Heat exchange methods and apparatus

Claim 2

Gas to liquid to gas heat exchange apparatus comprising; a first flow means for a heated gas; a second flow means for a cooler gas, said second flow means being independent of and separated from the first flow means; means for transferring heat from a gas in the first flow means to a gas in the second flow means which includes at least two flow circuits for fluid heat exchange media, each such circuit comprising a heat exchanger in the first flow means, a heat exchanger in the second flow means, conduit means extending between the first and second flow means and connecting the two heat exchangers into a closed circulation system, and pump means for circulating a heat exchange medium through the closed circulation system; a first heat exchange liquid in a first of said flow circuits; a second heat exchange liquid having a boiling or degradation point above that of the first heat exchange liquid in a second of said circuits; means for circulating the heated gas first to that heat exchanger of the second flow circuit in the first flow means and then to that heat exchanger of the first flow circuit in said first flow means; means for circulating the cooler gas first to that heat exchanger of the first flow circuit in said second flow means and then to that heat exchanger of the second flow circuit in said second flow means; means for independently controlling the rate of flow of the heat exchange liquid through each of the flow circuits; and means for independently controlling the flow of the gas through first and second flow means.

Claim 3

The heat exchange apparatus of claim 1, wherein the freezing point of the heat exchange liquid in one of said flow circuits is lower than the freezing point of the heat exchange liquid in the other of said flow circuits.

Claim 4

The heat exchange apparatus of claim 1, wherein one of said heat exchange liquids is water

Claim 5

Gas to liquid to Gas heat exchange apparatus comprising; a first flow means for a heated gas and a second flow means for a cooler gas, said second flow means being independent of and separated from the first flow means and each of said flow means having an inlet and an outlet; means for transferring heat from a gas in the first flow means to a gas in the second flow means which includes three flow circuits for fluid heat exchange media, each such circuit comprising a heat exchanger in the first flow means, a heat exchanger in the second flow means, conduit means extending between the first and second flow means and connecting the two heat exchangers into a closed circulation system, and pump means for circulating a heat exchange medium through the closed circulation system; water in one of said flow circuits; a second heat exchange liquid having a boiling or degradation point in excess of 212* F. in a second one of said circuits; and a third heat exchange liquid having a freezing point below 32* F. in the third of said circuits; the heat exchangers through which the second heat exchange liquid flows being nearest the inlet of the first flow means and nearest the outlet of the second flow means; the heat exchangers through which the third heat exchange liquid flows being nearest the outlet of the first flow means and nearest the inlet of the second flow means; and the heat exchangers through which the water flows being between the other two heat exchangers in both of said flow means; means for independently controlling the rate of flow of the heat exchange liquid through each of the flow circuits; and means for independently controlling the flow of the gas through the first and second flow means.

Claim 6

Gas to liquid to Gas heat exchange apparatus comprising; a first flow means for a heated gas and a second flow means for a cooler gas, said second flow means being independent of and separated from the first flow means and each of said flow means having an inlet and an outlet; means for transferring heat from a gas in the first flow means to a gas in the second flow means which includes three flow circuits for fluid heat exchange media, each such circuit comprising a heat exchanger in the first flow means, a heat exchanger in the second flow means, conduit means extending between the first and second flow means and connecting the two heat exchangers into a closed circulation system, and pump means for circulating a heat exchange medium through the closed circulation system; water in one of said flow circuits; a second heat exchange liquid having a boiling or degradation point in excess of 212* F. in a second one of said circuits; and a third heat exchange liquid having a freezing point below 32* F. in the third of said circuits; the heat exchangers through which the second heat exchange liquid flows being nearest the inlet of the first flow means and nearest the outlet of the second flow means; the heat exchangers through which the third heat exchange liquid flows being nearest the outlet of the first flow means and nearest the inlet of the second flow means; and the heat exchangers through which the water flows being between the other two heat exchangers in both of said flow means; means for independently controlling the rate of flow of the heat exchange liquid through each of the flow circuits; and means for independently controlling the flow of the gas through the first and second flow means.