JPS6277538A - Derfosting device of air conditioner - Google Patents

Abstract

PURPOSE:To obtain a proper defrosting timing by carrying out the control of defrosting start reference temperature such that it is decreased at a high output time and increased at a low output time. CONSTITUTION:In the case of detecting the frosted state of a heat source side coil, the device detects whether the ability of the compressor is high or low. When a reference temperature of defrosting starting temperature setting means 10 is decreased during a high output operation by the operation of reference temperature change instruction means 11 of a microcomputer 26 and during a low output operation, the reference temperature is increased. Particularly, starting of any unnecessary defrosting operation due to an erroneous judgement on the temperature lowering phenomenon of a heat source side coil when the air conditioner is operated at a high output, can be prevented. Further, since the state of the defrosting amount relates to the time required for the preceeding frosting, if the time required for the proceeding defrosting, is shorter than the reference defrosting time, the defrosting starting temperature at this time is decreased by reference temperature correction instructing means to prevent the air conditioner from entering into the defrosting operation. the frosting amount is set to a substantially predetermined value and defrosting time is brought close to the reference defrosting time and stabilized.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is applied to an air conditioner in which a heat pump heating operation is performed using outside air as a heat source, and the compression capacity of the compressor is adjusted depending on the size of the air conditioning load. The present invention relates to a defrosting device capable of (Prior art) It is widely known that in outside air heat source type air conditioners, frost forms on the heat source side coil during heating operation, reducing the heating capacity. Kosho 53-29
23) As disclosed in the publication, by utilizing the phenomenon that the temperature of the frosted part of the heat source side coil decreases due to frost formation,
If the temperature falls below a predetermined temperature, it is determined that frost has formed and the refrigeration circuit is reverse cycled to perform defrosting operation. (Problems to be Solved by the Invention) The above-mentioned defrosting device is a set that simply detects the frosting state by temperature change and performs the defrosting operation. Since the operation is carried out, many devices have recently been used that are combined with a timer to provide an interval of about 60 minutes, for example, to perform defrosting control in terms of both temperature and time. However, even such a defrosting control device has practical problems as described below. In other words, in an air conditioner equipped with a variable capacity expansion compressor whose capacity is automatically adjusted according to the air conditioning load, the compression capacity changes depending on the heating load. This results in a large change in the evaporation temperature of the engine, and especially when operating at high output, the drop in suction pressure causes the evaporation temperature to drop significantly, resulting in a state where the temperature drops below the set temperature value. As a result, the amount of frost buildup increases and defrosting becomes necessary, and there is the inconvenience that defrosting operation is started in vain even though defrosting is not necessary. -1. As shown in diagram gIJ7 of the frosting state of the heat source side coil in a heat pump air conditioner, region A is very prone to frosting, but region B is less frosty than region A.
Moreover, it is known that as the temperature decreases, the development of frost becomes even slower. Therefore, under low temperature and low humidity outside air conditions, the development of frost becomes extremely slow, and there is no need to perform defrosting operation. However, due to the drop in outside air temperature and the drop in the temperature of the heat source coil due to the high capacity of the compressor, the defrost control device judges that a considerable amount of frost has formed, and it continues to freeze for a certain period of time. This means that the defrosting operation will be repeated every time, resulting in an unnecessarily frequent defrosting operation. From this point of view, if humidity is detected in addition to temperature, and the defrosting operation start temperature is lowered as the humidity decreases, frequent defrosting operations can be completely prevented, but it is difficult to accurately detect humidity. There were problems in that it was difficult to do so, and the equipment for detecting humidity was expensive. The present invention has been made in order to address and improve the drawback that the conventional device frequently performs unnecessary defrosting operations. This function automatically corrects the compressor setting temperature by lowering it when the compressor is operating at high capacity and increasing it when the compressor is operating at low output, thereby preventing unnecessary defrosting operation. Both attempts to reduce the number of defrosting operations and improve the cumulative heating capacity by keeping the amount of frost formed at the time of defrosting constant. Furthermore, in the second invention, focusing on the fact that there is a relationship between the degree of frost formation and the time required for the previous defrosting, the previous defrosting time is the standard. Depending on the length of the frost time (set value), especially when the time of the previous defrost was short, the amount of frost formed can be reduced by lowering the defrost start temperature for the next defrost. When there is less 2
This is done by delaying the point at which defrosting begins, thereby eliminating unnecessary defrosting operations and further enhancing the advantage of increasing the cumulative heating capacity. . (Means for Solving the Problems) As is clear from FIG. 1 and FIG. 3 showing an embodiment, the present invention provides a compressor+11. Air-type heat source side coil 13
F. In an air conditioner equipped with a pressure reducer (4I, user side coil + 5) and in which heat pump heating operation is performed, a coil temperature detection means (8) and a compression capacity detection means (9), which will be described later, are used.
), a defrosting start temperature setting means (10), a reference temperature change command means fill, a defrosting operation command means α2, and a defrosting means [13]. The coil temperature detection means (8) detects the temperature of the frosted part of the heat source side coil (3), and is formed in a circuit or the like that outputs the temperature as an analog electrical signal. ) is the coil temperature detection means (
8) The compression capacity of the compressor is detected in synchronization with the detection operation of step 8), and if the motor of the compressor (1) is steplessly controlled to rotate by one set of inverters, the control It is formed into a circuit that outputs the command element frequency (Hz) as an analog electrical signal and -. The defrosting start temperature setting means (10) determines whether the frosting state that requires defrosting is set on the heat source side coil.

[3] Temperature drop in the frosted area e.g. -1
Assuming that it occurs at 2℃ or below, the standard temperature for starting defrosting is set at 11℃.
The temperature is set at 2° C., and is formed by a circuit that uses a variable resistor as an element and outputs the temperature as an analog electrical signal. Reference temperature change command means (11 is a compression capacity detection means (9)
), the defrosting start temperature setting means (10) calculates a temperature value having a linear function relationship with a negative coefficient for the compression capacity detected in
A temperature change signal is generated to lower the reference temperature when the compression capacity is large, and to raise it when the compression capacity is small. The defrosting operation command means α2 receives the coil temperature signal detected by the coil temperature detecting means (8) and the defrosting start temperature setting means (1).
0), and when the reference temperature signal value becomes equal to or less than the coil temperature signal value, a defrosting operation command signal is transmitted. Finally, the defrosting means 13 is activated by the defrosting and operation command signal sent by the defrosting operation command means (2), and the heat source side coil 1
3+ is heated until a defrosting end command is given, for example, the four-way switching valve in the refrigeration circuit is switched to the cooling cycle side, the fan for the heat source side coil +3) is stopped, and the compressor It has a function of defrosting the frosted part of the heat source side coil (3) by heating the frosted part of the heat source side coil (3) with the refrigerant itself by performing operations such as operating the +11 at the rated output. Furthermore, in the second invention of the present invention,
For the above configuration, the reference time of defrosting operation, i.e.
Appropriate defrosting time for standard frost amount, e.g. 4
A reference defrosting time setting means (14) which includes a clock pulse circuit for setting minutes and the time required for the previous defrosting operation is measured, for example, by detecting the operating time of the defrosting means [13]. In addition, a defrosting time measuring means (I5) stores the defrosting time until the start of the next defrosting, and a means for setting the actual defrosting time measured by the defrosting time measuring means (15) and a standard defrosting time. The defrosting start temperature setting means (1) compares the defrosting start temperature with the reference time set by
Reference temperature correction command means α that issues a temperature correction command signal that lowers the reference temperature (set value) of 0) by the temperature correction value.
G is added, and the second
As illustrated in the figure. In addition, as the defrosting operation command means α2, for example, the second
As shown in the figure, there is a defrosting release temperature setting means αB that can determine the completion of defrosting when the amount of frosting reaches a set temperature, and a maximum time that sets a limit time, for example, 10 minutes, for allowing the defrosting operation. Defrosting time setting means 08) and said defrosting means 0
Defrosting operation command output means (1
9), and comparators -, (211, and (221) that perform a comparison between the setting conditions and the temperature for one hour of defrosting operation. When detecting the frosting state of Lower the temperature at high output,
By increasing the output at low outputs, the heat source side coil 13), especially when operating at high outputs, may be mistakenly judged to be caused by frost formation, leading to unnecessary defrosting operations.
It has a function to prevent this from happening. Furthermore, the second invention focuses on the fact that the state of the frost amount is related to the time required for the previous defrosting, and the second invention focuses on the fact that the state of the frost amount is related to the time required for the previous defrosting. For example, the current defrosting start temperature is lowered by the reference temperature correction command means αG to prevent defrosting from occurring, and the amount of frosting is kept constant to ensure that the defrosting time approaches the reference defrosting time stably. It is possible to do so. In this way, the occurrence of frequent defrosting operations is reduced, and the cumulative heating capacity is improved and stabilized. (Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings. FIG. 3 is a refrigeration circuit diagram of a separate layer heater according to an embodiment of the present invention, in which an outdoor unit (0) includes a compressor (1
1. Four-way switching valve (2I, air type heat source side coil ca+
The indoor unit is equipped with a heat source side fan 161 and an accumulator (23) for the pressure reducer (4) such as a capillary tube and heat source side coil +3).

[Engineering] has
A user-side coil 15) and a user-side fan for the coil (7)
) is equipped with a reversible refrigeration cycle by connecting both units (03 and (1) with a liquid pipe (gas pipe I25) and connecting the piping as shown in the figure. During cooling operation, the heat source is The side coil (3) acts on the condenser, and the use side coil f5+ acts on the evaporator, respectively, and during heating operation, they act in the opposite relationship to the above. In the air-conditioning machine equipped with the above-mentioned refrigeration circuit, the micro-combinator (fourth
Figure) Compressor function force control means 13))
Similarly, it has a defrosting means α3) that is controlled when defrosting is required during heating operation, but it has a compression function power control means (α3).
)1, for example, the frequency of the AC voltage applied to the motor (IM) of the compressor 11) is set to 30 H2 to 120 H2.
An inverter H is used that can increase and decrease the voltage in multiple stages between 2 and 2, and can also change the voltage value accordingly, and is equipped with an outdoor unit. On the other hand, the defrosting means t13) includes a relay (not shown) that provides an output to switch the solenoid of the four-way switching valve (2) to the cooling cycle side, and a relay (not shown) that stops the operation of the heat source side fan 16). The outdoor unit (0) is equipped with the microcomputer (not shown) and the microcomputer (261) as shown in FIG.
2), a memory (storage device) t28), a clock generator (29) that generates a clock signal used to form a clock pattern inside the micropro sevensaro, and an input/output signal processing circuit (interface). 7.) A device consisting of a (301ECit, :I
Ih-tMK@an stage (8), for example, the outdoor unit (
The coil temperature signal from the thermistor disposed at the frosting part of [ω heat source side coil] 3) is inputted as a digital signal. Hereinafter, the control mode of the defrosting operation of the air conditioner will be explained with reference to the circuit diagram of FIG. 4 and the flow chart of FIG. 5. When heating operation is performed by turning on the operation switch (not shown), the air conditioner enters heating operation, but the inverter remains in operation until stable operation is reached approximately 1 minute after operation. (3N) while the frequency change command is issued and for a predetermined period of time (approximately 30 seconds) until the temperature stabilizes after the frequency change, temperature detection by the coil temperature detection means (8) is suspended, etc. during normal operation. A time guard is applied to prohibit similar control (step c)].The microprocessor determines whether to release the time guard due to an excess of 10 minutes [step G/1], and the coil temperature detection means (8) The detected coil temperature (Td) is input by the microprocessor at a set period of every second (step (-J). At the same time as this step, the capacity of the compressor (1) is checked (in this case, the control frequency ( H2)) (Step (e)), then check the reference temperature (however, there is an initial value) that is preset as the point at which defrosting must start (XI corresponds to the compressor output). Reference temperature (T
A microprocessor (271gc) is used to perform the calculation (step (to)) for changing the temperature to d).
Step (e) is the compression ability detection means (9), step (e)
) corresponds to the reference temperature change command means 111, and the reference temperature change command means (first) performs the following calculation as a specific example. ra= -aIP -l x 1 However, a: constant, tail 1P: operating frequency ()iz) Assuming that the output frequency of (3)) is 60 H2 within the range of 30 to 120 H2, Td =--, -12 key -16 rounded off to the decimal place. The calculation result is obtained and the temperature is changed to -16°C. Next, the temperature (T
Defrost start reference temperature (T) calculated in step (Q) and step (to)
d) (step (g)). This step (g) corresponds to the comparator eu c (Fig. 2) in the defrosting operation command means α2, and among the standard temperature values before change, the design standard temperature is set as an initial value at the time of air-conditioner design. (-12°C) corresponds to the defrosting start temperature setting means not (FIG. 2). If the comparison result in step (g) is To≦Td, the microprocessor (271) transmits a defrosting operation command signal (in step (h), the defrosting means (13) t
: Operate (step (S)). This step M corresponds to the defrosting operation command means (12+), and thus, by the operation of the defrosting means αJ, the four-way switching valve (21 is switched to the cooling cycle side). At the same time, the output frequency of the inverter (3)) was changed to the lowest 30H2, and the fan (61 and the fan 71 of the coil 13) on the heat source side (61 and the coil used +5) was stopped, and the defrosting operation using hot gas was started. In addition, after about 40 seconds have elapsed, the inverter Gυ is forced to change its output frequency to 90 H2, which is the standard for all. By flowing to the heat source side coil 13), the coil +3)
The frost that adheres to the surface is melted. It is detected by a known means such as a total temperature detector that defrosting has been completed. Return to heating operation [Step 4]. In this way, when determining whether defrosting is necessary, the capacity of the compressor +1) at that time is checked, and if the output is high, the defrost start temperature is lowered to prevent the phenomenon of a decrease in the evaporation temperature. Since the defrosting operation is made possible, unnecessary entry into defrosting operation can be avoided. Next, FIG. If the comparison result in step (G) is 're≦Td, the actual defrosting start reference temperature is corrected by the microprocessor port [step (blade)], and the next step (4) is performed. Value between the reference temperatures according to the actual situation X =--aF
-lTe1. This is Te (T
d, the reference temperature (Td) is changed by changing the flash value, so it is necessary to find (X) which corresponds to the temperature at the actual start of defrosting. . Step (1) Subsequently, the defrosting operation command signal is transmitted (step cause), and the defrosting means (3) is activated (step (1 sword). Synchronized with the operation of this step (su), the defrosting means (3) is activated every minute. The count of the defrosting operation time (td) is started (step (2)) is performed, and step [+7] corresponds to the defrosting time measuring means (15). The set defrost release temperature (Tf) and coil detection temperature (Te) are compared (step force), and the defrost operation time (td) and maximum defrost time (tf) are set to 10 minutes, for example. (Step (Tsukasa), To) If Tf or Te≦Tf, or td>tf, that is, the coil temperature (Te) has risen after defrosting has finished, or the coil temperature (Te) has increased after 10 minutes. Once the time has elapsed, the transmission of the defrosting operation command signal is canceled, the defrosting is completed, and the original heating operation C is resumed (step 4). What is performed is the defrosting release temperature setting means [171, and this temperature (Tf)
The comparator ω of the defrosting operation command means 110) compares the detected coil temperature (Te). Further, the maximum defrosting time setting means a8 in the defrosting operation command means u21 sets the maximum defrosting time (tf).
The comparator Qz of the defrosting operation command means u2) compares the difference in magnitude between the holding intervals (ta) and (tf). Therefore, around the same time as the return to heating operation (step 4), the defrosting operation time (ta) and the preset standard defrosting time (tm) are input and the temperature correction signal is calculated (2 (
ta-tm)) and the setting change of adding this calculation result to the set temperature (Ta) is performed by the microprocessor [271 (step H)), and the defrosting operation is made to wait for the next defrosting operation. In this case, what sets the reference defrosting time (tm) is the reference defrosting time setting means 04), which is set in advance at the time of designing the air conditioner. Also, for the calculation of Td-)-2(td-tm), σl
This step of changing the settings corresponds to the reference temperature correction command means (161). For example, if the previous defrosting time (td) was 3 minutes,
-4) "-2,! If it is 5 minutes, calculate the calculation result of 2 (5-4) = 2 and set this as the set temperature (Td), for example -16℃
The value of -18°C or -14°C added to that will be the next defrosting start temperature. This means that when the actual defrosting time is shorter than the standard defrosting time (tm), a signal is issued to lower the N removal start temperature by 2°C, and conversely, when it is longer than the standard defrosting time, a signal is issued to raise it by 2°C. This clearly indicates that the correction value has a function of changing the correction value depending on the length of ≦. In this way, when the time required for the previous defrosting is longer than the standard defrosting time (tm), it is determined that the amount of frost formation is large and the defrosting start standard temperature is set higher, and conversely, when the time required for the previous defrosting is shorter than the standard defrosting time (tm), frost formation Judging that the amount is small, the defrosting start standard temperature is set lower, so that the amount of frost at the start of defrosting is kept constant regardless of changes in the outdoor environment, and the defrosting time is approximately the same. This makes it possible to keep the humidity constant, and avoid dehumidification malfunctions, especially at low temperatures and low humidity. By correcting the standard defrosting start temperature in conjunction with changing the standard temperature in accordance with the size of the compression output, unnecessary defrosting operations can be eliminated in a way that is more in line with the actual situation. will be exposed. (Effects of the Invention) As described in detail above, the present invention provides that in an air conditioner in which the compression output is adjusted high or low, the phenomenon in which the evaporation temperature of the heat source side coil fluctuates due to changes in the compression output affects the start of defrosting. To prevent this, the defrosting start reference temperature is lowered at high output.
Since the control is performed to increase the output when the output is low, appropriate defrosting timing can be obtained by avoiding starting the operation when defrosting is not necessary or performing the defrosting operation too early. Furthermore, the invention of the second port uses the time required for the previous defrosting as a barometer, and when it is shorter than the standard defrosting time, the gate determines that the amount of frost formation is low and starts the next defrosting. By further adding control to lower the starting temperature, the inconvenience of misjudging and defrosting only when necessary is eliminated, especially when no frost formation occurs in low temperature and low humidity conditions. Since defrosting is performed, frequent defrosting operations are eliminated and the cumulative heating capacity is improved and stabilized. Further, the present invention has the effect of increasing reliability by compensating for differences in defrosting start timing due to variations in performance of products in air conditioners.

[Brief explanation of drawings]

FIG. 1 is a block diagram clearly showing the configuration of the present invention, FIG. 2 is a block diagram clearly showing the configuration of the second invention of the present invention,
Fig. 3 is a device circuit diagram of an air conditioner/heater according to an embodiment of the present invention, Fig. 4 is a control circuit schematic diagram, and Figs. 5 and 6 are operations corresponding to Figs. 1 and 2, respectively. The explanatory flowchart, diagram gIJ7, is a temperature-humidity diagram showing a contrast between a frosted area and a lightly frosted area. Ill...Compressor, (3)...Heat source side coil. (41... pressure reducer, +5)... user side coil. (8) Coil temperature detection means. (9) Compression ability detection means. 1101...Defrosting start temperature setting means 1 (111...
Reference temperature change command means. 1121...Defrosting operation command means. a3...Defrosting means. (141... Reference defrosting time setting means. (15:... Defrosting time measuring means. 0ω... Reference temperature correction command means. 1st [(1 Fig. 5 Fig. 6

Claims (1)

[Claims] 1. A compressor (1) whose compression capacity is adjusted to a high or low level according to the air conditioning load, an air-type heat source side coil (3), a pressure reducer (
4) In an air conditioner that is provided with a user side coil (5) and performs heat pump heating operation, the coil temperature detection means (8) detects the temperature of the frosted part of the heat source side coil (3); Compression capacity detection means (9) detects the compression capacity of the compressor (1) in synchronization with the detection operation of the coil temperature detection means (8); 3), a negative coefficient is applied to the compression capacity detected by the defrosting start temperature setting means (10) that sets the reference temperature for starting defrosting, and the compression capacity detection means (9). calculate a temperature value having a linear function relationship, and issue a temperature change command signal to lower the reference temperature of the defrosting start temperature setting means (10) when the compression capacity is large, and to raise it when the compression capacity is small. The reference temperature change command means (11) compares the coil temperature signal detected by the coil temperature detection means (8) with the reference temperature signal from the defrosting start temperature setting means (10), and determines the reference temperature. A defrosting operation command means (12) that transmits a defrosting operation command signal when the signal value becomes equal to or less than the coil temperature signal value, and a defrosting operation command signal that the defrosting operation command means (12) transmits. A defrosting device for an air conditioner, comprising: a defrosting means (13) that is activated and heats the heat source side coil (3) until a defrosting termination command is given. 2. A compressor (1) whose compression capacity is adjusted according to the air conditioning load, an air-type heat source side coil (3), and a pressure reducer (
4) In an air conditioner that is provided with a user side coil (5) and performs heat pump heating operation, the coil temperature detection means (8) detects the temperature of the frosted part of the heat source side coil (3); Compression capacity detection means (9) detects the compression capacity of the compressor (1) in synchronization with the detection operation of the coil temperature detection means (8); ) defrosting start temperature setting means (10) for setting a reference temperature for starting defrosting, and reference defrosting time setting means (14) for setting a reference time for defrosting operation, based on the temperature drop in the frosted part of the a defrosting time measuring means (15) that measures and stores the time required for the last defrosting operation; the time measured by the defrosting time measuring means (15); and the reference defrosting time setting. When the time measured by the defrosting time measuring means (15) is shorter than the reference time by comparing the time with the reference time set by the means (14) and calculating a temperature correction value corresponding to the difference. , the defrosting start temperature setting means (10
); and a linear function relationship having a negative coefficient with respect to the compression capacity detected by the compression capacity detection means (9). The reference temperature, which is corrected by the first temperature change command signal of the defrosting start temperature setting means (10), is further lowered when the compression capacity is large, and conversely raised when it is small. second to let
Reference concentration change command means (11) for issuing a temperature change command signal
), the coil temperature signal detected by the coil temperature detection means (8) and the reference temperature signal after temperature correction from the defrosting start temperature setting means (10) are compared, and the reference temperature signal value is determined. a defrosting operation command means (12) that transmits a defrosting operation command signal when the temperature drops below the coil temperature signal value; and a defrosting operation command signal transmitted by the defrosting operation command means (12), A defrosting device for an air conditioner, comprising a defrosting means (13) that heats the heat source side coil (3) until a defrosting end command is given.