JPS6155018B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an air conditioning system having a heat pump cycle, and in particular uses combustion heat from a combustor as a heat source for the heat pump during heating. Conventionally, heating devices using a heat pump cycle have been proposed, but since the air is used as the heat pump heat source, sufficient heat cannot be obtained in winter, in cold regions, or when the outside temperature drops in the morning or evening.
It has the characteristics that the heating capacity decreases and the heating load temperature rises slowly. On the other hand, if the temperature of the refrigerant flowing into the power supply side heat exchanger is lowered to increase the amount of heat absorbed from the atmosphere, there is a problem that frost will form on the heat exchanger and the heat exchange capacity will decrease. Air conditioning and heating systems of this type have not yet become widespread. Several improvement methods have been proposed to address the above-mentioned problems with heating and cooling systems using heat pump cycles. A simple method is shown in FIG. In the figure, 1 is a compressor, 2 is a four-way valve for switching the refrigerant circuit, 3 is an indoor heat exchanger, 4 is an indoor fan, 5 is its driving motor, 6 is a capillary, 7 is an outdoor heat exchanger, 8 is an outdoor fan, 9 is its drive motor, and each of the indoor and outdoor heat exchangers 3 and 7 is provided with an electric heater 1 for auxiliary heating.
0 and 11 are installed respectively. However, in the above-mentioned air-conditioning and heating devices using electric heaters, (a) the heater capacity is small, so it may not be enough to provide supplementary heating for room heating, and the range of use is limited. (b) Compared to other heat sources, it has disadvantages such as higher operating costs and more restrictions on power supply equipment. In addition, there is a system in which a hot water heater is attached to the outdoor heat exchanger, but this system requires a boiler, which increases equipment costs and increases the size of the system, requiring a large installation area. On the other hand, in the event of frost forming on the outdoor heat exchanger, some defrost methods are adopted through reverse cycle (cooling cycle) operation, but this reverse cycle operation has the disadvantage that cold air is blown toward the indoor side. There is. In addition, as a method to compensate for the lack of heating capacity, a method has been proposed in which a combustion device is incorporated into the indoor unit, as shown in FIG. That is, an outdoor unit 12 incorporating a compressor 1, a heat exchanger 7, etc. is installed outdoors, and an indoor unit 13 consisting of a heat exchanger 3, a fan 4, a capillary 6, etc. is installed indoors. The units 12 and 13 are connected by a refrigerant pipe 15 penetrating the wall 14 of the house, and a heat exchanger 3 in the indoor unit 13 is connected.
A combustor 16 is provided between the combustor 1 and the fan 4.
The structure is such that an air supply and exhaust pipe 17 connected to the air supply pipe 6 projects outside through the wall 14. However, this type of device
Since the fuel is present indoors, there are safety issues, piping is required for intake of combustion air and exhaust of combustion exhaust gas, and there are many installation restrictions. Therefore, conventionally, as a heat source for heating,
A system has been proposed in which a combustor is attached to an outdoor heat exchanger, and the combustion heat from the combustor is used to supplement the heat necessary for evaporating the refrigerant, thereby preventing a decrease in heating capacity when the outside air temperature drops. Figure 3 shows the air conditioning system of the above type.
The outdoor heat exchanger is divided into two, and the first outdoor heat exchanger 7a and the second outdoor heat exchanger 7b are arranged vertically and connected in series, and the second outdoor heat exchanger 7b is connected in series. The lower end side refrigerant circulation pipe is connected to the indoor heat exchanger 3 via the capillary 6, and the first
The upper end side refrigerant circulation pipe of the outdoor heat exchanger 7a is connected to the compressor 1 via the four-way valve 2. and the second
A combustion burner 18 is disposed between the lower surface of the heat exchanger 7b and the outdoor fan 8. However, the refrigerant passage structure of the heat source side heat exchanger in this type of system is designed to ensure good heat exchange only when passed by an outdoor fan (outside air is the heat source). Even if an attempt is made to directly supply the combustion heat from the burner to the burner, a sufficient heat supply effect cannot be obtained, and the refrigerant is inflowed through the refrigerant circuit of the first and second outdoor heat exchangers 7a and 7b that is closer to the combustion burner 18. Since the piping is arranged with the far side as the refrigerant outlet, it is not possible to increase the degree of superheating of the refrigerant at the refrigerant outlet due to the heat supply from the combustion burner. This means that the heat supply from the combustor only assists heating capacity when the outside temperature drops.
This is because it is used as an auxiliary element for the purpose of preventing frost formation, and because the resistance of the capillary that performs adiabatic expansion before the outdoor heat exchanger is large. In addition, if the resistance of the throttle is large, that is, the compression ratio becomes large, so the power required for the compressor becomes large, and when the outside temperature is low, the difference between the evaporation temperature and the outside air temperature becomes small, so the refrigerant In order to increase the degree of superheating, it is necessary to increase the heat transfer area of the outdoor heat exchanger on the heat source side, which results in an extremely large outdoor unit. In other words, all of the conventional methods focused on solving technical problems such as avoiding an increase in the power supply capacity of the system or improving energy efficiency during heating, so they neglected the main purpose of the system, which was the comfort of heating and cooling. Currently, the problems of mediocre heating capacity and low temperatures remain unresolved. Therefore, this invention operates a heat pump using the outside air as a heat source with high energy efficiency when the outside temperature is high, and uses a pump transport type heating cycle operation when heat is supplied by the combustion device as the outside temperature drops. In addition to increasing heating capacity and eliminating defrosting, it also reduces the heat transfer area of the heat exchanger on the heat source side, making the outdoor unit more compact and reducing electrical input. An object of the present invention is to provide an air-conditioning/heating device that improves the comfort of the air conditioner and ensures refrigerant circulation when restarting pump-transport heating cycle operation. Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows an example of a heating and cooling system according to the present invention, in which 20 is a compressor for compressing and transporting refrigerant, 21 is a four-way valve for switching the refrigerant circuit provided on the suction and discharge side of the compressor 20, and 22 is an indoor heat exchanger whose refrigerant inlet end is connected to the four-way valve 21 via the refrigerant circulation pipe 23, and functions as an evaporator during the cooling cycle and as a condenser during the heating cycle. Reference numeral 24 denotes an indoor fan, which is disposed close to the indoor heat exchanger 22 and is driven by a motor 25. 26 is a first outdoor heat exchanger installed outdoors, and its upper refrigerant inflow end is connected to a refrigerant circulation pipe 27
is connected to the refrigerant outflow end of the indoor heat exchanger 22 through the second outdoor heat exchanger 2 at its lower end.
8 and connect it to the first outdoor heat exchanger 2.
6 in series, and the refrigerant outflow end of the second outdoor heat exchanger 28 is connected to the four-way valve 21 via a circulation pipe 29. The outdoor heat exchanger 26,
28 functions as a condenser during the cooling cycle, and functions as an evaporator during the heating cycle. Further, a liquid reservoir 30 for storing refrigerant liquid is interposed in series in the circulation pipe 27 that connects the indoor heat exchanger 22 and the first outdoor heat exchanger 26,
This liquid reservoir 30 is arranged at a position where the refrigerant liquid in the second outdoor heat exchanger 28 is full and the liquid level L is maintained, and
A pump 31 for transporting refrigerant is located below the liquid reservoir 30 and connected in series to the circulation pipe 27, and a series circuit consisting of a solenoid valve 32 and a capillary 33 is connected in parallel to the pump 31. . The reason why the liquid reservoir 30 is arranged so that the refrigerant level L of the second outdoor heat exchanger 28 is maintained and the pump 31 is positioned below the liquid reservoir 30 is because the pump 31 is driven. When pumped heating cycle operation is stopped for a relatively long period of time, the refrigerant in the system cools and liquefies.
This will accumulate in a low-level part of the system, but in this case, if the inlet of the pump 31 is not in the refrigerant liquid but opens into the air layer of the system, the pump 31 will be activated when restarting the heating cycle operation. Even if it is driven, the circulation of the refrigerant will be hindered, and in the worst case, the circulation of the refrigerant may not be possible. In addition, due to poor circulation of the refrigerant, the outdoor heat exchanger 28 will be overheated more than necessary, and the refrigerant pipes will be damaged. This is to prevent the risk of red heat or melting. At the lower position of the second outdoor heat exchanger 28,
A combustion burner 34 and an outdoor fan 35 that supply heat to the liquid refrigerant during the heating cycle are arranged, respectively.
The outdoor fan 35 is driven by a motor 36. Further, the suction and discharge ports of the compressor 20 to which the four-way valve 21 is connected are connected by a bypass passage 37, and a solenoid valve 38 for opening and closing the bypass passage 37 is connected in series. In the air conditioning system having the above configuration, during the heating cycle, when the outside temperature is relatively high, the solenoid valve 32 is kept open, the solenoid valve 38 is kept closed, and the pump 31 and burner 34 are kept in a stopped state. Therefore, the refrigerant accompanying the operation of the compressor 20 is adiabatically expanded in the capillary 33, absorbs heat from the outside air in the first and second outdoor heat exchangers 26 and 28, and is further sucked into the compressor 20 where it is adiabatically compressed. After that, the air is pumped to the indoor heat exchanger 22, and its condensation action heats the indoor air, thereby performing a so-called conventional heat pump type heating cycle operation. When the outside temperature drops, the compressor 20 is stopped, the solenoid valve 32 is kept closed, and the solenoid valve 38 is kept open, and at the same time, the burner 34 starts the combustion operation and the refrigerant is lowered below the liquid level L. The pump 31 located at is activated to simply transport the refrigerant. As a result, while the refrigerant passes through the first and second outdoor heat exchangers 26 and 28, it is heated by the combustion heat of the burner 34 in the second outdoor heat exchanger, and becomes superheated steam. This gas-phase refrigerant flows through the bypass passage 37 and the solenoid valve 3.
8 to the indoor heat exchanger 22, and the heat exchanger 22 radiates the heat, thereby performing a pump transport type heating cycle operation. At this time, the compressor 20 is stopped and the refrigerant is transported by the pump 31, so that the power for transporting the refrigerant during heating cycle operation can be extremely reduced. During the cooling cycle, the burner 34 is kept in a combustion stopped state, the solenoid valve 32 is opened, the solenoid valve 38 is kept closed, the pump 31 is also stopped, and the compressor 20 is operated as usual. Do this in cycles. FIG. 5 shows another embodiment of the present invention in which the first outdoor heat exchanger 26 and the second outdoor heat exchanger 28 are arranged in parallel. In the same figure, the fourth
Components that are the same as those in the figures are given the same reference numerals, and a description of the structure thereof will be omitted, and the explanation will focus on the components that are different from FIG. 4. That is, the first outdoor heat exchanger 26 and the second outdoor heat exchanger 28 are connected in parallel and inserted in series in a refrigerant circuit connecting the four-way valve 21 and the pump 31,
A solenoid valve 39 is connected in series to the refrigerant inflow side of the first outdoor heat exchanger 26, and a solenoid valve 40 is connected in series to the refrigerant outflow side of the second outdoor heat exchanger 28. In the circuit with the above configuration, during the heating cycle,
The solenoid valves 32 and 39 are kept closed and the solenoid valves 38 and 40 are kept open regardless of the level of the outside temperature, and the pump 31 located below the refrigerant liquid level L is driven to transport the refrigerant. As a result, the refrigerant flows into the liquid reservoir 30 -
Pump 31 - Second outdoor heat exchanger 28 - Solenoid valve 4
It is circulated through the path of 0-four-way valve 21-bypass path 37-indoor heat exchanger 22-liquid sump 30, and while passing through the second outdoor heat exchanger 28, the burner 34
It is heated by the heat of combustion and becomes superheated steam. When this gas phase refrigerant is sent to the indoor heat exchanger 22, heat is radiated by the heat exchanger 22 to form a heating cycle. Further, during the cooling cycle, the combustion operation of the burner 34 is stopped, the pump 31 is stopped, and the solenoid valve 32 is kept open and the solenoid valve 38 is kept closed. In this state, the compressor 20 is operated to perform normal cooling cycle operation. At this time, if the outside temperature is high and a large heat radiation area is required, both the solenoid valves 39 and 40 are opened, and the refrigerant adiabatically expanded in the capillary 33 passes through the first and second outdoor heat exchangers 26 and 28. let Further, when the outside temperature is slightly low, the solenoid valve 39 is opened and the solenoid valve 40 is closed to use only the first outdoor heat exchanger 26 for the cooling cycle. Note that if the setting is made such that only the first outdoor heat exchanger 26 can cover the outdoor heat exchange area corresponding to the required cooling capacity under the standard temperature conditions, the heat exchange area of the second outdoor heat exchanger 28 can be reduced. The increase will provide a large margin in terms of cooling capacity. Next, the state of the refrigerant during the heating cycle will be explained. The heating cycle when the outdoor heat exchangers 26 and 28 are configured in series and the outside temperature is high
(a) The heating cycle when the outdoor heat exchangers 26 and 28 are configured in series and the outside temperature is low (b) The heating cycle when the outdoor heat exchangers 26 and 28 are configured in parallel
When the state of each refrigerant is drawn on the Mollier diagram in Figure 6 as (c), (a) is an EBFG cycle, and (B) and (C) are an ABCD cycle. In the case of (a) above, the refrigerant is adiabatically expanded by the capillary 33 and has a considerably high humidity, and in the cases of (b) and (c), the liquid refrigerant is sent to the first outdoor heat exchanger by the pump 31. 26 or directly into a second outdoor heat exchanger 28, where heat is supplied to the refrigerant by a burner 34. At this time, the refrigerant in the second outdoor heat exchanger 28 and the burner 34
The heat exchange with the combustion gas is in a counterflow manner, so the refrigerant at the outlet of the second outdoor heat exchanger 28 becomes superheated steam and has a high degree of superheat. This superheated steam with a large degree of superheating is transferred to the four-way valve 21
Since the refrigerant bypasses the compressor 20 through the refrigerant, it is not adiabatically compressed and the refrigerant temperature does not rise above the temperature at the outlet of the second outdoor heat exchanger 28. The heat energy of the refrigerant sent to the indoor heat exchanger 22 is radiated and condensed in the heat exchanger, returns to the liquid reservoir 30, and is transported again by the pump 31. Here, in the concept of compression ratio, the pressure on the high pressure side of the cycle is determined by the condensation temperature in the indoor heat exchanger 22, while in operation with the pump 31, the pressure on the low pressure side is reduced by the pressure loss in the cycle pipeline. As a result, a cycle with a very low compression ratio on the pressure side is obtained. Furthermore, since the electrical input to the pump can be reduced, if the power is controlled in synchronization with the burner combustion amount, stepless control of the heating capacity becomes possible very easily. In FIG. 6, l indicates a saturated liquid line, and ν indicates a saturated vapor line. Furthermore, if the indoor heat exchanger 22 also exchanges heat with the indoor air in a counterflow, the temperature of the condensed refrigerant at the outlet of the indoor heat exchanger 22 will be approximately close to room temperature, and the Mollier line shown in FIG. As is clear from the figure, supercooling can be achieved up to c rather than f in the conventional case, and the heating capacity becomes larger to bc than bf. Furthermore, the evaporation capacity is increased due to the heat supply from the burner 34.
It is possible to draw a heat pump cycle with a narrow width of ABCD on the Mollier diagram in Figure 6. Next, the heating capacity, cooling capacity, work of the compressor or pump, and system energy efficiency of the present invention and the conventional example are compared based on the Mollier diagram shown in FIG. 6, as shown in the table below.

[Table] In the table, iG is the enthalpy of combustion energy. Here, if the amount of refrigerant circulation in the system is the same in the embodiment of the present invention and the conventional example, the heating capacity and cooling capacity in the embodiment of the present invention are much greater, and the work of the pump 31 is also reduced to the compressor 20. It will be understood that in addition to being comparatively smaller, the energy efficiency of the system is greater and is superior to the conventional example. In addition, considering the thermal combustion energy, the energy efficiency of the system is small compared to the conventional system, but the workload of the pump is greatly reduced compared to the compressor 20, the electrical input can be reduced, and the comfort of heating and cooling can be improved. Considering these considerations, being able to increase the heating capacity when the outside temperature drops sufficiently satisfies the purpose of the present invention. Further, the refrigerant liquid level L of the second outdoor heat exchanger 28 when the refrigerant cycle is stopped is set such that the outdoor heat exchanger 28 is full, and the arrangement position of the liquid reservoir 30 is set, and the pump 3
1 is located below the liquid reservoir 30, which is lower than the refrigerant liquid level L, so that the suction port of the pump 31 can always be placed in the refrigerant liquid, and accordingly, when restarting the pump transport type heating cycle operation, In addition to ensuring refrigerant circulation, the heat exchanger 28 is connected to the burner 3.
4 can prevent overheating and melting. As described above, according to the present invention, since the pump transport type heating cycle operation is performed using combustion heat as the heat source, the refrigerant transport power can be extremely reduced, and therefore the following effects can be achieved. can get. (a) It allows for a significant reduction in electrical input; (b) It allows for a stable supply of sufficient heating capacity. (c) Cold air blowing can be prevented by abolishing defrosting operation. (d) The outdoor unit can be made smaller by reducing the heat transfer area of the heat exchanger on the heat source side. (e) Stepless control of heating capacity is possible. (f) Refrigerant circulation can be ensured when restarting pumped heating cycle operation.

[Brief explanation of the drawing]

1 to 3 are schematic configuration diagrams showing an example of a conventional heating and cooling device, FIG. 4 is a schematic configuration diagram showing an example of a heating and cooling device according to the present invention, and FIG. 5 is a schematic configuration diagram showing an example of a heating and cooling device according to the present invention. FIG. 6 is a schematic configuration diagram of the air-conditioning apparatus shown in FIG. 20... Compressor, 21... Four-way valve, 22... Indoor heat exchanger, 24... Indoor fan, 26... First
outdoor heat exchanger, 28... second outdoor heat exchanger,
30...Liquid reservoir, 31...Pump, 32...Solenoid valve, 33...Capillary, 34...Burner, 3
5...Outdoor fan, 37...Bypass path, 38...
...Solenoid valve, 39,40...Solenoid valve.

Claims (1)

[Claims] 1. A heat pump cycle is formed by a compressor, a four-way valve, an indoor heat exchanger, a capillary, an outdoor heat exchanger, etc., and heat is supplied to at least a part of the outdoor heat exchanger during the heating cycle. In an air conditioning system having a combustion device, a liquid reservoir is provided in a refrigerant circulation path connecting the indoor heat exchanger and the outdoor heat exchanger, and the liquid reservoir is used to control the refrigerant liquid level in the outdoor heat exchanger when the refrigerant cycle is stopped. At the same time, a refrigerant transport pump is installed below the refrigerant liquid level in the refrigerant circulation path connecting the liquid reservoir and the outdoor heat exchanger; A heating and cooling system characterized in that the compressor that is stopped during use is provided with a refrigerant bypass path that bypasses refrigerant heated by at least a portion of the outdoor heat exchanger to the indoor heat exchanger. 2. The heating and cooling device according to claim 1, wherein the refrigerant transport pump is connected in parallel to a series circuit of a capillary and a solenoid valve that is opened during cooling operation. 3. The heating and cooling device according to claim 1, wherein the refrigerant bypass path is opened and closed by a solenoid valve. 4 A plurality of outdoor heat exchangers are provided, and each of these outdoor heat exchangers is connected in parallel so as to be able to communicate with the refrigerant circuit separately, and at least one of the outdoor heat exchangers is provided with a combustion device for heat supply. The heating and cooling device according to claim 1, further comprising the following: