JP3044868B2 - Heat transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer apparatus for transferring heat to a use side by utilizing pressure at the time of heating a refrigerant as a heat medium during heating.

[0002]

2. Description of the Related Art Conventionally, as a heat transfer apparatus for heating by this type of refrigerant heating, for example, Japanese Patent Application Laid-Open No. 57-101263.
As shown in the publication, there is a configuration as shown in FIG.

That is, a compressor 41, a flow path switching valve 42,
An outdoor heat exchanger 44 having an outdoor blower 43, a first electromagnetic valve 45, a capillary tube 46, an indoor heat exchanger 48 having an indoor blower 47, a second electromagnetic valve 49, a check valve 50, and an accumulator 51 are sequentially piped. Construct a circuit. Further, a series piping circuit of a refrigerant heater 55 having a third electromagnetic valve 52, a refrigerant pump 53, and a burner 54 is connected between the downstream of the capillary tube 46 and the upstream of the second electromagnetic valve 49. In the heating operation, the refrigerant heater 55 is heated by the burner 54 to serve as an evaporator, the indoor heat exchanger 48 is used as a condenser, and a refrigerant pump is used as a refrigerant conveying means to constitute a heating cycle. It constitutes the cooling cycle of the system.

[0004] As another conventional heat transfer device for heating by heating a refrigerant, cooling is performed by a conventional method driven by a compressor, and heating is performed by using the compressor for cooling as a refrigerant gas pump. (Not shown)

[0005]

However, in the above configuration, a refrigerant pump or a compressor must be driven as a transport means for circulating the refrigerant during the heating operation, and a relatively large power for heat transport is required. It consumes electric input and has a heating capacity of about 4000 Kcal / h and a refrigerant pump of 50
There is a problem that the heating running cost is increased by about 60 to 60 W and about 300 to 400 W by the compressor.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to minimize heat transfer power during heating and to enable a stable heating operation.

[0007]

In order to solve the above-mentioned problems, a heat transfer device according to the present invention comprises an annular passage formed by pipe connection of a refrigerant heater having a burner and a gas-liquid separator provided above the refrigerant heater. A liquid receiver provided above the gas-liquid separator, a first check valve connecting the liquid receiver and the gas-liquid separator, and a second pressure equalizing pipe provided in the gas-liquid separator and the liquid receiver. A heating circuit in which an indoor heat exchanger is connected to a refrigerant pipe to a refrigerant heating and heat transfer unit having a first on-off valve and a second check valve provided upstream of the liquid receiver; A cooling circuit having an outdoor heat exchanger and a compressor additionally connected to the leverage heating circuit, and a supercooling degree of the liquid refrigerant passing through the second check valve by the opening / closing operation cycle of the first opening / closing valve at the time of the maximum combustion of the burner. 20deg ℃ -40de
An opening / closing control device for setting the temperature in the range of g ° C. is provided.

[0008]

According to the heat transfer device of the present invention, the liquid refrigerant filled in the receiver by the opening operation of the first on-off valve communicating with the receiver is connected to the gas-liquid connected to the refrigerant heater by the annular passage. The saturated gas refrigerant in the receiver is pushed by the evaporation pressure generated in the refrigerant heater by the closing operation and the cooling operation of the supercooled liquid refrigerant that has entered through the second check valve. It condenses, and the new liquid refrigerant is drawn into the receiver by the rapid depressurizing action at the time of the condensation. The opening / closing cycle of the first on-off valve includes a change in the length of a refrigerant pipe connecting the indoor heat exchanger and the refrigerant heating / transporting section, a change in the amount of refrigerant charged in the heat transporting apparatus, a setting variation in a burner combustion amount, The supercooling degree of the liquid refrigerant passing through the second check valve is set in the range of 20 ° C. to 40 ° C. in various fluctuation ranges of the heat transfer operation conditions such as the change of the atmosphere temperature and the flow rate of the indoor heat exchanger. By setting the opening / closing time, stable heating operation that does not cause abnormal overheating can be realized with very little heat transfer power regardless of the above-mentioned various fluctuation factors.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a refrigerant heater, 2 is a gas-liquid separator provided above the refrigerant heater 1, and 3 is a refrigerant heater 1 and a gas-liquid separator 2
, A liquid receiver provided above the gas-liquid separator 2, a first check valve provided in a pipe connecting the liquid receiver 4 and the gas-liquid separator 2. A valve, 6 is a first opening / closing valve provided in a pressure equalizing pipe 7 communicating with the gas-liquid separator 2 and the liquid receiver 4, 8 is an indoor heat exchanger having an indoor blower 9, and 10 is a gas-liquid separator 2 and a chamber. A gas refrigerant pipe connecting the inner heat exchanger 8, a liquid refrigerant pipe 11 connecting the indoor heat exchanger 8 and the receiver 4, 1
2 is a second check valve provided near the upstream side of the inlet of the liquid receiver 4 of the liquid refrigerant pipe 11, 13 is a third check valve provided on the gas refrigerant pipe 10 on the side of the gas-liquid separator 2, and 14 is A burner 15 provided in the refrigerant heater 1 is a fuel flow control unit for the burner 14, 16.
Is a temperature detector provided on the refrigerant outlet side of the refrigerant heater 1 in the annular passage 3, and 17 is an opening / closing control device electrically connected to the first opening / closing valve 6, the temperature detector 16, and the flow control unit 15.

Reference numeral 18 denotes an outdoor heat exchanger 21 having a compressor 19, an outdoor blower 20, a first pressure reducing device 22, and a second on-off valve 2.
3, one end of which is connected to the gas refrigerant pipe 10 via the flow path switching valve 24 and the compressor 19
Of the gas refrigerant pipe 1 through the fourth check valve 26 through the discharge pipe 25
0 is connected between the third check valve 13 and the flow path switching valve 24 composed of a four-way valve. The other end of the cooling circuit 18 is the refrigerant heater 1
And the pressure equalizing pipe 7. 27 connects the inlet side of the refrigerant heater 1 of the annular passage 3 to the liquid refrigerant pipe 11 and connects the third on-off valve 2
8 and a cooling circuit having a second pressure reducing device 29.

The remaining refrigerant circuit except for the cooling circuits 18 and 27 is the heating circuit among all the refrigerant circuits connected by piping. 30 is a gas side service valve provided in the gas refrigerant pipe 10, 31 is a liquid side service valve provided in the liquid refrigerant pipe 11, 32 is a gas side joint provided on the indoor heat exchanger 8 side of the gas refrigerant pipe 10, 33 Is a liquid-side joint provided on the indoor heat exchanger 8 side of the liquid refrigerant pipe 11, and is a gas-side and liquid-side service valve 3.
The length of the connecting refrigerant pipe between 0, 31 and the gas-side and liquid-side joints 32, 33 can be arbitrarily set according to the installation distance between the outside and the inside of the room.

In the above configuration, the heating is performed by the refrigerant heater 1.
The liquid refrigerant heated by the combustion heat in the burner 14 flows into the gas-liquid separator 2 in a gas-liquid two-phase state, and the liquid refrigerant flows into the refrigerant heater 1 again from below the gas-liquid separator 2. On the other hand, the gas refrigerant separated into gas and liquid flows into the inner heat exchanger 8 through the gas refrigerant pipe 10, and the refrigerant radiated to the indoor side by the operation of the indoor blower 9 is condensed and liquefied to further become a supercooled liquid. When the first opening / closing valve 6 of the pressure equalizing pipe 7 communicating with the liquid receiver 4 is closed by the opening / closing control device 17, the supercooled liquid pushed by the evaporation pressure in the refrigerant heater 1 passes through the second check valve 12. The saturated gas refrigerant in the receiver 4 slightly flows into the receiver 4 and is cooled and condensed by the slightly cooled supercooled liquid. The cooling liquid refrigerant flows at once, and fills the inside of the liquid receiver 4. Next, when the first opening / closing valve 6 is opened by the opening / closing control device 17, the pressure of the liquid receiver 4 and the gas-liquid separator 2 is communicated by the equalizing pipe 7 to become the same pressure, and the liquid refrigerant in the liquid receiver 4 is vaporized by gravity. Liquid separator 2
And the liquid refrigerant is supplied to the refrigerant heater 1. This
By repeating the closing and opening of the first on-off valve 6,
The refrigerant is circulated by repeating the inflow and outflow of the liquid refrigerant to the receiver 4.
Ring. If an electromagnetic valve is used for the first on-off valve 6, the refrigerant
The conveying power for circulating need only power consumption of the solenoid valve, can be circulated refrigerant in the order of substantially 3~4Wh small conveying power by opening and closing operation of the solenoid valve about the rated input 7W.

On the other hand, cooling is performed by switching the flow path switching valve 24 in the direction of the dashed line in FIG. 1 and opening the second opening / closing valve 23 and the third opening / closing valve 28 and operating the compressor 19 and the indoor / outdoor blowers 9 and 20. Cooling driven by the electric compressor is performed.

As described above, it is necessary to satisfy the characteristics of both heating and cooling.
It is necessary to employ a refrigerant having a relatively small specific volume at the time of gas or the like and a small pressure loss.

The operation characteristics during the heating operation when a refrigerant that also satisfies the cooling characteristics is used will be described.

The main changes in the heat transfer operating conditions are as follows:
Changes in the length of the connected refrigerant pipes connecting the indoor and outdoor areas (hereinafter referred to as pipe length changes), changes in the amount of refrigerant in the heat transfer device (more precisely, changes in the amount of refrigerant in the heating circuit), and burner combustion And the heat radiation conditions such as the air volume and room temperature in the indoor heat exchanger. The heat transfer device of the present invention can be put to practical use only when a stable heating operation is realized for all of these factors within the fluctuation range.

[0017] Figure 2 is relative to pipe length change shows a relationship between the evaporation temperature T _E at the minimum required subcooling SCmin and refrigerant heater necessary for the system to operate. S due to the rise of T _E
Cmin increases and SCmin increases as the pipe length increases. Here, Lmax indicates the maximum pipe length, and Lmin indicates the minimum pipe length. The required minimum supercooling degree SCmin is larger than the magnitude of the pressure reducing action required to overcome the flow path resistance of the liquid refrigerant pipe 11 and complete the inflow into the receiver 4 while the first on-off valve 6 is closed. It is decided. The evaporation temperature T _E is the air volume reduction and room temperature increase in the indoor heat exchanger, further increased by increasing the amount of combustion in the burner.

FIG. 3 shows the effect of the heat transfer Q on the required minimum supercooling degree SCmin when the internal volume of the liquid receiver 4 is fixed.
The maximum transfer heat amount Qmax at the time of maximum combustion taking into account the maximum value of the burner combustion amount and the maximum value due to variations is more necessary than the minimum transfer heat amount Qmin taking the minimum combustion amount and the minimum variation width into account. The degree of supercooling SCmin increases. It is a very important factor to keep the initial cooling sealing amount in the heat transfer device constant and to balance the system within the fluctuation range of each change factor.

[0019] Figure 4 shows a system operation supercooling degree SC _S when the enclosed amount of the heating circuit is constant, excess refrigerant amount to when Lmax pipe length is greatest when the pipe length is minimum Lmin next system operation supercooling degree SC _S increases. The upper limit Gmax of the amount of refrigerant in the heating circuit is determined by the initial amount of the charged refrigerant. However, in practical use, the refrigerant leaks to the outside of the heat transfer device due to aging, or the refrigerant accumulates in the cooling circuit. Minimum refrigerant amount Gmin
Occurs.

[0020] To stably operate the system for these variables, you must first protect the lower limit SC _L of the supercooling degree, the system operating subcooling SC _S requires minimum degree of supercooling SCmin in all areas It must be controlled at least equal.

[0021] Figure 5 shows an summarizes the same view of the system operation supercooling degree SC _S and the required minimum subcooling SCmin, maximum transport heat Qmax, if the minimum refrigerant quantity Gmin SC _S1
≧ SCmin ₁ and SC _S2 ≧ SCmin ₂ are required. Lower limit SC _B supercooling degree as in this figure the maximum pipe length Lmax
And exists at the time of the evaporation temperature lower limit value T _E min.

[0022] Here, if the maximum pipe length Lmax was 10m supercooling lower limit SC _L has 20 deg ° C. were obtained in the experiment.

On the other hand, subcooling limit SC _H is the maximum amount of refrigerant Gmax, the maximum pipe length Lmax, the minimum necessary degree of supercooling SC determined by the maximum conveying heat Qmax and evaporation temperature upper limit T _E max
It exceeds the min is condition, maximum system operating subcooling SC _S is above the minimum requirements supercooling degree SCmin becomes when a minimum pipe length Lmin enough.

[0024] However, subcooling limit SC _H from the heat dissipation characteristics of the indoor heat exchanger is present. FIG. 6 shows the relationship between the heat release amount Q of the indoor heat exchanger and the degree of subcooling SC of the heat exchanger outlet,
When the degree of supercooling exceeds SC = 30 ° C., the heat radiation ability starts to decrease. When the degree of supercooling exceeds SC = 40 ° C., the heat radiation ability decreases more severely, and the maximum heat transfer amount Qmax cannot be dissipated.

Therefore, the supercooling degree upper limit SCH is set to 40
It is necessary to keep deg ℃. As described above, in the heating operation, the combustion amount of the burner 14 detected by the flow control unit 15 and
Based on the evaporation temperature detected by the temperature detector 16 provided on the refrigerant outlet side of the refrigerant heater 1, the opening / closing control device 17 opens and closes the first opening / closing valve 6 and passes through the second check valve 12.
The degree of supercooling is determined from the difference between the temperature of the liquid refrigerant and the temperature of the temperature detector 16.
Ask for. When the degree of supercooling is small (for example,
20 ° C or less), the first opening / closing by the opening / closing controller 17
Opening / closing cycle per unit time by extending the opening / closing cycle of valve 6
Reduce the number of refrigerants by reducing the number
Supercooling by promoting cooling by extending the residence time of the refrigerant at 8
Increase the degree. When the degree of supercooling is large (for example,
(40 ° C or higher) shortens the cycle of the opening and closing operation of the first on-off valve 6.
In this way, the number of open / close operations per unit time
To shorten the residence time of the refrigerant in the indoor heat exchanger 8.
To reduce the degree of supercooling. Thus, burner 1
4 at the time of maximum combustion, the degree of supercooling of the liquid refrigerant passing through the second check valve 12 is set to 20 deg.
By setting the temperature in the range of ℃, stable heating operation can be realized with very little heat transfer power for all conditions in the fluctuation range, the reliability of the system is improved, and the fluctuation range can be expanded. Practicality is improved.

In addition, it becomes possible to provide an integrated heating / cooling machine which can be operated at low running cost for heating, and the convenience is improved.

[0027]

According to the heat transfer device of the present invention, the following effects can be obtained. (1) Since the degree of supercooling of the liquid refrigerant is set in the range of 20 ° C. to 40 ° C., stable heating operation can be realized with very little heat transfer power over a wide fluctuation range, and practicality is improved. effective. (2) Heating and cooling can be provided with an integrated heating and cooling machine that can be operated at low running cost, so that convenience can be improved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a heat transfer device of the present invention.

FIG. 2 is a characteristic diagram of a required minimum supercooling degree using a pipe length as a parameter.

FIG. 3 is a characteristic diagram of a required minimum supercooling degree with a heat transfer amount as a parameter.

FIG. 4 is a diagram of a system operation subcooling degree characteristic using a refrigerant amount as a parameter.

FIG. 5 is a diagram showing the relationship between the degree of system operation subcooling and the required minimum degree of supercooling.

FIG. 6 is a diagram showing heat radiation characteristics with respect to the degree of subcooling of the indoor heat exchanger.

FIG. 7 is a system configuration diagram showing a conventional example of a heat transfer device that performs heating by refrigerant heating.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 refrigerant heater 2 gas-liquid separator 3 annular passage 4 liquid receiver 5 first check valve 6 first on-off valve 7 equalizing tube 8 indoor heat exchanger 12 second check valve 14 burner 17 opening / closing control device 18 cooling Circuit 19 Compressor 21 Outdoor heat exchanger 24 Flow switching valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 13/00 341

Claims (1)

(57) [Claims] An annular passage connecting a refrigerant heater having a burner and a gas-liquid separator provided above the refrigerant heater; a liquid receiver provided above the gas-liquid separator; A first check valve for connecting the liquid separator, a first on-off valve provided on a pressure equalizing pipe communicating with the gas-liquid separator and the receiver, and a second check valve provided on the upstream side of the receiver A heating circuit in which an indoor heat exchanger is connected to a refrigerant heating and heat transfer section having a refrigerant pipe, and a cooling circuit having an outdoor heat exchanger and a compressor additionally connected to this heating circuit via a flow path switching valve or the like. A heat transfer device provided with an opening / closing control device for setting the degree of supercooling of the liquid refrigerant passing through the second check valve to a range of 20 deg. .