U.S. patent application number 10/218909 was filed with the patent office on 2003-02-27 for connected chilling-heating system.
Invention is credited to Fujimoto, Masakazu, Okada, Takashi.
Application Number | 20030037919 10/218909 |
Document ID | / |
Family ID | 19077054 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030037919 |
Kind Code |
A1 |
Okada, Takashi ; et
al. |
February 27, 2003 |
Connected chilling-heating system
Abstract
The present invention provides a connected chilling-hating
system capable of saving delivering power during reduced load
periods. The system comprises load-side equipment, a set of
chiller-heater modules connected in parallel, and a cold/hot water
pipe connected between the load-side equipment and the set of
chiller-heater modules to form a loop, wherein each chiller-heater
module is connected to a cold/hot water inlet pipe for supplying
cold/hot water to the module and a cold/hot water outlet pipe for
collecting cold/hot water from the module, said inlet or outlet
pipe having a flow valve, wherein the flow control of cold/hot
water is accomplished by opening or closing the respective flow
valves placed on the cold/hot water inlet pipes or the cold/hot
water outlet pipes of the chiller-heater modules in response to the
number of chiller-heater modules in operation.
Inventors: |
Okada, Takashi; (Kanagawa,
JP) ; Fujimoto, Masakazu; (Kanagawa, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN & HATTORI, LLP
1725 K STREET, NW.
SUITE 1000
WASHINGTON
DC
20006
US
|
Family ID: |
19077054 |
Appl. No.: |
10/218909 |
Filed: |
August 15, 2002 |
Current U.S.
Class: |
165/206 ;
165/101; 165/205; 165/59 |
Current CPC
Class: |
F25D 17/02 20130101;
F24F 3/06 20130101; F25D 31/005 20130101; F25B 2400/06
20130101 |
Class at
Publication: |
165/206 ; 165/59;
165/205; 165/101 |
International
Class: |
F24F 007/00; F28F
027/02; F24F 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2001 |
JP |
247796/2001 |
Claims
What is claimed is:
1. A connected chilling-heating system comprising load-side
equipment, a set of chiller-heater modules connected in parallel,
and a cold/hot water pipe connected between the load-side equipment
and the set of chiller-heater modules to form a loop, wherein the
set of chiller-heater modules is connected to a cooling/heat source
water pipe, in addition to the cold/hot water pipe, wherein the
cold/hot water pipe comprises a cold/hot water supply pipe for
supplying cold/hot water from the chiller-heater modules to the
load-side equipment and a cold/hot water return pipe for returning
cold/hot water from the load-side equipment to the chiller-heater
modules, wherein the cooling/heat source water pipe comprises a
cooling/heat source water return pipe for collecting cooling/heat
source water from the chiller-heater modules and a cooling/heat
source water supply pipe for supplying cooling/heat source water to
the chiller-heater modules, wherein each chiller-heater module is
connected to a cold/hot water inlet pipe for supplying cold/hot
water to the module and a cold/hot water outlet pipe for collecting
cold/hot water from the module, said inlet and/or outlet pipe
having a flow valve, wherein the system has a means for regulating
the number of chiller-heater modules in operation depending on
chilling/heating load, and the flow control of cold/hot water is
accomplished by opening or closing the respective flow valves
placed on the cold/hot water inlet pipes and/or the cold/hot water
outlet pipes of the chiller-heater modules in response to the
number of chiller-heater modules in operation.
2. The connected chilling-heating system of claim 1, which further
comprises a speed-controller-equipped pump or a plurality of pumps
placed on the route of the cold/hot water pipe between the set of
chiller-heater modules and the load-side equipment, wherein a
variation in discharge pressure of the pump(s) or differential
pressure between the cold/hot water supply pipe and the cold/hot
water return pipe, produced by opening or closing the flow valves,
is adjusted to ensure optimum pressure by the action of the speed
controller equipped on the pump or by controlling the number of
pumps in operation.
3. The connected chilling-heating system of claim 2, which further
comprises a bypass channel connecting the cold/hot water supply
pipe and the cold/hot water return pipe, said bypass channel being
placed on the route of the cold/hot water pipe between the set of
chiller-heater modules and the load-side equipment, wherein the
bypass flow through the bypass channel is adjusted to approach zero
by the action of the speed controller equipped on the pump or by
controlling the number of pumps in operation.
4. The connected chilling-heating system of claim 2, which further
comprises a cold/hot water supply header placed on the cold/hot
water supply pipe and a cold/hot water return header placed on the
cold/hot water return pipe, wherein a variation in differential
pressure between these two headers, produced by opening or closing
the flow valves, is adjusted to ensure optimum pressure by the
action of the speed controller equipped on the pump or by
controlling the number of pumps in operation.
5. The connected chilling-heating system of claim 3, which further
comprises a cold/hot water supply header placed on the cold/hot
water supply pipe, a cold/hot water return header placed on the
cold/hot water return pipe, and a bypass channel connecting these
two headers, wherein the bypass flow through the bypass channel is
adjusted to approach zero by the action of the speed controller
equipped on the pump or by controlling the number of pumps in
operation.
6. The connected chilling-heating system of claim 1, wherein each
chiller-heater module is further connected to a cooling/heat source
water inlet pipe for supplying cooling/heat source water to the
module and a cooling/heat source water outlet pipe for collecting
cooling/heat source water from the module, said inlet and/or outlet
pipe having a flow valve, wherein the flow control of cooling/heat
source water is accomplished by opening or closing the respective
flow valves placed on the cooling/heat source water inlet pipes
and/or the cooling/heat source water outlet pipes of the
chiller-heater modules in response to the number of chiller-heater
modules in operation.
7. The connected chilling-heating system of claim 6, which further
comprises a speed controller-equipped pump or a plurality of pumps
placed on the route of the cooling/heat source water pipe, wherein
a variation in discharge pressure of the pump(s) or differential
pressure between the cooling/heat source water return pipe and the
cooling/heat source water supply pipe, produced by opening or
closing the flow valves, is adjusted to ensure optimum pressure by
the action of the speed controller equipped on the pump or by
controlling the number of pumps in operation.
8. The connected chilling-heating system of claim 7, which further
comprises a bypass channel connecting the cooling/heat source water
supply pipe and the cooling/heat source water return pipe, said
bypass channel being placed on the route of the cooling/heat source
water pipe, wherein the bypass flow through the bypass channel is
adjusted to approach zero by the action of the speed controller
equipped on the pump or by controlling the number of pumps in
operation.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a connected
chilling-heating system. More specifically, the present invention
relates to a connected chilling-heating system comprising a set of
chiller-heater modules connected in parallel to form an integrated
unit, each module having a compressor, a cooler, a condenser and a
throttling system to form a cold/hot water cycle. The connected
chilling-heating system of the present invention allows
inlet/outlet temperature control, flow control and delivery
pressure control of cold/hot water.
[0002] A prior art connected chilling-heating system is illustrated
by reference to the overall schematic view shown in FIG. 4. The
symbols found in FIG. 4 are defined as follows:
[0003] 1: an inlet connecting pipe;
[0004] 2: a pump for cold/hot water or brine;
[0005] 3, 4, 5, 6, 7: a chiller-heater module;
[0006] 8: an outlet connecting pipe;
[0007] 9: inlet temperature;
[0008] 10: outlet temperature;
[0009] 11: a supply header;
[0010] 12: a return header;
[0011] 13: a cold/hot water bypass valve;
[0012] 14, 15: a load heat exchanger such as an air conditioner,
etc.;
[0013] 16, 17: a load control valve;
[0014] 18: a pump for cooling water or heat source water
(cooling/heat source water);
[0015] 19: a circulating tank for cooling/heat source water;
[0016] 20: a one-way source for cooling/heat source water;
[0017] 21: a one-way receiver for cooling/heat source water;
and
[0018] 22, 23, 24, 25: a one-way/circulation switching valve.
[0019] As shown in the figure, the connected chilling-heating
system comprises load-side equipment 14 and 15 such as an air
conditioner, a set of chiller-heater modules 3 to 7 connected in
parallel, and a cold/hot water pipe connected between the load-side
equipment and the set of chiller-heater modules to form a loop. The
set of chiller-heater modules is connected to a cooling/heat source
water pipe, in addition to the cold/hot water pipe. The cold/hot
water pipe comprises a cold/hot water supply pipe for supplying
cold/hot water from the chiller-heater modules to the load-side
equipment and a cold/hot water return pipe for returning cold/hot
water from the load-side equipment to the chiller-heater modules.
Likewise, the cooling/heat source water pipe comprises a
cooling/heat source water return pipe for collecting cooling/heat
source water from the chiller-heater modules and a cooling/heat
source water supply pipe for supplying cooling/heat source water to
the chiller-heater modules. In the system shown in FIG. 4, supply
header 11 and return header 12 are placed on the cold/hot water
supply pipe and the cold/hot water return pipe, respectively.
[0020] In this system, cold/hot water or brine is pumped by pump 2
from return header 12 into chiller-heater modules 3, 4, 5, 6 and 7,
where cold/hot water or brine is chilled or heated. At this stage,
cold/hot water or brine receives temperature control to ensure
constant outlet temperature 10 of cold/hot water mixed in outlet
connecting pipe 8. Cold/hot water or brine is then delivered from
supply header 11 to the individual load-side equipment 14 and
15.
[0021] FIG. 4 shows chilling operation where cold water or brine is
chilled. When the chilling load starts to decrease in this
operation, the volume of cold water or brine delivered to the load
heat exchangers is reduced by throttling load control valves 16 and
17, while the number of chiller-heater modules in operation is
reduced by number control processing. However, if chiller-heater
modules 6 and 7 are stopped, cold water or brine chilled in the
operating chiller-heater modules 3, 4 and 5 is combined in outlet
connecting pipe 8 with cold water or brine passed at inlet
temperature 9 through the stopped chiller-heater modules 6 and 7,
whereby outlet temperature 10 becomes higher than it is during
fleet operation. In this case, in order to attain the same outlet
temperature 10 as when fleet operation is performed (all of
chiller-heater modules 3-7 are operated), the respective
temperatures at the outlets of the operating chiller-heater modules
3, 4 and 5 must be controlled such that they become lower than when
fleet operation is done.
[0022] For example, in a case where inlet temperature 9 is
10.0.degree. C. and outlet temperature 10 should be regulated to
7.0.degree. C., the respective temperatures at the outlets of
chiller-heater modules 3, 4 and 5 must be set to 5.0.degree. C.
[0023] Likewise, cooling/heat source water also passes through the
chiller-heater modules at rest as well as the modules in
operation.
[0024] This prior art chilling-heating system involves the
following problems:
[0025] (i) in order to ensure constant outlet temperature 10,
another control system is required for changing the temperature
setting of cold/hot water at the inlet or outlet of each
chiller-heater module in accordance with the number of operating
chiller-heater modules, in addition to a control system for
maintaining the temperature of cold/hot water at the inlet or
outlet of each chiller-heater module at the intended
temperature;
[0026] (ii) there occurs a decrease in C.O.P (coefficient of
performance) due to a reduced temperature setting (elevated
temperature setting in heating operation) at the inlet or outlet of
each chiller-heater module in operation, which leads to unwanted
overconsumption of energy;
[0027] (iii) extra delivering power is required because load
control valves 16 and 17, when throttled in response to a decrease
in load, cause an excessive amount of cold/hot water or brine to
pass through cold/hot water bypass valve 13;
[0028] (iv) for the same reason, extra delivering power is required
by the cooling water system during cold water production or by the
heating water system during hot water production (where a heat pump
is driven) in response to a decrease in the number of operating
chiller-heater modules during reduced load periods; and
[0029] (v) internal pipes in the chiller-heater modules at rest are
excessively stained.
[0030] To overcome the above problems involved in the prior art,
the present invention is aimed at providing a connected
chilling-heating system that not only ensures the intended
temperature and optimum flow of cold/hot water supplied to
load-side equipment without changing the temperature setting at the
inlet or outlet of each chiller-heater module, but also allows
power saving in delivering cooling/heat source water, when some of
the connected chiller-heater modules are stopped to control the
number of chiller-heater modules in operation.
SUMMARY OF THE INVENTION
[0031] In order to achieve the aim mentioned above, the present
invention provides:
[0032] (1) a connected chilling-heating system comprising load-side
equipment, a set of chiller-heater modules connected in parallel,
and a cold/hot water pipe connected between the load-side equipment
and the set of chiller-heater modules to form a loop,
[0033] wherein the set of chiller-heater modules is connected to a
cooling/heat source water pipe, in addition to the cold/hot water
pipe,
[0034] wherein the cold/hot water pipe comprises a cold/hot water
supply pipe for supplying cold/hot water from the chiller-heater
modules to the load-side equipment and a cold/hot water return pipe
for returning cold/hot water from the load-side equipment to the
chiller-heater modules,
[0035] wherein the cooling/heat source water pipe comprises a
cooling/heat source water return pipe for collecting cooling/heat
source water from the chiller-heater modules and a cooling/heat
source water supply pipe for supplying cooling/heat source water to
the chiller-heater modules,
[0036] wherein each chiller-heater module is connected to a
cold/hot water inlet pipe for supplying cold/hot water to the
module and a cold/hot water outlet pipe for collecting cold/hot
water from the module, said inlet and/or outlet pipe having a flow
valve,
[0037] wherein the system has a means for regulating the number of
chiller-heater modules in operation depending on chilling/heating
load, and the flow control of cold/hot water is accomplished by
opening or closing the respective flow valves placed on the
cold/hot water inlet pipes and/or the cold/hot water outlet pipes
of the chiller-heater modules in response to the number of
chiller-heater modules in operation.
[0038] The present invention further includes the following
preferred embodiments:
[0039] (2) the connected chilling-heating system of (1) above,
which further comprises a speed controller-equipped pump or a
plurality of pumps placed on the route of the cold/hot water pipe
between the set of chiller-heater modules and the load-side
equipment,
[0040] wherein a variation in discharge pressure of the pump(s) or
differential pressure between the cold/hot water supply pipe and
the cold/hot water return pipe, produced by opening or closing the
flow valves, is adjusted to ensure optimum pressure by the action
of the speed controller equipped on the pump or by controlling the
number of pumps in operation;
[0041] (3) the connected chilling-heating system of (2) above,
which further comprises a bypass channel connecting the cold/hot
water supply pipe and the cold/hot water return pipe, said bypass
channel being placed on the route of the cold/hot water pipe
between the set of chiller-heater modules and the load-side
equipment,
[0042] wherein the bypass flow through the bypass channel is
adjusted to approach zero by the action of the speed controller
equipped on the pump or by controlling the number of pumps in
operation;
[0043] (4) the connected chilling-heating system of (2) above,
which further comprises a cold/hot water supply header placed on
the cold/hot water supply pipe and a cold/hot water return header
placed on the cold/hot water return pipe,
[0044] wherein a variation in differential pressure between these
two headers, produced by opening or closing the flow valves, is
adjusted to ensure optimum pressure by the action of the speed
controller equipped on the pump or by controlling the number of
pumps in operation;
[0045] (5) the connected chilling-heating system of (3) above,
which further comprises a cold/hot water supply header placed on
the cold/hot water supply pipe, a cold/hot water return header
placed on the cold/hot water return pipe, and a bypass channel
connecting these two headers,
[0046] wherein the bypass flow through the bypass channel is
adjusted to approach zero by the action of the speed controller
equipped on the pump or by controlling the number of pumps in
operation;
[0047] (6) the connected chilling-heating system of any one of (1)
to (5) above, wherein each chiller-heater module is further
connected to a cooling/heat source water inlet pipe for supplying
cooling/heat source water to the module and a cooling/heat source
water outlet pipe for collecting cooling/heat source water from the
module, said inlet and/or outlet pipe having a flow valve, wherein
the flow control of cooling/heat source water is accomplished by
opening or closing the respective flow valves placed on the
cooling/heat source water inlet pipes and/or the cooling/heat
source water outlet pipes of the chiller-heater modules in response
to the number of chiller-heater modules in operation;
[0048] (7) the connected chilling-heating system of (6) above,
which further comprises a speed controller-equipped pump or a
plurality of pumps placed on the route of the cooling/heat source
water pipe,
[0049] wherein a variation in discharge pressure of the pump(s) or
differential pressure between the cooling/heat source water return
pipe and the cooling/heat source water supply pipe, produced by
opening or closing the flow valves, is adjusted to ensure optimum
pressure by the action of the speed controller equipped on the pump
or by controlling the number of pumps in operation; and
[0050] (8) the connected chilling-heating system of (7) above,
which further comprises a bypass channel connecting the
cooling/heat source water supply pipe and the cooling/heat source
water return pipe, said bypass channel being placed on the route of
the cooling/heat source water pipe,
[0051] wherein the bypass flow through the bypass channel is
adjusted to approach zero by the action of the speed controller
equipped on the pump or by controlling the number of pumps in
operation.
[0052] This specification includes part or all of the contents as
disclosed in the specification and/or drawings of Japanese Patent
Application No. 2001-247796, which is a priority document of the
present application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 is an overall schematic view showing a
chilling-heating system according to an embodiment of the present
invention, which comprises a set of connected chiller-heater
modules and load-side equipment connected to the modules.
[0054] FIG. 2 is an overall schematic view showing a
chilling-heating system according to another embodiment of the
present invention, which comprises a set of connected
chiller-heater modules and load-side equipment connected to the
modules.
[0055] FIG. 3 is a conceptual view of individual chiller-heater
modules used in the present invention.
[0056] FIG. 4 is an overall schematic view of a prior art
chilling-heating system, which comprises a set of connected
chiller-heater modules and load-side equipment connected to the
modules.
DETAILED DESCRIPTION OF THE INVENTION
[0057] A preferred embodiment of the present invention is a
connected chilling-heating system comprising a set of
chiller-heater modules connected in parallel,
[0058] wherein the inlet or outlet temperature of cold/hot water is
controlled in each chiller-heater module,
[0059] wherein the number of chiller-heater modules in operation is
controlled in response to a change in load,
[0060] wherein the total flow rate of cold/hot water passed through
the set of chiller-heater modules is controlled by opening or
closing the respective flow valves placed on the cold/hot water
inlet pipes or the cold/hot water outlet pipes of the
chiller-heater modules in response to the number of chiller-heater
modules in operation,
[0061] wherein an increase in discharge pressure of the pump(s) or
differential pressure between the cold/hot water supply pipe and
the cold/hot water return pipe, produced by opening or closing the
flow valves, is adjusted to ensure optimum pressure by the action
of the speed controller equipped on the pump or by controlling the
number of pumps in operation, whereby the waste of delivering power
is avoided to save energy.
[0062] Another preferred embodiment of the present invention is a
connected chilling-heating system comprising a set of
chiller-heater modules connected in parallel,
[0063] wherein the inlet or outlet temperature of cold/hot water is
controlled in each chiller-heater module,
[0064] wherein the number of chiller-heater modules in operation is
controlled in response to a change in load,
[0065] wherein the total flow rate of cooling/heat source water
passed through the set of chiller-heater modules is controlled by
opening or closing the respective flow valves placed on the
cooling/heat source water inlet pipes or the cooling/heat source
water outlet pipes of the chiller-heater modules in response to the
number of chiller-heater modules in operation,
[0066] wherein an increase in discharge pressure of the pump(s) or
differential pressure between the cooling/heat source water supply
pipe and the cooling/heat source water return pipe, produced by
opening or closing the flow valves, is adjusted to ensure optimum
pressure by the action of the speed controller equipped on the pump
or by controlling the number of pumps in operation, whereby the
waste of delivering power is avoided to save energy.
[0067] Next, the present invention will be illustrated by reference
to drawings.
[0068] FIG. 1 shows an overall schematic view of a chilling-heating
system according to an embodiment of the present invention, which
comprises 5 connected chiller-heater modules and 2 load-side
equipments connected to the modules. FIG. 1 is explained below in
terms of chilling operation by way of example.
[0069] This figure also contains specific information on the
temperature and flow rate of cold water during a reduced load
period, given that the temperature of cold water or brine in each
chiller-heater module is preset to 7.0.degree. C. and the flow rate
of cold water or brine per chiller-heater module is represented by
Q.
[0070] Symbols 1 to 25 found in FIG. 1 are as defined above in FIG.
4. Symbols 26 to 41 are defined as follows:
[0071] 26, 27, 28, 29, 30: a flow valve for cold/hot water;
[0072] 31, 32, 33, 34, 35: a flow valve for cooling/heat source
water;
[0073] 36: a pumping pressure detector for cold/hot water or
brine;
[0074] 37: a pressure controller;
[0075] 38: a speed controller for cold/hot water or brine;
[0076] 39: a pumping pressure detector for cooling/heat source
water;
[0077] 40: a pressure controller; and
[0078] 41: a speed controller for cooling/heat source water.
[0079] The action of the connected chilling-heating system shown in
FIG. 1 is explained. In a case where chiller-heater modules 6 and 7
are stopped to control the number of chiller-heater modules in
response to a decrease in load, flow valves 29 and 30 are closed to
prevent the flow of cold water or brine into chiller-heater modules
6 and 7 at rest. As a result, the temperature of cold water or
brine is maintained at 7.0.degree. C. at the outlets of the
individual chiller-heater modules 3, 4 and 5 in operation, which in
turn ensures outlet temperature 10 of 7.0.degree. C. Thus, cold
water or brine at 7.0.degree. C. can be supplied to the load-side
equipment.
[0080] Meanwhile, the closed flow valves 29 and 30 elevate the
discharge pressure of pump 2. This elevated discharge pressure is
detected by pumping pressure detector 36 and then transmitted to
pressure controller 37, which in turn controls speed controller 38
to reduce the discharge pressure of pump 2. In this way, extra
delivering power can be saved. Also, load control valves 16 and 17
allow the flow of excess cold/hot water to pass through cold/hot
water bypass valve 13 when the load control valves are throttled in
response to a decrease in load. This flow through cold/hot water
bypass valve 13 is able to approach zero by reducing the discharge
quantity of pump 2, which leads to a further saving in delivering
power.
[0081] Regarding cooling water, if chiller-heater modules 6 and 7
are stopped, flow valves 34 and 35 are closed to prevent the flow
of cooling water into the chiller-heater modules at rest.
[0082] Since the closed flow valves 34 and 35 elevate the discharge
pressure of pump 18, the discharge pressure is detected by pumping
pressure detector 39 and then transmitted to pressure controller
40, which in turn controls speed controller 41 to reduce the
discharge pressure of pump 18. In this way, extra delivering power
can also be saved in the cooling water system.
[0083] FIG. 2 shows an overall schematic view of a chilling-heating
system according to another embodiment of the present invention,
which is different from FIG. 1.
[0084] In the system of FIG. 2, symbols 1 to 35 are as defined in
FIG. 1. Additional symbols are defined as follows:
[0085] 2': a pump for cold/hot water or brine;
[0086] 18': a pump for cooling/heat source water;
[0087] 36': a header differential pressure detector;
[0088] 37': a differential pressure controller;
[0089] 39': a differential pressure transmitter for cooling water;
and
[0090] 40': a differential pressure controller.
[0091] In the case of this system, the header differential pressure
between supply header 11 and return header 12 is detected by
differential pressure detector 36', instead of detecting the
discharge pressure of pump 2. The detected differential pressure is
then transmitted to differential pressure controller 37', which in
turn controls the number of pumps 2 and 2'. In this way, extra
delivering power can be saved. Although FIG. 2 shows an embodiment
including two pumps for cold/hot water or brine, the same can be
applied to the case of using more than two pumps. Likewise, the
same can also be applied to the case of using secondary pumps 42
and 43 for cold/hot water or brine.
[0092] Regarding cooling/heat source water for the chiller-heater
modules, the differential pressure between the cooling water supply
pipe and the cooling water return pipe is detected by differential
pressure controller 39', instead of detecting the discharge
pressure of the pump for cooling/heat source water. The detected
differential pressure is then transmitted to differential pressure
controller 40', which in turn controls the number of pumps 18 and
18'. In this way, extra delivering power can also be saved in the
cooling/heat source water system. Although FIG. 2 shows an
embodiment including two pumps for cooling/heat source water, the
same can be applied to the case of using more than two pumps.
[0093] Incidentally, FIGS. 1 and 2 illustrate a system in which a
supply header and a return header for cold/hot water are provided
at a supply pipe and a return pipe for cold/hot water,
respectively. However, the present invention may also apply to a
system in which headers are not provided. For example, in the
system of FIG. 1, a bypass channel is provided directly between the
supply pipe and the return pipe for cold/hot water without
providing supply header 11 and return header 12, and discharge
quantity of pump 2 may be regulated so as to approach the flow of
cold/hot water through the bypass channel to zero. Further, in the
system of FIG. 2, a differential pressure detector 36'and a bypass
channel may be provided directly between the supply pipe and the
return pipe for cold/hot water without providing supply header 11
and return header 12.
[0094] Although an explanation was given on chilling operation
where cold water or brine was chilled, the same can be said for
heating operation where hot water is heated.
[0095] FIG. 3 shows a conceptual view of individual chiller-heater
modules used in the present invention.
[0096] In FIG. 3, symbols 44, 45, 46 and 47 represent a cooler, a
compressor, a condenser and a throttling system, respectively.
[0097] The refrigeration cycle of the chiller-heater module shown
in FIG. 3 is explained. A refrigerant gas vaporized in cooler 44 is
compressed in compressor 45 and then introduced into condenser 46
to be cooled with cooling water 48 for liquefaction. The liquefied
refrigerant is decompressed by throttling system 47 and then
introduced into a refrigerating chamber in cooler 44, where the
refrigerant absorbs heat from cold water or brine entering from
inlet nozzle 1 and hence vaporizes itself again before entering a
second refrigeration cycle. In this way, cold water or brine is
chilled and then flows out of outlet nozzle 8.
[0098] According to the present invention, the use of the control
mechanism as stated above enables a connected chilling-heating
system to have the following features:
[0099] (i) no additional control system is required for changing
the temperature setting (intended temperature) of cold/hot water at
the inlet or outlet of each chiller-heater module even where the
number of chiller-heater modules in operation is reduced as the
result of load reduction;
[0100] (ii) a decrease in C.O.P (coefficient of performance) can be
avoided because there is no need to reduce the temperature setting
of cold/hot water at the inlet or outlet of each chiller-heater
module in operation even where some of the chiller-heater modules
are stopped, whereby cold/hot water can be supplied to the
load-side equipment at the intended temperature;
[0101] (iii) delivering power can be saved because the optimum flow
of cold/hot water and cooling/heat source water is ensured in
response to a specific chilling or heating load; and
[0102] (iv) excessive staining of internal pipes in the
chiller-heater modules at rest can be prevented.
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