Thermal energy recovery

Patent metadata

Field	Value
Publication number	US-9234530-B1
Application number	US-201313798259-A
Country	US
Kind code	B1
Filing date	Mar 13, 2013
Priority date	Mar 13, 2013
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Towards recovering thermal energy, an accumulator buffers a working fluid over an energy recovery cycle that includes two processes: one in which working fluid is accumulated in the accumulator at increasing pressure and the other that draws working fluid from the accumulator at decreasing pressure. Heat storage fluid is displaced in a storage fluid conduit towards a heat storage region in response to increasing pressure in the accumulator and towards a reservoir region in response to decreasing pressure in the accumulator. One or more heat exchange conduits traverse the storage fluid conduit to come in thermal contact with the heat storage fluid where they transfer heat to the heat storage fluid during the first process of the energy recovery cycle and transfer heat from the heat storage fluid during the other process.

First claim

What is claimed is:

1. An apparatus comprising:
an accumulator to buffer a working fluid over an energy recovery cycle that, by one process thereof, accumulates working fluid in the accumulator at increasing pressure and, by another process thereof, draws from the working fluid from the accumulator at decreasing pressure;
a storage fluid conduit in communication with the accumulator and storing an amount of a heat storage fluid therein such that, in response to increasing pressure of the working fluid in the accumulator, the heat storage fluid is displaced within the storage fluid conduit to a heat storage region and, in response to decreasing pressure of the working fluid in the accumulator, the heat storage fluid is displaced within the storage conduit to a reservoir region; and
at least one heat exchange conduit traversing a boundary of the storage fluid conduit to be in thermal contact with the heat storage fluid therein, the heat exchange conduit conveying the working fluid to transfer heat to the heat storage fluid during the process of the energy recovery cycle and to transfer heat from the heat storage fluid during the other process of the energy recovery cycle.

2. The apparatus of claim 1 further comprising:
an accumulator/reservoir vessel to enclose the accumulator and reservoir region in common containment;
an interface displaceable within the accumulator/reservoir vessel and mechanically separating the buffered working fluid and the heat storage fluid therein; and
an expansion vessel applying mechanical force to the heat storage fluid in the heat storage region so that, in response to the decreasing pressure of the buffered working fluid in the accumulator/reservoir vessel, the heat storage fluid is motivated to the reservoir region by the applied mechanical force.

3. The apparatus of claim 2 , wherein the expansion vessel includes an elastic biasing device that opposes motion of the heat storage fluid therein to apply the mechanical force.

4. The apparatus of claim 3 , wherein the biasing device is a spring.

5. The apparatus of claim 3 , wherein the biasing device is a quantity of compressible gas.

6. The apparatus of claim 2 further comprising:
a valve at a working fluid entry port of the accumulator/reservoir vessel that prohibits flow of the working fluid in a closed position thereof, allows unidirectional flow of the working fluid into the accumulator/reservoir vessel in an open position and allows unidirectional flow of the working fluid out of the accumulator/reservoir in another open position.

7. The apparatus of claim 6 further comprising:
a processor configured to:
determine whether the process or the other process of the energy recovery cycle is initiated;
generate a valve control signal to:
compel the valve into the open position responsive to the determination that the process of the energy recovery cycle is initiated;
compel the valve into the other open position responsive to the determination that the other process of the energy recovery cycle is initiated; and

compel the valve into the closed position otherwise.

8. The apparatus of claim 1 , wherein the working fluid is compelled to flow in the heat exchange conduit in a direction opposite to the flow of the heat storage fluid in both the process of the energy recovery cycle and the other process of the energy recovery cycle.

9. The apparatus of claim 1 , wherein the at least one heat exchange conduit includes a plurality of heat exchange conduits traversing the boundary of the storage fluid conduit, where the working fluid in each of the heat exchange conduits are in a thermodynamic state distinct from the working fluid in the others of the heat exchange conduits.

10. An apparatus comprising:
an accumulator/reservoir vessel to store a working fluid over an energy recovery cycle that, by one process thereof, accumulates the working fluid in an accumulator region of the accumulator/reservoir vessel at increasing pressure and, by another process thereof, draws from the working fluid from the accumulator region at decreasing pressure, the accumulator/reservoir vessel including a reservoir region to store a heat storage fluid therein, the reservoir region having an elastic boundary that remains in contact with both the working fluid in the accumulator region and the heat storage fluid as the pressure of the working fluid in the accumulator region increases and decreases;
a storage expansion vessel storing the heat storage fluid in a heat storage region thereof, the heat storage region having an elastic boundary that remains in contact with the heat storage fluid as the heat storage fluid is displaced to occupy the reservoir region;
a transfer/storage vessel in fluid communication with the reservoir region of the accumulator/reservoir vessel and with the heat storage region of the storage expansion vessel, the transfer/storage vessel being in constant occupancy by the heat storage fluid as the heat storage fluid is displaced to occupy the reservoir region; and
at least one heat exchange conduit traversing a boundary of the transfer/storage vessel to be in thermal contact with the heat storage fluid therein, the heat exchange conduit conveying the working fluid to transfer heat to the heat storage fluid during the process of the energy recovery cycle and to transfer heat from the heat storage fluid during the other process of the energy recovery cycle.

11. The apparatus of claim 10 , wherein the elastic boundary of the storage expansion vessel is elastically biased in opposition to the displacement of the heat storage fluid into heat storage region to apply a force to the heat storage fluid towards the reservoir region of the accumulator/reservoir vessel.

12. The apparatus of claim 11 , wherein a force on the heat storage fluid by the pressure of the working fluid in the accumulator region and the force on the heat storage fluid by the elastically biased boundary of the heat storage region combine to apply pressure to the heat storage fluid that is sufficient to raise a phase transition temperature of the heat storage fluid.

13. The apparatus of claim 10 , wherein the at least one heat exchange conduit includes a plurality of heat exchange conduits traversing the boundary of the transfer/storage vessel, where the working fluid in each of the heat exchange conduits are in a thermodynamic state distinct from the working fluid in the others of the heat exchange conduits.

Assignees

• Exelis Inc

Inventors

• Sneddon Keith C

Classifications

• F28D15/00 Primary

  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

• F15B1/025 Primary

  used for thermal compensation, e.g. to collect expanded fluid and to return it to the system as the system fluid cools down · CPC title

• B60T8/443

  using compressed air (B60T8/445, B60T8/446, B60T8/448 take precedence) · CPC title

• F28D19/00

  Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium {(F28D15/02 takes precedence)} · CPC title

• Y02E60/14

  Thermal energy storage · CPC title