U.S. patent application number 11/621881 was filed with the patent office on 2008-07-10 for apparatus and method for producing sustainable power and heat.
Invention is credited to Kevin M. O'Brien.
Application Number | 20080163625 11/621881 |
Document ID | / |
Family ID | 39593111 |
Filed Date | 2008-07-10 |
United States Patent
Application |
20080163625 |
Kind Code |
A1 |
O'Brien; Kevin M. |
July 10, 2008 |
APPARATUS AND METHOD FOR PRODUCING SUSTAINABLE POWER AND HEAT
Abstract
An integrated system provides electricity and heat from solar,
waste heat, biomass and fossil fuel energy. The system operates
with a volatile organic working fluid that circulates in a variable
speed heat engine type cycle, that is heated either to its boiling
point, to a saturated state or above its boiling point, or to a
superheated gas state, expanded through an expander, with working
fluid injected therein such that the fluid exiting the expander is
cooled in a condenser in thermal communication with a facility's
domestic hot water, space heating or process heating systems, and
circulated by a pump. Heat exchange loops define hot water
production capability for use in a facility while a generator is
coupled to the expander to produce electricity and is connected to
the utility grid at fixed frequency and voltage in either a
paralleling or island mode.
Inventors: |
O'Brien; Kevin M.; (St.
Louis, MO) |
Correspondence
Address: |
CHARLES C. MCCLOSKEY
763 S. NEW BALLAS ROAD STE. 170
ST. LOUIS
MO
63141
US
|
Family ID: |
39593111 |
Appl. No.: |
11/621881 |
Filed: |
January 10, 2007 |
Current U.S.
Class: |
60/651 ;
60/671 |
Current CPC
Class: |
F01K 25/08 20130101;
Y02E 20/14 20130101 |
Class at
Publication: |
60/651 ;
60/671 |
International
Class: |
F01K 17/02 20060101
F01K017/02; F01K 25/00 20060101 F01K025/00; F01K 25/08 20060101
F01K025/08 |
Claims
1. An integrated system producing electricity and heat for a
facility comprising: at least one heat source producing one of a
saturated liquid or superheated vapor; an expander heat engine,
receiving one of a saturated liquid or a superheated vapor from
said at least one heat source, and having ports for injection of
subcooled volatile organic fluid into an expansion chamber of the
expander such that said volatile organic fluid exiting said heat
engine expander is in a saturated state; a first circuit configured
to transport said volatile organic working fluid, said first
circuit in thermal communication with said heat source where heat
transferred therefrom raises the temperature of said volatile
organic working fluid to one of a saturated bi-phase state or a
superheated gas state, said first circuit further comprising: said
heat engine expander being driven by said volatile organic working
fluid under heat and pressure producing mechanical power to an
output shaft; an alternator operatively coupled to said output
shaft generating electricity; a converter-controller, converting
the electricity from said alternator into specified alternating
current and controlling the operations of said system; a heat
exchanger in fluid communication with said expander reducing the
temperature of said volatile organic working fluid, said volatile
organic working fluid exiting said expander in a liquid state and
transferring latent and specific heat of said volatile organic
working fluid to said facility's heating system, domestic hot water
system, and process heat system; and, a variable speed pump
pressurizing and circulating said volatile organic working fluid
through said system, the speed of said pump responding to signals
from said converter controller and determining the state of said
volatile organic working fluid entering said expander, the amount
of electricity produced versus thermal power produced by said
system; a second circuit in thermal communication between said
variable speed pump and said expander and transporting said
volatile organic working fluid exiting said pump to said expander
such that said volatile organic working fluid exits said expander
in a saturated state, said second circuit further comprising: an
injection valve dynamically controlling the flow of said volatile
organic working fluid into said expander based on signals from said
converter-controller.
2. An integrated combined heat and electricity system according to
claim 1, wherein said heat source is at least one solar collector
directly heating said working fluid.
3. An integrated combined heat and electricity system according to
claim 2, wherein said heat source includes waste heat from said
facility's air conditioning or refrigeration system, said
facility's attic space, or said facility's process heat.
4. An integrated combined heat and electricity system according to
claim 1, wherein said heat source is a combustion burner consuming
one of fossil fuel or biomass fuel.
5. An integrated combined heat and electricity system according to
claim 4, wherein said heat source is a fossil fuel combustion
burner.
6. An integrated combined heat and electricity system according to
claim 5, wherein said volatile organic working fluid is heated
directly by said heat source.
7. An integrated combined heat and electricity system according to
claim 1, further comprising: said volatile organic working fluid
being heated by one of at least one solar collector, waste heat
from said facility's air conditioner, biomass fuel combustion, or
fossil fuel combustion; and, a transfer fluid transferring heat to
said volatile organic fluid through said heat exchanger.
8. An integrated combined heat and electricity system according to
claim 1, wherein said volatile working fluid is heated by waste
heat from another lo power generator system including an internal
combustion generator, turbine, micro turbine, or fuel cell, said
waste heat exceeding 200.degree. F.
9. An integrated combined heat and electricity system according to
claim 1, wherein said first circuit includes a receiver downstream
of said expander to provide a reservoir for cooled volatile organic
working fluid and a head for said variable speed pump.
10. An integrated combined heat and electricity system according to
claim 1, wherein said expander is cooled by an evaporative cooling
tower.
11. An integrated combined heat and electricity system according to
claim 1, wherein said first circuit includes an emergency bypass
around said expander for said volatile organic working fluid.
12. An integrated combined heat and electricity system according to
claim 1, wherein said converter-controller compares temperature and
pressure signals in said heating device and said expander to
determine amount said organic working fluid is saturated and
superheated and controls the amount of said working fluid injected
and the speed of said pump to control the state of the working
fluid entering said expander.
13. An integrated combined heat and electricity system according to
claim 1, wherein said converter-controller operates in an
interconnecting paralleling mode and an island mode when an utility
electric grid fails.
14. A method for utilizing thermal energy for the production of
mechanical power, electrical power, hot water, space heating or
process heat for a facility by controlling the temperature,
pressure and state of a volatile organic fluid entering and exiting
an expander of a heat engine cycle comprising: a) circulating and
substantially adiabatically pressurizing said volatile organic
fluid through a heat engine system; b) circulating a portion of the
pressurized volatile organic fluid to a heat exchanger of said
system; c) circulating the balance of the pressurized volatile
organic fluid to injectors that communicate directly with an
expansion volume of said expander; d) providing an external heat
energy source and passing said external heat energy source in heat
exchange relationship with said circulating volatile organic fluid;
e) transferring the heat from the external heat energy source in a
substantially isobaric manner to the circulating volatile organic
fluid to one of a saturated or superheated state; f) further
circulating the heated volatile organic fluid from the heater to
said expander; g) injecting the unheated portion of the pressurized
volatile organic fluid into the expansion volume of the expander so
that the volatile organic fluid exits the expander in a saturated
state; h) providing a flow path for the volatile organic fluid
through the expander, substantially adiabatically expanding said
volatile organic fluid and exhausting the combined mass flow of
said volatile organic fluid from the expander; i) passing thermal
transfer fluid from one of the facility's domestic hot water
system, space heating system or process heat system in a heat
exchange relationship with said volatile organic fluid exiting the
expander; wherein said volatile organic fluid from the expander is
in saturation state at a temperature sufficient to transfer heat
from said volatile organic fluid to one of the domestic hot water
system, space heating system or process heat system, at a minimum
delta temperature between said volatile fluid and the heat transfer
media; j) removing heat of condensation of said volatile organic
fluid medium in substantially isobaric manner to create a liquid
phase condensate at a saturation temperature approximating the
minimum reliable approach difference above the lowest temperature
of said coolant fluid; k) returning the liquid phase condensate
produced to circulation in said system; l) controlling the
saturation temperature and pressure of said volatile organic fluid
leaving the heater in response to the dynamic temperatures and
pressures of the thermal energy to the system, ambient conditions
and electrical and thermal loads of the facility; and, m)
controlling the saturation temperature and pressure of said
volatile organic fluid in response to load demands of the facility
and the targeted temperatures of the domestic hot water system, the
space heating system and the process heat system to foster the
saturation conditions of said volatile organic working fluid medium
permits condensation.
15. The method of claim 14, wherein controlling the temperature,
pressure and state of said volatile organic fluid entering the
expander includes sensing changes in temperature of the heater and
the temperature of volatile organic fluid and controlling the mass
flow through heater and volatile organic fluid by controlling the
circulation of said volatile organic fluid and pressurizing said
volatile organic fluid.
16. The method of claim 14, wherein controlling the temperature,
pressure and state of the volatile organic fluid leaving the
expander includes sensing changes in electrical and thermal loads
of the facility and controlling the lo mass flow through heater and
volatile organic fluid in response thereto.
17. The method of claim 14, wherein controlling the temperature,
pressure and state of the volatile organic fluid entering the
expander includes sensing changes in temperature of a condenser and
the temperature of said volatile organic fluid and controlling the
mass flow through a condenser and volatile organic fluid in
response to the sensed changes in said fluid temperatures.
18. The method of claim 14, wherein controlling the temperature,
pressure and state of the volatile organic fluid leaving the
expander from the heater comprising sensing changes in electrical
and thermal loads of the facility and controlling the mass flow
through heater and volatile organic fluid in response to the sensed
changes in facility electrical and thermal loads.
19. The method of claim 14, wherein controlling the mass flow to
the expander comprises providing valve controlled injectors which
introduce mass flow quantities of one of liquid, vapor or biphase
volatile organic fluid into an expansion volume for mixing with the
vapor phase fluid in transit therethrough, said valve controlled
injectors locating along the travel path through the turbine.
20. The method of claim 14 wherein said external heat source
includes at least one solar collector.
21. The method of claim 20 wherein the external heat source
includes waste heat recovered from one of said facility's air
conditioner or refrigeration equipment, attic, or other process
waste heat.
22. The method of claim 21 wherein the external heat source
includes heat from a separate heat engine system.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the onsite
production of heat and power from sustainable resources such as
solar, waste heat and biomass system for the supply of electrical
power, domestic hot water and space heating operating either in
parallel or in isolation from the central grid, and more
specifically, to a modular, scalable systems that enables maximum
harvesting of solar energy, waste heat energy and heat from the
combustion of fuel, to produce electrical power and useable heat in
a closed loop heat engine cycle using a volatile organic working
fluid in a system dynamically responsive to the source temperature,
sink temperature, facility's electrical and thermal loads and
ambient conditions.
[0002] In recent years, six major trends have emerged that are
reshaping the energy industry. First, millions of consumers have
experienced more frequent, more prolonged and more devastating
electrical outages from failure of the central grid caused by more
frequent, more severe and more costly hurricanes and storms and the
increasing dependency of modern society on electrical devices
including, computers, modems, televisions, and the like. Second,
the cost of fossil fuel has spiked including gasoline, diesel fuel,
natural gas and coal stimulated by the unprecedented demand for
energy from emerging nations and the more severe storms. Third, the
nearly universal acknowledgement of the detrimental impact caused
by air pollution and specifically large fossil fuel plants in
global warming. Fourth, the deregulation of the electrical industry
has substantially reduced obstacles to interconnection by
distributed generation resources. Fifth, substantial incentives
from various governments spur more sustainable energy technologies.
And, sixth, the increasing availability of real time pricing for
all classes of electrical customers places a premium on
technologies that can reduce grid electrical demand during high
demand/high price situations.
[0003] Although there is an abundance of solar energy received by
the Earth, its intensity at the Earth's surface is actually very
low and varying with the time of day, time of year and the
conditions of the Earth's atmosphere. Conventional heat engine
cycles have been analyzed based on the on the ideal heat engine
cycle Carnot disclosed in 1824 which postulates an infinite heat
source and an infinite heat sink. In such hypothesized system, the
efficiency of the power systems is determined by:
[0004] (i) the temperatures of the available heat source and
sink;
[0005] (ii) the selection of the state points, thereby describing
the adopted thermodynamic cycle;
[0006] (iii) the behavior of the working fluid used;
[0007] (iv) the irreversibility's in the mechanical systems
involved; and,
[0008] (v) the temperature and pressure limitations of the
materials used in the devices.
[0009] In a similar fashion the more practical Rankine and its
associated organic Rankine cycles (ORCs) also assume infinite
source and sink temperature and requires the evaporation and
typically superheating of the working fluid in the heating device
before entering the expander.
DESCRIPTION OF THE PRIOR ART
[0010] In 1977, S. S. Wilson & M. S. Radwan in "Appropriate
Thermodynamics for Heat Engine Analysis and Design" disclosed a
modified organic heat engine cycle, called the trilateral flash
cycle (TFCs) based on the matching and optimization of heat source
and sink, cycle, working fluid, expander and load characteristics
which heats the liquid working fluid only to the point of boiling,
saturation, and expands the heated high pressure saturated working
fluid using positive displacement expanders in a cycle that
optimizes the amount of the finite heat energy recoverable and
electricity produced from a finite heat source. All previous
disclosed closed loop heat engine systems utilizing a volatile
organic working fluid were designed to operate in one of the two
distinct modes, super heated, (ORC) or saturated liquid, (TFC) and
did not contemplate the advantages or the ability to dynamically
switch between the two modes in response to changing fuel load and
operating conditions. Clearly, it is desirable to overcome the
limitations and deficiencies of the ORC and TFC to provide a method
which dynamical adjusts the heating of the working liquid only up
to its boiling point, TFC or beyond its boiling point, ORC
depending on the fuel, load, and ambient conditions.
[0011] During the expansion of volatile organic working fluid in an
expander, almost invariably the working fluid leaves the expander
in the superheated state and has to be cooled in the condenser or
requires a recuperator heat exchanger to transfer the heat to
preheat the relatively high pressure liquid. Everything else being
equal the greater the superheat in the exhausted working fluid
exiting the expander, the lower the efficiency of the
mechanical/electrical generating heat engine cycle. Clearly
dispensing with the need for a recuperator and producing more
electrical energy from the same thermal energy is desirable through
the injection of relatively high pressure liquid into the expansion
volume of the expander and modulating the mass flow of the injected
liquid such that the combined mass flow of the working fluid exits
the expander in a saturated state and produces more net power.
[0012] Combined heat and power (CHP) systems using internal
combustion engines, turbines, micro turbines, and fuel cells have
been known for some time as a way to improve overall efficiency by
an order of magnitude in energy production systems. In a typical
CHP system, heat and electricity are produced from a combustion
process engine that drives an electric generator, as well as heat
water, or air. Although historically CHP systems tend to be rather
large, because of the six forces outline above, micro CHP systems
consuming fossil fuel are emerging technologies. Because of the
dramatic increase in power outages and fossil fuel prices, there is
a huge market for dispatchable, sustainable energy systems.
[0013] In view of the limitations of the existing art, the present
invention fulfills the long felt need to optimize the production of
electricity and heat in response to the varying availability of
solar energy, waste heat and the varying load requirements of the
facility, to dynamically optimize the electric power production by
operating the system with a superheated working fluid entering the
expander as in a Carnot or Rankine cycles or with a saturated
liquid entering the expander in the trilateral flash cycle and
minimizing the superheat of the working fluid exiting the expander
and to provide a more reliable and secure source of electricity and
heat not subject to the numerous power outages of central grid
systems. The above and other objects and advantages of the present
invention will become apparent from the following specifications,
drawings and claims. It will be understood that the particular
embodiments of the invention are shown by way of illustration only
and not as limitation of the invention. The principle features of
this invention may be employed in various embodiments without
departing from the scope of the invention.
[0014] While the above-described systems fulfill their respective,
particular objectives and requirements, the aforementioned systems
do not describe a system that uses beneficial portions of the
Rankine and Carnot cycles to produce electricity and heat at
minimal amounts of energy. Therefore, a need exists for a new and
improved apparatus and method for producing sustainable power and
heat that in its structure allows for multiple fuels to generate
heat. The present invention substantially fulfills this need.
Further, the present invention substantially departs from the
conventional concepts and designs of the prior art.
SUMMARY OF THE INVENTION
[0015] The present invention is an integrated system to provide
both electric power and heat from various energy sources including
solar, waste heat, biomass and fossil fuels. The combined heat and
power system operates with a volatile organic working fluid that
circulates in a variable speed heat engine type cycle, where the
organic working fluid is heated to either its boiling point, a
saturated state or past its boiling point, a superheated gas state,
expanded through an expander, with relatively high pressure
subcooled liquid working fluid injected into the expansion chambers
of the expander such that the volatile organic working exiting the
expander is in a saturated state, cooled in a condenser in thermal
communication with the domestic hot water or space heating system,
and pressurized and circulated by a pump. Heat exchange loops
within the system define hot water production capability for use in
space heating, domestic hot water, and/or process heat while the
generator is coupled to the expander to produce electricity which
is interconnected to the grid at fixed frequency and voltage in
either a paralleling or island mode.
[0016] The foregoing has outlined, in general, the physical aspects
of the invention and has served as an aid to better understanding
the detailed description. Thus, the present invention is not
limited to the method or detail of construction, fabrication,
material, or application of use described and illustrated herein.
Any other variation of fabrication, use, or application should be
considered apparent as an alternative embodiment of the present
invention.
[0017] There has thus been outlined, rather broadly, the more
important features of the invention in order that the detailed
description thereof that follows may be better understood and in
order that the present contribution to the art may be better
appreciated.
[0018] Numerous objects, features and advantages of the present
invention will be readily apparent to those of ordinary skill in
the art upon a reading of the following detailed description of
presently preferred, but nonetheless illustrative, embodiments of
the present invention when taken in conjunction with the drawings.
In this respect, before explaining the current embodiment of the
invention in detail, it is to be understood that the invention is
not limited in its application to the details of construction and
to the arrangements of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments and of being practiced and carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein are for the purpose of description
and should not be regarded as limiting.
[0019] As such, those skilled in the art will appreciate that the
conception, upon which this disclosure is based, may readily be
utilized as a basis for the designing of other structures, methods
and devices for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and the scope of the present invention.
[0020] It is therefore a principal object of the present invention
to provide a method and apparatus which will maximize the overall
energy efficiency of the energy process of harvesting and
converting solar energy to usable electrical power and heat, while
overcoming the disadvantages and drawbacks of known methods of
solar photovoltaic, solar thermal electric, and solar thermal
systems.
[0021] Still another object of the present invention is to provide
an integrated method and apparatus for operating the combined power
and heat system in parallel when the grid is functioning and
independently of the central grid system when the grid has
failed.
[0022] Still another object of the invention is to provide an
integrated method and apparatus for dynamically controlling the
amount and ratio of electrical to thermal output of the system.
[0023] Still another object of the invention is to provide an
integrated method and apparatus for optimizing the conversion of
heat energy into electrical power and minimizing the power losses
from the expansion of the working fluid to a superheated
condition.
[0024] Still another object is to provide an integrated method and
apparatus for energy recovery system, utilizing the waste heat
usually rejected from the condenser of a facility's air
conditioning and refrigeration system, the facility's attic or
other sources of waste heat, to generate electric power and useable
heat.
[0025] It is intended that any other advantages and objects of the
present invention that become apparent or obvious from the detailed
description or illustrations contained herein are within the scope
of the present invention.
[0026] These together with other objects of the invention, along
with the various features of novelty that characterize the
invention, are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and the
specific objects attained by its uses, reference should be had to
the accompanying drawings and descriptive matter in which there are
illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In referring to the drawings,
[0028] FIG. 1 indicates a schematic diagram for a single source
directly heated combined heat and power system; and,
[0029] FIG. 2 indicates a schematic diagram for a multiple source
directly heated combined heat and power system.
[0030] The same reference numerals refer to the same parts
throughout the various figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] The present art overcomes the prior art limitations by
providing a combined electricity and heat producing system fueled
by various sources, primarily solar and other renewable sources
integrated with combustion of fossil fuels for a supplemental heat
source. With reference to the drawings, FIG. 1 illustrates a
possible configuration of the principal hardware components
comprising a system embodying the operating mechanisms to affect
the benefits described. It is noted however that variations in
equipment may be made and would be within the ambit of a person
skilled in the art. Referring initially to FIG. 1, one embodiment
of the integrated Combined Heat and Power System 10 is a
directly-heated, single closed loop system that includes a first
(or primary) circuit thermal fluid conduit 15 and a secondary
circuit thermal fluid conduit 78. An advantage of the directly
heated system is that it eliminates the inherent loss resulting
from the pinch points of the various heat sources and sinks thus
maximizing the efficiency of the cycle. First circuit 15 conducts
the heated volatile organic working fluid from heating device 20 to
the expander 30. The expander 30 houses a positive displacement
expander such as a rotary vane, scroll, screw, reciprocating or
nutating engine. As the heated organic working fluid proceeds along
an ideally isentropic path through the expander, its pressure and
temperature fall, its volume expands, and accompanying those
changes in state conditions, its enthalpy is converted to
mechanical energy creating rotating shaft power which drives the
alternator, 40. Organic working fluid generally become drier and
superheated because of the characteristic of their saturation
envelope and the current practice is volatile organic working fluid
exit the expander in a superheated state. The alternator, 40
delivers variable frequency and variable voltage output electric
power to the transmission line, 42 connecting the alternator to the
converter controller. The converter controller converts the
variable frequency and variable voltage electric power to a fixed
frequency and voltage that within tight parameters that enable the
convert controller to synchronize its electric output with the
electric grid or to maintain it within operating specifications if
the grid has failed and the system is operating in an island mode.
The conditioned power from the converter controller 45 is feed to
the main circuit panel for distribution to the rest of the facility
or the attached electric grid. Converter controller, 45 also
monitors the temperature, pressure, electric power output and
thermal output. Through sensors and control lines, 76. The expander
also features a port(s) for injection of subcooled liquid volatile
organic working fluid. Injection of this subcooled liquid
eliminates the superheat lo normally produce by expansion in
organic Rankine cycle systems and enable useable mechanical power
from the superheat created by expansion of the volatile organic
working fluid. The combined mass flow of primary circuit 15 and
secondary injection circuit 76 arrives at its exit conduit 16 at
the saturation pressure and temperature for the volatile organic
working fluid employed as the heat engine thermodynamic medium, a
minimum approach difference above the temperature established in
condenser 62. The converter controller 45 determines the target
condensing temperature based on ambient conditions, the available
heat energy in heater 20, the electrical and thermal load of the
facility in real time. The converter controller can also be program
to respond to "real time electric" pricing parameters that may
present opportunities to arbitrage the real time price of
electricity versus the cost of producing that same electricity from
sustainable fuel. Spent ambient coolant is returned to the cooling
tower or other ambient coolant source via conduit 38. The spent
saturate working fluid exiting the expander 30 is conducted by
primary circuit 16 to condensing heat exchanger 62. Condensing heat
exchanger transfer the latent heat of condensation and the specific
heat of subcooling to the facility's space heating system, or
domestic hot water heating system or process heating system. The
primary circuit 15 conducts the subcooled working fluid in a liquid
state to the working fluid pump, 70. where it is pumped to the
operating of pressure of heater 20, En route from working fluid
pump 70, a portion of the flow is separated from conduit 16 via
secondary circuit, 78 to supply the injector valves 76 which
modulate the mass flow of the liquid working fluid into the
expansion volume of the expander 30, such that the working fluid
exits the expander 30 in a saturated state. It enters heater 20 via
conduit 15 to repeat the heat engine with organic working fluid
cycle.
[0032] Converter Controller 45 controls the temperature of the
working fluid exits the heater, 20. Although the Carnot cycle
proves that the maximum power that lo can be generated from a heat
engine cycle is the maximum delta temperature between the source
and the sink temperature, this optimization does not necessarily
hold true for integrated combine heat and power systems. For
instance the greater the delta temperature difference of the
conduits leading up to heater 20 the greater the heat losses from
the entire system so that the amount of available energy at heater
20 is substantially less that it would be if the circuit was
operated at a lower temperature but with more available energy to
convert to power and useable heat. Moreover, the Carnot and Rankine
cycles require superheating the fluid which means that the amount
of heat energy available below the temperature of evaporation is
not available to the power cycle. However, the trilateral flash
cycle captures the heat available down to the condensing
temperature and produces power from it. Based on the thermodynamic,
economic parameters and the load profile converter controller, 45
can modulate the speed of the working fluid pump, 70 such that the
working fluid exiting the heater 20 can be in a saturate or
superheated state.
[0033] Referring next to FIG. 2, an alternate embodiment of the
directly heated integrated combined heat and Power system 2 is
shown. Here, waste heating device, 80 consist of a heat exchanger
in the refrigerant loop of the facility's air conditioner or
refrigeration equipment located between the compressor and
condenser of said system. This waste heating device, 80 can
transfer the cooling BTUs as well as the heat of compression from
the compressor to preheat the liquid volatile organic working
fluid. Conduit 82 conducts the preheated liquid working fluid from
the waste heating device 80 to high temperature solar collectors,
20. The higher temperature solar collectors can be various style
solar collectors designed to produce heat above 200.degree. F. As
the solar collectors, 80 heats the fluid the velocity of the
working fluid through the expanders can be controlled by the speed
of the variable speed working fluid pump, 70. By controlling the
speed of this pump, the converter controller can determine if the
working fluid will leave the solar collectors by a conduit 82 in a
saturated bi-phase state or in a superheated state. The working
fluid exiting the collectors can be either directed to the
combustion heater, 90 via conduits 82 and 83, or directed to bypass
the combustion heater, 90 via conduit 87. If the working fluid is
directed to the combustion heater 90, the energy output of the
combustion heater 90 can be modulated to produce either saturated
working fluid or superheated working fluid as determined by
converter controller 45 by controlling the modulation of the
combustion heater 90 and the speed of the variable speed pump 70.
The heated working fluid exiting the combustion heater, 90 can be
directed by conduit 84 directly to the expander or directed by
conduit 85 to bypass the expander. Upon enter the expander, 30, the
heated organic working fluid proceeds along an ideally isentropic
path through the expander, its pressure and temperature fall, its
volume expands, and accompanying those changes in state conditions,
its enthalpy is converted to mechanical energy creating rotating
shaft power which drives the alternator, 40. Organic working fluid
generally becomes drier and superheated because of the
characteristic of their saturation envelope. The current practice
in organic Rankine cycle systems is to have the volatile organic
working fluid exit the expander in a superheated state. The
alternator, 40 delivers variable frequency and variable voltage
output electric power to the transmission line, 42 connecting the
alternator to the converter controller. The converter controller
converts the variable frequency and variable voltage electric power
to a fixed frequency and voltage that within tight parameters that
enable the convert controller to synchronize its electric output
with the electric grid or to maintain it within operating
specifications if the grid has failed and the system is operating
in an island mode. The conditioned power from the converter
controller 45 is feed to the main circuit panel for distribution to
the rest of the facility or the attached electric grid. Converter
controller, 45 also monitors the temperature, pressure, electric
power output and thermal output. Through sensors and control lines,
76. The expander also features a port(s) for injection of subcooled
liquid volatile organic working fluid. Injection of this subcooled
liquid working fluid eliminates the superheat normally produce by
expansion in organic Rankine cycle systems and produces useable
mechanical power from the superheat energy created by expansion of
the volatile organic working fluid. The combined mass flow of
primary circuit 84 and secondary injection circuit 76 arrives at
its exit conduit 16 at the saturation pressure and temperature for
the volatile organic working fluid employed as the heat engine
thermodynamic medium, a minimum approach difference above the
temperature established in condenser 60. The converter controller
45 determines the target condensing temperature based on ambient
conditions, the available heat energy in heater 20, the electrical
and thermal load of the facility, and real time pricing
information. The converter controller can also be program to
respond to "real time electric" pricing parameters that may present
opportunities to arbitrage the real time price of electricity
versus the cost of producing that same electricity from onsite
electric generation. Spent ambient coolant is returned to the
cooling tower or other ambient coolant source can transfer all or a
portion of the heat of the spent working fluid depending on the
load of the facility, ambient conditions and operating parameters
of the building. The spent saturate working fluid exiting the
expander 30 is conducted by first circuit 34 to space heating heat
exchanger, 62. Space heating heat exchanger 62, can transfer all or
a portion of the heat of the spent working fluid depending on the
load of the facility, ambient conditions and operating parameters
of the building. The spent working fluid exiting heat exchanger, 62
is conducted by first circuit 34 to domestic hot water heat
exchanger 64. Domestic hot water heat exchanger 64 can transfer all
or a portion of the heat of the spent working fluid depending on
the load of the facility, ambient conditions and operating
parameters of the building. The spent working fluid exiting
domestic hot water heat exchanger 64 is conducted by first circuit
34 to ambient condenser, 60. Ambient condenser 60 removes heat from
the spent working fluid so that the working fluid condenses in to a
liquid and is slightly subcooled. The condensed liquid working
fluid exits the ambient condenser 60 and is conducted by first
circuit 34 to a receiving vessel, 65. Receiving vessel stores
excess working fluid to compensate for the dynamic operating
conditions of the system. The liquid working fluid exiting the
condenser, 65 is conducted by primary circuit 34 to the variable
speed working fluid pump. The variable speed working fluid pump
pressurizes the working liquid working fluid to a pressure above
the pressure produced in the hottest of the heat sources 80, 20, or
90. The pressurized liquid working fluid leaves the working fluid
pump, 70 and is conducted by conduit 16 to an oil separator, 75
were substantially all of the oil is removed from the working
fluid. The oil removed by the oil separator 75 is conducted by
conduit 74 back to the expander where it is injected into the oil
port of the expander using the pressure developed by the working
fluid pump. The evaporation temperature produced by the condensing
heat exchanger transfers the latent heat of condensation and the
specific heat of subcooling to the facility's space heating system,
or domestic hot water heating system or process heating system. The
primary circuit 15 conducts the subcooled working fluid in a liquid
state to the working fluid pump, 70. where it is pumped to the
operating of pressure of the heater 20, En route from working fluid
pump 70, a portion of the flow is separated from conduit 16 via
secondary circuit, 78 to supply the injector valves 76 which
modulate the mass flow of the liquid working fluid into the
expansion volume of the expander 30, such that the working fluid
exits the expander 30 in a saturated state. It enters heater 20 via
conduit 15 to repeat the heat engine with organic working fluid
cycle. The expander 30 houses a positive displacement expander such
as a rotary vane, scroll, screw, reciprocating or nutating engine.
As the heated organic converter controller 45 can control the
system such that the volatile organic working fluid exiting the
solar collectors, 20 is either in a saturate state or a superheated
state. working fluid proceeds along an ideally isentropic path
through the expander, its pressure and temperature fall, its volume
expands, and accompanying those changes in state conditions, its
enthalpy is converted to mechanical energy creating rotating shaft
power which drives the alternator, 40.
[0034] From the aforementioned description, an apparatus and its
method for producing sustainable electricity and heat has been
described. The apparatus, as a system, is uniquely capable of
producing both electricity and heat from sustainable fuels at
minimal energy input. The apparatus as described and its various
components may be manufactured from many materials, including but
not limited to aluminum, steel, polymers, high density
polyethylene, nylon, ferrous and non-ferrous metals, their alloys,
and composites.
[0035] As such, those skilled in the art will appreciate that the
conception, upon which this disclosure is based, may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. Therefore, the claims include such equivalent
constructions insofar as they do not depart from the spirit and the
scope of the present invention.
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