U.S. patent application number 13/144608 was filed with the patent office on 2011-11-10 for water heat exchanger and hot water heat source apparatus.
Invention is credited to Hyunyoung Kim, Mitsuharu Numata, Kaori Yoshida.
Application Number | 20110271711 13/144608 |
Document ID | / |
Family ID | 42355790 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110271711 |
Kind Code |
A1 |
Yoshida; Kaori ; et
al. |
November 10, 2011 |
WATER HEAT EXCHANGER AND HOT WATER HEAT SOURCE APPARATUS
Abstract
A water heat exchanger exchanges heat between a refrigerant and
water, and includes a pair of flat refrigerant pipes and a flat
water pipe. Each flat refrigerant pipe has a plurality of
refrigerant passageway holes. The flat water pipe has at least one
water passageway hole. The number of water passageway holes is
fewer than the number of refrigerant passageway holes of the flat
refrigerant pipes. Long side surfaces of the flat water pipe and a
long side surface of each of the pair of flat refrigerant pipes are
in tight contact with each other as viewed in cross section. The
flat water pipe is interposed by the pair of flat refrigerant
pipes.
Inventors: |
Yoshida; Kaori; (Osaka,
JP) ; Numata; Mitsuharu; (Osaka, JP) ; Kim;
Hyunyoung; (Osaka, JP) |
Family ID: |
42355790 |
Appl. No.: |
13/144608 |
Filed: |
January 19, 2010 |
PCT Filed: |
January 19, 2010 |
PCT NO: |
PCT/JP2010/000265 |
371 Date: |
July 14, 2011 |
Current U.S.
Class: |
62/515 ;
165/177 |
Current CPC
Class: |
F25B 39/04 20130101;
F28F 1/022 20130101; F28F 9/04 20130101; F25B 2339/047 20130101;
F28D 7/0025 20130101; F28D 7/0033 20130101; F28F 1/04 20130101 |
Class at
Publication: |
62/515 ;
165/177 |
International
Class: |
F25B 39/02 20060101
F25B039/02; F28F 1/00 20060101 F28F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 20, 2009 |
JP |
2009-009599 |
Claims
1. A water heat exchanger configured to exchange heat between a
refrigerant and water, the water heat exchanger comprising: a pair
of flat refrigerant pipes, each flat refrigerant pipe having a
plurality of refrigerant passageway holes arranged to have the
refrigerant flow therethrough; and a flat water pipe having at
least one water passageway hole arranged to have the water flow
therethrough, the number of water passage holes being fewer than
the number of refrigerant passageway holes of the flat refrigerant
pipes, long side surfaces of the flat water pipe and a long side
surface of each of the pair of flat refrigerant pipes are in tight
contact with each other as viewed in cross section, and the flat
water pipe being interposed by the pair of flat refrigerant
pipes.
2. The water heat exchanger according to claim 1, wherein the
number of the water passageway holes of the flat water pipe is one
or two.
3. The water heat exchanger according to claim 1, wherein the flat
water pipe is joined to each of the pair of flat refrigerant pipes
by brazing using a brazing filler material or by adhesives.
4. The water heat exchanger according to claim 1, wherein at least
one of the flat refrigerant pipes and the flat water pipe is formed
by drawing or extruding.
5. The water heat exchanger according to claim 1, wherein the flat
water pipe is formed by bending a flat plate.
6. The water heat exchanger according to claim 5, wherein the flat
water pipe is an electro-resistance welded pipe formed by bringing
two sides of the flat plate into contact by the bending, and then
joining the two sides.
7. The water heat exchanger according to claim 5, wherein the flat
plate is embossed prior to the bending.
8. The water heat exchanger according to claim 1, wherein the
refrigerant that flows through an interior of the flat refrigerant
pipes and the water that flows through an interior of the flat
water pipe flow in mutually opposing directions.
9. The water heat exchanger according to claim 1, wherein the
refrigerant is CO.sub.2.
10. A hot water heat source apparatus configured to be used with a
refrigerant circuit using a supercritical refrigerant, a high
pressure side of a refrigeration cycle being in a supercritical
region in the refrigerant circuit, the hot water heat source
apparatus comprising: a compressor arranged to compress the
supercritical refrigerant; a water heat exchanger arranged to cool
the supercritical refrigerant and to heat water by exchanging heat
between the water and the high temperature and high pressure
supercritical refrigerant compressed by the compressor; an
expansion mechanism arranged to reduce pressure of the
supercritical refrigerant cooled by the water heat exchanger; and
an evaporator arranged to evaporate the refrigerant whose pressure
was reduced by the expansion mechanism, the water heat exchanger
including a pair of flat refrigerant pipes, each refrigerant pipe
having a plurality of refrigerant passageway holes arranged to have
the refrigerant flow therethrough, and a flat water pipe having at
least one water passageway hole arranged to have the water flow
therethrough, the number of water passage holes being fewer than
the number of the refrigerant passageway holes of the flat
refrigerant pipes; a refrigerant inlet header having inlets of the
pair of flat refrigerant pipes connected thereto; and a refrigerant
outlet header having outlets of the pair of flat refrigerant pipes
connected thereto, long side surfaces of the flat water pipe and a
long side surface of each of the pair of flat refrigerant pipes are
in tight contact with each other as viewed in cross section, the
flat water pipe being interposed by the pair of flat refrigerant
pipes, and the refrigerant that flows through an interior of the
flat refrigerant pipes and the water that flows through an interior
of the flat water pipe flowing in mutually opposing directions.
Description
TECHNICAL FIELD
[0001] The present invention relates to a water heat exchanger that
exchanges heat between a refrigerant and water.
BACKGROUND ART
[0002] In the conventional art, among refrigeration apparatuses
within heat pump type hot water supply apparatuses, those that
comprise a compression type refrigerant circuit are widely used. A
refrigerant circuit uses, for example, CO.sub.2 as the refrigerant
and comprises a water heat exchanger. The water heat exchanger
comprises a refrigerant pipe, wherethrough the refrigerant flows,
and a water pipe, wherethrough the water flows; furthermore, heat
is exchanged between these fluids by disposing their pipes such
that they are opposed to one another. Specifically, the water is
heated by exchanging heat between the high temperature and high
pressure refrigerant and the low temperature and low pressure
water. As a result, it is possible to output high temperature water
by taking advantage of the characteristics of CO.sub.2 in the
supercritical region.
[0003] As an example of the conventional art of water heat
exchangers, a structure is known, as disclosed in Patent Document 1
(i.e., Japanese Unexamined Patent Application Publication No.
2004-218946), wherein a flat pipe is used as the water pipe and,
furthermore, multiple refrigerant pipes are brought into tight
contact with one another.
SUMMARY OF THE INVENTION
<Technical Problem>
[0004] Nevertheless, in the art disclosed in Patent Document 1
(i.e., Japanese Unexamined Patent Application Publication No.
2004-218946), in a working example 1, a large portion of the water
pipe (i.e., at least half the surface of the water pipe) does not
contact the refrigerant pipe, and consequently there is a risk that
the heat of the water flowing through the water pipe, which was
obtained from the refrigerant, will dissipate externally. In
addition, while in a working example 2 of the Patent Document 1
(i.e., Japanese Unexamined Patent Application Publication No.
2004-218946), the water pipe has a cross shaped cross section and
is brought into tight contact with four refrigerant pipes disposed
therearound, and therefore a smaller portion of the water pipe than
in the working example 1 does not contact the refrigerant pipes,
the number of components is greater than in the working example 1,
and therefore the structure is more complicated. Consequently, the
manufacture of the heat exchanger according to the working example
2 is not simple and is more costly.
[0005] An object of the present invention is to provide a water
heat exchanger that can efficiently exchange heat between water and
a refrigerant and that is simple to manufacture.
<Solution to Problem>
[0006] A water heat exchanger according to a first aspect of the
invention is a water heat exchanger that exchanges heat between a
refrigerant and water and comprises a pair of refrigerant pipes and
a water pipe. The pair of refrigerant pipes each are a many holed
flat pipe that has a plurality of refrigerant passageway holes
wherethrough the refrigerant can flow. The water pipe is a sparely
holed flat pipe. The sparely holed flat pipe, wherethrough the
water can flow, has fewer water passageway holes than the
refrigerant pipes have refrigerant passageway holes. Furthermore,
in a cross section, the long side surfaces of the water pipe and
one of the long side surfaces of each of the pair of refrigerant
pipes are in tight contact with one another. Furthermore, the water
pipe is interposed by the pair of refrigerant pipes.
[0007] The water heat exchanger of the present invention is
configured such that the water pipe is interposed by the pair of
the refrigerant pipes. Furthermore, in a cross section, the long
side surfaces of the water pipe interposed by the pair of the
refrigerant pipes and one of the long side surfaces of each of the
refrigerant pipes are in tight contact with another.
[0008] Thus, because configuring the water heat exchanger in this
manner brings most of the periphery of the water pipe into tight
contact with the refrigerant pipes, it is possible to maximally
prevent any heat transmitted to the water from the refrigerant from
being transmitted to any substance surrounding the water heat
exchanger (e.g., the air around the water heat exchanger). In
addition, because the pair of refrigerant pipes and the water pipe
are brought into tight contact with one another along their long
side surfaces, which are flat surfaces, in a cross section, the
configuration is simple and assembly is easy.
[0009] In addition, because the water heat exchanger of the present
invention comprises the many holed flat pipe wherein the
refrigerant pipe has a plurality of the refrigerant passageway
holes, the coefficient of heat transfer on the refrigerant side can
be increased by reducing the pipe diameter.
[0010] A water heat exchanger according to a second aspect of the
invention is the water heat exchanger according to the first aspect
of the invention, wherein the number of the water passageway holes
of the sparely holed flat pipe is one or two.
[0011] In the water heat exchanger of the present invention, the
number of the water passageway holes formed inside the sparely
holed flat pipe, which is the water pipe, is one or two. Thus,
reducing the number of the water passageway holes to one or two
makes it possible to simplify the formation of the sparely holed
flat pipe and to adopt, for example, various methods as needed to
form the sparely holed flat pipe.
[0012] A water heat exchanger according to a third aspect of the
invention is the water heat exchanger according to the first or
second aspect of the invention, wherein the water pipe and each of
the pair of refrigerant pipes are joined by brazing using a brazing
filler material or by adhesives.
[0013] In the water heat exchanger of the present invention, in a
cross section, the long side surfaces of the water pipe and one of
the long side surfaces of the pair of refrigerant pipes are joined
to one another (i.e., their flat surfaces are joined to one
another) by brazing or by the application of the adhesive.
Accordingly, it is possible to achieve a state wherein there is
virtually no thermal resistance caused by the contact between the
pair of refrigerant pipes and the water pipe. Consequently, the
heat exchanging efficiency between the refrigerant and the water
can be improved.
[0014] A water heat exchanger according to a fourth aspect of the
invention is the water heat exchanger according to any one aspect
of the first through third aspects of the invention, wherein the
refrigerant pipes and/or the water pipe is formed by drawing or
extruding.
[0015] Accordingly, the refrigerant pipes or the water pipe, or
both, can be formed easily.
[0016] A water heat exchanger according to a fifth aspect of the
invention is the water heat exchanger according to any one aspect
of the first through fourth aspects of the invention, wherein the
sparely holed flat pipe is formed by bending a flat plate.
[0017] In the water heat exchanger of the present invention, the
sparely holed flat pipe is formed by bending the flat plate. For
example, the flat pipe is formed after the flat plate is fabricated
into a pipe shape by bending.
[0018] Accordingly, the flat pipe can be formed after performing
some kind of fabrication (e.g., drilling, embossing, or forming a
multilayer structure of different materials) on the flat plate.
Namely, the prescribed fabrication can be performed easily on the
sparely holed flat pipe.
[0019] A water heat exchanger according to a sixth aspect of the
invention is the water heat exchanger according to the fifth aspect
of the invention, wherein the sparely holed flat pipe is an
electro-resistance welded pipe that is formed by bringing two sides
of the flat plate into contact by the bending, and then joining the
two sides.
[0020] In the water heat exchanger of the present invention, the
sparely holed flat pipe is formed as a member whose cross section
is C shaped by bending the flat plate so that the two sides that
constitute the end parts of the flat plate mate with one another.
Furthermore, subsequently, the pipe shaped member is formed by
joining (e.g., by electro-resistance welding or brazing) the two
mated sides.
[0021] Accordingly, the flat pipe can be formed after performing
some kind of fabrication (e.g., embossing, drilling, or forming a
multilayer structure of different materials) on the flat plate.
Thereby, it is possible to make, for example, the axial cross
sectional shape of the sparely holed flat pipe (particularly the
shape of the inner surface of the sparely holed flat pipe) into a
shape that varies with its position in the direction of water flow.
Consequently, turbulence can be created in the flow of water inside
the sparely holed flat pipe, which makes it possible to improve the
coefficient of heat transfer. In addition, for example, it is
possible to easily perform a corrosion prevention process on the
interior of the sparely holed flat pipe. Consequently, corrosion of
the sparely holed flat pipe owing to water can be prevented.
[0022] A water heat exchanger according to a seventh aspect of the
invention is the water heat exchanger according to the fifth or
sixth aspect of the invention, wherein the flat plate is embossed
prior to the bending.
[0023] In the water heat exchanger of the present invention, the
sparely holed flat pipe is formed by bending the flat plate.
Furthermore, the flat plate can be embossed before the bending.
[0024] Accordingly, the flat pipe can be formed after the embossing
of the flat plate. Thereby, it is possible to make, for example,
the axial cross sectional shape of the sparely holed flat pipe
(particularly the shape of the inner surface of the sparely holed
flat pipe) into a shape that varies with its position in the
direction of water flow. Consequently, turbulence can be created in
the flow of water inside the sparely holed flat pipe, which
promotes water convection; furthermore, the sparely holed flat pipe
can be shaped so as to promote heat exchange efficiency.
[0025] A water heat exchanger according to an eighth aspect of the
invention is the water heat exchanger according to any one aspect
of the first through seventh aspects of the invention, wherein the
refrigerant that flows through the interior of the refrigerant
pipes and the water that flows through the interior of the water
pipe flow in mutually opposing directions.
[0026] Accordingly, it is possible to secure a temperature
differential between the refrigerant and the water. In addition,
the temperature differential between the refrigerant and the water
can be made nearly uniform over the entire water heat exchanger,
which can improve heat exchanging efficiency, particularly if, as
in the case wherein the refrigerant is a supercritical refrigerant,
temperature changes occur over the entire heat exchanging area and
the temperature at the beginning of the heat exchanger and the
temperature at the end of the heat exchanger differ greatly.
[0027] A water heat exchanger according to a ninth aspect of the
invention is the water heat exchanger according to any one aspect
of the first through eighth aspects of the invention, wherein the
refrigerant is CO.sub.2.
[0028] In the present invention, CO.sub.2 refrigerant is used as
the refrigerant. CO.sub.2 refrigerant is a so-called supercritical
refrigerant wherein the high pressure side in the refrigeration
cycle is in the supercritical region. For example, if the water
heat exchanger of the present invention is adapted to a heat pump
type water heater, then the water heat exchanger functions as a
radiator. Unlike the use of a fluorocarbon based refrigerant, the
use of a supercritical refrigerant gives rise to temperature
changes over the entire area inside the water heat exchanger;
consequently, if, for example, the vicinity of the outlet of the
water pipe contacts the center part of the refrigerant pipe, then
the refrigerant temperature at that portion might decrease to a
temperature lower than the temperature in the vicinity of the
outlet of the water, leading to a heat loss.
[0029] In the water heat exchanger of the present invention, a
structure is adopted wherein the single sparely holed flat pipe is
interposed by the two many holed flat pipes. Consequently, there is
hardly any difference between the temperature of the refrigerant
inside one of the many holed flat pipes and the temperature of the
refrigerant inside the other many holed flat pipe, which makes it
possible to produce high temperature water with hardly any drop in
the heat exchanging efficiency between the refrigerant and the
water.
[0030] In addition, the global warming coefficient of CO.sub.2
refrigerant is 1, which is approximately several hundred to ten
thousand times far lower than that of conventional refrigerants,
for example, fluorocarbon refrigerant.
[0031] Thus, the use of CO.sub.2 refrigerant, which carries only a
small environmental load, can help to reduce degradation of the
global environment.
[0032] A hot water heat source apparatus according to a tenth
aspect of the invention is a hot water heat source apparatus that
uses a refrigerant circuit, which uses a supercritical refrigerant
wherein the high pressure side of a refrigeration cycle is in the
supercritical region, and that comprises: a compressor, a water
heat exchanger, an expansion mechanism, and an evaporator. The
compressor compresses the supercritical refrigerant. The water heat
exchanger cools the supercritical refrigerant and heats water by
exchanging heat between the water and the high temperature and high
pressure supercritical refrigerant compressed by the compressor.
The expansion mechanism reduces the pressure of the supercritical
refrigerant cooled by the water heat exchanger. The evaporator
evaporates the refrigerant whose pressure was reduced by the
expansion mechanism. The water heat exchanger comprises a pair of
refrigerant pipes, a water pipe, a refrigerant inlet header, and a
refrigerant outlet header. The pair of refrigerant pipes each are a
many holed flat pipe. Each of the many holed flat pipe has a
plurality of refrigerant passageway holes wherethrough the
refrigerant can flow. The water pipe is a sparely holed flat pipe.
The sparely holed flat pipe, wherethrough the water can flow, has
fewer water passageway holes than the refrigerant pipes have
refrigerant passageway holes. The inlets of the pair of refrigerant
pipes are connected to the refrigerant inlet header. The outlets of
the pair of refrigerant pipes are connected to the refrigerant
outlet header. In a cross section, the long side surfaces of the
water pipe and one of the long side surfaces of each of the pair of
refrigerant pipes are in tight contact with one another. The water
pipe is interposed by the pair of refrigerant pipes. The
refrigerant that flows through the interior of the refrigerant
pipes and the water that flows through the interior of the water
pipe flow in mutually opposing directions.
[0033] In the hot water heat source apparatus of the present
invention, the working refrigerant is a so-called supercritical
refrigerant, wherein the high pressure side in the refrigeration
cycle is in the supercritical region. For example, if the water
heat exchanger of the present invention is adapted to a heat pump
type water heater, then the water heat exchanger functions as a
radiator. Unlike the use of a fluorocarbon based refrigerant, the
use of a supercritical refrigerant gives rise to temperature
changes over the entire area of the water heat exchanger.
[0034] In the hot water heat source apparatus of the present
invention, a structure is adopted wherein the single sparely holed
flat pipe is interposed between the two many holed flat pipes. In
the pair of refrigerant pipes, the refrigerant flows from the
refrigerant inlet header into the inlets of the pair of refrigerant
pipes, passes through the outlets of the pair of refrigerant pipes,
and then flows out from the refrigerant outlet header. The
refrigerant that flows through the interior of the refrigerant
pipes and the water that flows through the interior of the water
pipe flow in mutually opposing directions. The inlets of the many
holed flat pipes, which are the pair of refrigerant pipes, are both
connected to the refrigerant inlet header.
[0035] Accordingly, it is possible to exchange heat between the
high temperature refrigerant, which flows from the refrigerant
inlet header into the pair of the refrigerant pipes, and the water
inside the water pipe. Consequently, unlike the case wherein, for
example, one refrigerant pipe that has been folded into a zigzag
and one water pipe are combined, the amount of heat dissipated from
the water pipe into the atmosphere is small and virtually no
temperature differences arise in the refrigerant on both sides of
the water pipe, which makes it possible to obtain high temperature
water efficiently.
<Advantageous Effects of Invention>
[0036] In the water heat exchanger according to the first through
third aspects of the invention, the heat exchanging efficiency
between the refrigerant and the water can be improved.
[0037] In the water heat exchanger according to the fourth aspect
of the invention, the refrigerant pipes or the water pipe, or both,
can be formed easily.
[0038] In the water heat exchanger according to the fifth aspect of
the invention, the prescribed fabrication can be performed easily
on the sparely holed flat pipe.
[0039] In the water heat exchanger according to the sixth aspect of
the invention, the flat pipe can be formed after performing some
kind of fabrication on the flat plate.
[0040] In the water heat exchanger according to the seventh aspect
of the invention, turbulence can be created in the flow of water
inside the sparely holed flat pipe, which promotes water
convection; furthermore, the sparely holed flat pipe can be shaped
so as to promote heat exchange efficiency.
[0041] In the water heat exchanger according to the eighth aspect
of the invention, it is possible to secure a temperature
differential between the refrigerant and the water.
[0042] In the water heat exchanger according to the ninth aspect of
the invention, the use of CO.sub.2 refrigerant, which carries only
a small environmental load, can help to reduce degradation of the
global environment.
[0043] In the water heat exchanger according to the tenth aspect of
the invention, it is possible to obtain high temperature water
efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a system diagram of a heat pump type hot water
supplying apparatus that comprises a refrigeration apparatus
according to a first embodiment.
[0045] FIG. 2 is a cross sectional view that shows the internal
structure of the refrigeration apparatus.
[0046] FIG. 3 is a block diagram of a control apparatus of the
refrigeration apparatus.
[0047] FIG. 4 is an oblique view that shows the configuration of a
water heat exchanger of the refrigeration apparatus.
[0048] FIG. 5(a) is a schematic diagram that shows a portion of a
refrigerant inlet header and a water outlet header of the water
heat exchanger.
[0049] FIG. 5(b) is a schematic diagram that shows a portion of a
refrigerant outlet header and a water inlet header of the water
heat exchanger.
[0050] FIG. 6 is a cross sectional view of the water heat
exchanger.
[0051] FIG. 7 is a schematic diagram of a water heat exchanger
joining method.
[0052] FIG. 8 is an internal piping diagram of the water heat
exchanger according to a modified example (1).
[0053] FIG. 9 is a schematic diagram of a water heat exchanger
joining method according to a modified example (4).
[0054] FIG. 10 is a cross sectional view of the water heat
exchanger according to a modified example (7).
[0055] FIG. 11 is a diagram that shows a process of forming
protruding parts by embossing a flat plate according to a modified
example (8).
[0056] FIG. 12 is a diagram that shows a process of forming a
single hole flat pipe by bending the flat plate formed with the
protruding parts according to the modified example (8).
[0057] FIG. 13 is a diagram that shows a process of forming a
single hole flat pipe by bending the flat plate formed with the
protruding parts according to a modified example (9).
[0058] FIG. 14 is a schematic diagram of a water heat exchanger
joining method according to a modified example (10).
[0059] FIG. 15 is a hot water circulation system that comprises a
refrigeration apparatus according to a second embodiment.
DESCRIPTION OF EMBODIMENTS
<1> First Embodiment
<Configuration of a Heat Pump Type Hot Water Supplying
Apparatus>
[0060] FIG. 1 shows a system of a heat pump type hot water
supplying apparatus that comprises a refrigeration apparatus
according to a first embodiment. A heat pump type hot water
supplying apparatus 1 comprises a refrigeration apparatus 2, which
is a hot water heat source apparatus, and a hot water storage
apparatus 3. The refrigeration apparatus 2 comprises a compression
type refrigerant circuit 20 wherein a compressor 21, refrigerant
pipes 22a inside a water heat exchanger 22, an expansion valve 23
that serves as a pressure reducing means, and an air heat exchanger
24 are connected in a ring by a refrigerant piping 25.
[0061] Furthermore, a gas heat exchanger 26, which is for
exchanging heat between a high pressure and high temperature
refrigerant that exits the water heat exchanger 22 and a low
pressure and low temperature refrigerant that exits the air heat
exchanger 24, is disposed in the refrigerant circuit 20.
Specifically, heat is exchanged between a refrigerant passageway
that links the water heat exchanger 22 and the expansion valve 23
and a refrigerant passageway that links the air heat exchanger 24
and the compressor 21.
[0062] The hot water storage apparatus 3 comprises a water
circulation circuit 30, wherein a hot water storage tank 31, a
water pipe 22b inside the water heat exchanger 22, and a water
circulating pump 32 are connected in a ring by a water piping
35.
[0063] The refrigeration apparatus 2 is provided with an outdoor
air temperature sensor 8, which detects the outdoor air temperature
of the installation location, a discharge pipe temperature sensor
9, which detects the discharge pipe temperature of the compressor
21, and a temperature sensor 10, which detects the temperature of
the air heat exchanger 24; furthermore, the detection signals of
these sensors are input to a microcontroller 6.
[0064] The water circulating pump 32 controls the amount of
circulation of the water such that the temperature of the water
heated by the water heat exchanger 22 is, for example, 85.degree.
C. The microcontroller 6 controls the opening degree of the
expansion valve 23 to secure the refrigerant temperature needed to
obtain water of 85.degree. C.
<Structure of Refrigeration Apparatus>
[0065] FIG. 2 is a cross sectional view that shows the internal
structure of the refrigeration apparatus 2. In FIG. 2, the section
on the right side of a heat insulating wall 2c is a machine chamber
2a, and the section on the left side of the heat insulating wall 2c
is a fan chamber 2b. The compressor 21 and the expansion valve 23
are disposed in the machine chamber 2a.
[0066] In the front view of FIG. 2, a fan 27 is disposed in and to
the front of the fan chamber 2b. A motor that drives the fan 27 is
disposed behind the fan 27 in the state wherein the motor is fixed
to a motor support platform 28. The water heat exchanger 22 is
disposed below the fan chamber 2b separated by a heat insulating
wall 2d. Inside the water heat exchanger 22, heat is exchanged
between the refrigerant that flows through the refrigerant pipes
22a (refer to FIG. 1) and the water that flows through the water
pipe 22b (refer to FIG. 1).
[0067] In addition, in FIG. 2, the air heat exchanger 24 is
disposed along a left side wall and a rear surface wall of the fan
chamber 2b, and a right end of the air heat exchanger 24 protrudes
as far as the center of the machine chamber 2a. A control box 4 is
disposed such that it spans an upper part of the machine chamber 2a
and an upper part of the fan chamber 2b. A control apparatus 5,
wherein the microcontroller 6 (refer to FIG. 3) and an inverter 7
(refer to FIG. 3) are installed, is built into the control box
4.
<Controlling the Operation of the Refrigeration
Apparatus>
[0068] FIG. 3 is a control block diagram of the refrigeration
apparatus 2. In the microcontroller 6, a target discharge pipe
temperature setting unit 62 sets a target discharge pipe
temperature based on detection signals from the outdoor air
temperature sensor 8 and the temperature sensor 10 of the air heat
exchanger 24. Furthermore, the microcontroller 6 controls the
opening degree of the expansion valve 23 via an expansion valve
opening degree control unit 63 such that the discharge pipe
temperature detected by the discharge pipe temperature sensor 9
approaches the target discharge pipe temperature. Furthermore, data
needed to set the target discharge pipe temperature is prestored
inside the target discharge pipe temperature setting unit 62.
[0069] Furthermore, the microcontroller 6 controls the operating
frequency of the compressor 21 via an inverter control unit 64,
taking into consideration the effect that the outdoor air
temperature has upon the fire-up capability of the refrigeration
apparatus 2 as well as the fact that the hot water supply load
varies with the time of day. For example, to prevent hot water from
running out at a time when the outdoor air temperature is low and
the hot water supply load is large, the operating frequency of the
compressor 21 is increased, ignoring efficiency. Moreover, at a
time when the outdoor air temperature is high and the hot water
supply load is small, the operating frequency of the compressor 21
may be set to a high efficiency point.
[0070] When the hot water supply load is large, the microcontroller
6 controls the operation of the compressor 21 such that, with a
view toward protecting the compressor 21, the discharge pipe
temperature does not exceed 120.degree. C. In actuality, when the
discharge pipe temperature is 120.degree. C., the internal
temperature of the compressor 21 reaches 140-145.degree. C.;
furthermore, if the internal temperature rises and exceeds
150.degree. C., then the magnetic force of the internal magnet of
the compressor 21 will decrease and the oil will deteriorate,
leading to a breakdown. Accordingly, in the present embodiment, the
upper limit of the discharge pipe temperature is set to 120.degree.
C.
[0071] However, when an outdoor air temperature t1 is equal to or
less than -20.degree. C., then the compressor 21 tends to become
overloaded; therefore, as an additional safety measure, it is
necessary to set an ample amount of compensation for the detection
value of the discharge pipe temperature sensor 9 and to set the
detection value of the discharge pipe temperature sensor 9 to
120.degree. C. before the actual discharge pipe temperature reaches
120.degree. C. Accordingly, the amount of compensation for when the
outdoor air temperature t1 is equal to or less than -20.degree. C.
is derived empirically, and is stored in a second compensating
means 61b of a temperature compensating unit 61 of the
microcontroller 6.
[0072] Furthermore, a first compensating means 61a performs
compensation when the outdoor air temperature t1>-20.degree.
C.
<Structure of Water Heat Exchanger>
[0073] FIG. 4 is an oblique view that shows the configuration of
the water heat exchanger 22. In this figure, the water heat
exchanger 22 is represented schematically.
[0074] The water heat exchanger 22 comprises the refrigerant pipes
22a, the water pipe 22b, a refrigerant inlet header 53, a
refrigerant outlet header 54, a water inlet header 55, and a water
outlet header 56. The water heat exchanger 22 exchanges heat
between the fluid that flows through the refrigerant pipes 22a and
the fluid that flows through the water pipe 22b. As a specific
structure, the water heat exchanger 22 principally comprises: a
pair of many holed flat pipes 41A, 41B, which constitutes the
refrigerant pipes 22a; a single hole flat pipe 42, which serves as
a sparely holed flat pipe that constitutes the water pipe 22b; the
refrigerant inlet header 53; the refrigerant outlet header 54; the
water inlet header 55; and the water outlet header 56.
[0075] FIG. 5(a) is a schematic diagram that shows a portion of the
refrigerant inlet header 53 and the water outlet header 56 of the
water heat exchanger 22. FIG. 5(b) is a schematic diagram that
shows a portion of the refrigerant outlet header 54 and the water
inlet header 55 of the water heat exchanger 22. As shown in FIG.
5(a), in the water heat exchanger 22, the refrigerant inlet header
53 is connected to inlet sides of the refrigerant pipes 22a, and
the refrigerant outlet header 54 is connected to outlet sides of
the refrigerant pipes 22a. In addition, as shown in FIG. 5(b), in
the water heat exchanger 22, the water inlet header 55 is connected
to an inlet side of the water pipe 22b, and the water outlet header
56 is connected to an outlet side of the water pipe 22b. In the
water heat exchanger 22 of the present embodiment, the water heat
exchanger 22 shown in FIG. 4 is stacked in three stages (not shown)
and each of the headers 53-56 extends in its axial directions.
[0076] As shown in FIG. 6, each of the many holed flat pipes 41A,
41B comprises a flat part main body 46. Each of the flat part main
bodies 46 extends lengthwise, as shown in FIG. 4. Each of the flat
part main bodies 46 has an opposing surface 46a and an opposite
side surface 46b on the opposite side of the opposing surface 46a;
furthermore, the opposing surface 46a and the opposite side surface
46b oppose one another. Inside each of the flat part main bodies
46, a plurality of (in the present embodiment, 11) refrigerant
passageway holes 47, which are holes wherethrough the refrigerant
can flow, is formed in one row. Making the refrigerant pipe by
forming a plurality of holes in a flat pipe in this manner improves
the coefficient of heat transfer on the refrigerant side.
[0077] Each of the many holed flat pipes 41A, 41B is made of, for
example, aluminum. Furthermore, the many holed flat pipes 41A, 41B
may be manufactured by drawing, extruding, and the like.
[0078] The single hole flat pipe 42 is a member that extends along
the pair of the many holed flat pipes 41A, 41B; as can be seen in
the figure, in a cross section the single hole flat pipe 42
comprises two opposing linear portions 42a and two curved portions
42b, which connect the two linear portions 42a. Furthermore, it
also comprises one water passageway hole 48, which is different
from the many holed flat pipes 41A, 41B and wherethrough the water
is capable of flowing. The length of the linear portions 42a is the
same as that of the opposing surfaces 46a.
[0079] The single hole flat pipe 42 is made of aluminum and the
like.
[0080] As shown in FIG. 7, the many holed flat pipes 41A, 41B and
the single hole flat pipe 42 are brought into tight contact with
one another by brazing, wherein brazing filler material 49 is
interposed between the single hole flat pipe 42 and each of the
many holed flat pipes 41A, 41B. Thereby, most of the surface of the
single hole flat pipe 42 (i.e., most of the linear portions 42a)
can be brought into tight contact with the many holed flat pipes
41A, 41B, which makes it possible to maximally prevent the
dissipation of heat from the single hole flat pipe 42 to the
surrounding air.
[0081] As shown in FIG. 4, the pair of many holed flat pipes 41A,
41B is folded into a zigzag shape such that the zigs and the zags
are parallel to one another. For example, in FIG. 4, zigzag shape
refers to a shape wherein the linear portions that extend linearly
and the bent portions that are bent in a hairpin shape alternate
repeatedly and, as a result, the plurality of the linear portions
are disposed such that they are proximate to one another. In other
words, the plurality of the linear portions are disposed such that
they overlap one another. Thus, a compact structure can be achieved
because the overall shape of the water heat exchanger 22 is a
zigzag.
[0082] In the water heat exchanger 22, CO.sub.2 flows inside the
refrigerant pipes 22a, and water flows inside the water pipe 22b in
a direction that opposes that of the CO.sub.2 (refer to the solid
arrows and the broken arrow, respectively, in FIG. 5). As a result,
heat is exchanged between the fluids flowing therethrough, and
thereby the water is heated. Here, because the heat transfer area
is enlarged by the use of flat pipes, the heat exchange performance
is high.
[0083] In addition, the linear portions of each of the many holed
flat pipes 41A, 41B are adjacent to one another in the stacking
directions; however, gaps 43 are established therebetween. The size
of the gaps 43 is set such that heat is not exchanged between
portions of adjacent flat pipes (i.e., between pipes of differing
temperatures) owing to heat conduction. Thereby, the overall heat
exchanging efficiency of the water heat exchanger 22 does not
decline and, as a result, the water heat exchanger 22 can output
hot water of a high temperature. In addition, the effects of
thermal deformation can be reduced and, consequently, reliability
is improved.
<Characteristics>
[0084] (1)
[0085] The water heat exchanger 22 of the present embodiment is
configured such that the single hole flat pipe 42 is interposed by
the pair of the many holed flat pipes 41A, 41B. Furthermore, in a
cross section, the long side surfaces of the single hole flat pipe
42 interposed by the pair of the many holed flat pipes 41A, 41B are
in tight contact with the many holed flat pipes 41A, 41B.
Furthermore, the many holed flat pipes 41A, 41B and the single hole
flat pipe 42 are joined by brazing or by coating with an
adhesive.
[0086] Thus, because configuring the water heat exchanger brings
most of the periphery of the single hole flat pipe 42 into tight
contact with the many holed flat pipes 41A, 41B, it is possible to
maximally prevent any heat transmitted to the water from the
refrigerant from being transmitted to any substance surrounding the
water heat exchanger (e.g., the air around the water heat
exchanger). In addition, because the pair of many holed flat pipes
41A, 41B and the single hole flat pipe 42 are brought into tight
contact with one another along their long side surfaces, which are
flat surfaces, in a cross section, the configuration is simple and
assembly is easy. In addition, because the pair of many holed flat
pipes 41A, 41B and the single hole flat pipe 42 are joined by
brazing, it is possible to create a state wherein there is
virtually no thermal resistance between the pair of the many holed
flat pipes 41A, 41B and the single hole flat pipe 42. Consequently,
the heat exchanging efficiency between the refrigerant and the
water can be improved.
(2)
[0087] In the water heat exchanger 22 of the present embodiment,
CO.sub.2, which is a supercritical refrigerant, is used as the
working refrigerant. If a supercritical refrigerant like CO.sub.2
refrigerant is used in the heat pump type hot water supplying
apparatus 1, then the water heat exchanger 22 will function as a
radiator. Unlike the temperature of a fluorocarbon based
refrigerant, the temperature of CO.sub.2 refrigerant varies over
the entire area of the water heat exchanger. In addition, in the
water heat exchanger 22 of the present embodiment, the structure
wherein the singular single hole flat pipe 42 is interposed by the
two many holed flat pipes 41A, 41B is connected in parallel by the
headers 53-56.
[0088] Accordingly, it is possible to exchange heat between the
high temperature refrigerant, which flows from the refrigerant
inlet header 53 into the pair of the refrigerant pipes 22a, and the
water inside the water pipe 22b. Consequently, unlike the case
wherein, for example, one refrigerant pipe that has been folded
into a zigzag and one water pipe are combined, the amount of heat
dissipated from the water pipe into the atmosphere is small and
virtually no temperature differences arise in the refrigerant on
both sides of the water pipe, which makes it possible to obtain
high temperature water.
Modified Examples
[0089] The text above explains the first embodiment of the present
invention, but the present invention is not limited to the above
embodiment, and it is understood that variations and modifications
may be effected without departing from the spirit and scope of the
invention.
(1)
[0090] In the abovementioned embodiment, the water heat exchanger
22 is folded into a zigzag such that its zigs and zags are parallel
to one another as shown in FIG. 4, but the present invention is not
limited thereto; for example, as shown in FIG. 8, the water heat
exchanger 22 may have a spiral shape. Spiral shape refers to a
shape wherein, for example, in a water heat exchanger 52 in FIG. 8,
linear portions that extend linearly and right angle portions that
are bent at right angles alternate repeatedly, the bending
directions of the right angle portions are all in the same
rotational directions, and the linear portions become shorter as
the number of folded locations, namely, the right angle portions,
increases. In other words, in the spiral, too, as in the zigzag,
the plurality of the linear portions are disposed such that they
overlap one another, and thereby a compact structure can be
achieved. Furthermore, in the water heat exchanger 52, too, as in
the water heat exchanger 22 of the abovementioned embodiment, the
refrigerant inlet header 53 is connected to the inlet sides of
refrigerant pipes 52a, and the refrigerant outlet header 54 is
connected to the outlet sides of the refrigerant pipes 52a, as
shown in FIG. 5(a). In addition, in the water heat exchanger 52, as
shown in FIG. 5(b), the water inlet header 55 is connected to the
inlet side of a water pipe 52b, and the water outlet header 56 is
connected to the outlet side of the water pipe 52b.
[0091] In addition, because the angle of the folded portion (i.e.,
the bent part) is larger in the spiral water heat exchanger 52 than
in the zigzag water heat exchanger 22, it is possible to minimize
any deformation in the thickness directions of each of the flat
pipes 41, 42 at the bent parts. Consequently, in the water heat
exchanger 52 of the present modified example (1), it is possible to
reduce the amount of deformation in the cross sectional shape of
each of the flat pipes 41, 42 (particularly the single hole flat
pipe 42). Furthermore, in FIG. 8, the refrigerant pipes 52a of the
water heat exchanger 52 correspond to the refrigerant pipes 22a of
the water heat exchanger 22 in the abovementioned embodiment, and
the water pipe 52b of the water heat exchanger 52 corresponds to
the water pipe 22b of the water heat exchanger 22 in the
abovementioned embodiment.
(2)
[0092] In the abovementioned embodiment, the single hole flat pipe
42 comprises, in a cross section, two linear portions 42a and two
curved portions 42b, which connect the two linear portions 42a, but
the present invention is not limited thereto; for example, the two
portions that connect the two linear portions 42a do not have to be
curved. For example, they may be linear portions that are shorter
than the two linear portions 42a.
(3)
[0093] In the abovementioned embodiment, the 11 refrigerant
passageway holes 47 are arrayed in one row inside the flat part
main body 46 of each of the many holed flat pipes 41A, 41B, but the
present invention is not limited thereto. For example, the number
and arrangement of the holes 47 may be set arbitrarily.
(4)
[0094] In the abovementioned embodiment, the many holed flat pipes
41A, 41B and the single hole flat pipe 42 are joined by brazing,
but the present invention is not limited thereto. For example, the
surfaces of each of the many holed flat pipes 41A, 41B on the
single hole flat pipe 42 side may be coated with an adhesive 50, as
shown in FIG. 9, and the members may then be joined together;
conversely, the surfaces of the single hole flat pipe 42 on the
linear portion sides in a cross section may be coated with the
adhesive 50, and the members may then be joined together.
(5)
[0095] In the abovementioned embodiment, as shown in FIG. 4 and the
like, the two linear portions 42a of the single hole flat pipe 42
are disposed such that they are oriented in the horizontal
directions, but the present invention is not particularly limited
to those directions. For example, the two linear portions 42a may
be disposed such that they are oriented in the vertical
directions.
(6)
[0096] In the abovementioned embodiment, each of the many holed
flat pipes 41A, 41B has a many holed structure wherein the flat
pipe is formed into an integral member, but the structure is not
limited to an integral member. For example, in FIG. 10, a many
holed flat pipe 71A, which is disposed on one of the linear portion
side surfaces of the single hole flat pipe 42, comprises two,
arrayed many holed flat pipes 71a, 71b, and a many holed flat pipe
71B, which is disposed on the other linear portion side surface of
the single hole flat pipe 42, comprises two arrayed many holed flat
pipes 71c, 71d. Thus, the many holed flat pipe on one side of the
single hole flat pipe 42 may comprise a plurality of many holed
flat pipes. In addition, a single many holed flat pipe may be
formed by joining multiple capillary tubes together. However, in
the case wherein the many holed flat pipe is configured by a
plurality of members in this manner, too, it is still possible to
prevent the dissipation of heat from the single hole flat pipe 42
to the surrounding air by bringing the many holed flat pipe into
tight contact with the two linear portion side surfaces of the
single hole flat pipe 42.
(7)
[0097] In the abovementioned embodiment, the single hole flat pipe
42 is formed by extruding or drawing, but the present invention is
not limited thereto; for example, as shown in FIGS. 11, 12,
protruding parts 81 may be embossed on a flat plate 80 (refer to
FIG. 11), after which a single hole flat pipe 82, whose cross
section is flat, may be formed. FIG. 11 is a diagram that shows the
process of forming the protruding parts 81 by embossing the flat
plate 80. In so doing, the plurality of the protruding parts 81 are
distributed on the flat plate 80 at fixed intervals. In the present
modified example (7), six rows of protruding parts 81a-81f (refer
to the portions enclosed by broken lines in FIG. 11) are formed
such that they are arrayed in the direction of the water flow.
Furthermore, the first row protruding parts 81a through the third
row protruding parts 81c are disposed in a first area A1, which
forms one of the long side surfaces of the single hole flat pipe 82
in a cross section; furthermore, the fourth row protruding parts
81d through the sixth row protruding parts 81f are disposed in a
second area A2, which forms the other long side surface of the
single hole flat pipe 82 in a cross section. More specifically, the
area of the flat plate 80 from a centerline L1 (refer to the chain
line in FIG. 11) in the short side directions to a side 80a
(discussed below) is the first area A1, and the area of the flat
plate 80 from the centerline L1 to a side 80b (discussed below) is
the second area A2.
[0098] The flat plate 80, whereon the protruding parts 81 are
formed, is bent into a member 83 such that it is C shaped in a
cross section. The member 83, which is C shaped in a cross section,
is formed such that the surface of the flat plate 80, whereon the
protruding parts 81 are formed, is on the inner side (refer to FIG.
12). FIG. 12 is a diagram that shows the process of forming the
single hole flat pipe 82 by bending the flat plate 80, whereon the
protruding parts 81 are formed. Furthermore, the uppermost drawing
in FIG. 12 is a cross section taken along the XII-XII line of the
flat plate 80 in FIG. 11. Both ends of the flat plate 80, namely,
the sides 80a, 80b, are mated to one another by bending the flat
plate 80 as shown in FIG. 12. The mated side 80a and side 80b on
both ends of the flat plate 80 are joined by electro-resistance
welding. An electro-resistance welded pipe 84 joined by
electro-resistance welding is squashed from both side surfaces such
that the electro-resistance welded portion is interposed
therebetween. Furthermore, the single hole flat pipe 82, wherein
the first area A1 and the second area A2 of the flat plate 80 are
disposed on the long side surfaces of the flat pipe 82 in a cross
section such that they oppose one another, is formed.
[0099] The multiple rows of the protruding parts 81a-81f formed in
the single hole flat pipe 82 are disposed as described below. The
tips of the first row protruding parts 81a disposed in the first
area A1 and the tips of the sixth row protruding parts 81f disposed
in the second area A2 oppose one another. The tips of the second
row protruding parts 81b disposed in the first area A1 and the tips
of the fifth row protruding parts 81e disposed in the second area
A2 oppose one another. The tips of the third row protruding parts
81c disposed in the first area A1 and the tips of the fourth row
protruding parts 81d disposed in the second area A2 oppose one
another. Namely, the protruding parts 81a-81c formed in the first
area A1 and the protruding parts 81d-81f formed in the second area
A2 are disposed at positions at which they mate with one
another.
[0100] Thereby, by bending the single hole flat pipe 82, the tips
of the protruding parts 81a-81c and the tips of the protruding
parts 81d-81f mate with one another even if the single hole flat
pipe 82 deforms in the thickness directions. Consequently, it is
possible to minimize any deformation and crushing of the single
hole flat pipe 82 in the thickness directions. In addition,
providing the protruding parts 81 inside the single hole flat pipe
82 produces turbulence in the flow of water, which makes it
possible to improve the coefficient of heat transfer.
(8)
[0101] In the modified example (7), the single hole flat pipe 82
has a structure that reduces deformation by the embossing of the
flat plate 80, but methods other than embossing can also be used.
For example, as shown in FIG. 13, a single hole flat pipe 92 may be
formed by bending a flat plate 90. The flat plate 90 is bent in its
short side directions, and thereby a member 93 (refer to the
drawing in the middle in FIG. 13), whose cross section is B shaped,
is formed such that sides 90a, 90b on both ends of the flat plate
90 face the inside of the single hole flat pipe 92. In so doing,
portions in the vicinities of the sides 90a, 90b on both ends of
the flat plate 90 become support parts 91, which extend along the
direction of water flow in the single hole flat pipe 92.
Furthermore, in the member 93, whose cross section is B shaped, the
single hole flat pipe 92 is formed by pinching the portions at
which the support parts 91 are formed and the side surface on the
opposite side thereof, and then crushing the member 93, whose cross
section is B shaped, from both side surfaces. By performing the
fabrication described above, the single hole flat pipe 92, wherein
the support parts 91 are formed in order to reduce deformation, may
be formed. Furthermore, in this case, the portion at which the two
support parts 91 contact one another does not have to be joined by
electro-resistance welding and the like, as described in the
modified example (7) discussed above. This is because, in this
single hole flat pipe 92, even if the process of joining by
electro- resistance welding and the like is not performed, the
single hole flat pipe 92 is interposed between the many holed flat
pipes 41A, 41B and brazed, and thereby the water passageway holes
are formed.
[0102] Thus, providing the support parts 91 to the single hole flat
pipe 92 makes it possible for the support parts 91 to minimize
deformation of the single hole flat pipe 92 even if deformation
should occur owing to bending of the single hole flat pipe 92 in
its thickness directions. Furthermore, in the modified example (8),
the single hole flat pipe 92 has one water passageway hole, but
that water passageway hole may be divided into two water passageway
holes by the support parts 91. Thus, in a case wherein the support
parts 91 divide the water passageway hole into two water passageway
holes, the water pipe 22b would become the two holed flat part
92.
(9)
[0103] In modified examples (7), (8), no particular reference is
made to whether the material of the flat plates 80, 90 is
monolayered or multilayered. However, as shown in FIG. 14, for
example, a material that is pre-clad with brazing filler materials
85b, 95b (i.e., a cladding material), which is an alloy whose
melting point is lower than that of base materials 85a, 95a of the
flat plates 80, 90, may be used on one surface or both surfaces of
the flat plates 80, 90, and thereby the single hole flat pipes 82,
92 may be formed; at least their outer surface sides are clad with
the brazing filler materials 85b, 95b. Furthermore, in the many
holed flat pipes 41A, 41B shown in FIG. 14, parts that are the same
as those in the abovementioned embodiment are assigned the same
symbols.
[0104] Thereby, because the material on the outer surface sides of
the single hole flat pipes 82, 92 consists of the brazing filler
materials 85b, 95b, the outer surface sides can be brazed as in the
abovementioned embodiment without separately interposing the
brazing filler materials 49 between the single hole flat pipe 42
and each of the many holed flat pipes 41A, 41B. In addition,
although not shown, it is also possible to make the structure of
the single hole flat pipes 82, 92 such that corrosion owing to
water is prevented inside the single hole flat pipes 82, 92 by, for
example, coating the inner surface sides of the single hole flat
pipes 82, 92 with a coating agent for corrosion prevention or by
using a material that has a three- layer structure that
incorporates a material resistant to corrosion by water.
Furthermore, in FIG. 14, for the sake of explanatory convenience,
the protruding parts 81, the support parts 91, and the like are
omitted.
(10)
[0105] In the abovementioned embodiment, the many holed flat pipes
41A, 41B and the single hole flat pipe 42 are brought into tight
contact with one another by hard soldering, wherein the brazing
filler materials 49 are interposed between the single hole flat
pipe 42 and each of the many holed flat pipes 41A, 41B, after which
brazing (i.e., in-furnace brazing) is performed; however, the
brazing method is not limited thereto; for example, soft soldering,
wherein, for example, solder is used as the brazing filler
material, may be performed; furthermore, even in the case of hard
soldering, the brazing method may be induction brazing, resistance
brazing, atmosphere brazing, vacuum brazing, infrared brazing,
preplaced brazing, aluminum brazing using a high frequency heating
apparatus (e.g., ultrasonic soldering), and the like.
<2> Second Embodiment
<Configuration of Hot Water Circulation System>
[0106] FIG. 15 is a schematic block diagram of a hot water
circulation system 101 according to a second embodiment of the
present invention.
[0107] The hot water circulation system 101 comprises a heat pump
circuit 110, a hot water circulation circuit 160, a hot water
supply circuit 190, an intermediate pressure water heat exchanger
140, and a high pressure water heat exchanger 150. The hot water
circulation system 101 uses the heat obtained by the heat pump
circuit 110 not only as the heat for heating via the hot water
circulation circuit 160 but also as the heat for supplying hot
water via the hot water supply circuit 190. Furthermore, the heat
pump circuit 110 is provided to a heat pump apparatus 102, which is
a hot water heat source apparatus.
(Water Heat Exchangers)
[0108] The intermediate pressure water heat exchanger 140 and the
high pressure water heat exchanger 150 exchange heat between the
CO.sub.2 refrigerant, which serves as the primary refrigerant and
circulates through the heat pump circuit 110, and the water, which
serves as the secondary refrigerant and circulates through the hot
water circulation circuit 160. Furthermore, a configuration the
same as that of, for example, the water heat exchanger 22 in the
first embodiment and the water heat exchanger 52 in the modified
example (1) is adopted for the intermediate pressure water heat
exchanger 140 and the high pressure water heat exchanger 150.
(Heat Pump Circuit)
[0109] The heat pump circuit 110 uses CO.sub.2 refrigerant, which
is a natural refrigerant, as the primary refrigerant. The heat pump
circuit 110 comprises a low pressure stage compressor 121, a high
pressure stage compressor 125, an economizer heat exchanger 107, an
injection passageway 170, a primary refrigerant heat exchanger 108,
a primary bypass 180, an expansion valve 105a, an evaporator 104, a
fan 104f, and a control unit 111. The evaporator 104 is installed,
for example, in the outdoor space.
[0110] The intermediate pressure water heat exchanger 140 is
connected to the discharge side of the low pressure stage
compressor 121 and the intake side of the high pressure stage
compressor 125. In addition, refrigerant piping from the injection
passageway 170 (discussed below) joins with the refrigerant piping
between a downstream side end part of the intermediate pressure
water heat exchanger 140 and the intake side of the high pressure
stage compressor 125.
[0111] The high pressure water heat exchanger 150 is connected to
the discharge side of the high pressure stage compressor 125 and an
upstream side end part in the flow direction of the primary
refrigerant that flows toward the expansion valve 105a side via the
primary refrigerant heat exchanger 108. The downstream side end
part of the economizer heat exchanger 107 in the flow direction of
the primary refrigerant that flows toward the expansion valve 105a
side is connected to the upstream side end part of the primary
refrigerant heat exchanger 108 in the flow direction of the primary
refrigerant that flows toward the expansion valve 105a.
[0112] The primary refrigerant heat exchanger 108 exchanges heat
between the primary refrigerant that exits the economizer heat
exchanger 107 and flows toward the expansion valve 105a and the
refrigerant after it has been evaporated by the evaporator 104.
Furthermore, in the primary refrigerant heat exchanger 108, the
passageway wherethrough the former refrigerant flows is a primary
heat exchange high pressure side passageway 108a, and the
passageway wherethrough the latter refrigerant flows is a primary
heat exchange low pressure side passageway 108b. In the primary
refrigerant heat exchanger 108, the downstream side end part of the
primary heat exchange high pressure side passageway 108a is
connected to the expansion valve 105a. In addition, in the primary
refrigerant heat exchanger 108, the upstream side end part of the
primary heat exchange low pressure side passageway 108b is
connected to the downstream side end part of the evaporator 104,
and the downstream side end part of the primary heat exchange low
pressure side passageway 108b is connected to the intake side of
the low pressure stage compressor 121.
[0113] The expansion valve 105a is connected to the upstream side
end part of the evaporator 104.
[0114] The downstream side end part of the evaporator 104 is
connected to the intake side of the low pressure stage compressor
121 via the primary heat exchange low pressure side passageway 108b
of the primary refrigerant heat exchanger 108.
[0115] The injection passageway 170 is a refrigerant piping that
branches from the refrigerant piping between the refrigerant piping
downstream side end part of the high pressure water heat exchanger
150 and the economizer heat exchanger 107. The injection passageway
170 comprises an injection expansion valve 173. The economizer heat
exchanger 107 exchanges heat between the refrigerant that flows
through the injection passageway 170 and whose pressure is reduced
by the injection expansion valve 173 and the refrigerant whose heat
was dissipated by the high pressure water heat exchanger 150.
Namely, after the pressure of the refrigerant that flows through
the injection passageway 170 is reduced by the injection expansion
valve 173, the economizer heat exchanger 107 exchanges heat between
that refrigerant and the refrigerant on the high pressure side, and
that refrigerant then merges with the intake side of the high
pressure stage compressor 125.
[0116] Thus, in the heat pump circuit 110, the adoption of the
injection passageway 170 makes it possible to improve the
coefficient of performance of the heat pump circuit 110.
Furthermore, if, for example, the heating load is small and
therefore even if a cooling effect of the primary refrigerant
sufficient to improve the efficiency of the heat pump circuit 110
cannot be obtained in the intermediate pressure water heat
exchanger 140, operation efficiency can be improved by increasing
the amount of injection passing through the injection passageway
170. Furthermore, in the heat pump circuit 110, the injection
passageway 170 joins the passageway between the intermediate
pressure water heat exchanger 140 and the high pressure stage
compressor 125, and consequently the high temperature primary
refrigerant discharged from the low pressure stage compressor 121
can be supplied to, without being cooled prior to reaching, the
intermediate pressure water heat exchanger 140, thereby maintaining
the high temperature state as is. Consequently, the temperature of
the water for heating that passes through the intermediate pressure
water heat exchanger 140 can be made sufficiently high.
[0117] The primary bypass 180 functions as a bypass between the
refrigerant piping that is between the downstream side end part of
the economizer heat exchanger 107 and the upstream side end part of
the primary heat exchange high pressure side passageway 108a of the
primary refrigerant heat exchanger 108 and the refrigerant piping
that is between the expansion valve 105a and the upstream side end
part of the evaporator 104. A primary bypass expansion valve 105b
is provided to the primary bypass 180.
[0118] Thus, because the primary bypass expansion valve 105b is
provided to the primary bypass 180, the control unit 111 can
regulate the amount of the primary refrigerant that passes through
on the primary refrigerant heat exchanger 108 side. Consequently,
the primary refrigerant taken in by the low pressure stage
compressor 121 can be regulated such that the primary refrigerant
has an appropriate degree of superheating. Specifically, if the
control unit 111 reduces the valve opening degree of the primary
bypass expansion valve 105b, the flow volume of the primary
refrigerant that passes through the primary refrigerant heat
exchanger 108 will increase, which makes it possible to increase
the degree of superheating of the primary refrigerant taken in by
the low pressure stage compressor 121; thereby, it is possible to
reduce the compression ratio needed to make the discharge
refrigerant temperature of the low pressure stage compressor 121
reach the target temperature. In addition, if the control unit 111
increases the valve opening degree of the primary bypass expansion
valve 105b, then the flow volume of the primary refrigerant that
passes through the primary refrigerant heat exchanger 108 will
decrease, which makes it possible to reduce the degree of
superheating of the primary refrigerant taken in by the low
pressure stage compressor 121; thereby, it is possible to avoid the
situation wherein the density of the refrigerant taken into the low
pressure stage compressor 121 decreases markedly, making it
impossible to ensure the required amount of circulation.
[0119] Based on values detected by various sensors (not shown) and
the like, the control unit 111 controls the low pressure stage
compressor 121, the high pressure stage compressor 125, the
injection expansion valve 173, the expansion valve 105a, the
primary bypass expansion valve 105b, the fan 104f, and the
like.
(Hot Water Circulation Circuit)
[0120] Water, which serves as the secondary refrigerant, circulates
in the hot water circulation circuit 160. The hot water circulation
circuit 160 comprises radiators 161, a hot water pump 163, a hot
water mixing valve 164, a hot water feed pipe 165, a hot water
return pipe 166, an intermediate pressure side branch passageway
167, a high pressure side branch passageway 168, a hot water
storage tank 191, a hot water branching valve 192, and a hot water
supply side branch passageway 195.
[0121] The hot water branching valve 192 divides the flow of the
hot water heated by the intermediate pressure water heat exchanger
140 or the high pressure water heat exchanger 150 between the
radiators 161 and the hot water storage tank 191 in accordance with
their thermal loads.
[0122] The radiators 161 are installed in the space to be heated,
and heating is performed by warming the air of the target space
using the flow of the warm water, which serves as the secondary
refrigerant, inside the target space. Although not shown, each of
the radiators 161 has a feed port, which is for receiving the warm
water delivered from the hot water pump 163, and a return port,
which is for delivering the water after its heat has been
dissipated in the radiator 161 to the intermediate pressure water
heat exchanger 140 and the high pressure water heat exchanger 150.
The hot water return pipe 166 is connected to the return port of
each of the radiators 161.
[0123] A hot water supply heat exchanging part 191a inside the hot
water storage tank 191 exchanges heat between the water flowed from
the hot water supply side branch passageway 195 and the water for
the hot water supply stored inside the hot water storage tank 191,
and heat is dissipated by the heating of the water for the hot
water supply. The hot water return pipe 166 is connected to a
circulation return port of the hot water storage tank 191, and the
water whose heat was dissipated by the hot water supply heat
exchanging part 191a merges with the water in the hot water return
pipe 166. Here, although not shown, a circulation feed port and a
circulation return port are provided to the hot water storage tank
191.
[0124] In the hot water return pipe 166, the water whose heat has
been dissipated in the radiators 161 or the hot water storage tank
191 is diverged to the intermediate pressure side branch passageway
167, which delivers the water to the intermediate pressure water
heat exchanger 140 side, and the high pressure side branch
passageway 168, which delivers the water to the high pressure water
heat exchanger 150 side.
[0125] In the hot water storage tank 191, room temperature water
delivered from an external municipal water service (not shown) via
a water supply pipe 194 is supplied from the vicinity of a lower
end part of the hot water storage tank 191 to the interior of the
hot water storage tank 191.
[0126] A hot water supply pipe 198 guides the hot water that has
accumulated inside the hot water storage tank 191 from the vicinity
of an upper end part of the hot water storage tank 191 to a
location at which it is to be used (not shown). The hot water
supply pipe 198 directs the flow from the hot water storage tank
191 toward the location at which it is used. In the water supply
pipe 194, the flow toward the hot water storage tank 191 side is
diverged by a hot water supply bypass pipe 199. The hot water
supply bypass pipe 199 is connected to a hot water supply mixing
valve 193, whereto the hot water supply pipe 198 is provided. The
hot water supply mixing valve 193 can regulate the mixing ratio
between the hot water that is delivered from the hot water storage
tank 191 via the hot water supply pipe 198 and the room temperature
water that is supplied from the municipal water service via the hot
water supply bypass pipe 199. The temperature of the water
delivered to the usage location is regulated by the hot water
supply mixing valve 193 regulating the mixing ratio.
[0127] The water diverged to the intermediate pressure side branch
passageway 167 is heated by the intermediate pressure water heat
exchanger 140 exchanging heat between that water and the CO.sub.2
refrigerant, which is the primary refrigerant, after which that
water merges with the water in the hot water feed pipe 165 via the
hot water mixing valve 164. Here, in the intermediate pressure
water heat exchanger 140, the CO.sub.2 refrigerant, which serves as
the primary refrigerant, and the water, which serves as the
secondary refrigerant for heating and hot water supply, flow in
mutually opposing directions.
[0128] The water diverged to the high pressure side branch
passageway 168 is heated by the high pressure water heat exchanger
150 exchanging heat between that water and the CO.sub.2
refrigerant, which is the primary refrigerant, after which that
water merges with the water in the hot water feed pipe 165 via the
hot water mixing valve 164. Here, in the high pressure water heat
exchanger 150, the CO.sub.2 refrigerant, which serves as the
primary refrigerant, and the water, which serves as the secondary
refrigerant for heating and hot water supply, flow in mutually
opposing directions.
[0129] Furthermore, based on, for example, the temperature detected
by the various sensors and the like, the control unit 111 controls
the diverging ratio of the hot water mixing valve 164 and the flow
volume of the hot water pump 163, or controls the diverging ratio
of the hot water branching valve 192 such that secondary
refrigerant of the required temperature can be supplied to the
radiators 161.
<Characteristics>
[0130] Unlike the first embodiment, the intermediate pressure water
heat exchanger 140 and the high pressure water heat exchanger 150
according to the second embodiment are used in a closed circuit,
wherethrough water circulates as the secondary refrigerant.
Consequently, mixing a corrosion prevention agent into the water
that circulates as the secondary refrigerant makes it possible to
prevent corrosion of the water heat exchangers 22, 52 (particularly
the water pipes 22b, 52b), even if the inner surfaces of the water
pipes 22b, 52b in particular do not undergo a corrosion prevention
process.
INDUSTRIAL APPLICABILITY
[0131] The water heat exchanger according to the present invention
is used as a water heat exchanger that can prevent a decrease in
heat exchanging efficiency, can be configured simply, and can
exchange heat between a refrigerant and water.
REFERENCE SIGNS LIST
[0132] 2 Refrigeration apparatus [0133] 20 Refrigerant circuit
[0134] 21 Compressor [0135] 22, 52 Water heat exchangers [0136]
22a, 52a Refrigerant pipes [0137] 22b, 52b Water pipes [0138] 23
Expansion valve (expansion mechanism) [0139] 24 Air heat exchanger
(evaporator) [0140] 41A, 41B, 71A, 71B Many holed flat pipes [0141]
42, 82, 92 Single hole flat pipes (sparely holed flat pipes) [0142]
47 Refrigerant passageway hole [0143] 48 Water passageway hole
[0144] 49 Brazing filler material [0145] 50 Adhesive [0146] 53
Refrigerant inlet header [0147] 54 Refrigerant outlet header [0148]
55 Water inlet header [0149] 56 Water outlet header [0150] 80, 90
Flat plates [0151] 80a, 80b Sides on both ends (two sides) [0152]
102 Heat pump apparatus [0153] 104 Evaporator [0154] 105a Expansion
valve (expansion mechanism) [0155] 105b Primary bypass expansion
valve (expansion mechanism) [0156] 110 Heat pump circuit
(refrigerant circuit) [0157] 121 Low pressure stage compressor
(compressor) [0158] 125 High pressure stage compressor (compressor)
[0159] 140 Intermediate pressure water heat exchanger (water heat
exchanger) [0160] 150 High pressure water heat exchanger (water
heat exchanger)
Citation List
Patent Literature
Patent Document 1
[0161] Japanese Unexamined Patent Application Publication No.
2004-218946
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