JPH0359352B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a refrigeration system, and in particular, it is possible to effectively utilize the heat held by the heat source side air heat exchanger when switching from defrosting operation to heating operation, etc. The present invention relates to a refrigeration device configured as described above.

(Prior Art) As a prior art in the technical field to which the present invention pertains, there is a refrigeration system described in Japanese Utility Model Application Publication No. 8264/1983. In this known heat pump type refrigeration system, as is clear from the electric circuit shown in FIG.
Fan motors 52 and 53 for the heat source side air heat exchanger are connected in series to 51B, respectively.
At the end of the defrosting operation, that is, at the same time as the defrosting relays 50, 51 are demagnetized, the fan motors 52, 53 are restarted. In addition, in FIG. 4, numerals 50A and 51A are normally open contacts of defrosting relays 50 and 51, 54 and 55 are four-way switching valve relays, and 5
Reference numeral 6 indicates a compressor relay, and 57 and 58 indicate de-icers, respectively.

(Problems to be Solved by the Invention) When the conventional example described above is configured to restart the fan motor for the air heat exchanger on the heat source side at the same time as the defrosting operation ends, the following problems occur. .

Immediately after the defrosting operation ends, high-temperature liquid refrigerant at 50 to 80°C (condensed liquefied compressor discharge gas used for defrosting) remains inside the air heat exchanger on the heat source side, and the heat source Even though the components of the side air heat exchanger (e.g. fins, heat exchanger tubes, etc.) are also warmed, the hot liquid refrigerant and the heat source are The residual heat of the side air heat exchanger components is wastefully released into the outside air, resulting in a loss in thermal efficiency.

The present invention has been made in view of the above points, and
The purpose of this is to recover the amount of heat remaining in the heat source side air heat exchanger into the refrigerant system (i.e., the user side heat exchanger side) at the end of the defrosting operation, thereby making effective use of heat. .

(Means for Solving the Problems) In the present invention, as a means for solving the above problems, a compressor, a heat source-side air heat exchanger equipped with a fan, an expansion mechanism, and a user-side heat exchanger are sequentially connected. In a refrigeration system configured to circulate refrigerant, after a defrosting operation in which the discharge gas of the compressor is supplied to the heat source side air heat exchanger to remove frost, the heat source side air heat exchanger is A delay means is provided which acts to delay the restart of the fan until the temperature on the inlet side of the heat exchanger detected by a thermostat provided on the inlet side during heating operation becomes less than a predetermined value.

(Function) In the present invention, the following effects can be obtained by the above means.

That is, after the defrosting operation is completed, the delay means is activated until the temperature on the inlet side of the heat exchanger, which is detected by the thermostat installed at the inlet side during the heating operation of the air heat exchanger on the heat source side, becomes equal to or less than a predetermined value. By delaying the restart of the fan for the heat source side air heat exchanger, the amount of heat remaining in the heat source side air heat exchanger side at the end of the defrosting operation is recovered to the user side heat exchanger. .

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows a refrigerant system diagram when a refrigeration system according to an embodiment of the present invention is used as a heat pump type water heater.

This refrigeration system includes a compressor 1, a four-way switching valve 2, a heat source side air heat exchanger 4 equipped with a fan 3, an expansion mechanism (for hot water generation and defrosting) 5, 6, a refrigerant tank 7, a hot water The utilization side heat exchanger 8 and the accumulator 9 are connected in sequence so that the refrigerant can be reversibly circulated by the switching operation of the four-way switching valve 2. In this refrigeration system, a high-pressure control valve 10, a refrigerant tank 11, and a capillary tube 12 are connected in series between the outlet side of the refrigerant tank 7 and the inlet side of the accumulator 9. In FIG. 1, reference numeral 13 indicates a check valve that allows refrigerant flow only during defrosting operation, 15 indicates a thermostat provided at a position on the inlet side of the heat source side air heat exchanger 4 during heating operation, and 16 indicates is a pressure switch.

In this refrigeration system, during hot water generation operation, the refrigerant flows in the direction shown by the solid arrow, and the heat absorbed from the air by the heat source side air heat exchanger 4 is radiated to the hot water W by the use side heat exchanger 8. This hot water is used for hot water supply. During this hot water generation operation,
When the temperature of the hot water W increases, the high pressure also increases, so the high pressure control valve 10 is opened and the refrigerant is stored in the refrigerant tank 11. By doing so, the high pressure is lowered and hot water generation operation can be continued. At this time, a small amount of liquid refrigerant always flows from the refrigerant tank 11 through the capillary tube 12 to the inlet side of the accumulator 9, which also serves as a liquid injection for lowering the discharge gas temperature.

On the other hand, if frost forms on the heat source side air heat exchanger 4 due to a drop in outside temperature, etc., the four-way switching valve 2 is switched.
Defrosting operation is performed by circulating the refrigerant in the direction shown by the dotted arrow. At this time, fan 3 is stopped. In this defrosting operation, the high temperature discharge gas of the compressor 1 is supplied to the heat source side air heat exchanger 4, and the frost on the heat source side air heat exchanger 4 is thawed and removed by the discharged gas. be done. At the end of defrosting operation, the discharged gas is condensed and liquefied into high-temperature liquid refrigerant (temperature = 50 to 80
°C) and remains in the heat source side air heat exchanger 4. In addition, in this state, the heat source side air heat exchanger 4
, such as the fins 4a and the heat exchanger tubes 4b.
etc. are also heated by liquid refrigerant. When the defrosting operation is completed, the four-way switching valve 2 is switched again to return to the hot water generation operation, but in this embodiment, as will be described later, even if the defrosting operation end signal is issued, Fan 3 is activated by the delay means.
without restarting the heat source side air heat exchanger 4.
The stopped state is continued until the temperature of the engine falls below a predetermined value. By doing this, the amount of heat remaining in the heat source side air heat exchanger 4 is returned to the refrigerant system without being released into the outside air, and is recovered to the user side heat exchanger 8 side. becomes. Note that during this defrosting operation, the liquid refrigerant in the refrigerant tank 7 is to be circulated within the refrigerant system, and is used to improve the defrosting effect.

Generally, the hot water generation capacity including frosting and defrosting in a refrigeration system is illustrated in FIG. 3.

Here, SR: Hot water generation capacity per cycle SF: Loss capacity due to frost formation per cycle SD: Loss capacity due to defrosting per cycle According to this, the nominal capacity is [(SR+SF)/
(unit time)], but the actual ability is [(SR−
SD)/(unit time)], and the ratio is usually 70~
It will be 85%. On the other hand, in the case of the present invention, the hot water generation capacity SA is increased by the amount of heat remaining on the heat source side air heat exchanger 4 side at the end of the defrosting operation, which is recovered to the utilization side heat exchanger 8. Actually 2～
A 3% improvement in performance was obtained.

Next, the control mechanism of the fan 3 in the refrigeration system having the above configuration will be described in detail with reference to the electric circuit diagram shown in FIG.

In FIG. 2, reference numeral 15 indicates a thermostat;
18 is the operation switch, 19 is the compressor relay, 2
0 is the fan motor of the fan 3 for cooling the air heat exchanger on the heat source side, 21 is the relay for the four-way switching valve, 22 is the day icer that controls the defrosting operation, 23 is the defrosting relay, and 24 is interlocked with the thermostat 15. relay, Th indicates hot water thermostat, respectively.

And the normally open contact 23 of the defrosting relay 23
A is connected in series with the four-way switching valve relay 21 and relay 24, respectively, and the thermostat 15 is connected in series with the relay 24 and in parallel with the normally open contact 23A of the defrosting relay 23. has been done. The relay 24 is self-maintained by connecting its normally open contact 24A to the thermostat 15 in series. Further, the normally closed contact 24B of the relay 24 is connected in series with the fan motor 20.

The thermostat 15 is provided at a position on the inlet side during heating operation of the heat source side air heat exchanger 4, and operates by detecting the temperature on the inlet side of the heat source side air heat exchanger 4. That is, this thermostat 15
is configured to turn off when the temperature on the inlet side of the heat source side air heat exchanger 4 is below a predetermined value (0° C. in this embodiment). In addition, thermostat 15 is ON.
The return to the state is performed at a temperature 5° C. higher than the predetermined value to prevent hunting.

In the above configuration, the control mechanism in the refrigeration system of this embodiment operates as follows.

That is, when the day icer 22 is activated, the defrosting relay 23 is energized, its normally open contact 23A is closed, the four-way switching valve relay 21 and the relay 24 are energized, and the four-way switching valve 2 is opened. At the same time as switching to the frost operation side, the normally closed contact 24B of the relay 24 is opened, and the fan motor 20 is stopped (that is, the fan 3 is stopped). At this time, the heat source side air heat exchanger 4 is heated by the high-temperature liquid refrigerant (50 to 80 degrees Celsius) that is the condensation of the high-temperature discharge gas supplied during the defrosting operation, so the thermostat 15 is in the ON state. Yes, the relay 24
The relay 24 is self-held by closing the normally open contact 24A. After the defrosting operation is completed, the four-way switching valve relay 23 is demagnetized and the four-way switching valve 2 is switched to the hot water generation operation, but the temperature on the inlet side of the heat source side air heat exchanger 4 remains at a predetermined level. The thermostat 15 is kept in the ON state until the temperature drops below the temperature value (0° C. in this embodiment). When the temperature on the inlet side of the heat source side air heat exchanger 4 falls below a predetermined value, the thermostat 15 is turned off.
Relay 24 is demagnetized. Therefore, the normally closed contact 24B of the relay 24 is closed, and the fan motor 20 is restarted (that is, the fan 3 is restarted).
be done. In other words, in the case of this embodiment, restarting of the fan 3 is delayed until the temperature on the inlet side of the heat source side air heat exchanger 4 falls below a predetermined value after the defrosting operation is completed. . As described above, when the inlet temperature of the heat source side air heat exchanger 4 is detected by the thermostat 15 and the starting and stopping of the fan 3 is controlled based on the detected temperature, the starting and stopping of the fan 3 is controlled by the timer. It is possible to perform more accurate heat recovery than those that are controlled. In addition, a thermostat 1 is installed on the inlet side of the air heat exchanger 4 on the heat source side.
5, the temperature-sensing part of the thermostat 15 is located inside the casing and does not come into direct contact with the outside air. Accurate temperature detection can be performed without being affected by the degree of superheating, etc.

The example described above is a heat pump type water heater that uses the generated hot water for hot water supply, but this hot water can be used for heating if it is supplied to an indoor heat exchanger. Therefore, it can also be used as a heat pump type heating device. It can also be used as a heat pump type air conditioning device such as a heat pump type chiller.

Further, in the above example, the user-side heat exchanger is for water, but it may be for air.

Furthermore, in the above example, the four-way switching valve can be replaced by the following circuit. That is, a bypass pipe with a solenoid valve interposed is provided from the discharge gas pipe of the compressor to the pipe at the outlet of the expansion mechanism and the inlet of the heat source side air heat exchanger, and this solenoid valve is opened during defrosting operation. It is sufficient to provide a circuit with

(Effects of the Invention) As described above, according to the present invention, after the defrosting operation is completed, the heat detected by the thermostat 15 provided at the inlet side during the heating operation of the heat source side air heat exchanger 4 is The restart of the heat source side air heat exchanger fan 3 is delayed by the action of the delay means until the exchanger inlet side temperature falls below a predetermined value. Since the remaining heat is returned to the refrigerant system without being released into the outside air and can be recovered in the heat exchanger 8 on the user side, the capacity of the refrigeration system (heating or hot water supply, etc.) can be improved. This has the excellent effect of improving operating efficiency.

Furthermore, a thermostat 15 is provided on the inlet side of the air heat exchanger 4 on the heat source side, and based on the temperature at the inlet side of the heat exchanger detected by the thermostat 15, the start/stop of the fan 3 is controlled after the defrosting operation is completed. As a result, the temperature-sensing part of the thermostat 15 is located inside the casing and does not come into direct contact with the outside air. Since it is not affected by temperature fluctuations, etc., accurate temperature detection can be performed, and by controlling the start and stop of the fan 3 based on the detected temperature, it is possible to accurately detect the temperature compared to a method that controls the start and stop of the fan 3 using a timer. It also has the effect of being able to be collected.

[Brief explanation of drawings]

FIG. 1 is a refrigerant system diagram of a heat pump type water heater which is a specific example of the refrigeration system of the present invention, FIG. 2 is an electric circuit diagram showing an example of fan control in the water heater shown in FIG. FIG. 4 is a characteristic diagram showing the relationship between operating time and capacity when the refrigeration apparatus is used for generating hot water, and FIG. 4 is an electric circuit diagram of a conventionally known refrigeration apparatus. 1... Compressor, 3... Fan, 4... Heat source side air heat exchanger, 5, 6... Expansion mechanism, 8... User side heat exchanger, 15... Thermostat, 16... Pressure switch, 19... Compressor relay, 20...
Fan motor, 22... Day icer, 23...
Defrosting relay, 24...Relay.

Claims (1)

[Claims] 1. In a refrigeration system configured to circulate a refrigerant by sequentially connecting a compressor 1, a heat source side air heat exchanger 4 with a fan 3, an expansion mechanism 5, and a user side heat exchanger 8, the heat source side air heat exchanger After completion of a defrosting operation in which the discharge gas of the compressor 1 is supplied to the heat exchanger 4 to remove frost, a thermostat is installed at a position on the inlet side during the heating operation of the heat source side air heat exchanger 4. 15. A refrigeration system characterized in that a delay means is provided which acts to delay restarting of the fan 3 until the temperature at the inlet side of the heat exchanger detected by the heat exchanger 15 becomes equal to or less than a predetermined value.