Title: Load bank
Abstract: A system and method is disclosed for creating and/or maintaining an electrical load on a diesel engine generator for use on a marine vessel in order to avoid the harmful effects of no-load or low-load operation of the diesel engine. The parasitic load bank system 10 utilizes the heat transfer fluid 23 contained in the closed circulation loop 28 of a chille7d-fluid air conditioning system 14 for creating and/or maintaining the electrical load on the diesel engine generator 12 by utilizing a load bank controller 44 for diverting a portion 23c of the heat transfer fluid 23a being supplied to the vessel's air handlers 42 into heat exchange relationship with the heat transfer fluid 20b discharged from the air conditioning system's source of heat transfer 18 such that the heat exchanged heat transfer fluid 23f activates the source of heat transfer 18, which may be a chiller, reverse-cycle chiller or heat pump, to create an electrical power demand on the diesel engine generator 12.
Patent Number: 6,993,923 Issued on 02/07/2006 to Beers
| Inventors:
|
Beers; Richard F. (Ft. Lauderdale, FL)
|
| Assignee:
|
Rich Beers Marine, Inc. (Ft. Lauderdale, FL)
|
| Appl. No.:
|
491506 |
| Filed:
|
October 5, 2001 |
| PCT Filed:
|
October 5, 2001
|
| PCT NO:
|
PCT/US01/31299
|
| 371 Date:
|
March 30, 2004
|
| 102(e) Date:
|
March 30, 2004
|
| PCT PUB.NO.:
|
WO03/031881 |
| PCT PUB. Date:
|
April 17, 2003 |
| Current U.S. Class: |
62/228.1; 62/240; 62/513; 322/7 |
| Current Intern'l Class: |
F25B 1/00 (20060101); F25B 49/00 (20060101); B63B 25/26 (20060101) |
| Field of Search: |
62/2281,513,113,185,239,240,98,99,197
322/7,8
|
References Cited [Referenced By]
U.S. Patent Documents
| 4147296 | Apr., 1979 | Spethmann.
| |
| 4268787 | May., 1981 | Sloan.
| |
| 4463574 | Aug., 1984 | Spethmann et al.
| |
| 4506516 | Mar., 1985 | Lord.
| |
| 4926649 | May., 1990 | Martinez, Jr.
| |
| 5237832 | Aug., 1993 | Alston.
| |
| 5565716 | Oct., 1996 | Tierney, Jr.
| |
| 5584185 | Dec., 1996 | Rumble et al.
| |
| 5946926 | Sep., 1999 | Hartman.
| |
| 6208038 | Mar., 2001 | Campbell.
| |
| 6240867 | Jun., 2001 | Hoyle et al.
| |
| 6263689 | Jul., 2001 | Dodge et al.
| |
Primary Examiner: Norman; Marc
Attorney, Agent or Firm: Law Offices of Kenneth F. Dusyn, Dusyn; Kenneth F.
Claims
What is claimed is:
1. A system for maintaining an electrical load on a diesel engine generator for
use on a marine vessel comprising:
a) a closed-loop fluid air conditioning system for exchanging heat with the air
in said vessel, comprising
(i) first heat transfer means that receives therein and discharges therefrom
a first heat transfer fluid for ultimately exchanging heat with a second heat transfer
fluid, said second heat transfer fluid being supplied to and returned from said
vessel within a closed circulation loop for exchanging heat with the air in said
vessel; and
b) a load bank comprising
(i) controller means for diverting at least a portion of the second heat transfer
fluid being supplied to said vessel, into heat exchange relationship with a third
heat transfer fluid; and
(ii) second heat transfer means for exchanging heat between said diverted second
heat transfer fluid and said third heat transfer fluid;
whereby the diverted, heat-exchanged second heat transfer fluid is returned to
said first heat transfer means for activation thereof thereby creating an electrical
power demand on the diesel engine generator.
2. The system according to claim 1 wherein the third heat transfer fluid is the
first heat transfer fluid discharged from said first heat transfer means.
3. The system according to claim 2 wherein the first heat transfer fluid comprises seawater.
4. The system according to claim 2 optionally comprising, in addition to said
second heat transfer means, a plurality of electrically operated resistant water
heaters arranged in parallel relationship relative to each other.
5. The system according to claim 1 wherein the third heat transfer fluid comprises seawater.
6. The system according to claim 1 wherein said secondary heat transfer fluid
comprises water, a mixture of ethylene glycol and water, or a mixture of propylene
glycol and water, the glycol component being present in its respective mixture
in an amount of from about 5 percent to about 25 percent, based on the total volume
of the mixture.
7. The system according to claim 1 wherein the first heat transfer means comprises
at least one chiller, reverse-cycle chiller or heat pump.
8. The system according to claim 1 wherein the first heat transfer means comprises
a plurality of chillers, reverse-cycle chillers, or heat pumps, or combinations
thereof, arranged in parallel relationship relative to each other.
9. The system according to claim 1 wherein said portion of second heat transfer
fluid being supplied to the vessel is diverted in response to a predetermined temperature
value of the returning second heat transfer fluid.
10. The system according to claim 1 wherein said controller means comprises at
least one valve for diverting said portion of said second heat transfer fluid being
supplied to the vessel.
11. The system according to claim 10 wherein said valve is operably coupled with
a thermostat, said valve being operated in response to a thermostat setting reflective
of a predetermined temperature of the returning second heat transfer fluid.
12. The system according to claim 11 wherein said controller means comprises
a plurality of valves and corresponding thermostats.
13. The system according to claim 12 wherein each valve is operably coupled with
its corresponding thermostat, each of said thermostats being in temperature sensing
relationship with the returning second heat transfer fluid, each of said valves
being operated in response to a signal generated by its corresponding thermostat
reflective of a predetermined temperature of the returning second heat transfer
fluid detected upstream of its corresponding valve.
14. The system according to claim 1 wherein the second heat transfer means comprises
a heat exchanger.
15. The system according to claim 14 wherein the heat exchanger is a plate type
heat exchanger, a shell and tube type heat exchanger, or a tube and tube type heat exchanger.
16. The system according to claim 1 optionally comprising, in addition to said
second heat transfer means, one or more electrical resistant fluid heating devices
in communication with the returning second heat transfer fluid for heating the same.
17. The system according to claim 16 wherein said fluid heating device is a resistant
water heater.
18. A system for maintaining an electrical load on a diesel engine generator
for use on a marine vessel comprising:
a) a closed-loop chilled-fluid air conditioning system for cooling the air in
said vessel comprising:
(i) at least one source of heat transfer that receives therein and discharges
therefrom a first heat transfer fluid for ultimately exchanging heat with a second
heat transfer fluid, said second heat transfer fluid being supplied to and returned
from said vessel within a closed circulation loop for cooling the air in said vessel; and
b) a load bank comprising
(i) a controller for diverting at least a portion of the second heat transfer
fluid being supplied to said vessel, into heat exchange relationship with a third
heat transfer fluid; and
(ii) a heat exchanger for transferring heat from the third heat transfer fluid
to the diverted portion of second heat transfer fluid;
whereby the heated, diverted second heat transfer fluid is returned to said source
of heat transfer for activation thereof to create an electrical power demand on
the diesel engine generator for maintaining a load thereon.
19. The system according to claim 18 wherein the third heat transfer fluid is
the first heat transfer fluid discharged from said source of heat transfer.
20. The system according to claim 19 wherein the first heat transfer fluid comprises seawater.
21. The system according to claim 20 wherein the second heat transfer fluid comprises
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, the glycol component being present in its respective mixture in an amount
of from about 5 percent to about 25 percent, based on the total volume of the mixture.
22. The system according to claim 21 wherein the air conditioning system comprises
a plurality of chillers or reverse-cycle chillers, or combinations thereof, arranged
in parallel relationship relative to each other.
23. The system according to claim 22 wherein the controller comprises a plurality
of valves and corresponding thermostats, said thermostats being in temperature
sensing relationship with the returning second heat transfer fluid, and each of
said valves being operated in response to a signal generated by its corresponding
thermostat reflective of a predetermined temperature of the returning second heat
transfer fluid detected upstream of its corresponding valve.
24. The system according to claim 18 wherein
(a) the first heat transfer fluid comprises seawater;
(b) the second heat transfer fluid comprises water, a mixture of ethylene glycol
and water, or a mixture of propylene glycol and water, the glycol component being
present in its respective mixture in an amount of from about 5 percent to about
25 percent, based on the total volume of the mixture; and
(c) the third heat transfer fluid comprises seawater provided to said heat exchanger
independently of said source of heat transfer.
25. The system according to claim 18 wherein said source of heat transfer comprises
a chiller or reverse-cycle chiller.
26. The system according to claim 18 wherein the controller comprises at least
one valve for diverting said portion of said second heat transfer fluid being supplied
to the vessel.
27. The system according to claim 26 wherein said valve is operably coupled with
a thermostat, said valve being operated in response to a thermostat setting reflective
of a predetermined temperature of the returning second heat transfer fluid.
28. The system according to claim 27 wherein the controller comprises a plurality
of valves and corresponding thermostats.
29. The system according to claim 18 wherein the heat exchanger is a plate type
heat exchanger, a shell and tube type heat exchanger, or a tube and tube type heat exchanger.
30. The system according to claim 18 optionally comprising, in addition to said
heat exchanger, one or more electrical resistant fluid heating devices, powered
by said diesel engine generator, in communication with the returning second heat
transfer fluid for transferring heat to the same.
31. The system according to claim 30 wherein the fluid heating device comprises
an electrically operated resistant water heater.
32. A system for maintaining an electrical load on a diesel engine generator
for use on a marine vessel comprising:
a) a closed-loop chilled-fluid air conditioning system for cooling the air in
said vessel comprising
(i) at least one source of heat transfer that receives therein and discharges
therefrom a first heat transfer fluid for ultimately exchanging heat with a second
heat transfer fluid, said second heat transfer fluid being supplied to and returned
from said vessel within a closed circulation loop for cooling the air in said vessel; and
b) a load bank comprising
(i) fluid heating means comprising one or more electrical resistant fluid heating
devices operably coupled with a controller means for heating the second heat transfer
fluid returning from the vessel to said source of heat transfer in response to
a predetermined temperature of the returning heat transfer fluid detected upstream
of the fluid heating means;
whereby the heated second heat transfer fluid is returned to said source of heat
transfer for activation thereof to create an electrical power demand on the diesel
engine generator for maintaining a load thereon.
33. The system according to claim 32 wherein the first heat transfer fluid comprises
seawater and the second heat transfer fluid comprises water, a mixture of ethylene
glycol and water, or a mixture of propylene glycol and water, the glycol component
being present in its respective mixture in an amount of from about 5 percent to
about 25 percent, based on the total volume of the mixture.
34. The system according to claim 33 wherein the source of heat transfer comprises
a plurality of chillers or reverse-cycle chillers, or combinations thereof, arranged
in parallel relationship relative to each other.
35. The system according to claim 34 wherein said fluid heating means comprises
a plurality of electrically operated resistant water heaters arranged in parallel
relationship relative to each other and powered by said diesel engine generator.
36. The system according to claim 34 wherein said load bank comprises a plurality
of electrically operated resistant water heaters, arranged in parallel relationship
relative to each other, each water heater being powered by said diesel engine generator
and operably coupled with and controlled by a corresponding thermostat in response
to a thermostat setting reflective of a predetermined temperature of the returning
second heat transfer fluid detected upstream of its corresponding water heater.
37. The system according to claim 32 wherein the source of heat transfer comprise
a chiller or reverse-cycle chiller.
38. The system according to claim 32 wherein said fluid heating means comprises
at least one electrically operated resistant water heater powered by said diesel
engine generator.
39. The system according to claim 32 wherein said controller means comprises
at least one thermostat, said thermostat being in temperature sensing relationship
with the returning second heat transfer fluid.
40. A system for maintaining an electrical load on a diesel engine generator
for use on a marine vessel comprising:
a) a closed-loop fluid air conditioning system for heating the air in said vessel comprising:
(i) at least one source of heat transfer that receives therein and discharges
therefrom a first heat transfer fluid for ultimately exchanging heat with a second
heat transfer fluid, said second heat transfer fluid being supplied to and returned
from said vessel within a closed circulation loop for heating the air in said vessel; and
b) a load bank comprising
(i) a controller for diverting at least a portion of the second heat transfer
fluid being supplied to said vessel, into heat exchange relationship with a third
heat transfer fluid; and
(ii) a heat exchanger for transferring heat from the third heat transfer fluid
to the diverted portion of second heat transfer fluid;
whereby the heated, diverted second heat transfer fluid is returned to said source
of heat transfer for activation thereof to create an electrical power demand on
the diesel engine generator for maintaining a load thereon.
41. The system according to claim 40 wherein the third heat transfer fluid is
the first heat transfer fluid discharged from said source of heat transfer.
42. The system according to claim 41 wherein the first heat transfer fluid comprises seawater.
43. The system according to claim 42 wherein the second heat transfer fluid comprises
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, the glycol component being present in its respective mixture in an amount
of from about 5 percent to about 25 percent, based on the total volume of the mixture.
44. The system according to claim 43 wherein the air conditioning system comprises
a plurality of reverse-cycle chillers or heat pumps, or combinations thereof, arranged
in parallel relationship relative to each other.
45. The system according to claim 44 wherein the controller comprises a plurality
of valves and corresponding thermostats, said thermostats being in temperature
sensing relationship with the returning second heat transfer fluid, and each of
said valves being operated in response to a signal generated by its corresponding
thermostat reflective of a predetermined temperature of the returning second heat
transfer fluid detected upstream of its corresponding valve.
46. The system according to claim 40 wherein
(a) the first heat transfer fluid comprises seawater;
(b) the second heat transfer fluid comprises water, a mixture of ethylene glycol
and water, or a mixture of propylene glycol and water, the glycol component being
present in its respective mixture in an amount of from about 5 percent to about
25 percent, based on the total volume of the mixture; and
(c) the third heat transfer fluid comprises seawater provided to said heat exchanger
independently of said source of heat transfer.
47. The system according to claim 40 wherein said source of heat transfer comprises
a reverse-cycle chiller or heat pump.
48. The system according to claim 40 wherein the controller comprises at least
one valve for diverting said portion of said second heat transfer fluid being supplied
to the vessel.
49. The system according to claim 48 wherein said valve is operably coupled with
a thermostat, said valve being operated in response to a thermostat setting reflective
of a predetermined temperature of the returning second heat transfer fluid.
50. The system according to claim 49 wherein the controller comprises a plurality
of valves and corresponding thermostats.
51. The system according to claim 40 wherein the heat exchanger is a plate type
heat exchanger, a shell and tube type heat exchanger, or a tube and tube type heat exchanger.
52. The system according to claim 40 optionally comprising, in addition to said
source of heat transfer, one or more electrical resistant fluid heating devices,
powered by said diesel engine generator, in communication with the second heat
transfer fluid being supplied to the vessel for heating the same.
53. The system according to claim 52 wherein the fluid heating device comprises
an electrically operated resistant water heater.
54. A load bank for a marine diesel engine generator electrically coupled with
a source of heat transfer in a closed-loop fluid air conditioning system that receives
and discharges a primary heat transfer fluid for ultimately exchanging heat with
a secondary heat transfer fluid, the secondary heat transfer fluid being supplied
to and returned from the compartments of a marine vessel within a closed circulation
loop for exchanging heat with the air in the vessel compartments, comprising:
(a) controller means for diverting at least a portion of the secondary heat transfer
fluid supply into heat exchange relationship with a tertiary heat transfer fluid; and
(b) a heat exchanger for exchanging heat between the diverted secondary heat
transfer fluid and the tertiary heat transfer fluid;
whereby the diverted, heat-exchanged, secondary heat transfer fluid is returned
to said source of heat transfer for activation thereof to create an electrical
power demand on the diesel engine generator for maintaining a load thereon.
55. The load bank according to claim 54 wherein the primary heat transfer fluid
and tertiary heat transfer fluid is seawater.
56. The load bank according to claim 55 wherein the tertiary heat transfer fluid
is the seawater discharged from said source of heat transfer.
57. The system according to claim 55 wherein said secondary heat transfer fluid
comprises water, a mixture of ethylene glycol and water, or a mixture of propylene
glycol and water, the glycol component being present in its respective mixture
in an amount of from about 5 percent to about 25 percent, based on the total volume
of the mixture.
58. The load bank according to claim 54 wherein the controller means comprises
at least one valve.
59. The load bank according to claim 58 wherein said valve is operably coupled
with a thermostat that is in temperature sensing relationship with the returning
secondary heat transfer fluid from said vessel, said valve being operated in response
to a signal generated by said thermostat reflective of a predetermined temperature
of the returning secondary heat transfer fluid detected upstream of said valve.
60. The load bank according to claim 59 wherein the controller means comprises
a plurality of valves and corresponding thermostats, said valves being arranged
in parallel relationship relative to each other.
61. The load bank according to claim 54 wherein the heat exchanger is a plate
type heat exchanger, a shell and tube type heat exchanger or a tube and tube type
heat exchanger.
62. A method for maintaining a load on a diesel engine generator onboard a marine
vessel utilizing the circulating heat transfer fluid contained within the closed
circulation loop of a fluid air conditioning system to exchange heat with the air
in said vessel, comprising:
(a) transporting a primary heat transfer fluid through a first heat transfer
means of the closed circulation loop fluid air conditioning system for ultimately
exchanging heat with the circulating heat transfer fluid;
(b) supplying and returning the circulating heat transfer fluid in the closed
circulation loop to and from the vessel, respectively, for heat exchange with the
air therein;
(c) diverting at least a portion of the circulating heat transfer fluid being
supplied to the vessel, into heat exchange relationship with a tertiary heat transfer
fluid; and
(d) returning the diverted, heat-exchanged circulating heat transfer fluid to
said first heat transfer means whereby said first heat transfer means is activated
to create an electrical power demand on the diesel engine generator for maintaining
a load thereon.
63. The method according to claim 62 wherein the first heat transfer means comprises
a chiller, a reverse-cycle chiller or a heat pump.
64. The method according to claim 62 wherein the first heat transfer means comprises
a plurality of chillers, a reverse-cycle chillers or heat pumps, or combinations
thereof, arranged in parallel relationship relative to each other.
65. The method according to claim 62 wherein the heat exchange of the diverted
portion of circulating heat transfer fluid and primary heat transfer fluid is undertaken
by a second heat transfer means comprising a heat exchanger.
66. The method according to claim 65 wherein the portion of circulating heat
transfer fluid being supplied to the vessel is diverted in response to a predetermined
temperature value of the returning primary heat transfer fluid.
67. The method according to claim 66 wherein the portion of circulating heat
transfer fluid is diverted by a controller means comprising at least one valve.
68. The method according to claim 67 wherein said valve is operably coupled with
a thermostat that is in temperature sensing relationship with the returning circulating
heat transfer fluid, said valve being operated in response to a thermostat setting
reflective of the temperature of the returning circulating heat transfer fluid
detected upstream of said valve.
69. The method according to claim 66 wherein the controller means comprises a
plurality of valves and corresponding thermostats.
70. The method according to claim 65 wherein the heat exchanger is a plate type
heat exchanger, a shell and tube type heat exchanger, or a tube and tube type heat exchanger.
71. The method according to claim 62 wherein the primary heat transfer fluid
comprises seawater.
72. The method according to claim 71 wherein the tertiary heat transfer fluid
comprises seawater.
73. The method according to claim 71 wherein the tertiary heat transfer fluid
comprises the seawater discharged from said first heat transfer means.
74. The method according to claim 62 wherein the circulating heat transfer fluid
comprises water, a mixture of ethylene glycol and water, or a mixture of propylene
glycol and water, the glycol component being present in its respective mixture
in an amount of from about 5 percent to about 25 percent, based on the total volume
of the mixture.
75. A method for maintaining a load on a diesel engine generator onboard a marine
vessel utilizing the circulating heat transfer fluid contained within the closed
circulation loop of a chilled fluid air conditioning system that includes at least
one chiller or reverse-cycle chiller, comprising:
(a) supplying and returning the heat transfer fluid in the closed circulation
loop to and from the vessel, respectively, for cooling the air therein;
(b) heating the heat transfer fluid returning from the vessel to said chiller
or reverse-cycle chiller; and
(c) returning the heated heat transfer fluid to the chiller or reverse-cycle
chiller for activating the same to create an electrical power demand on the diesel
engine generator for maintaining a load thereon.
76. The method according to claim 75 wherein the heat transfer fluid is heated
with at least one electrical resistant fluid heating device.
77. The method according to claim 76 wherein said fluid heating device comprises
an electrically operated resistant water heater.
78. The method according to claim 76 wherein said resistant fluid heating device
is operated in response to a predetermined temperature value of the returning heat
transfer fluid.
79. The method according to claim 78 wherein the operation of said fluid heating
device is controlled by a thermostat, said thermostat being in temperature sensing
relationship with the returning heat transfer fluid upstream of said fluid heating device.
80. The method according to claim 75 wherein the returning heat transfer fluid
is heated by a plurality of resistant water heaters, each water heater being operably
controlled by a corresponding thermostat in response to a thermostat setting reflective
of a predetermined temperature of the returning heat transfer fluid detected upstream
of said resistant water heaters.
81. The method according to claim 75 wherein the heat transfer fluid comprises
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, the glycol component being present in its respective mixture in an amount
of from about 5 percent to about 25 percent, based on the total volume of the mixture.
82. A system for maintaining an electrical load on a diesel engine generator
for use on a marine vessel comprising:
(a) a closed-loop fluid air conditioning system for heating the air in said vessel comprising:
(i) a fluid heating means, powered by said diesel engine generator, comprising
at least one electrical resistant fluid heating device for heating a first heat
transfer fluid being supplied to and returned from said vessel within a closed
circulation loop for heating the air in said vessel; and
(b) a load bank comprising
(i) controller means for diverting at least a portion of the first heat transfer
fluid being supplied to said vessel, into heat exchange relationship with a second
heat transfer fluid; and
(ii) a heat exchanger for exchanging heat between the second heat transfer fluid
and the diverted portion of the first heat transfer fluid;
whereby the heat-exchanged, diverted first heat transfer fluid is returned to
said fluid heating means for activation thereof to create an electrical power demand
on the diesel engine generator for maintaining a load thereon.
83. The system according to claim 82 wherein said first heat transfer fluid comprises
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, said glycols being present in their respective mixtures in an amount
of from about 5 percent to about 25 percent, based on the total volume of the mixture.
84. The system according to claim 83 wherein said fluid heating means comprises
a plurality of electrically operated resistant water heaters arranged in parallel
relationship relative to each other.
85. The system according to claim 83 wherein the second heat transfer fluid comprises seawater.
86. The system according to claim 82 wherein said fluid heating means comprises
an electrically operated resistant water heater.
87. The system according to claim 82 wherein said controller means comprises
at least one valve for diverting said portion of said heat transfer fluid being
supplied to the vessel.
88. The system according to claim 87 wherein said valve is operably coupled with
a thermostat, said valve being operated in response to a thermostat setting reflective
of a predetermined temperature of the returning first heat transfer fluid.
89. The system according to claim 82 wherein said controller means comprises
a plurality of valves and corresponding thermostats.
90. The system according to claim 89 wherein each valve is operably coupled with
its corresponding thermostat, each of said thermostats being in temperature sensing
relationship with the returning first heat transfer fluid upstream of its corresponding
valve, each of said valves being operated in response to a signal generated by
its corresponding thermostat reflective of a predetermined temperature of the returning
first heat transfer fluid.
91. The system according to claim 82 wherein the heat exchanger is a plate type
heat exchanger, a shell and tube type heat exchanger or a tube and tube type heat exchanger.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a load bank for diesel engines and more particularly
to a system, apparatus and method that modifies and utilizes a chilled-fluid air
conditioning system onboard a marine vessel for creating and/or maintaining an
electrical load on one or more diesel engine-powered generators to avoid the deleterious
and/or damaging effects of low-load or no-load operation for the diesel engine.
2. Background of the Invention
Marine diesel engine generators are designed for operation at predetermined
temperatures and pressures that can only be achieved when the diesel engine powering
the generator is operated under load, generally sixty percent of the engine's rated
load capacity or greater. The operation of a diesel engine generator at low loads,
particularly over a long period of time, can lead to undesirable consequences,
among which are incomplete combustion of the diesel fuel resulting in fouled fuel
injectors and valves; condensation formation within the engine which can cause
the various parts of the internal engine to corrode and can also lead to a breakdown
or degradation of the engine's lubricating oil; condensation of exhaust within
the engine's exhaust stacks, commonly referred to as "wet stacking," as well as
condensation in the manifolds thereby causing system corrosion and valve damage;
system carbon buildup in the exhaust system resulting in the risk of an exhaust
system fire; improper seating of the engine's gaskets and seals resulting in oil
leaks; and improper seating of the engine's piston rings which will ultimately
be responsible for excessive oil consumption and shortened piston and ring longevity
thereby leading to reduced horse power for the engine. The foregoing effects of
low load operation are cumulative over a period of time.
Load demands on diesel engine generators, particularly those used in marine
operations onboard a seafaring vessel, are generally created by the vessel's electrical
requirements. Marine engine generators are therefore designed and sized for the
maximum anticipated load for providing electrical power to operate the vessel's
air conditioning, pumps, motors, galley requirements, and appliances, etc., in
the event that all of the vessel's electrical apparatus is on-line at any point
in time.
One of the more varying electrical power demands onboard a seafaring vessel,
and a common source for low-load engine operation, is created by the vessel's air
conditioning system due to the substantial electrical requirements and the fluctuating
conditions of the weather. The majority of larger marine vessels, such as yachts,
utilize conventional fluid-chilled air conditioning systems to heat and cool the
vessel as circumstances warrant. In the cooling mode, these systems employ a circulating
heat transfer fluid for removing heat from various compartments and staterooms
of the vessel. As shown in FIG. 1, the heat transfer fluid
23, typically
fresh water, is pumped through a closed circulation loop
28 that extends
through one or more sources of heat transfer, typically one or more chillers or
reverse-cycle chillers represented by diagram box
18, for ultimately exchanging
its heat with seawater
21 transported through the chiller(s) by the action
of seawater pump
19. Once sufficiently cooled, the heat transfer fluid
23
is circulated to one or more air handlers (represented by diagram box
42)
distributed throughout various locations of the vessel for absorbing the heat from
the air in the vessel's compartments. The heat-absorbed return heat transfer fluid
23 is then circulated back to the chiller(s) by the action of circulating
pump
24 where it is cooled once again to complete the air conditioning cycle.
The power for operating the chiller(s), pumps and other electrical apparatus in
the air conditioning system is derived from diesel engine generator
12 when
the vessel is at sea.
The conventional chiller, an example of which is described and illustrated in
U.S. Pat. No. 4,926,649, comprises an evaporator in combination with a compressor
and condenser for cooling the heat transfer fluid contained within the closed circulation
loop. In applications for use onboard marine vessels, electrical power is supplied
to the compressor by the diesel engine generator for drawing low pressure refrigerant
gas from an evaporator, compressing it, and then discharging it in a higher pressurized
gaseous state to a condenser. The condenser in turn condenses the hot gaseous refrigerant
into a liquid by transmitting its heat to a second heat transfer fluid, typically
seawater, pumped through the condenser. As the sea water is pumped through the
chiller condenser, it absorbs the heat from the hot gaseous refrigerant and is
returned back to the sea.
In the heating mode, i.e., when it is desired to supply heat to the circulating
heat transfer fluid, a reversing valve is employed in the chiller for reversing
the flow of refrigerant to the chiller's condenser in order to absorb heat from
the sea water and transfer it to the circulating heat transfer fluid. In this mode
of operation, the chiller acts as a heat pump and is referred to as a reverse-cycle
chiller. A conventional heat pump may also be utilized, particularly when the vessel
is relegated to cold climate operations.
As an example, a one hundred foot vessel may employ four 5-ton chillers to satisfy
the air conditioning needs of the vessel's compartments. During the summer daytime
hours, the heat load for the vessel will be sufficient to require that all of the
four chillers be online. The electrical power demand for the operation of the chillers
will create a sufficient load on the diesel engine generator(s) thereby more than
satisfying the minimum load requirements for the generator(s). After sunset, however,
the climate air temperature will drop and the heat load of the vessel will be substantially
reduced. As the weather cools, the chillers will begin to stage off one by one,
and only one of the four chillers will probably be needed to satisfy the vessel's
cooling needs. It is during this time that the diesel engine which powers the generator(s)
will be operating under very low-load conditions.
The situation is reversed when the vessel is navigating through a cooler climate
or operating in cool-climate conditions. During the evening hours, the heating
demand for the vessel will be sufficient to require that all four reverse-cycle
chillers be online. Alternatively, resistant in-line water heaters may be employed
in lieu of the reverse-cycle chillers. In any evert, their activation will require
electrical power for the operation of all the reverse-cycle chillers (or in-line
resistant water heaters, as the case may be), and the minimum required load on
the diesel engine will be more than satisfied. After sunrise, however, the air
temperature will increase and the heating demand for the vessel will be reduced.
As the weather temperature increases, the reverse-cycle chillers will stage off
one by one, and only one or two of the four chillers will probably be needed to
maintain the vessel's heating needs. Once again, the engine generator(s) will be
operating under low-load conditions.
3. The Related Art
An example of a refrigeration apparatus powered by a diesel engine generator
is
described in U.S. Pat. No. 5,584,185, issued to Rumble et al. on Dec. 17, 1996.
The refrigeration apparatus comprises a compressor, a water-cooled condenser, a
chiller/evaporator and a positive displacement circulating pump, all of which are
arranged in heat exchange relationship with a recirculating coolant circuit. The
engine and refrigeration apparatus utilize an electronic control system that senses
when electrical power is required or when the coolant temperature rises above a
datum level so as to initiate a prescribed start sequence for the engine, and further,
will automatically shut down the engine when a no-load is sensed for the engine.
In the latter circumstance, the engine will remain on standby awaiting a power demand.
Multiple chilled-fluid producers are also disclosed in U.S. Pat. No. 6,240,867
B1, issued to Hoyle et al. on Jun. 5, 2001. The patent discloses their distribution
within a watertight zone of a multiple-zoned naval ship for independent operation
to avoid or reduce the risk of the vessel's functioning capability when impacted
by a missile or torpedo. The chilled fluid producers disclosed may also require
a flow of water, either sea or fresh water, into which heat can be rejected. U.S.
Pat. No. 4,926,649 issued to Martinez, Jr. on May 22, 1990 also discloses the use
of multiple chillers to cool a commercial building in a way that utilizes less
energy by turning off one or more of the multiple chillers, and also by varying
the total water flow through the chillers.
Various controllers for operating multiple chillers are also disclosed in
the patent literature. For example, in U.S. Pat. No. 4,506,516 issued to Lord on
Mar. 26, 1985, the use of a microprocessor is disclosed for operating multiple
chillers, and in U.S. Pat. No. 4,463,574 issued to Spethmann et al. on Aug. 7,
1984, a controller is disclosed for optimally selecting a combination of chillers
having dissimilar efficiency characteristics to efficiently meet a building's air
conditioning load. Electric controller systems for efficiently operating air conditioning
systems are also known, as for example in U.S. Pat. No. 4,147,296, issued to Spethmann
on Apr. 3, 1979, which discloses an electric controller system for reducing and/or
limiting a building's electrical power consumption by a proportional amount in
order to prevent the power consumption from exceeding a predetermined demand limit;
and in U.S. Pat. No. 5,946,926 issued to Hartman on Sep. 7, 1999, wherein a single-circuit,
chilled fluid cooling system incorporates a variable flow chilled water distribution
system to obtain stable operation at reduced variable flow rates of the circulating
chilled fluid.
Finally, various approaches have been taken to compensate for low-load operation
of a diesel engine generator onboard marine vessels. For example, load banks have
been formulated whereby resistive load elements in the form of heating coils are
inserted into a separately fabricated intake line coupled with a seawater pump
to receive and discharge seawater from and to the vessel. Heating the seawater
in this manner demands electrical power from the generator which in turn creates
a load on the diesel engine powering the generator. In addition to requiring added
space onboard the vessel, and the associated costs for assembling and incorporating
the load bank into the vessel, the coils used to heat the seawater encounter calcification
over a period of time due to the seawater's high mineral content. This results
in the coils being coated with calcium and other minerals that quickly leads to
the inability of the coils to transmit heat to the seawater. Consequently, the
calcified coils become an added maintenance item in that they must be descaled
by repeated acid washing, or simply replaced. Load banks utilizing this method
of operation are available from a variety of sources, one of which is Simplx, Inc.
of Springfield, Ill.
SUMMARY OF THE INVENTION
In accordance with a broader aspect of the invention, a system, apparatus and
method is provided for maintaining an electrical load on a marine diesel engine
generator utilizing the heat transfer fluid contained within the closed fluid circulation
loop of marine vessel's chilled fluid air conditioning system. More specifically,
a system is provided that comprises a closed-loop fluid air conditioning system
for exchanging heat with the air in the vessel, comprising a first heat transfer
means, e.g., one or more sources of heat transfer that comprises a chiller, reverse-cycle
chiller or heat pump, preferably a plurality arranged in parallel relationship
relative to each other, that receives therein and discharges therefrom a first
heat transfer fluid, typically seawater, for ultimately exchanging heat with a
second heat transfer fluid, generally water, a mixture of water and propylene glycol,
or a mixture of water and ethylene glycol, the glycol component being present in
an amount of from about 5 to about 25 percent by volume based on the total volume
of the mixture. The second heat transfer fluid is supplied to and returned from
the vessel within a closed circulation loop for exchanging heat with the air in
the vessel.
The system additionally comprises a load bank comprising (i) controller means
for diverting at least a portion of the second heat transfer fluid being supplied
to the vessel, into heat exchange relationship with a third heat transfer fluid;
and (ii) second heat transfer means, e.g., a heat exchanger, for exchanging heat
between the diverted second heat transfer fluid and the third heat transfer fluid.
In a preferred embodiment of the invention, the third heat transfer fluid is
the
first heat transfer fluid in the form of seawater discharged from the first heat
transfer means. Thus, the first heat transfer fluid will generally comprise seawater,
although in another embodiment of the invention, the first heat transfer fluid
will comprise seawater; and the third heat transfer fluid will comprise seawater
provided to the second heat transfer means or heat exchanger independently of the
seawater being received by the source of heat transfer.
Once heat-exchanged, the diverted second heat transfer fluid is returned to
the first heat transfer means for activation thereof to create an electrical power
demand on the diesel engine generator.
In another preferred embodiment of the invention, the diversion by the controller
means of the portion of second heat transfer fluid being supplied to the vessel,
is undertaken in response to a predetermined temperature value of the returning
second heat transfer fluid, i.e., the second heat transfer fluid returning from
the vessel after it has exchanged heat with the air in the vessel. In order to
accomplish this, and in accordance with yet another embodiment of the invention,
the controller means comprises at least one valve for admitting the diverted portion
of second heat transfer fluid supply therethrough. In order to facilitate the diversion,
it is preferential that the valve be operably coupled with a thermostat that is
in temperature sensing relationship with the returning second heat transfer fluid.
A plurality of valves and corresponding thermostats making up the controller means
allows varying amounts of the second heat transfer fluid to be diverted to the
second heat transfer means, e.g., a heat exchanger. Each of the valves is preferably
operated in response to a thermostat setting reflective of the temperature of the
returning second heat transfer fluid. As a further embodiment, each of the thermostats
is in temperature sensing relationship with the returning second heat transfer
fluid such that each of the valves is operated in response to a signal generated
by its corresponding thermostat reflective of a predetermined temperature of the
returning second heat transfer fluid detected upstream of its corresponding valve.
While not intending to exclude variations or other types, the heat exchanger
may be of the plate, shell and tube, or tube and tube type heat exchanger, the
plate type heat exchanger being preferred due to its relatively minimal space occupancy
when incorporated into the system.
When the closed-loop fluid air conditioning system is used to cool the air in
the vessel compartments, the source of heat transfer takes the form of either a
chiller or reverse-cycle chiller. In larger vessels, a plurality of chillers or
reverse-cycle chillers, or combinations thereof, are generally utilized, the chillers
and/or reverse-cycle chillers being arranged in parallel relationship relative
to each other. In order to assist in the heating of the returning second heat transfer
fluid, the system may optionally comprise, in addition to the second heat transfer
means or heat exchanger, one or more electrical resistant fluid heating devices
in communication with the returning second heat transfer fluid for transferring
heat thereto. The fluid heating device is preferably in the form of one or more
electrically operated resistant water heaters, preferably a plurality arranged
in parallel relationship relative to each other.
In another embodiment of the invention, and as an alternative to the use of a
heat exchanger and valves for heating a diverted portion of the second heat transfer
fluid when the closed-loop chilled fluid air conditioning system is used to cool
the vessel air, the load bank may comprise a fluid heating means comprising one
or more electrical resistant fluid heating devices operably coupled with a controller
means for heating the second heat transfer fluid returning from the vessel to the
source(s) of heat transfer in response to a predetermined temperature of the returning
heat transfer fluid detected upstream of the fluid heating means. The fluid heating
means comprises at least one electrically operated resistant water heater powered
by the diesel engine generator. The controller means comprises at least one thermostat
in temperature sensing relationship with the returning second heat transfer fluid.
The load bank preferably comprises a plurality of electrically operated resistant
water heaters, arranged in parallel relationship relative to each other, each water
heater being powered by the diesel engine generator and operably coupled with and
controlled by a corresponding thermostat in response to a thermostat setting reflective
of a predetermined temperature of the returning second heat transfer fluid detected
upstream of its corresponding water heater.
When the closed-loop fluid air conditioning system is used to heat the air in
the vessel compartments, the source of heat transfer will take the form of either
a reverse-cycle chiller or heat pump, preferably a plurality of reverse-cycle chillers
or heat pumps, or combinations thereof, arranged in parallel relationship relative
to each other. When the vessel is operating in very cold climate conditions, it
will be appreciated that additional sources of heat may be required to heat the
circulating second heat transfer fluid for supplying an adequate amount of heat
to the vessel compartments. Therefore, in addition to the source(s) of heat transfer,
the system may optionally comprise one or more electrical resistant fluid heating
devices, powered by the diesel engine generator and preferably in the form of an
electrically operated resistant water heater, in communication with the second
heat transfer fluid being supplied to the vessel for heating the same.
Another embodiment of the invention includes a load bank for a marine diesel
engine generator electrically coupled with a source of heat transfer in a closed-loop
fluid air conditioning system that receives and discharges a primary heat transfer
fluid for ultimately exchanging heat with a secondary heat transfer fluid, the
secondary heat transfer fluid being supplied to and returned from the compartments
of a marine vessel within a closed circulation loop for exchanging heat with the
air in the vessel compartments, comprising (a) controller means for diverting at
least a portion of the secondary heat transfer fluid supply into heat exchange
relationship with a tertiary heat transfer fluid; and (b) a heat exchanger for
exchanging heat between the diverted secondary heat transfer fluid and the tertiary
heat transfer fluid; whereby the diverted, heat-exchanged, secondary heat transfer
fluid is returned to the source of heat transfer for activation thereof to create
an electrical power demand on the diesel engine generator for maintaining a load
thereon. The primary, secondary and tertiary heat transfer fluids correspond respectively
with the first, second and third heat transfer fluids of the system described above
and include the various embodiments set forth for the first, second and third heat
transfer fluids as part of the present load bank.
The controller means of the load bank comprises at least one valve which is usually
operably coupled with a thermostat that is in temperature sensing relationship
with the returning secondary heat transfer fluid from the vessel. When coupled
with the thermostat, the valve is operated in response to a signal generated by
the thermostat reflective of a predetermined temperature of the returning secondary
heat transfer fluid detected upstream of the valve. In another embodiment, the
load bank controller means comprises a plurality of valves and corresponding thermostats,
the valves being arranged in parallel relationship relative to each other. As with
the heat exchanger described for the system above, the heat exchanger of the load
bank may be a plate type heat exchanger, a shell and tube type heat exchanger or
a tube and tube type heat exchanger.
It will be understood that the closed-loop fluid air conditioning system according
to the invention is not restricted to the use of a chiller, reverse-cycle chiller
or heat pump for heating and/or cooling the circulating heat transfer fluid contained
within the closed circulation loop. Instead, the closed-loop air conditioning system
forming part of the system for maintaining an electrical load on a diesel engine
generator for use on a marine vessel, may comprise (a) a fluid heating means, powered
by the diesel engine generator, comprising at least one electrical resistant fluid
heating device for heating a first heat transfer fluid being supplied to and returned
from the vessel within a closed circulation loop for heating the air in the vessel.
In this case, the first heat transfer fluid is the circulating heat transfer fluid
contained within the closed circulation loop. The system for maintaining an electrical
load on a diesel engine generator also comprises (b) a load bank comprising (i)
controller means for diverting at least a portion of the first heat transfer fluid
being supplied to the vessel, into heat exchange relationship with a second heat
transfer fluid; and (ii) a heat exchanger for exchanging heat between the second
heat transfer fluid and the diverted portion of the first heat transfer fluid whereby
the heat-exchanged, diverted first heat transfer fluid is returned to the fluid
heating means for activation thereof to create an electrical power demand on the
diesel engine generator for maintaining a load thereon.
The first heat transfer fluid or circulating heat transfer fluid may comprise
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, the glycols being present in their respective mixtures in an amount
of from about 5 percent to 25 percent based on the total volume of the mixture.
The second heat transfer will generally comprise seawater.
In this embodiment of the invention, the fluid heating means comprises at least
one electrically operated resistant water heater, preferably a plurality arranged
in parallel relationship relative to each other.
It is understood that the controller means and heat exchanger of the load bank
for this embodiment of the invention correspond with the controller means and heat
exchanger described hereinbefore. They also include the various embodiments of
the previously described controller means and heat exchanger of the load bank associated
with the use of a chiller, reverse-cycle chiller or heat pump as part of the closed-loop
fluid air conditioning system.
The invention also encompasses a method for maintaining a load on the diesel
engine generator onboard a marine vessel utilizing the circulating heat transfer
fluid contained within the closed circulation loop of a fluid air conditioning
system to exchange heat with the air in the vessel, comprising (a) transporting
a primary heat transfer fluid through a first heat transfer means of the closed
circulation loop fluid air conditioning system for ultimately exchanging heat with
the circulating heat transfer fluid; (b) supplying and returning the circulating
heat transfer fluid in the closed circulation loop to and from the vessel, respectively,
for heat exchange with the air therein; (c) diverting at least a portion of the
circulating heat transfer fluid being supplied to the vessel, into heat exchange
relationship with a tertiary heat transfer fluid; and (d) returning the diverted,
heat-exchanged circulating heat transfer fluid to the first heat transfer means
whereby the first heat transfer means is activated to create an electrical power
demand on the diesel engine generator for maintaining a load thereon. In accordance
with the method, the first heat transfer means may comprise a chiller, reverse-cycle
chiller or heat pump, preferably a plurality of chillers, reverse-cycle chillers
or heat pumps, or combinations thereof, arranged in parallel relationship relative
to each other.
The portion of circulating heat transfer fluid being supplied to the vessel is
preferably diverted in response to a predetermined temperature value of the returning
primary heat transfer fluid, usually by a controller means comprising at least
one valve. As a preference, the valve is operably coupled with a thermostat that
is in temperature sensing relationship with the returning circulating heat transfer
fluid, the valve being operated in response to a thermostat setting reflective
of the temperature of the returning circulating heat transfer fluid which is detected
upstream of the valve. In order to more effectively control the actuation of the
sources of heat transfer, the controller means will generally comprise a plurality
of valves and corresponding thermostats, the valves being arranged in parallel
relationship relative to each other.
The heat exchange of the diverted portion of circulating heat transfer fluid
and primary heat transfer fluid is generally undertaken by a second heat transfer
means comprising a heat exchanger which may be a plate type heat exchanger, a shell
and tube type heat exchanger, or a tube and tube type heat exchanger.
The primary and tertiary heat transfer fluids correspond respectively with the
first and third heat transfer fluids of the system described above and include
the various embodiments set forth for the first and third heat transfer fluids
as part of the present method. The circulating heat transfer fluid may comprise
water, a mixture of ethylene glycol and water, or a mixture of propylene glycol
and water, the glycol component being present in its respective mixture in an amount
of from about 5 to 25 percent based on the total volume of the mixture.
Also encompassed by the invention is a method for maintaining a load on a diesel
engine generator onboard a marine vessel utilizing the circulating heat transfer
fluid contained within the closed circulation loop of a chilled-fluid air conditioning
system comprising at least one chiller or reverse-cycle chiller, the method comprising
(a) supplying and returning the heat transfer fluid in the closed circulation loop
to and from the vessel, respectively, for cooling the air therein; (b) heating
