JP2002071244A - Heat pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump outputting heat to the load side in which the effect of defrost operation is minimized. SOLUTION: In a heat pump where switching can be made between load corresponding operation for outputting heat to the load side while collecting head from the atmospheric air A by operating an air heat exchanger 2 for exchanging heat between refrigerant R and the atmospheric air A as a refrigerant evaporator E, and defrost operation for defrosting the air heat exchanger 2 by operating it as a refrigerant condenser C, a control means 11 performing defrost operation when a load Z decreases below a set threshold load Zs due to variation of load during the load corresponding operation is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump device for collecting heat from atmospheric air, and more particularly, to a heat pump device for exchanging heat between refrigerant and atmospheric air, which functions as a refrigerant evaporator to collect heat from atmospheric air. A heat pump that can switch between a load-adaptive operation that outputs heat to the load side and a defrosting operation that removes adhering frost in the air heat exchanger by using the air heat exchanger as a refrigerant condenser. Related to the device.

[0002]

2. Description of the Related Art Conventionally, in this type of heat pump device,
In the above-mentioned load-compatible operation, frost formation on the surface of the air heat exchanger (especially in winter) due to the cooling of moisture in the air due to the heat collection from the atmospheric air (especially in winter) A detecting means for detecting the state is provided, and when the detecting means detects frost formation of a predetermined amount or more, the operation is automatically switched from the load corresponding operation to the defrosting operation to perform the defrosting.

[0003] With respect to the detection of the frost formation state, the surface temperature of the air heat exchanger and the refrigerant evaporation temperature have fallen below a predetermined threshold temperature (a fixed threshold temperature or a threshold temperature changed according to the outside air temperature). A method of judging that the amount of frost has become a predetermined amount or more is generally adopted.

[0004]

However, in the above-described defrosting operation, since heat is taken from the load side that requires heat, even if heat is taken from a heat source different from the load side, the heat is transferred to the load side. In any case, since the thermal output is stopped or decreased, the load responsiveness is reduced.However, in the conventional device that performs the defrosting operation when the frost amount is equal to or more than a predetermined amount as described above,
It is uncertain when the defrosting operation is to be performed during the load corresponding operation, and the defrost operation is performed when the load during the load corresponding operation is large (that is, when the heat demand on the load side is large). In the form of adjusting the thermal output according to the load, the amount of heat taken from the air heat exchanger increases when the load is large, and the defrost operation is performed when the load is large. There is also a problem that the load responsiveness is greatly reduced by the defrosting operation in these points.

[0005] In view of this situation, the main problems of the present invention are:
The reason is that by reasonably performing the defrosting operation, it is possible to effectively suppress a decrease in load responsiveness caused by the defrosting operation.

[0006]

Means for Solving the Problems [1] In the invention according to claim 1, an air heat exchanger for exchanging heat between a refrigerant and atmospheric air functions as a refrigerant evaporator to extract heat from the atmospheric air to the load side. In a heat pump device that enables switching between a load corresponding operation that outputs heat and a defrosting operation that removes adhering frost in the air heat exchanger by functioning the air heat exchanger as a refrigerant condenser, A control unit is provided for performing the defrosting operation when the load becomes smaller than a set threshold load due to a load change during the execution of the load corresponding operation.

In other words, according to this configuration, the defrosting operation is performed when the load becomes smaller than the set threshold load (ie, when the required amount of heat on the load side becomes smaller) in the load corresponding operation. It is uncertain when the defrosting operation is to be performed during the load corresponding operation, and the defrosting operation is often performed at the time of a large load with a large thermal demand on the load side. The required heat can be more stably and reliably supplied to the load side in a state more appropriately responding to the heat demand on the side, and a reduction in load response caused by the defrosting operation can be effectively suppressed. .

In the case where the load device is a snow melting device or an anti-freezing device, the conventional heat pump device takes a load from the load side during a heavy load during a load operation (in other words, when the temperature on the load side is low). When the heating defrosting operation is performed, the temperature on the load side may be further reduced to cause a freezing trouble on the load side. However, when the load is small as described above (that is, when the temperature on the load side is somewhat high). If the defrosting operation is performed at (time), even if the defrosting operation is performed by collecting heat from the load side, it is possible to effectively prevent such a freezing trouble on the load side, and in this respect, it is even more excellent. It becomes a heat pump device.

[0009] In the practice of the invention according to claim 1, the defrosting operation is performed by taking heat from the load side, or
Heat is taken from a heat source different from the load side, or
Any of those combinations may be used.

In addition, various types of determination can be adopted for the determination of the load. In the type in which the thermal output to the load is adjusted in response to the increase or decrease of the load in the load operation, the output is adjusted to the load. When it is necessary to adjust the thermal output of the engine to a lower side than the predetermined threshold output (including the output adjustment by stopping the operation), it is determined that the load has become smaller than the set threshold load, and the defrosting operation is performed. Is also good.

[2] According to the invention according to claim 2, claim 1
In carrying out the invention according to the present invention, a detection unit for detecting a frost state in the air heat exchanger is provided, and the control unit is configured to detect when a predetermined amount or more of frost is detected by the detection unit, and The defrosting operation is performed each time the load during the operation is smaller than the set threshold load.

In other words, in this configuration, similar to the above-described conventional heat pump device, the defrosting operation is performed when the amount of frost of the air heat exchanger exceeds a predetermined amount. By performing the defrosting operation even when the load becomes smaller than the set threshold load in the load corresponding operation, compared to the conventional heat pump device that performs the defrosting operation only for the It is possible to reduce the frequency of performing the defrosting operation with respect to the predetermined amount or more, thereby making it possible to perform the defrosting operation with respect to the frosting amount being equal to or more than the predetermined amount at the time of a large load during the load corresponding operation. It can be effectively suppressed, and in this regard, taking advantage of the effect of the invention according to claim 1,
It is possible to effectively prevent the load responsiveness from being reduced due to the defrosting operation, and to enhance the function of preventing freezing trouble on the load side.

[0013] In addition to performing the defrosting operation when the load becomes smaller than the set threshold load, the defrosting operation is also performed when the frost amount exceeds a predetermined amount. In a load-compatible operation, frost formation in the air heat exchanger is promoted due to external air conditions (temperature and humidity conditions of atmospheric air) and the like, resulting in excessive frost formation, leading to a large decrease in operation performance and operation trouble. Such a situation can be reliably avoided, and as a result, a heat pump device can be obtained that is more excellent in operation stability while effectively improving load responsiveness as a whole.

[3] According to the third aspect of the present invention, the first aspect
In the implementation of the invention according to the second or third aspect, after the defrosting operation is performed, the control unit may control the load during execution of the load corresponding operation to be smaller than the set threshold load during the set non-execution time. It is configured to omit the execution of the defrosting operation.

That is, according to this configuration, after the defrosting operation is performed, the time after the load-response operation is restarted is still short, and the stage or the time when the frost formation in the air heat exchanger has not yet been achieved has been reached. At a stage where the frost is still slight, the load becomes smaller than the set threshold load, so that the defrosting operation can be effectively prevented from being wastefully re-executed. A decrease in load responsiveness caused by driving can be more effectively suppressed, and load responsiveness can be further enhanced.

[4] In the invention according to the fourth aspect, the first aspect is provided.
In practicing the invention according to any one of the above-described items 3, the control means normally adjusts the thermal output to the load side in accordance with the increase or decrease of the load in the load corresponding operation, whereas the load corresponding operation is performed in the load corresponding operation. When the load is smaller than the set threshold load and the defrosting operation is performed, the configuration is such that the load corresponding operation in the excessive output state is extended for a set extension time and then the defrosting operation is performed. .

In other words, according to this configuration, the defrosting operation for the load becoming smaller than the set threshold load is performed by extending the load handling operation in an excessive output state as described above, thereby preliminarily applying an extra heat. The defrosting operation can be performed in a state in which the defrosting operation is performed at a small load with little effect on the load side, and the defrosting operation can be performed in a state of supplying heat to the load side. The adverse effect of heat can be reduced more effectively, and the load responsiveness can be more effectively improved. In particular, when the defrosting operation is performed by collecting heat from the load side, extra heat applied to the load side With
Freezing trouble on the load side due to heat collection from the load side can be more reliably prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a snow melting facility using a heat pump device, 1 is a liquid heat exchanger for exchanging heat of a refrigerant R with a heat source side heat transfer fluid W, and 2 is a refrigerant R with atmospheric air A. A heat exchanger for heat exchange, 2a is a fan for passing air A to be exchanged with the air heat exchanger 2, and 3 is a heat exchanger for load, which exchanges the refrigerant R with the load side heat transfer fluid L. It is.

The heat source side heat transfer fluid W and the load side heat transfer fluid L
, Various heat medium liquids such as water and brine can be used.

4 is a compressor, 5 is an expansion valve, 6 is a refrigerant guide circuit in which four check valves 6a to 6d are combined in a bridge circuit, 7 is a receiver, and V1 to V3 are first to third refrigerant path switching. The third four-way valves V4 and V5 are first and second on-off valves for switching the refrigerant path, and the heat pump circuit (refrigeration circuit) includes these and the three heat exchangers 1, 2, and 3 as main constituent devices. ) H is formed.

Reference numeral 8 denotes a snow melting heat exchanger as a load device that melts snow at a target of snow melting using the load side heat transfer fluid L as a heat source, and 9 denotes a snow melting heat exchanger 8 and a load heat exchanger. 3 is a load-side circulating passage for circulating the load-side heat transfer fluid L by the circulation pump 10.

In this snow melting facility, the four-way valve V
The following operations (a) to (e) are selectively performed by switching the refrigerant paths by 1 to V3 and the on-off valves V4 and V5.

(A) Operation corresponding to load of air heat source In this operation, as shown in FIG. 2, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-pair load heat exchanger 3-refrigerant guide circuit 6 -Receiver 7-Expansion valve 5-Refrigerant guide circuit 6-Second four-way valve V2-Air heat exchanger 2- First
The four-way valve V1-the third four-way valve V3-the compressor 4 are circulated in this order.

That is, the refrigerant circulation causes the heat exchanger for air 2 to function as the refrigerant evaporator E and the heat exchanger for load 3 to function as the refrigerant condenser C.
In the form of collecting heat from the air A, the load-side heat transfer medium L sent to the snow-melting heat exchanger 8 is heated and heated to the load side, and the heat is used to melt snow.

(B) Operation corresponding to the load of the two heat sources (air → liquid) In this operation, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-to-load heat exchanger 3 as shown in FIG. -Refrigerant guide circuit 6-receiver 7-expansion valve 5-refrigerant guide circuit 6-second four-way valve V2-air heat exchanger 2-first
The on-off valve V4-the liquid heat exchanger 1-the third four-way valve V3-the compressor 4 are circulated in this order.

That is, by this refrigerant circulation, the heat exchanger for air 2 and the heat exchanger for liquid 1 are made to function as a refrigerant evaporator E in a serial arrangement in that order, and the heat exchanger for load 3
Function as a refrigerant condenser C, thereby heating the load-side heat medium liquid L sent to the snow-melting heat exchanger 8 in the form of collecting heat from both the air A and the heat-source-side heat medium liquid W to the load side. The heat is output, and the snow melts with this heat.

(C) Operation corresponding to load of liquid heat source In this operation, as shown in FIG. 4, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-to-load heat exchanger 3-refrigerant guide circuit 6 -Receiver 7-Expansion valve 5-Refrigerant guide circuit 6-Second four-way valve V2-Liquid heat exchanger 1-Third four-way valve V3-Compressor 4

That is, by this refrigerant circulation, the liquid heat exchanger 1 functions as the refrigerant evaporator E and the load heat exchanger 3 functions as the refrigerant condenser C.
In a mode in which heat is taken from the heat source side heat medium liquid W, the load side heat medium liquid L sent to the snow melting heat exchanger 8 is heated to output heat to the load side, and the heat is used to melt snow.

(D) Defrosting operation of liquid heat source In this operation, as shown in FIG. 5, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-air heat exchanger 2-second on-off valve. V5-receiver 7-expansion valve 5-refrigerant guide circuit 6-second four-way valve V2-liquid heat exchanger 1-third four-way valve V3-compressor 4

That is, by this refrigerant circulation, the liquid heat exchanger 1 functions as the refrigerant evaporator E and the air heat exchanger 2 functions as the refrigerant condenser C.
The defrosting of the air heat exchanger 2 is performed in such a manner that heat is taken from the heat source side heat medium liquid W.

(E) Defrosting operation of load side heat source In this operation, as shown in FIG. 6, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-air heat exchanger 2-second four-way valve. Valve V2-refrigerant guide circuit 6-receiver 7
-Expansion valve 5-refrigerant guide circuit 6-load heat exchanger 3-first
The four-way valve V1-the third four-way valve V3-the compressor 4 are circulated in this order.

That is, the refrigerant circulation causes the heat exchanger 3 on the load side to function as the refrigerant evaporator E and the heat exchanger 2 on the air to function as the refrigerant condenser C, thereby collecting the heat from the load side. The defrost of the air heat exchanger 2 is performed in a heated form.

S 1 is a sensor for detecting the temperature t 1 of the heat source side heat transfer fluid W supplied to the liquid heat exchanger 1, S 2 is a sensor for detecting the temperature t 2 of the air A passing through the air heat exchanger 2,
S3 is the temperature t3 of the load side heat transfer fluid L sent to the snow melting heat exchanger 8.
Is a sensor that detects

A controller 11 automatically selects and executes each of the above-mentioned operations based on the temperatures detected by the sensors S1 to S3. This controller 11 automatically controls the operations corresponding to the loads (a) to (c). As a selection, a state point P (t1, t2) using the temperature t1 of the heat source side heat transfer fluid W detected by the sensors S1 and S2 and the temperature t2 of the air A as parameters is selected as shown in FIG. In the situation in the area K1 on the criterion D1, the load corresponding operation of (a) in which heat is taken only from the air A is selected and executed, and in the situation where the state point P (t1, t2) is in the area K2, The operation corresponding to the load (b) in which heat is taken from both the heat source side heat transfer fluid W is selected and executed, and the state point P
In a situation where (t1, t2) is in the region K3, the load corresponding operation of (c) in which heat is taken only from the heat source side heat transfer fluid W is selected and executed.

In each of the load-aware operations (a) to (c), the controller 11 adjusts the thermal output according to the snow melting load Z based on the temperature t3 detected by the sensor S3. The output G is adjusted stepwise or continuously as shown in FIG. 9 by capacity control, inverter control, or the like, and the temperature t3 of the load-side heat transfer fluid L to be sent to the snow melting heat exchanger 8 falls within a set appropriate temperature range. To keep.

In the load-response operation (a) or (b), which involves taking heat from the air A, the controller 11 reduces the amount of frost in the air heat exchanger 2 during the operation. When the above is detected by the detecting means, and
When it is necessary to adjust the output G of the compressor 4 to a lower side than the set threshold output Gs in the above-described output adjustment (in the present embodiment, the compressor 4 in a stepwise manner as shown in FIG.
The operation is automatically switched to the defrosting operation of (d) or (e) for each of the cases (when it is necessary to stop the compressor in the output adjustment of (1)).

Then, as an automatic selection of the defrosting operation of (d) or (e), the controller 11 removes the temperature t1 of the heat source side heat transfer fluid W detected by the sensor S1 and the (e). The state point Q in which the temperature t3 of the load-side heat transfer fluid L detected by the sensor S3 during execution of the frost operation is used as a parameter.
In the situation where (t1, t3) is in the region M1 on the preset selection criterion D2 as shown in FIG. 8, the heat source side heat transfer fluid W
In the situation where the state point Q (t1, t3) is in the region M2, the defrosting operation of (e) for collecting heat from the load side is selectively performed. .

It should be noted that (d) and (e) for the defrosting amount exceeding the predetermined amount and for the need to stop the compressor due to the output adjustment of the compressor 4 (d). ,
The defrosting operation of (e) automatically ends according to a termination criterion determined for each, such as terminating at the time of detection of completion of defrosting, terminating at the elapse of the set defrosting time, and the like.
Thereafter, the process returns to the selection execution of the load corresponding operation of (a) to (c).

In FIG. 7, ta is a set threshold air temperature for determining whether or not to take heat from the heat source side heat transfer fluid W in the load corresponding operation, and tb, tc are heat source side heat transfer fluid W side in FIG. Freezing dangerous temperature and freezing caution temperature set for
d and te are the freezing dangerous temperature and the freezing caution temperature set for the load side, and in the automatic selection of the defrosting operation, the detected heat medium liquid temperature t on the heat source side and the load side by the sensors S1 and S3.
When the temperatures 1 and t3 are both between the freezing dangerous temperature and the freezing caution temperature, and when both of them are higher than the freezing caution temperature, the defrosting operation of (d) is selected and performed, so that the heat source as a whole is The defrosting operation of (d), in which heat is taken from the side heat medium liquid W, is prioritized, so that the heat taken from the load side is reduced as much as possible.

As shown in FIG. 9, the controller 11 further controls the compressor 4 in the load corresponding operation (a) or (b).
When it is necessary to stop the compressor in the output adjustment, the load operation at the current compressor output G (that is, the load operation in the excessive output state) is set longer than when the output is adjusted to another stage. After extending for the time Te (for example, about 30 minutes to 2 hours), the process shifts to the execution of the defrosting operation (d) or (e).

That is, this allows the defrosting operation to be performed in a state in which extra heat is applied to the load side in advance, whereby the defrosting operation is affected by the influence on the load side as described above. Along with performing when a small amount of compressor stoppage is necessary (that is, when the snow melting load Z is small), it is possible to more effectively suppress the adverse effect on the heat supply side that the defrosting operation has on the load side, and (E) In the selective execution of the defrosting operation of (e), the freezing trouble on the load side caused by the heat collection from the load side is more reliably prevented.

As shown in FIGS. 10 and 11, after the previous defrosting operation, the controller 11 performs the load corresponding operation during the non-setting time Tx (for example, about 10 to 24 hours). Execution of the defrosting operation (defrosting operation indicated by a broken line in FIG. 11) for the necessity of stopping the compressor due to the output adjustment of the compressor 4 is omitted, and thus, after the defrosting operation is performed, the load corresponding operation is performed. The time after restarting is still short, and the useless defrosting operation is prevented at a stage where frost formation in the air heat exchanger 2 has not yet been achieved or at a stage where frost formation is still slight.

As described above, in the present embodiment, the controller 11
Indicates that the load Z is smaller than the set threshold load Zs (corresponding to the set threshold output Gs described above) in the (A) or (B) load operation in which the air heat exchanger 2 functions as the refrigerant evaporator E. Control means for performing a defrosting operation each time when it is detected and when it is detected that the amount of frost in the air heat exchanger 2 has exceeded a predetermined amount.

After the defrosting operation is performed, the controller 11 sets the load Z smaller than the set threshold load Zs in the load corresponding operation (a) or (b) during the set non-execution time Tx. Omission of the defrosting operation for that,
In (a) or (b) load operation, the thermal output (corresponding to the compressor output G) to the load side is normally adjusted in accordance with the change in the load Z, whereas (b) or (b) When the load Z is smaller than the set threshold load Zs and the defrosting operation is performed in the load corresponding operation, the load corresponding operation in the excessive output state is extended for the set extension time Te and then the defrost operation is performed. Configuration.

In the snow melting facility of the present embodiment, in addition to the above operations (a) to (e), the following (f)
(H) operation can be selected and executed.

(F) Operation corresponding to load of reverse two heat sources (liquid → air) In this operation, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-to-load heat exchanger 3-refrigerant guide circuit. 6-Receiver 7-Expansion valve 5-Refrigerant guide circuit 6-Second four-way valve V2-Liquid heat exchanger 1-Third four-way valve V3-Second
Four-way valve V2-to air heat exchanger 2-first four-way valve V1-third
Circulate in the order of the four-way valve V3-compressor 4.

That is, due to the refrigerant circulation, the liquid heat exchanger 1 and the air heat exchanger 2 are both arranged in series in this order to function as the refrigerant evaporator E, and the heat exchanger for load 3
Function as a refrigerant condenser C, thereby heating the load-side heat medium liquid L sent to the snow melting heat exchanger 8 in the form of collecting heat from both the heat-source-side heat medium liquid W and the air A to the load side. The heat is output, and the snow melts with this heat.

(G) Combined operation for defrost / load In this operation, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-air heat exchanger 2-second four-way valve V2-third. Four-way valve V3-first four-way valve V1-load heat exchanger 3-refrigerant guide circuit 6-receiver 7-expansion valve 5-refrigerant guide circuit 6-second four-way valve V2-liquid heat exchanger 1-third
Circulate in the order of the four-way valve V3-compressor 4.

That is, by this refrigerant circulation, the liquid heat exchanger 1 functions as the refrigerant evaporator E, and the air heat exchanger 2 and the load heat exchanger 3 are condensed together in a serial arrangement in that order. The load-side heat medium liquid L sent to the snow melting heat exchanger 8 is heated and melted in the form of collecting heat from the heat source-side heat medium liquid W. The defrost of the heat exchanger 2 is performed.

(H) 2 heat source defrosting operation In this operation, in the heat pump circuit H, the refrigerant R is supplied to the compressor 4-first four-way valve V1-air heat exchanger 2-second four-way valve V2-refrigerant guide circuit 6 -Receiver 7-Expansion valve 5-Refrigerant guide circuit 6-Load heat exchanger 3-First four-way valve V1-Third four-way valve V3-Second four-way valve V2-Liquid heat exchanger 1-Third
Circulate in the order of the four-way valve V3-compressor 4.

That is, by this refrigerant circulation, the heat-to-load heat exchanger 3 and the liquid-to-liquid heat exchanger 1 are made to function as a refrigerant evaporator E in a serial arrangement in that order, and the heat-to-air heat exchanger 2
Function as a refrigerant condenser C, whereby the defrosting of the air heat exchanger 2 is performed in such a manner that heat is collected from both the load side and the heat source side heat transfer fluid W.

[Another Embodiment] Next, another embodiment will be described.

In the above-described embodiment, the defrosting operation in which heat is taken from the load side and the defrosting operation in which heat is taken from a heat source different from the load side are selected and executed. The present invention may be applied in a form in which only the operation is performed.

Further, in the above-described embodiment, the load corresponding operation in which heat is taken from the atmospheric air A, the load corresponding operation in which heat is taken from the heat source side heat transfer fluid W, and both the atmospheric air A and the heat source side heat transfer fluid W are used. However, the present invention can also be applied to a heat pump apparatus that does not perform the load corresponding operation of collecting heat from a heat source other than the atmospheric air A.

In the case where heat is taken from the heat source side heat transfer fluid W as in the above-described embodiment, the heat source side heat transfer fluid W includes natural water such as river water, lake water, groundwater, spring water, or the like. Various liquids can be used as long as they can collect heat, such as water or brine circulated with other devices such as a ground heat exchanger, a sewage heat exchanger, and a waste heat recovery heat exchanger.

In the above-described embodiment, when it is necessary to stop the operation by adjusting the thermal output (adjustment of the compressor output G) according to the load Z in the load corresponding operation, the load Z is set to the set threshold load Zs.
Although the defrosting operation is performed assuming that the temperature has become smaller, a load value that does not need to be stopped (for example, a load value corresponding to about 50% of the maximum thermal output) is used as the set threshold load Zs. May be.

In order to detect that the load Z has become smaller than the set threshold load Zs due to a load change during the execution of the load-corresponding operation, for example, the temperature or condition on the load side is detected.
Various load detection methods can be adopted, and the present invention is also applied to a heat pump device that does not adjust the thermal output according to the load Z but performs a load-compatible operation at a set constant thermal output. it can.

In the above-described embodiment, when the load Z during the load corresponding operation becomes smaller than the set threshold load Zs, and
The defrosting operation is performed for each of the cases where the amount of frost of the air heat exchanger 2 is detected to be equal to or more than a predetermined amount. However, in the case of use conditions where the amount of frost is relatively small, Alternatively, the defrosting operation may be performed only when the load Z during the load corresponding operation becomes smaller than the set threshold load Zs.

When the defrosting operation is performed when the load Z becomes smaller than the set threshold load Zs and when the frost amount exceeds a predetermined amount, the setting is not performed after the defrosting operation. During the time Tx, instead of only omitting the execution of the defrosting operation when the load Z becomes smaller than the set threshold load Zs, the execution of the defrosting operation when the frost amount becomes equal to or more than a predetermined amount is also omitted. You may make it.

In the case where the omission of the defrosting operation during the setting non-execution time Tx as described above is adopted, an appropriate time may be selected as the setting non-execution time Tx according to use conditions and the like. In some cases, the omission of the defrosting operation during the setting non-execution time Tx may not be performed.

Normally, in the load handling operation, the thermal output to the load side is adjusted in accordance with the increase or decrease of the load Z. On the other hand, in the load handling operation, the load Z becomes smaller than the set threshold load Zs, and the defrosting operation is started. When performing the defrosting operation after performing the load corresponding operation in the excess output state by the set extension time Te when performing the excess output, the excess output is the current output or the current output. The output may be any of large outputs, and an appropriate time may be selected as the set extension time Te in accordance with use conditions and the like.

The detecting means for detecting that the amount of frost in the air heat exchanger 2 has become equal to or more than a predetermined amount includes the surface temperature of the air heat exchanger 2, the refrigerant evaporation temperature, or the refrigerant evaporation pressure. Various types of detection methods, such as a method of detecting the amount of frost and a method of optically or electrically detecting the amount of frost, can be adopted.

The present invention can be applied not only to a heat pump apparatus for snow melting equipment but also to a heat pump apparatus for various uses. It may be something.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a snow melting facility using a heat pump device.

FIG. 2 is a diagram showing a flow of a refrigerant in a load operation of an air heat source.

FIG. 3 is a diagram illustrating a flow of a refrigerant in a load corresponding operation of two heat sources.

FIG. 4 is a diagram showing a flow of a refrigerant in a load operation of a liquid heat source.

FIG. 5 is a diagram illustrating a flow of a refrigerant in a defrosting operation of a liquid heat source.

FIG. 6 is a diagram showing a flow of a refrigerant in a defrosting operation of a load-side heat source.

FIG. 7 is a diagram showing selection criteria for load-adaptive operation.

FIG. 8 is a diagram showing selection criteria for a defrosting operation.

FIG. 9 is a graph showing an output adjustment mode.

FIG. 10 is a flowchart of defrosting operation execution control.

FIG. 11 is a graph showing an embodiment of a defrosting operation.

[Explanation of symbols]

 2 Heat exchanger for air 11 Control means A Atmospheric air C Refrigerant condenser E Refrigerant evaporator R Refrigerant Te Setting extension time Tx Setting non-performing time Z Load Zs Setting threshold load

Claims (4)

[Claims] 1. A load-adaptive operation in which a heat exchanger for air that exchanges heat between a refrigerant and atmospheric air functions as a refrigerant evaporator to extract heat from the atmospheric air and output heat to the load side, and the heat exchanger for air. A heat pump device that functions as a refrigerant condenser and enables switching to be performed with a defrosting operation that removes adhering frost in the air heat exchanger, wherein the load changes due to a load change during the execution of the load corresponding operation. A heat pump device provided with control means for performing the defrosting operation when the load becomes smaller than a set threshold load. 2. A detecting means for detecting a frosting state in the air heat exchanger, wherein the controlling means detects when a predetermined amount or more of frosting is detected by the detecting means, and when the load handling operation is performed. The heat pump device according to claim 1, wherein the defrosting operation is performed each time the load during execution becomes smaller than the set threshold load. 3. The defrosting operation according to claim 2, wherein after the defrosting operation is performed, the load during the execution of the load corresponding operation becomes smaller than the set threshold load during a setting non-performing time. 3. The heat pump device according to claim 1, wherein the heat pump device is configured to omit the operation. 4. The load control device according to claim 1, wherein the controller adjusts the thermal output to the load side in accordance with the increase or decrease of the load in the normal operation in the load corresponding operation, whereas the load in the load corresponding operation is smaller than the set threshold load. When performing the defrosting operation as described above, the load corresponding operation in an excessive output state is configured to perform the defrosting operation after performing the extension for a set extension time. Item 2. The heat pump device according to item 1.