Refrigeration – Refrigeration producer – Sorbent type
Reexamination Certificate
1999-07-12
2001-05-15
Doerrler, William (Department: 3744)
Refrigeration
Refrigeration producer
Sorbent type
C062S494000, C062S484000, C062S141000
Reexamination Certificate
active
06230517
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an absorption cooling apparatus that is used as an outdoor machine for an absorption air conditioning system and which cools the heat transfer medium used to activate the cooling operation of an indoor air conditioner.
Among the known absorption cooling apparatuses is the one that is described in the Unexamined Japanese Patent Application Publication No. Hei 10-26437 and which is applied to an absorption air conditioning system. This absorption cooling apparatus uses water as a refrigerant and lithium bromide as an absorbent. The general layout of the cooling apparatus is shown in FIG.
8
and comprises the following components: a high-temperature generator having a fin-and-tube heat exchanger
112
which uses the heat of combustion from a burner
111
to heat an aqueous solution of lithium bromide (which is hereunder referred to simply as either a low-concentration solution, a medium-concentration solution or a high-concentration solution depending upon the concentration of lithium bromide), or a low-concentration absorbing liquid supplied from a solution pump
150
; a gas-liquid separator
113
for high-temperature generator (which is hereunder referred to simply as a high-temperature separator) with which the low-concentration solution heated with the high-temperature generator
110
is separated into steam and a medium-concentration solution; a low-temperature generator
120
with which the medium-concentration solution being sent to a fin-and-tube heat exchanger
121
is heated with the steam separated in the high-temperature separator
113
; a gas-liquid separator
122
for low-temperature generator (which is hereunder referred to simply as a low-temperature separator) with which the heated medium-concentration solution is separated into steam and a high-concentration solution; a condenser
130
which cools the steam from the low-temperature separator
122
to liquefy; an evaporator
141
which evaporates the water condensed in the condenser
130
and the low-temperature generator
120
; and an absorber
142
that allows the steam from the evaporator
141
to be absorbed by the high-concentration solution.
The evaporator
141
and the absorber
142
have a dual pipe structure consisting of a cold water pipe
160
extending from an indoor cooler (not shown) surrounded with a coaxial outer pipe
140
and they are formed integrally with an evaporating/absorbing compartment
143
formed between the cold water pipe
160
and the outer pipe
140
. The absorber
142
is connected to the high-temperature generator
110
via a solution circulating path K on which are provided the following three components: the solution pump
150
which supplies in circulation a low-concentration solution to the high-temperature generator
110
; a low-temperature heat exchanger
151
which performs heat exchange with the high-concentration solution being sent from the low-temperature separator
122
; and a high-temperature heat exchanger
152
which performs heat exchange with the medium-concentration solution being sent from the high-temperature separator
113
. A pressure reducing valve
114
is provided on the solution circulating path extending from the high-temperature heat exchanger
152
to the low-temperature generator
120
.
This absorption cooling apparatus operates as follows in a cooling mode. The solution pump
150
starts to operate and the burner
111
ignites, whereupon the low-concentration solution flowing through the fin-and-tube heat exchanger in the high-temperature generator
110
is heated to generate steam, which is separated from the medium-concentration solution in the high-temperature separator
113
. The medium-concentration solution has the temperature thereof lowered in the high-temperature heat exchanger
152
and is thereafter supplied into the low-temperature generator
120
. As it flows through the fin-and-tube heat exchanger in the low-temperature generator
120
, the medium-concentration solution is reheated by the steam from the high-temperature separator
113
and enters the low-temperature separator
122
, where it is separated into steam and the high-concentration solution. The high-concentration solution has the temperature thereof lowered in the low-temperature heat exchanger
151
and is thereafter dripped on the inner surface of the outer pipe
140
. The steam is cooled to condense in the condenser
130
and dripped on the outer surface of the cold water pipe
160
in the evaporating/absorbing compartment
143
. The dripping water evaporates under the low pressure in the evaporating/absorbing compartment
143
and cools the water flowing through the cold water pipe
160
by depriving it of the heat equivalent to the heat of vaporization; the resulting cold water circulates through the cold water pipe
160
and is directed to the indoor cooler to perform a cooling operation. The high-concentration solution absorbs the water vapor (steam) to become a low-concentration solution which is forced by the solution pump
150
to pass through the low-temperature heat exchanger
151
and the high-temperature heat exchanger
152
, so that the temperature thereof is raised; thereafter, the low-concentration solution is sent to the high-temperature generator
110
.
The above-described absorption cooling apparatus has various problems. If a pressure reducing means such as an orifice is not provided between the high-temperature separator
113
and the low-temperature generator
120
, the pressure difference between the two components will increase during normal operation of the cooling apparatus and steam flows into the high-temperature heat exchanger
152
, making it impossible to perform appropriate heat exchange, thus upsetting the balance in the refrigeration cycle to interfere with the appropriate operation. Another problem is that if the pressure reducing means such as an orifice is the only element that is provided between the high-temperature separator
113
and the low-temperature generator
120
, the head of the high-temperature separator
113
is not sufficient to assure the appropriate flow of the solution during a diluting operation, a start-up period or other stages where only small pressure difference exists between the two components. The same difficulty occurs between the low-temperature separator
122
and the low-temperature heat exchanger
151
. A further problem arises with the low-temperature separator
122
: due to the high concentration of the solution formed therein, lithium bromide tends to crystallize out if the solution stays for a long period. The reducing pressure valve
114
provided in the conventional absorption cooling apparatus is not capable of accommodating the variations in pressure difference.
SUMMARY OF THE INVENTION
The present invention has been accomplished in order to solve the aforementioned problems. It is a first object of the invention to provide an absorption cooling apparatus that maintains an appropriate level of pressure difference between a gas-liquid separator and a high-temperature or low-temperature heat exchanger during normal operation and which yet is capable of ensuring a sufficient flow of solution from the gas-liquid separator during a diluting operation. A second object of the invention is to provide an absorption cooling apparatus that is capable of preventing the solute of an absorbing liquid from crystallizing out within the gas-liquid separator.
The first object of the invention can be attained by the absorption cooling apparatus according to aspect
1
which comprises a pump for supplying in circulation an absorbing liquid of high refrigerant content, a generator for heating the absorbing liquid supplied from the pump, a gas-liquid separator with which the absorbing Liquid heated with the generator is separated into an absorbing liquid of low refrigerant content and a refrigerant vapor, a heat exchanging unit for performing heat exchange between the absorbing liquid separated by the gas-liquid separator and the absorbing liquid which is yet
Ishiguro Katsusuke
Kamiya Hiroshi
Maruyama Akira
Doerrler William
Oliff & Berridge PLC.
Paloma Industries Limited
Shulman Mark
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