Refrigeration – Automatic control – Of closed system sorbent type
Reexamination Certificate
1999-09-27
2001-02-27
Doerrler, William (Department: 3744)
Refrigeration
Automatic control
Of closed system sorbent type
C062S497000, C062S476000
Reexamination Certificate
active
06192694
ABSTRACT:
TECHNICAL FIELD
The present invention relates to double-effect absorption chillers wherein the vapor of a refrigerant produced by a high temperature generator is supplied to a low temperature generator for condensation, and the refrigerant liquefied on condensation is supplied to a condenser.
BACKGROUND ART
FIG. 12
shows a double-effect absorption chiller which comprises an upper shell
1
comprising a condenser
11
and low temperature generator
12
, a lower shell
2
comprising an evaporator
21
and absorber
22
, a high temperature generator
3
incorporating a burner
31
, a high temperature heat exchanger
4
, a low temperature heat exchanger
5
, etc. These components are interconnected by piping to recycle an absorbent through the high temperature generator
3
, low temperature generator
12
and absorber
22
by an absorbent pump
6
and realize refrigeration cycles.
With the chiller of the type described, a pipe
7
for supplying the refrigerant liquefied by the low temperature generator
12
to the condenser
11
therethrough is provided with an orifice
70
as shown in
FIG. 13
to reduce the pressure of the refrigerant liquefied by the generator
12
before the refrigerant is supplied to the condenser
11
. Thus, the generator
12
is maintained at a low internal pressure so that the vapor of refrigerant produced in the generator
12
is liquefied on condensation in the condenser
11
.
On the other hand, the high temperature generator
3
produces vapor of refrigerant, which is condensed in a heat transfer tube within the low temperature generator
12
to liquefy while giving the heat of condensation to the absorber. The liquefied refrigerant is supplied to the condenser
11
via the orifice
70
and then returned to the evaporator
21
along with the portion of refrigerant which is liquefied in the condenser
11
.
As shown in
FIG. 12
, a gas valve
32
is mounted on a pipe for supplying a fuel gas to the burner
31
of the high temperature generator
3
. The opening degree of the gas valve
32
is controlled to adjust the rate of supply of the fuel gas in order to maintain the temperature cold water outlet temperature Tc_out) of cold water flowing out of the evaporator
21
at a target value.
With the double-effect absorption chiller, it is ideal that the heat input to the high temperature generator
3
cause the generator
3
to produce an amount of vapor corresponding to the quantity of heat input for the amount of vapor to produce vapor having the same quantity of heat in the low temperature generator
12
. A maximum efficiency is achieved at this time. To obtain a state as close as to the ideal, it is necessary to optimize the diameter of the orifice
70
to effect a suitable pressure reduction. The optimum pressure reduction varies with the magnitude of the refrigeration load.
Since there is an approximate proportional relationship between the amount of vapor released from the absorbent and the absorbent concentration difference between the inlet and the outlet of the low temperature generator
12
and the high temperature generator
3
, an efficiency approximate to a maximum is obtained when the concentration difference between the absorbent (strong solution) in the low temperature generator
12
and the absorbent (intermediate solution) in the high temperature generator
3
is equal to the concentration difference between the absorbent (weak solution) in the absorber
22
and the absorbent (intermediate solution) in the high temperature generator
3
.
However, since the conventional double-effect absorption chiller uses a fixed orifice of definite diameter as the orifice
70
, the pressure reduction differs from the optimum value with variations in the refrigeration load.
Further when the absorption chiller is started up, the flow rate of refrigerant from the low temperature generator
12
becomes greater than in the state of stabilized load, so that the orifice
70
used has a greater diameter than is optimum in view of the increase in the flow rate. The conventional chiller of the type described therefore has the problem that while the chiller is in operation with a stabilized refrigeration load after the start-up, the pressure reduction becomes insufficient to result in a lower efficiency. The chiller has another problem that when the refrigeration load decreases, impairment of the efficiency becomes pronounced owing to the escape of vapor.
When remaining unchanged in con cent ration, the absorbent evaporates more easily at a lower temperature because of a drop in boiling point. Accordingly, it is possible to adjust the amount of evaporation by controlling the pressure. However, the pipe
7
for supplying the refrigerant liquefied in the low temperature generator
12
to the condenser
11
is merely provided with the orifice
70
of definite diameter, so that the conventional double-effect absorption chiller is not adapted for the active control of pressure. As a result, even if the high temperature generator
3
and the low temperature generator
12
are rated at a ratio of 1:1 in the amount of evaporation when designed, this balance of 1:1 is upset due to variations in the refrigeration load, leading to a lower efficiency.
Further with the chiller of the type described, the absorbent (intermediate solution) in the high temperature generator
3
is supplied to the low temperature generator
12
by virtue of the pressure difference between these generators
3
and
12
, whereby the concentration of the absorbent (strong solution) collected in the low temperature generator
12
is determined. Thus, the concentration of the strong solution is not controlled positively. Nevertheless, the lower the concentration of the strong solution, the greater the flow rate of the recycling absorbent is, entailing an increased energy consumption for the rise of sensible heat of the absorbent, hence the problem of impaired efficiency.
An object of the present invention is to provide a double-effect absorption chiller which achieves a higher efficiency than conventionally regardless of the operating conditions such as refrigeration load.
Another object of the invention is to provide an absorption chiller which is adapted to pass the refrigerant to the condenser without stagnation when the chiller is started up or in the event of a sudden increase in the load and which is capable of giving a suitable reduced pressure to the refrigerant during steady-state operation so as to achieve a higher operating efficiency than in the prior art.
Another object of the invention is to positively control the concentration of the strong solution to achieve an improvement in operation efficiency over the prior art.
DISCLOSURE OF THE INVENTION
The present invention provides a first absorption chiller which is characterized in that a pipe
7
for supplying a refrigerant liquefied in a low temperature generator
12
to a condenser
11
therethrough is provided with pressure adjusting means for reducing the pressure of the refrigerant flowing through the pipe and adjusting the pressure reduction, the pressure reduction being adjusted according to the magnitude of the refrigeration load.
Accordingly, an optimum pressure reduction can be set despite the refrigeration load, with the result that each of a high temperature generator
3
and the low temperature generator
12
produces a sufficient amount of vapor in accordance with the quantity of heat input to the generator
3
to realize a higher operation efficiency than in the prior art.
Stated more specifically, the pressure adjusting means comprises an orifice
71
provided in the pipe
7
, a bypass pipe
8
bypassing the orifice
71
, a control valve
81
provided at an intermediate portion of the bypass pipe
8
, and a control circuit
9
for controlling the opening degree of the control valve
81
.
With this specific construction, the pressure reduction of the refrigerant passing through the orifice
71
and the control valve
81
is adjusted by adjusting the opening degree of the control valve
81
.
Further stated specifically, the qua
Fujihara Tadato
Hiro Naoki
Kurogi Yasuharu
Ozawa Yoshio
Yamada Toshihiro
Armstrong, Westerman Hattori, McLeland & Naughton
Doerrler William
Sanyo Electric Co,. Ltd.
Shulman Mark
LandOfFree
Absorption type refrigerating machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Absorption type refrigerating machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absorption type refrigerating machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2563364