Refrigeration – Automatic control – Of closed system sorbent type
Reexamination Certificate
2001-12-04
2003-02-25
Esquivel, Denise L. (Department: 3744)
Refrigeration
Automatic control
Of closed system sorbent type
C062S112000, C062S476000
Reexamination Certificate
active
06523357
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an absorption refrigerator including an evaporator having an evaporating heat exchanger pipe operable to evaporate refrigerant on an outer surface thereof so as to cool liquid to be cooled running in the pipe, an absorber containing absorbent liquid for absorbing the refrigerant evaporated at the evaporator, a regenerator for heating and concentrating the absorbent liquid supplied from the absorber by using heat source fluid, and a condenser for condensing steam or vapor of refrigerant supplied from the regenerator and supplying the condensed refrigerant to the evaporator.
2. Description of the Related Art
An absorption refrigerator of the above-noted type utilizes heat source fluid such as hot water heated by utilizing exhaust heat from other device, a plant, etc. As a plant utilizing exhaust heat, a co-generation system (to be referred to as “CGS” hereinafter) is known.
In general, a CGS including an absorption refrigerator is designed for obtaining power from an electric power generator rotatably driven by a gas turbine or an engine. The system is adapted for improving total system efficiency by supplying to the absorption refrigerator the heat source fluid which was obtained by recovering heat from the exhaust gas exhausted from an engine and jacket water of the engine.
As shown in
FIG. 3
, a hot water steam absorption refrigerator provided in the engine CGS utilizing engine exhaust heat is adapted for utilizing heat of jacket water JW and exhaust gas E of the engine
151
acting as a driving unit of an electric power generator
152
. More particularly, the heat of the jacket water JW and the exhaust gas E is recovered by way of cooling water CW
1
(an example of “heat source fluid”) which is circulated by a circulator pump
155
between a jacket water heat exchanger
153
and an exhaust gas heat exchanger
154
and the resultant heated cooling water CW
1
is supplied as hot water to a regenerator
101
to be described later.
At the hot water steam absorption refrigerator
300
, with an absorbing action of absorbent liquid K which is lithium bromide solution contained at the absorber
103
, this absorbent liquid K absorbs refrigerant W evaporated at the evaporator
104
, whereby the inside of the evaporator
104
is depressurized. This promotes evaporation of the refrigerant water W on the surface of a evaporating heat exchanger pipe
105
, which refrigerant water W is scattered or sprayed over the outer surface of the evaporating heat exchanger pipe
105
by means of a circulating pump
110
of the evaporator
104
, so that latent heat of vaporization is absorbed from the refrigerant W, whereby the refrigerant water W and the cooling water C (an example of “liquid to be cooled”) running in the evaporated heating pipe
105
mounted within the evaporator
104
are cooled.
At the absorber
103
, as the absorbent liquid K absorbs the refrigerant W evaporated at the evaporator
104
, the absorbent liquid K is diluted This diluted absorbent liquid K is supplied by a pump
106
via a low temperature heat exchanger passage
107
to the regenerator
101
. The regenerator
101
circulates the cooling water CW heated by the exhaust heat of the engine
151
to a heating heat exchanger pipe
108
, so that the diluted absorbent liquid K is heated to evaporate the refrigerant absorbed therein, whereby the liquid is regenerated. The absorbent liquid K concentrated at the regenerator
101
is returned to the absorber
103
via the low temperature heat exchanger
107
. The low temperature heat exchanger
107
effects a heat exchange reaction between the absorbent liquid K heated at the regenerator
101
and the absorbent liquid K from the absorber
103
, so that the absorbent liquid K supplied from the absorber
103
to the regenerator
101
is heated by the absorbent liquid K supplied from the regenerator
101
to the absorber
103
.
The steam of the refrigerant W evaporated at the regenerator
101
is sent to the condenser
102
, in which the steam is condensed by cooling water CW
2
running in a cooling water heat exchanger pipe
109
mounted in the condenser
102
. The condensed refrigerant water W is sent to the evaporator
104
.
On the other hand, heat is discharged from the cooling water CW
2
running in this cooling water heat exchanger pipe
109
of the condenser
102
at a cooling tower
112
as the water is being circulated by a pump
113
. As this water runs through a cooling water heat exchanger pipe
111
, the water is utilized for heat radiation at the absorber
3
. Then, the water is supplied to the cooling water heat exchanger pipe
109
of the condenser
102
.
Generally, the CGS is used for generation of electric power and recovery of heat. If the generation of electric power is its main purpose, it is expected that the load of electric power generation should be constant. Further, in case the chilled water C generated as a result of the heat recovery at the absorption refrigerator
300
is to be used for air cooling purpose, it is necessary to stop the absorption refrigerator
300
when the cooling load is small, since the cooling load varies according to the operating hour and the outside air temperature.
With some CGS's used for electric power generation, the engine
1
acting as the driving source of the electric generator must not or cannot be stopped. In such cases, in order to reduce the coolability of the evaporator
104
in response to reduction in the cooling load, an arrangement is made for preventing the cooling water CW
1
from entering the regenerator
101
of the absorption refrigerator
300
. However, in order to realize this, it is necessary to provide additional components including a hot-water three-way valve for causing the cooling water CW
1
to bypass the regenerator
101
, a radiation cooling tower
121
for the cooling water CW
1
which has a high temperature as having bypassed the regenerator
101
, and a further hot-water three-way valve
122
for supplying hot water to the radiation cooling tower
121
. All these increase the costs of the system.
Similarly, in the case of a system using a turbine instead of the engine
151
and supplying exhaust gas from the turbine directly to the regenerator of the absorption refrigerator, if necessity arises to reduce the coolability of this absorption refrigerator in response to reduction in the cooling load, it is necessary to provide a three-way damper for bypassing the exhaust gas. And, as this exhaust gas has a high pressure, the gas may leak from seals of the damper even when it is fully closed. As a result, a small amount of exhaust gas may be inadvertently supplied to the shutdown regenerator of the absorption refrigerator, thus inviting temperature rise in the regenerator as well as low temperature corrosion of the same.
Moreover, if the engine or turbine is stopped and started repeatedly without using such components as the exhaust gas three-way damper, hot-water three-way valve, the blades of the turbine or the piston of the engine may be damaged by heat shock. Finally, the shutdown of the engine or turbine disables the electric power generation needed.
In view of the above, there has been proposed an absorption refrigerator which prevents shutdown of the engine due to rise in the engine cooling temperature when the absorption refrigerator is stopped (Japanese patent application laid-open No. Hei. 5-196319). In the case of this absorption refrigerator, the hot-water three-way valve for recovering exhaust heat is not provided. And, when the cooling temperature drops due to reduction in the cooling load, the engine is not shut down. Instead, a pump for absorbent liquid of the absorption refrigerator is shut down, thereby to stop heat input to the absorption refrigerator even when hot water is supplied to the regenerator. And, by supplying refrigerant water into a pipe extending from the regenerator holding the concentrated absorbent liquid therein to the absorber, the absorbent liquid is diluted for preventi
Takuma Co., Ltd.
Webb Ziesenhiem Logsdon Orkin & Hanson P.C.
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