically connected to the at least one working chamber, and
• recovering energy from the work done by working fluid on the at least one working chamber while the working fluid expands,
• wherein the thermal storage media is transferred into the at least one transfer chamber from the heat exchange chamber, the volume of the at least one working chamber increases and the working fluid in the at least one transfer chamber is expanded, and then the thermal storage media and at least some of the expanded working fluid is transferred to the heat exchange chamber.

A method of transferring thermal storage me a from a media store to a heat exchange chamber, or vice versa, across a pressure differential, in an apparatus comprising a working fluid circulation pathway, the working fluid circulation pathway comprising a heat exchanger which comprises the heat exchange chamber, wherein the apparatus is a pumped heat energy storage apparatus, the thermal storage media is a solid and the working fluid, as a gas, is brought into direct contact with the thermal storage media in the heat exchange chamber and thereby transfers heat to or from the thermal storage material, the method comprising:

• receiving thermal storage media into at least one transfer chamber in the presence of gaseous working fluid,
• decreasing or increasing the volume of at least one working chamber to thereby compress or expand working fluid in least one transfer chamber while the at least one transfer chamber is fluidically connected to the at least one working chamber, and
• recovering energy from the work done by working fluid on the at least one working chamber while the working fluid expands,
• wherein working fluid is pressurised and introduced into the heat exchange chamber periodically or continuously to maintain the mass of working fluid circulating in the working fluid circulation pathway.

A method of transferring thermal storage me a from a media store to a heat exchange chamber, or vice versa, across a pressure differential, in an apparatus comprising a working fluid circulation pathway, the working fluid circulation pathway comprising a heat exchanger which comprises the heat exchange chamber, wherein the apparatus is a pumped heat energy storage apparatus, the thermal storage media is a solid and the working fluid, as a gas, is brought into direct contact with the thermal storage media in the heat exchange chamber and thereby transfers heat to or from the thermal storage material, the method comprising:

• receiving thermal storage media into at least one transfer chamber in the presence of gaseous working fluid,
• decreasing or increasing the volume of at least one working chamber to thereby compress or expand working fluid in least one transfer chamber while the at least one transfer chamber is fluidically connected to the at least one working chamber, and
• recovering energy from the work done by working fluid on the at least one working chamber while the working fluid expands,
• wherein at least one transfer chamber is located above the heat exchange chamber and comprises a valve which when actuated allows thermal storage media within the at least one transfer chamber to fall into the heat exchange chamber by gravity, and wherein at least one transfer chamber is located below the heat exchange chamber and comprises a valve which when actuated allows thermal storage media within the heat exchange chamber to fall into the at least one transfer chamber by gravity.

A method of transferring thermal storage me a from a media store to a heat exchange chamber, or vice versa, across a pressure differential, in an apparatus comprising a working fluid circulation pathway, the working fluid circulation pathway comprising a heat exchanger which comprises the heat exchange chamber, wherein the apparatus is a pumped heat energy storage apparatus, the thermal storage media is a solid and the working fluid, as a gas, is brought into direct contact with the thermal storage media in the heat exchange chamber and thereby transfers heat to or from the thermal storage material, the method comprising:

• receiving thermal storage media into at least one transfer chamber in the presence of gaseous working fluid,
• decreasing or increasing the volume of at least one working chamber to thereby compress or expand working fluid in least one transfer chamber while the at least one transfer chamber is fluidically connected to the at least one working chamber, and
• recovering energy from the work done by working fluid on the at least one working chamber while the working fluid expands,
• wherein the apparatus comprises first and second media stores for retaining media at different temperatures, a base temperature and an energy storage temperature which is higher or lower than the base temperature,
• wherein during energy storage, thermal storage media is transferred from the first media store to the heat exchange chamber, heated in the heat exchange chamber from direct contact with working fluid, and then stored at a higher temperature than the base temperature in the second media store,
• wherein during energy retrieval, thermal storage media is received from the second media store at a temperature which is higher than base temperature and then used to heat working fluid in the heat exchange chamber by direct contract with working fluid, and then stored in the first media store at base temperature,
• wherein the apparatus is a pumped heat energy storage apparatus comprising a working fluid circulation pathway retaining working fluid and a heat exchanger, the heat exchanger having a heat exchange chamber configured to bring thermal storage media into direct contact with working fluid in the working fluid circulation pathway to thereby exchange heat energy between the working fluid and the thermal storage media,
• wherein the working fluid is a gas within the heat exchange chamber and the thermal storage media is a solid,
• wherein the heat exchanger is configured to cause received thermal storage media to be moved into and out of the heat exchange chamber, and
• wherein the heat exchanger is reversible to transfer heat energy from the working fluid to the thermal storage media or vice versa in alternative first and second operating modes.

A pumped heat energy storage apparatus comprising:

• a solid thermal storage media,
• a thermal media store,
• a heat exchanger having a heat exchange chamber,
• a working fluid circulation pathway, the working fluid circulation pathway comprising the heat exchanger, and
• at least one transfer chamber and at least one working chamber,
• wherein the apparatus is at least configured to:
• transfer thermal storage media from the media store to the at least one transfer chamber and then to the beat exchange chamber or from the heat exchange chamber to the at least one transfer chamber and then to the thermal media store,
• decrease or increase the volume of the at least one working chamber to thereby compress of expand working fluid in the at least one transfer chamber while the at least one transfer be is fluidically connected to the at least one working chamber, and
• recover energy from the work done by on at least of working chamber while the working fluid is expanded,
• wherein the apparatus further comprises a plurality of chambers of variable volume which are operable as a said transfer chamber or a said working chamber in alternative operating modes of the apparatus, optionally wherein in a first operating mode, the first chamber is operable as a said transfer chamber and the second chamber is operable as a said working chamber and in a second operating mode, the first chamber is operable as a said working chamber and the second chamber is operable as a said transfer chamber.

A pumped heat energy storage apparatus comprising:

• a solid thermal storage media,
• a thermal media store,
• a heat exchanger having a heat exchange chamber,
• a working fluid circulation pathway, the working fluid circulation pathway comprising the heat exchanger, and
• at least one transfer chamber and at least one working chamber,
• wherein the apparatus is at least configured to:
• transfer thermal storage media from the media store to the at least one transfer chamber and then to the beat exchange chamber or from the heat exchange chamber to the at least one transfer chamber and then to the thermal media store,
• decrease or increase the volume of the at least one working chamber to thereby compress of expand working fluid in the at least one transfer chamber while the at least one transfer be is fluidically connected to the at least one working chamber, and
• recover energy from the work done by on at least of working chamber while the working fluid is expanded,
• wherein at least one transfer chamber is located above the heat exchange chamber and wherein the apparatus further comprises a valve which when actuated allows thermal storage media within the at least one transfer chamber to fall into the heat exchange chamber by gravity;
• and/or
• wherein the at least one transfer chamber comprises an outlet, through which thermal storage media may fall out of the at least one transfer chamber by gravity;
• and/or
• wherein at a first end of the heat exchange chamber a first chamber is located above the heat exchange chamber for transferring thermal storage media from a media store into the heat exchange chamber and a second chamber is located below the heat exchange chamber for transferring thermal storage media from the heat exchange chamber into a media store, which may be the same or a different media store, whereby the first and second chambers may therefore each displace thermal storage media into or out of the heat exchange chamber using gravity.

Pumped heat energy storage apparatus comprising

• a working fluid circulation pathway retaining working fluid, and
• a heat exchanger, the heat exchanger having a heat exchange chamber configured to bring thermal storage media into direct contact with working fluid in the working fluid circulation pathway to thereby exchange heat energy between the working fluid and the thermal storage media,
• wherein the working fluid is a gas and the thermal storage media is a solid,
• wherein the heat exchanger is configured to cause received thermal storage media to be moved into and out of the heat exchange chamber, and
• wherein the heat exchanger is reversible to transfer heat energy from the working fluid to the thermal storage media or vice versa in alternative first and second operating modes, configured so that in a first operating mode, the thermal storage media is received from a first media store into the heat exchanger and in the second operating mode the thermal storage media is output from the heat exchanger and transferred to the first media store, and configured such that in the first operating mode, the thermal storage media is output from the heat exchanger and transferred to a second media store, and that in the second operating mode the thermal storage media received into the heat exchanger from the second media store.