JPH02208437A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable a positive protection of freezing even under a state of reduction of amount of circulating water by a method wherein a compressor is operated or stopped in response to an output signal of a compressor operation termination water temperature discriminating means and then the compressor is stopped with an output signal from an outlet water temperature difference discriminating means. CONSTITUTION:When an output signal of a temperature sensor 10 reaches a signal level corresponding to a predetermined temperature, a compressor operation terminating means 15 may operate the compressor 1 in response to an output signal from the compressor operation termination water temperature discriminating means 11 and then the output signal of the temperature sensing unit 10 is stored in an outlet water temperature memory means 13. A compressor operation the measuring means 12 having received the output signal of the compressor operation termination water temperature discriminating means 11 may start a measurement of the operation time of the compressor 1 from that time, compare the output signal stored in the outlet water temperature memory means 13 with the output signal from the temperature sensor 10 after a predetermined time elapses. In case that its signal level does not reach a signal level difference corresponding to the set temperature difference, the compressor operation terminating means 15 may terminate the compressor 1 in response to the output of the outlet water temperature difference discriminating means 14.

Description

[Detailed description of the invention] This invention relates to an air conditioner that can stop the compressor without freezing the circulating water even if the temperature of the circulating water drops due to a malfunction, thereby preventing damage to the heat exchanger. be.

[Conventional technology]

Conventionally, the method of preventing freezing of circulating water for air conditioning in hydraulic air conditioners is to detect the outlet water temperature of the user side heat exchanger and stop the compressor if the water temperature drops below a certain level. It was commonly used, and was as shown in Figs. 4 and 5.

Of these figures 4 and 5, first, in figure 4, (1
) is a compressor, (2) is a heat exchanger on the non-use side to condense the refrigerant gas, (31 is a blower that sends cooling air to the heat exchanger on the non-use side (2), and (4) is a decompressor for liquid refrigerant. A squeezing device,
4, for example, circulates air conditioning water circulating between an air conditioning load device (7) such as a fan coil unit (hereinafter referred to as a fan coil unit) and a refrigerant supplied from the compressor (1). This is a user-side heat exchanger for exchanging heat, and together with the above devices constitutes a well-known refrigeration cycle.

The water inlet part (5a) and the water outlet part (51) of the user-side heat exchanger (51)
A fan coil unit (7) is connected between the air conditioning circulating water pipes (5b), a temperature regulator (64) is attached to the water inlet (5a), and a temperature regulator (64) is attached to the water outlet (5b).
) is equipped with an antifreeze temperature switch (60).

Next, the control circuit shown in FIG. 5 will be explained. Between both poles of the power supply, connect the contact (60a) of the antifreeze temperature switch (60).
(normally closed), an operation switch (61), a stop switch (62), and a self-holding relay coil (63) are connected in series.

A contact (63a) (normally open) of a self-holding relay coil (63) is connected in parallel to the operation switch (61).

In addition, a contact (63b) (
(normally open), the contact (64a) (normally closed) of the temperature regulator (64), and the operating electromagnetic switch coil (65) are connected in series.

Next, the operation will be explained. First, after turning on the power, when the operation switch (61) is turned on, the self-holding relay coil (63) is energized through the stop switch (62), its contacts (63a) and (63) are closed, and the contact (63a) The motion switch (61) is short-circuited, the self-holding relay coil (63) is self-holding, and the electromagnetic switch coil (65) for compressor operation is connected through the contact (64a) of the temperature regulator (64) by the contact <63b). ) is energized, and the compressor (1) and the blower (3) start operating in conjunction with this.

The refrigerant gas discharged from the compressor (1) is cooled by the blower (3) in the non-use side heat exchanger (2), becomes liquid refrigerant, is depressurized by the expansion device (2), and is used for heat exchange on the use side. Vessel (9
The refrigerant exchanges heat with the air-conditioning circulating water flowing in from the water inlet (5a), and the refrigerant absorbs heat, evaporates, and is gasified into the compressor (1).
Return to

In addition, the circulating water for air conditioning that has exchanged heat with the refrigerant is deprived of heat and becomes cold water, and the water is passed through the fan coil unit I from the water outlet (5b).
-m and cools the indoor air, and the water whose temperature has risen flows again into the user-side heat exchanger (51) and is cooled.

Air conditioning is performed by repeating the above refrigerant and water cycles.

When the cooling load at the fan coil unit outlet decreases, the temperature of the circulating water for air conditioning decreases because the amount of heat extracted from the indoor air decreases, and the temperature is lowered by the temperature controller (64).
When the set temperature is reached, the contact (64a) opens, so
The electromagnetic switch coil (65) is deenergized and the compressor (1)
The system will stop operating and wait for the temperature of the circulating water for air conditioning to rise.

After that, the inlet temperature of the water inlet part (5a) of the user-side heat exchanger ((5) in which the temperature sensing part of the temperature regulator (64) is installed increases, and the temperature increases When the return temperature is reached, the contact (64a) closes and the electromagnetic switch coil (64a) closes.
5) is energized, the compressor (1) starts operating again, and starts cooling.

In addition, when the flow rate of circulating water for air conditioning decreases or when the capacity of the refrigeration cycle increases due to a drop in outside air temperature, the water inlet (5a) and water outlet (5b) of the user side heat exchanger (51) Even if the water temperature difference becomes large and the water temperature at the water inlet (5a) is higher than the set temperature of the temperature regulator (64),
When the water temperature at the water outlet (5b) approaches the freezing temperature of water (=0°C), the antifreeze temperature switch (60) operates, and its contact (60a) cuts off the power to the control circuit, Since the switch coil (65) is deenergized, the operation of the compressor (1) is stopped, and freezing of the circulating water for air conditioning is prevented.

[Problem to be solved by the invention]

Conventional air conditioners have a heat exchanger on the user side (as described above).
5], the compressor (1) was stopped to prevent air conditioning circulating water from freezing, so if the amount of circulating water decreased and the antifreeze temperature switch (60) was activated, the compressor Even after (1) is stopped, the unevaporated liquid refrigerant remaining inside the refrigerant passage of the user-side heat exchanger (51) continues to evaporate by collecting heat from the circulating water. There were problems such as the temperature of the internal circulating water decreased and it partially froze, damaging the user side heat exchanger (5).

The present invention has been made to solve these problems, and an object of the present invention is to provide an air conditioner that can reliably provide freeze protection even when the amount of circulating water is reduced.

[Means to solve the problem]

The air conditioner according to the present invention generates an output signal for starting or stopping when the output signal of the temperature detector that detects the outlet water temperature of the user-side heat exchanger reaches a signal level corresponding to a preset temperature. a compressor operation stop water temperature determination means for determining the compressor operation stop water temperature; an outlet water temperature storage means for storing the output signal of the temperature detector when an operation output signal is generated from the compressor operation stop water temperature determination means; and an outlet water temperature storage means for storing the output signal of the temperature detector; When the measured time of the compressor operating time measuring means reaches a predetermined value, the output signal of the temperature detector is compared with the output signal stored in the outlet water temperature storage means. , when the signal level difference does not reach a signal level difference corresponding to a preset temperature difference, outlet water temperature temperature difference determining means that generates an output signal, and compressor operation stoppage water temperature determining means that generates an output signal. and a pressure tai operation stop means for operating or stopping the compressor and stopping the compressor based on the output signal of the outlet water temperature difference determining means.

[For production]

In this invention, when the output signal generated from the temperature detector reaches a signal level corresponding to a preset temperature, the compressor operation stop means is based on the output signal generated from the compressor operation stop water temperature determination means. starts operating the compressor, stores the output signal of the temperature detector in the outlet water temperature storage means, and receives the output signal of the compressor operation stop water temperature determination means, and the compressor operation time measuring means operates from that point onwards. The measurement of the operating time of the compressor is started, and after a predetermined period of time has elapsed, the output signal stored in the outlet water temperature storage means is compared with the output signal of the temperature detector, and the signal level difference is determined as a preset temperature difference. When the signal level difference corresponding to is not reached, the compressor operation stop means operates to stop the compressor based on the output of the outlet water temperature difference determination means.

〔Example〕

Embodiments of the air conditioner of the present invention will be described below based on the drawings. FIG. 1 is an overall configuration diagram of an air conditioner showing an embodiment of the present invention.

The refrigeration cycle side of this embodiment is the same as that of the conventional embodiment, but as is clear from the figure, the control part is configured as follows. That is, α[ is a temperature detector provided at the water outlet portion (5b) of the user-side heat exchanger (9) to detect the outlet water temperature and generate an output signal according to the outlet water temperature.

The compressor operation stop water temperature determination means (11) is a temperature detector Ql.
When the output signal reaches a signal level corresponding to a preset temperature, a run or stop output signal is generated.

When an operation output signal is generated from the compressor operation stop water temperature determination means (11), the compressor operation time measurement means (12)
) starts measuring the operating time of the compressor (1) and generates an output signal after a predetermined time elapses.

Further, based on the operation output signal from the compressor operation stop water temperature determination means (11), the outlet water temperature storage means (13) stores the output signal of the temperature detector 01 at that point in time.

The outlet water temperature temperature difference determining means (14) is a temperature detector 00).
The output signal is compared with the output signal stored in the outlet water temperature storage means (13), and when the signal level difference between them does not reach a signal level difference corresponding to a preset temperature difference, the output signal is It is something that occurs.

The compressor operation stop means (15) determines whether the compression is 1 or not based on the output signal from the compressor operation stop water temperature determination means (11). (11
The compressor (1) is operated or stopped based on the output signal of the outlet water temperature difference determining means (14).

FIG. 2 is a circuit diagram showing electrical connections of the air conditioner shown in FIG. 1. In the figure, (18) is a microcomputer in the control device (17), and has a CPU (19), a memory (20), an input circuit (21), and an output circuit (22). (24) is a resistor in series with the temperature sensor aO), (25) is the detection output of the temperature sensor 00),
It is an A/D converter that converts to digital, and its output is given to the input circuit (21).

(27) is a resistor in series with the operation switch (29), (28
) is a resistor in series with the protection device (30) of the compressor (1), and status signals of the operation switch (29) and the protection device (30) are also given to the input circuit (21), respectively.

The compressor operation stop means (15) is a compressor electromagnetic switch (
The base of the transistor (33) is connected to the output circuit (22) via a resistor (34). Its emitter is grounded and its collector is connected to the power supply via an auxiliary relay (31).

Next, the operation of the above embodiment will be explained with reference to FIG. Figure 3 shows the memory (2) of the microcomputer (18).
0) is a flowchart showing a program of the air conditioner of the present invention stored in FIG.

First, when the operation switch (29) is closed, the ON signal is inputted to the input circuit (21), step (36) shown in Fig. 3 is executed, and then step (37) is performed to check whether the water temperature is at which operation can be started. Start determining whether or not. This determination is made only when the operation switch (29) is set to "open" and "closed" to start operation, and the temperature at which the compressor (1) is stopped is determined by the temperature detector 0rjI, for example. When the temperature is set to 10° C., if the outlet water temperature is higher than the set temperature by, for example, 6° C. or more, rYES is determined. The temperature of the air conditioning circulating water detected in this judgment is detected by the user side heat exchanger (temperature detector α0 using the outlet water temperature of 51), and is detected by the A/D converter (25
) is digitized and input to the input circuit (21). Next, based on the determined result, if the determination is "N○", the determination is performed again, and the determination is repeated until the determination becomes rYEs, and if the determination becomes rYEsJ, step (
Proceeding to step 38), an output is output from the output circuit (22), turning on the transistor (33), energizing the auxiliary relay coil (31), closing the contact (31a), and connecting the terminal (32) to the compressor (not shown). A signal is output to the electromagnetic switch for compression i.
ll (11 and air blowing linked to this! (31 starts operation, and the outlet water temperature starts to decrease. Next step (39
), the compressor operating time is measured simultaneously with the operation of the compressor (1) by the CPU (1) of the microcomputer (+8).
9), the time is accumulated in the memory (20). In step (40), the water temperature To detected by the temperature detector 0ω at the water outlet (5b) of the heat exchanger 11A (51) on the user side at the same time as the compressor (1) is operating is detected by the microcomputer (18). Stored in memory (20).

Next, in step (41), it is determined whether there is any abnormality in the compressor (1), that is, the protective bag! <30) is not operating. If it is determined that there is an abnormality, the process proceeds to step (51) and the output circuit (
22) is no longer output, and the auxiliary relay coil (31)
) is deenergized, its contact (31a) opens, and the pressure is 1? ii
l (11 and the blower (3) stop.

A signal from the protection device (30) is input to the input circuit (21), and the determination of the presence or absence of an abnormality is performed by the CPU (+9).

If it is determined that there is no abnormality in step (41), the next step (42) is to check whether there is a risk of freezing of the circulating water for air conditioning. 5b), the water temperature To is the freezing temperature of water T [and To
>Tf is determined. If To>Tf, there is a risk of freezing, so the process proceeds to step (5I) and the compressor (1) is stopped in the same way as above.

If it is determined in step (42) that there is no risk of freezing, a determination is made in the next step (43) as to whether or not the compressor operating time is being measured, and if not, step ( 47), and if it has been performed, proceed to step (44) and check that the measured time Tmc is ′, Tlc≧ with respect to the preset time Tms (for example, 2 minutes).
It is determined whether or not Tms, and if Tic≧Tms, the process proceeds to step (47). In step (47), a compressor operation/stop water temperature determination operation is performed, and it is determined whether or not the detected outlet water temperature To and the set water temperature Ts satisfy To≦Ts. If TO≦Ts does not hold, the process returns to step (41) and steps (41) to (47) are repeated.

For example, two minutes after the start of measuring the operation time of the compression Rfil, in step (44), if it is determined that TlIC≧Tms, the process proceeds to step (45), the outlet water temperature temperature difference determination operation is performed, and the temperature detector αω Using the outlet water temperature To detected by and the temperature Td stored in the memory (20), it is determined whether 2<Td-To. In other words, by knowing the temperature difference between the outlet water temperature Td stored at the start of operation of compression fi (11) and the current outlet water temperature To, if the temperature difference is more than a certain value, the operation of the compressor (1) It can be determined that there is a temperature difference because the circulating water for air conditioning is cooled and the water flows through the user side heat exchanger (9).

If the temperature difference is extremely small, the water in the heat exchanger (6) on the user side is cooled by the operation of the compressor (1), but water may flow due to a blockage in the air conditioning circulating water piping or a malfunction of the pump. Therefore, it can be determined that the temperature of the water outlet portion (5b) does not decrease.

In the unlikely event that 2<Td-To, it is determined that the circulating water for air conditioning has been cut off, and the process proceeds to step (51), where the compressor (1) is stopped in the same manner as above.

If 2<Td-To, in step (46), the measurement of the operating time of the compressor (1) is finished, and the memory (20) is
The accumulated time will be reset.

Next, proceed to step (47) and proceed to a! To≦T
s, and if the outlet water temperature To is lower than the set water temperature Ts, the process proceeds to step (48);
The compressor (1) is thermally stopped, and then step (4)
Wait for the temperature of the circulating water for air conditioning to rise.

Next, if it is determined in step (50) that To>Ts+6 is not established, the process returns to step (49) and the above operation is repeated. In step (50), after the compressor (1) is stopped, the outlet water temperature To increases due to the temperature rise of the air conditioning circulating water, and the outlet water temperature To becomes lower than the preset temperature Ts.
For example, if the temperature rises by 6℃ or more, To>Ts+6,
It is determined that the compressor (1) is in operation, and the process returns to step (38), where the compression fi (11) and the blower (3) are operated, and thereafter, the operation and stop are repeated according to the above flowchart.

In addition, although the above embodiment describes the case of an air-cooled cooling-only air conditioner, the same applies to a water-cooled type.
Furthermore, the same effects as in the above embodiment can be achieved in a heat pump type air conditioner.

〔Effect of the invention〕

As explained above, in this invention, when the compressor starts operating, the output signal of the temperature sensor is stored, the operating time of the compressor is measured, and after a predetermined period of time, the stored signal and the output signal of the temperature sensor are stored. The compressor is stopped when the signal level difference does not reach a preset signal level difference corresponding to the temperature difference. Even if the air-conditioning circulating water stops flowing, it is possible to predict that it will freeze inside the user-side heat exchanger, so it is possible to eliminate the fear of freezing inside the user-side heat exchanger.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing electrical connections of the above embodiment, and FIG. 3 is a flowchart 1 to 4 showing the operation of the above embodiment. The figure is a block diagram of a conventional air conditioner, and FIG. 5 is an electric circuit diagram of a control section of the conventional air conditioner. In the figure, (1) is the compressor, (2) is the non-use side heat exchanger, ■ is the fan coil unit, ((5) is the use side heat exchanger, α (support) is the temperature detector, (11) (12) is compressor operation stop water temperature determination means; (12) is compressor operation time measurement means;
(13) is an outlet water temperature storage means, (14) is an outlet water temperature difference determination means, and (15) is a compressor operation stop means. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Patent Attorney Masu Oiwa Yusho Nagi 10: ``'L Ibaraki Inuki, Ding 2 Zusai 4 bu 5 0a "

Claims (1)

[Claims] A compressor that sucks in refrigerant and compresses and discharges it, a non-use side heat exchanger that exchanges heat between the refrigerant supplied from this compressor and the fluid to be heat exchanged, and an air conditioner that connects the refrigerant supplied from the compressor with a fan coil unit. A user-side heat exchanger that exchanges heat with the air conditioning circulating water that is circulated between the load device and a temperature detector that detects the outlet water temperature of this user-side heat exchanger and generates an output signal according to the temperature. , compressor operation stop water temperature determination means for generating an output signal for operation or stop when the output signal of the temperature detector reaches a signal level corresponding to a preset temperature; an output water temperature storage means for storing the output signal of the temperature detector when the operation output signal is generated; a compressor operation time measurement means for starting measuring the operation time of the compressor; When the measurement time reaches a predetermined value, the output signal stored in the outlet water temperature storage means and the output signal of the temperature detector are compared, and the signal level difference between them corresponds to a preset temperature difference. outlet water temperature difference determining means for generating an output signal when the signal level difference is not reached;
Compressor operation stop means for operating or stopping the compressor based on the output signal of the compressor operation stop water temperature determination means and for stopping the compressor based on the output signal of the outlet water temperature difference determination means. harmonization device.