Method and Apparatus for Combining a Heat Pump Cycle With A Power Cycle

Abstract

The working fluid for the heat pump cycle will be different than that for the power cycle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 13/919,408, filed Jun. 17, 2013, which is a continuation of U.S. patent application Ser. No. 13/110,255, filed May 18, 2011, which was a continuation of U.S. patent application Ser. No. 11/203,783, filed Aug. 15, 2005, which application is a non-provisional of U.S. Provisional Patent Application Ser. No. 60/604,663, filed Aug. 26, 2004, and a non-provisional of US Provisional Patent Application Ser. No. 60/602,270, filed Aug. 16, 2004.

Each of these applications are incorporated herein by reference. Priority of each of these applications is hereby claimed.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

REFERENCE TO A “MICROFICHE APPENDIX”

Not applicable

BACKGROUND

1. Field

The present invention relates to cycles. More particularly, the present invention relates to a method and apparatus for combining a power cycle with a refrigeration cycle or heat pump.

2. General Background

A general vapor power cycle can include a boiler, turbine, condenser and a pump. FIG. 1 shows a general power cycle. From “a” to “b” subcooled fluid can be heated to the saturated fluid temperature in the boiler. From “b” to “c” saturated fluid can be vaporized in the boiler, producing saturated gas. From “c” to “d” a superheater option can be used to increase the fluid temperature while maintaining pressure. From “d” to “e” vapor expands through a turbine and does work as it decreases in temperature, pressure, and quality. From “e” to “f” vapor is liquified in the condenser. From f to a liquid is brought up to the boiler pressure. The expansion process between states d and e is essentially adiabatic. Ideal turbine expansion also is isentropic.

The Carnot cycle is an ideal power cycle which is stated to set the maximum attainable work output from a power cycle or heat engine. Various property diagrams for a Carnot cycle are provided in FIGS. 2A through 2C. FIG. 2A shows a pressure-volume diagram. FIG. 2B shows a temperature-entropy diagram. FIG. 2C shows an enthalpy-entropy diagram. From “a” to “b” occurs isothermal expansion of a saturated fluid to a saturated gas. From “b” to “c” occurs isentropic expansion. From “c” to “d” occurs isothermal condensation. From “d” to “a” occurs isentropic compression. The thermal efficiency of the entire cycle is calculated by the following formula:

$n_{\mathrm{th}}=\frac{T_{\mathrm{high}}-T_{\mathrm{low}}}{T_{\mathrm{high}}}$

Refrigeration cycles are essentially power cycles in reverse. FIG. 3 is a schematic diagram of a refrigeration cycle. It is necessary to do work on the refrigerant in order to have it discharge energy, Q_H, to a high temperature sink After discharging energy to the high temperature heat sink the refrigerant is expanded through an expansion valve to drop its temperature allowing it to absorb energy, Q_L, from a low temperature heat source. A heat pump also operates on a refrigeration cycle. One difference between a refrigerator and a heat pump is the purpose of each. The refrigerator's main purpose is to cool a low temperature area and to reject the absorbed heat to a high temperature area. The heat pump's main purpose is to reject the absorbed heat to a high temperature area, having picked up that heat from a low temperature area.

Heat pumps use energy more efficiently than resistance heaters. For each kilowatt of energy used by the compressor of a heat pump, one kilowatt of compression heat is produced plus heat picked up through a refrigeration effect. The refrigeration effect of the heat pump can vary from ten to as high as five hundred percent or higher of the energy input into the compressor. This refrigeration effect is dependent on the temperatures involved and fluid used.

Up to this point it was believed that the Carnot cycle was the most efficient power cycle that could be used. However, this belief did not consider a refrigeration/heat pump cycle being combined with a power cycle. No one has used a refrigeration cycle or heat pump as a heat source in a power cycle.

While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”

BRIEF SUMMARY

The apparatus of the present invention solves the problems confronted in the art in a simple and straightforward manner. What is provided is an original process for the removal and use of energy from the ambient environment, including air, water, or earth. This energy is removed in the form of mechanical motion such as work, which may be used either directly or to drive electrical generators, or supply other energy needs.

In one embodiment the process can consist of a combined refrigeration/power cycle. A first media (Media No. 1) can be vaporized at ambient temperatures, compressed, and condensed at a higher temperature, T_H, in a first heat exchanger. This portion of the method and apparatus can be a cycle similar to conventional heat pumps.

The refrigeration/heat pump cycle can be combined with a second cycle in which a second media (Media No. 2) is vaporized at the higher temperature, T_H. Energy can then be extracted from Media No. 2 by flowing it through a mechanical drive turbine or other engine, then condensing Media No. 2 at ambient temperature in the condenser.

The heat pump cycle using Media No. 1 produces a quantity of available energy at T_H equal to the energy of evaporation of Media No. 1 at ambient temperature plus the energy of compression of Media No. 1. Thus, the energy available at T_H compared to the input of mechanical energy is:

E@T_H=E Evap.+E Mech. Input

The ratio of E@T_H to E Mechanical Input depends upon the thermodynamic properties of Media No. 1, the ambient temperature and condensation temperature, T_H at which the cycle is operating.

The second portion of this process is the cycle of Media No. 2. Media No. 2 is evaporated in Heat Exchanger No. 1 at T_H by the condensation of Media No. 1. Media No. 2 is then passed through a turbine or other engine where mechanical energy is removed, then condensed at ambient temperature in the condenser. The energy of Media No. 2 available for transformation into mechanical energy is the difference of the energy of:

1. Heating, evaporating and superheating of Media No. 2 in the Heat Exchanger No. 1, and:

2. The energy of condensation of Media No. 1 at ambient temperature in the condenser, or;

Available Energy=E (Heat Exchanger No. 1)−E (Condensation at condenser).

The theoretical output of the process is then determined by the product of:

$\frac{E@T_H}{E\mathrm{Mech}.\mathrm{Input}}$

of Cycle No. 1 and the per unit available energy of Cycle No. 2.
If the media for Cycle No. 1 and Cycle No. 2 and operating temperatures are properly selected such that the ratio of

$\frac{E@T_H}{E\mathrm{Mech}.\mathrm{Input}}$

of Cycle No. 1 is maximized and the available energy of Cycle No. 2 is maximized, then the theoretical mechanical output to mechanical input ratio exceeds unity. Thus, there is a net flow of energy from the ambient environment, which is converted into mechanical energy.

The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:

FIG. 1 is a schematic diagram of a power cycle.

FIGS. 2A through 2C are schematic diagrams of various diagrams of the properties in a Carnot cycle.

FIG. 3 is a schematic diagram of a refrigeration cycle.

FIG. 4 is a schematic diagram of a preferred embodiment of the invention.

FIG. 5 is a pressure—enthalpy diagram for R11.

FIG. 6 is a pressure—enthalpy diagram for R600.

DETAILED DESCRIPTION

Detailed descriptions of one or more preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in any appropriate system, structure or manner.

FIG. 4 is a schematic diagram of a preferred embodiment 10. In this embodiment a heat pump cycle 20 is used as the heat source for a power cycle 30. Heat pump cycle 20 can comprise expansion valve 60, evaporator 70, compressor 40, and a condenser. The condenser can be heat exchanger 50. Power cycle 30 can comprise engine 80, condenser 90, pump 100, and a heat source or boiler. The heat source or boiler can also be heat exchanger 50.

In heat pump cycle 20, a first media (Media No. 1) can be vaporized at ambient temperatures, compressed, and condensed at a higher temperature, T_H, in heat exchanger 50.

Heat pump cycle 20 is combined with a second cycle 30 in which a second media (Media No. 2) is vaporized at the higher temperature, T_H. Energy can then be extracted from Media No. 2 by flowing it through a mechanical drive turbine or other engine 80, then condensing Media No. 2 at ambient temperature in condenser 90.

Heat pump cycle 20 using Media No. 1 produces a quantity of available energy at T_H equal to the energy of evaporation of Media No. 1 at ambient temperature plus the energy of compression of Media No. 1. Thus, the energy available at T_H compared to the input of mechanical energy is:

E @T_H=E Evap.+E Mech. Input

The ratio of E @T_H to E Mechanical Input depends upon the thermodynamic properties of Media No. 1, the ambient temperature and condensation temperature, T_H at which the cycle is operating.

The second portion of this process is power cycle 30 using Media No. 2. Media No. 2 can be evaporated in heat exchanger 50 at T_H by the condensation of Media No. 1 of cycle 20. Media No. 2 is then passed through turbine or other engine 80 where mechanical energy is removed, then condensed at ambient temperature in condenser 90. The energy of Media No. 2 available for transformation into mechanical energy is the difference of the energy of:

1. Heating, evaporating and superheating of Media No. 2 in heat exchanger 50, and:

2. The energy of condensation of Media No. 1 at ambient temperature in condenser 90, or;

Available Energy=E (heat exchanger 50)−E (Condensation at condenser 90).

The theoretical output of overall process 10 is then determined by the product of:

$\frac{E@T_H}{E\mathrm{Mech}.\mathrm{Input}}\mathrm{of}\mathrm{Cycle}\mathrm{No}.1\left(\mathrm{cycle}20\right)\times \begin{array}{c}\mathrm{the}\mathrm{per}\mathrm{unit}\mathrm{available}\\ \mathrm{energy}\mathrm{of}\mathrm{Cycle}\mathrm{No}.2.\\ \left(\mathrm{cycle}30\right).\end{array}$

If the media for Cycle No. 1 and Cycle No. 2 and operating temperatures are properly selected such that the ratio of

$\frac{E@T_H}{E\mathrm{Mech}.\mathrm{Input}}$

of Cycle No. 1 (cycle 20) is maximized and the available energy of Cycle No. 2 (cycle 30) is maximized, then the theoretical mechanical output to mechanical input ratio exceeds unity for overall cycle 10. Thus, there is a net flow of energy from the ambient environment, which is converted into mechanical energy.

One example of a preferred embodiment 10 using specific fluids is shown in FIG. 4. This system uses refrigerant No. R11 as the media of Cycle No. 1(cycle 20), evaporating at an ambient temperature of 70° F. and condensing in heat exchanger 50 at 190° F. Refrigerant R600 is used in Cycle No. 2(cycle 30), evaporating in heat exchanger 50 and condensing at the ambient temperature of 70° F.

Cycle 20 shows refrigerant entering expansion valve 60 at 70° F., at a pressure of 90 pounds per square inch, and having a heat content of 22.4 BTUs per pound. After passing through expansion valve 60 the refrigerant is at a pressure of 13.39 pounds per square inch and maintain a heat content of 22.4 BTUs per pound. It should be noted that depending on the refrigerant used, an expansion turbine may be used in place of expansion valve 60 to enhance performance of the overall process. Next, the refrigerant enters evaporator 70. Fed into evaporator 70 can be water at 70° F. having a heat capacity of 78.3 BTUs per pound (or 166.2 BTUs per minute). The refrigerant leaves evaporator 70 at 70° F., at a pressure of 13.39 pounds per square inch, and having a heat content of 100.72 BTUs per pound. Next the refrigerant is compressed by compressor 40 which can require an input energy of 142 BTUs per pound (or 30.146 BTUs per minute). The refrigerant leaves compressor 40 at 200° F., at a pressure of 90 pounds per square inch, and having a heat content of 114.9 BTUs per pound. Finally, the refrigerant passing through heat exchanger 50 where it absorbs heat and leaves at 70° F., at a pressure of 90 pounds per square inch, and having a heat content of 22.4 BTUs per pound. The heat loss by the working fluid in heat exchanger 50 can be 92.5 BTUs per pound (or 196.37 BTUs per minute).

Cycle 30 shows a working fluid entering engine 80 (which can be a turbine) at 190° F., at a pressure of 173.25 pounds per square inch, and having a heat content of 256.374 BTUs per pound. Leaving engine 80 the working fluid can be at 70° F., at a pressure of 31.279 pounds per square inch, and having a heat content of 217.017 BTUs per pound. The mechanical output of engine 80 can be 39.357 BTUs per pound or 39.357 BTUs per minute. Next, the working fluid can enter condenser 90 and leave at 70° F., at a pressure of 31.279 pounds per square inch, and having a heat content of 59.867 BTUs per pound. To achieve such a change in properties of the working fluid water at 70° F. can be fed through condenser 90 and exiting at 157.15 BTUs per pound (or 157.15 BTUs per minute). Next, the working fluid is pumped by pump 100 and leaves at 70° F., at a pressure of 194.09 pounds per square inch, and having a heat content of 60.22 BTUs per pound. The mechanical input to pump 100 can be 0.3618 BTUs per pound or 0.3618 BTUs per minute. Next, the working fluid enters heat exchanger 50 and exits at 190° F., at a pressure of 173.25 pounds per square inch, and having a heat content of 256.374 BTUs per pound. The heat gain for the working fluid entering heat exchanger 50 can be 196.154 BTUs per pound (or 196.154 BTUs per minute).

The working fluid for cycle 20 can be R11. The working fluid for cycle 30 can be R600. The ratios of flow rates for R11 to R600 can be 2.123 to 1. For example, the flow rate of R11 can be 2.123 pounds per minute and the flow rate of R600 can be 1 pound per minute. FIG. 5 is a pressure—enthalpy diagram for R11. FIG. 6 is a pressure—enthalpy diagram for R600. In both FIGS. 5 and 6 pressure is on the y-axis and enthalpy is on the x-axis. Tables 1A and 1B list various thermophysical properties for R11. Tables 2A and 2B list various thermophysical properties for R600.

The performance index of Cycle No. 1 (cycle 20):

$\frac{Q@T_H}{Q\mathrm{Mech}.\mathrm{Input}}$

is 6.514. The per unit available energy of Cycle No. 2 (cycle 30) is 0.2006. The product of these performances, the net mechanical energy output per unit of mechanical energy per input is 6.514×0.2006=1.307. Thus, the system will sustain its own operation plus produce mechanical energy for other uses by extracting energy from the ambient environment.

The following is a list of reference numerals:

LIST FOR REFERENCE NUMERALS
(Part No.) (Description)
10         preferred embodiment of the present invention
20         refrigeration/heat pump cycle
30         power cycle
40         compressor
50         heat exchanger
60         expansion valve
70         evaporator
80         engine
90         condenser
100        pump
110        pressure
120        enthalpy
130        pressure
140        enthalpy

All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.

Claims

1. A method of power generation comprising:

(a) a power cycle; and

(b) a heat pump cycle, the heat pump cycle supplying heat to the power cycle wherein the heat pump extracts energy from an ambient environment and the combined power cycle and heat pump sustains its own operation plus produces an excess of mechanical energy.

2. The method of claim 1, wherein the power cycle includes a first media and the heat pump cycle includes a second media, the first media being different from the second media.

3. The method of claim 2, wherein the first media has a first flow rate and the second media has a second flow rate, the first flow rate being different from the second flow rate.

4. The method of claim 1, wherein the heat pump cycle includes an expansion valve.

5. The method of claim 1, wherein the heat pump cycle includes an expansion turbine.

6. The method of claim 3, wherein the first media is R600 and the second media is R11.

7. The method of claim 6, wherein the flow rate of the second media is about two times the flow rate of the second media.

8. The method of claim 1, wherein the heat pump cycle includes a heat exchanger for rejecting heat and the power cycle uses this heat exchanger as a source of heat.