A method for integrating a first thermal process a second thermal process and a third thermal process, wherein the rate of heat transfer from the first thermal process is different from the rate of heat transfer to the second thermal process, the method comprising: providing a first thermal store; managing receipt of the first thermal energy by the first thermal store by charging the first thermal store with the first thermal energy from the first thermal process by transferring the first thermal energy to the first thermal store at a first rate of energy transfer; and managing a supply of the stored first thermal energy by the first thermal store by discharging the first thermal store by transferring the stored first thermal energy from the first thermal store to components of the second thermal process at a second rate of energy transfer, wherein the second rate is different from the first rate, wherein the method further comprises providing a second thermal store; charging the second thermal store with second thermal energy from the second thermal process by transferring the second thermal energy to the second thermal store at a third rate of energy transfer; and discharging the second thermal store by transferring the second thermal energy stored in the second thermal store from the second thermal store to components of the third thermal process at a fourth rate of energy transfer, wherein the fourth rate is different from the third rate, characterised in that the first thermal store is an asymmetric thermal store comprising a first thermal mass, a second thermal mass and a third thermal mass, wherein the aspect ratios of at least two of the first, second and third thermal masses are different to one another, the aspect ratio being the ratio of the mean length of the thermal mass to the mean cross-sectional flow area of the thermal mass, and an arrangement of conduits and valves configured to direct a heat transfer fluid to pass through a combination of one or more of the thermal masses (1,2,3), wherein the arrangement of conduits and valves is such that the thermal masses (1,2,3) can be isolated from each other; and wherein the steps of charging and discharging the first thermal store comprise passing a heat transfer fluid through a combination of one or more of the thermal masses (1,2,3). providing a first thermal store; managing receipt of the first thermal energy by the first thermal store by charging the first thermal store with the first thermal energy from the first thermal process by transferring the first thermal energy to the first thermal store at a first rate of energy transfer; and managing a supply of the stored first thermal energy by the first thermal store by discharging the first thermal store by transferring the stored first thermal energy from the first thermal store to components of the second thermal process at a second rate of energy transfer, wherein the second rate is different from the first rate, wherein the method further comprises providing a second thermal store; charging the second thermal store with second thermal energy from the second thermal process by transferring the second thermal energy to the second thermal store at a third rate of energy transfer; and discharging the second thermal store by transferring the second thermal energy stored in the second thermal store from the second thermal store to components of the third thermal process at a fourth rate of energy transfer, wherein the fourth rate is different from the third rate, characterised in that the first thermal store is an asymmetric thermal store comprising a first thermal mass, a second thermal mass and a third thermal mass, wherein the aspect ratios of at least two of the first, second and third thermal masses are different to one another, the aspect ratio being the ratio of the mean length of the thermal mass to the mean cross-sectional flow area of the thermal mass, and an arrangement of conduits and valves configured to direct a heat transfer fluid to pass through a combination of one or more of the thermal masses (1,2,3), wherein the arrangement of conduits and valves is such that the thermal masses (1,2,3) can be isolated from each other; and wherein the steps of charging and discharging the first thermal store comprise passing a heat transfer fluid through a combination of one or more of the thermal masses (1,2,3).