Thermally driven heat pump for heating and cooling

• US 10,101,059 B2
• Filed: 11/26/2008
• Issued: 10/16/2018
• Est. Priority Date: 11/27/2007
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Thermavant Technologies, LLC, Curators of the University of Missouri (University of Missouri)
• Inventors: Ma, Hongbin, Boswell, Joseph A., Cheng, Peng
• Primary Examiner(s): Furdge, Larry
• Application Number:
  US12/745,168
• Publication Number:
  US 20110259039A1
• Time in Patent Office: 3,611 Days
• Field of Search: 62101, 62102, 62141, 62495, 62500
• CPC Class Codes: F25B 1/08 using vapour under pressure
• CPC Class Codes: F25B 15/02 without inert gas F25B15/004, F25B15/006, F25B15/008, F25B15/12, F25B15/14, F25B15/16 take precedence
• CPC Class Codes: F25B 2341/0011 Ejectors with the cooled primary flow at reduced or low pressure
• CPC Class Codes: F25B 2341/0015 using two or more ejectors
• CPC Class Codes: Y02A 30/27 Relating to heating, ventilation or air conditioning [HVAC] technologies
• CPC Class Codes: Y02B 30/62 Absorption based systems

Abstract

A thermally driven heat pump includes a low temperature evaporator for evaporating cooling fluid to remove heat A first heat exchanger located at an outlet of a converging/diverging chamber of a first ejector receives a flow of primary fluid vapor and cooling fluid vapor ejected from the first ejector for condensing a portion of the cooling fluid vapor An absorber located in the first heat exchanger absorbs cooling fluid vapor into an absorbing fluid to reduce the pressure in the first heat exchanger A second heat exchanger located at an outlet of a converging/diverging chamber of a second ejector receives primary fluid vapor and cooling fluid vapor ejected from the second ejector for condensing the cooling fluid vapor and the primary fluid vapor A separator in communication with the second ejector, the low temperature evaporator and the primary fluid evaporator separates the primary fluid from the cooling fluid.

Claims

1. A thermally driven heat pump comprising:

a low temperature evaporator for evaporating a cooling fluid to remove heat;

a primary fluid evaporator for evaporating primary fluid by application of heat;

an ejector including a converging/diverging chamber, nozzle apparatus in fluid communication with the primary fluid evaporator to receive the primary fluid vapor and to eject the primary fluid vapor into the converging/diverging chamber, the low temperature evaporator being in fluid communication with the converging/diverging chamber so that cooling fluid vapor from the low temperature evaporator is aspirated into the converging/diverging chamber;

a heat exchanger located at an outlet of the converging/diverging chamber of the ejector for receiving a flow of the primary fluid vapor and the cooling fluid vapor ejected from the ejector for condensing a portion of at least one of the cooling fluid vapor and the primary fluid vapor;

absorption apparatus located at the outlet of the converging/diverging chamber, the absorption apparatus including an absorber associated with the heat exchanger for absorbing the cooling fluid vapor into an absorbing fluid thereby to reduce a pressure in the heat exchanger;

a generator for separating the cooling fluid from the absorbing fluid; and

a separator in fluid communication with the heat exchanger, the low temperature evaporator and the primary fluid evaporator for use in separating the primary fluid from the cooling fluid for returning to the low temperature evaporator and the primary fluid evaporator, respectively.

2. A thermally driven heat pump as set forth in claim 1 wherein the absorption apparatus comprises at least one sprayer arranged to spray the absorbing fluid into a flow of the cooling fluid and the primary fluid exiting the outlet of the converging/diverging chamber.

3. A thermally driven heat pump as set forth in claim 1 in combination with the absorbing fluid and the primary fluid, wherein the absorbing fluid is immiscible with the primary fluid.

4. A thermally driven heat pump as set forth in claim 1 further comprising a return conduit extending between the separator and the primary fluid evaporator, the return conduit being in thermal communication with the generator for transferring heat from the cooling fluid leaving the generator to primary fluid in the return conduit.

5. A thermally driven heat pump as set forth in claim 1 further comprising a conduit between the heat exchanger and the generator for delivering a solution of the absorbing fluid and cooling fluid absorbed by the absorbing fluid to the generator, the conduit being in thermal communication with the generator for transferring heat from the absorbing fluid leaving the generator to the solution of the absorbing fluid and the cooling fluid entering the generator.

6. A thermally driven heat pump as set forth in claim 1 wherein the primary fluid is immiscible with the cooling fluid for separation by gravity from the cooling fluid in liquid phase and wherein the primary fluid and cooling fluid have global warming potentials of less than about 1000, the primary fluid being different from the cooling fluid and comprising a hydrofluoroether.

7. A thermally driven heat pump as set forth in claim 6 wherein the ratio of a molecular weight of the primary fluid to a molecular weight of the cooling fluid is at least about 5.0.

8. A thermally driven heat pump as set forth in claim 6 wherein the ratio of a heat of vaporization of the cooling fluid to a heat of vaporization of the primary fluid is at least about 2.0.

9. A thermally driven heat pump as set forth in claim 6 wherein the primary fluid evaporator includes a liquid reservoir compartment containing condensed cooling fluid, heat pipes and a wick separating the liquid reservoir compartment from the heat pipes, the wick being adapted to draw the cooling fluid through the wick and into the heat pipes, each heat pipe having an internal surface structure having microwicks for use in thin film evaporation of primary fluid.

10. A thermally driven heat pump as set forth in claim 6 wherein the low temperature evaporator includes a liquid reservoir compartment containing condensed cooling fluid, heat pipes and a wick separating the liquid reservoir compartment from the heat pipes, the wick being adapted to draw the cooling fluid through the wick and into the heat pipes, each heat pipe having an internal surface structure having microwicks for use in thin film evaporation of cooling fluid.

11. A thermally driven heat pump as set forth in claim 6 further comprising:

a second ejector including a converging/diverging chamber, a nozzle apparatus for ejecting primary fluid vapor into the second ejector'"'"'s converging/diverging chamber at high speed, the heat exchanger being in fluid communication with the converging/diverging chamber of the second ejector so that cooling fluid vapor and the primary fluid vapor in the heat exchanger are aspirated into the converging/diverging chamber of the second ejector;

a second heat exchanger located at an outlet of the converging/diverging chamber of the second ejector for removing heat from vapors and the primary fluid vapor to cool the cooling fluid vapor and the primary fluid vapor to facilitate condensation; and

a conduit to connect the second heat exchanger to the separator.

12. A thermally driven heat pump as set forth in claim 11 wherein the primary fluid evaporator constitutes a first primary fluid evaporator, the heat pump further comprising a second primary fluid evaporator for evaporation of primary fluid by application of heat, the second primary fluid evaporator being in fluid communication with the second ejector.

13. A thermally driven heat pump as set forth in claim 6 further comprising a return conduit containing the primary fluid connected to the separator and to the primary fluid evaporator for returning primary fluid to the primary fluid evaporator, wherein the return conduit is in thermal communication with the heat exchanger for pre-heating the primary fluid returning to the primary fluid evaporator.

14. A thermally driven heat pump as set forth in claim 6 wherein the converging/diverging chamber is shaped so that the velocity of the combined flow of the primary fluid and the cooling fluid is about Mach 1 at a throat of the converging/diverging chamber.

15. A thermally driven heat pump as set forth in claim 1 wherein the converging/diverging chamber has an inner wall, a centerline and an inlet adapted for connection to the low temperature evaporator for aspirating vaporized cooling fluid from the evaporator, and a rotating section rotatable about the centerline of the converging/diverging chamber, the rotating section including projections extending inwardly from the inner wall of the converging/diverging chamber and into the flow of the primary fluid and the cooling fluid in the converging/diverging chamber, the projections being arranged to mix the cooling fluid with the primary fluid, the projections being shaped to convert some of the kinetic energy of the flow of primary fluid and cooling fluid to rotational movement of the rotating section for mixing the primary fluid and cooling fluid.