JP6551783B2 - Heat pump device and hot water supply device provided with the same - Google Patents

Description

  The present invention relates to a heat pump device and a hot water supply device including the heat pump device.

There exists a thing of patent document 1 as an example of a heat pump apparatus.
In the heat pump device described in the document, frost formation is generated in the evaporative heat exchanger in the refrigeration cycle, and when this is detected, the defrosting operation is started. When frost is formed on the evaporative heat exchanger, the output and efficiency of the heat pump apparatus decrease, but such a defect can be eliminated by performing the defrosting operation.
Here, in the document, as a means for detecting frost formation, an example of judging the presence or absence of frost formation is given based on the amount of air blown from a fan and passing through the evaporative heat exchanger, for example. This is based on the fact that when frost formation occurs, the evaporation heat exchanger becomes clogged, and the air flow rate through the evaporation heat exchanger decreases. However, for example, clogging of the evaporative heat exchanger may occur due to a phenomenon other than frost formation. For example, the presence or absence of frost formation does not always correspond accurately with the passing air volume. For this reason, it can not be said that the above-mentioned means has a high accuracy in determining the presence or absence of frost formation.

  Therefore, as a means different from the above, the temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporator heat exchanger is detected, and when this temperature difference becomes equal to or more than a predetermined threshold, the evaporator heat exchanger is attached There is a means to judge that there was frost. Alternatively, when the change value of the temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporating heat exchanger becomes equal to or greater than a predetermined threshold with reference to the start of steady operation of the refrigeration cycle of the heat pump device. There is also means for determining that the evaporating heat exchanger has formed frost. In these means, when there is no frost formation in the evaporative heat exchanger and the heat exchange efficiency is high, the temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger is small, otherwise they are This is based on the principle that the temperature difference is large. According to such a method, it is possible to considerably increase the determination accuracy of the presence or absence of frost formation by a configuration that can be manufactured easily and inexpensively using a temperature sensor.

  However, the refrigerant outlet side temperature of the evaporative heat exchanger changes under the influence of the outside air temperature, the temperature of water entering the condensing heat exchanger for heating hot water during the refrigeration cycle, the outside air humidity, etc. Even when frost formation occurs, the temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger may not exceed a certain threshold value. For this reason, in the above-described means, the accuracy of determining the presence or absence of frost formation may be low, and there is room for improvement in this respect.

JP, 2012-207896, A

  The present invention has been conceived under the circumstances as described above, and it is possible to accurately judge the presence or absence of frost formation on the evaporative heat exchanger, and defrosting when frost formation occurs. It is an object of the present invention to provide a heat pump device that can appropriately operate and a hot water supply device including the heat pump device.

  In order to solve the above problems, the present invention takes the following technical means.

A heat pump apparatus provided by the first aspect of the present invention comprises: a condensing heat exchanger capable of heating water using a refrigerant; and a refrigeration cycle having an evaporation heat exchanger capable of absorbing heat from the outside air; A temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger is detected, and when this temperature difference becomes equal to or more than a predetermined first threshold, or when a predetermined steady operation of the refrigeration cycle is started. Control means for performing operation control to start the defrosting operation for the evaporative heat exchanger when the change value of the temperature difference as a reference becomes equal to or more than a predetermined second threshold value; In the heat pump apparatus, the first and second threshold values are changed according to a change in the temperature of the water so as to be lower as the temperature of the water entering the condensation heat exchanger becomes higher. Features that is composed To have.

According to such a configuration, the following effects can be obtained.
That is, when the temperature of water entering the condensation heat exchanger increases, the temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporation heat exchanger tends to be smaller, as in the case where the outside air temperature decreases. For this reason, when the incoming water temperature is high, the temperature difference when frosting occurs is a smaller value than when the incoming water temperature is low. On the other hand, if the threshold value for determining the presence or absence of frost formation is set to a lower value as the incoming water temperature becomes higher, the above-mentioned cause of frost formation occurs even if the temperature difference becomes smaller as described above. A change in temperature difference can be detected appropriately, and the accuracy of determining the presence or absence of frost formation can be increased. Since the said structure is a structure according to such a judgment method, when frost formation actually arises, a defrost operation is performed appropriately. As a result, as with the heat pump apparatus provided by the first aspect of the present invention, the heat pump apparatus is operated in an inefficient state without performing the defrosting operation despite the occurrence of frost formation. Is appropriately avoided.

According to a second aspect of the present invention, there is provided a heat pump apparatus comprising: a condensing heat exchanger capable of heating water using a refrigerant; and a refrigeration cycle having an evaporation heat exchanger capable of absorbing heat from the outside air; A temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger is detected, and when this temperature difference becomes equal to or more than a predetermined first threshold, or when a predetermined steady operation of the refrigeration cycle is started. Control means for performing operation control to start the defrosting operation for the evaporative heat exchanger when the change value of the temperature difference as a reference becomes equal to or more than a predetermined second threshold value; The heat pump apparatus, wherein the first and second threshold values are set to lower values as the outside air temperature is lower, and to lower values as the temperature of the water entering the condensation heat exchanger is higher. Temperature and the incoming water temperature It is characterized in that the is configured to be changed in accordance with each change.

  According to such a configuration, in order to change the threshold value for determining the presence or absence of frost formation based on both the parameters of the outside air temperature and the water entering temperature to the condensation heat exchanger, only the outside air temperature or the condensation heat is changed. It is possible to determine the presence or absence of frosting with higher accuracy than when the threshold value is changed based only on the incoming water temperature to the exchanger. Therefore, it is more preferable to prevent the heat pump device from being operated without performing the defrosting operation despite the occurrence of frost formation and to improve the efficiency of the heat pump device. In addition, the basic principle of the point that it is possible to improve the judgment accuracy of the presence or absence of frost by changing the threshold according to the outside air temperature and changing the threshold according to the temperature of water entering the condensing heat exchanger The same is as described for the heat pump apparatus provided by the first and second aspects of the present invention.

A hot water supply apparatus provided by a third aspect of the present invention includes the heat pump apparatus according to the present invention, and is characterized in that hot water heating for hot water supply is enabled by the heat pump apparatus.

  According to such a configuration, the same effect as described for the heat pump device according to the present invention can be obtained.

  Other features and advantages of the present invention will become more apparent from the description of the embodiments of the present invention given below with reference to the attached drawings.

It is explanatory drawing which shows an example of the hot-water supply apparatus provided with the heat pump apparatus which concerns on this invention. It is a flowchart which shows the example of the operation control performed in the heat pump apparatus of FIG. It is explanatory drawing which shows the example of the threshold value used by the operation control of FIG. It is a flowchart which shows the example of the other operation control performed in the heat pump apparatus of FIG. It is explanatory drawing which shows the example of the threshold value used by the operation control of FIG.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

A hot water supply device WH shown in FIG. 1 includes a heat pump device H and a hot water storage tank unit U.
The hot water storage tank unit U includes a hot water storage tank 2 and a main control unit 4 to which a remote controller 40 is connected. The hot water storage tank 2 is for storing hot water heated by the heat pump device H. A lower pipe 32 to which a water supply pipe 31 such as a water pipe is connected is connected to the lower part of the hot water storage tank 2, and water supplied from the water supply pipe 31 can enter the hot water storage tank 2 from the lower part. An upper pipe 33 having a three-way valve V1 is connected to the upper portion of the hot water storage tank 2, and a hot water discharge pipe 35 connected to the hot water supply plug 9 and a branch pipe 36 from the lower pipe 32 are connected to the upper pipe 33. It is connected via the mixing valve V2. Due to this, when the hot water supply plug 9 is opened, hot water is discharged by the water supply pressure to the hot water storage tank 2, and the hot and cold water discharged from the hot water storage tank 2 and the water from the branch pipe 36 are mixed and temperature controlled. Hot and cold water can be supplied to the hot water supply tap 9.

The heat pump device H includes a refrigeration cycle 1, a defrosting bypass path 18, and an auxiliary control unit 4A. The refrigeration cycle 1 includes, for example, an evaporation heat exchanger 10 for absorbing heat from the outside air (atmosphere), a compressor 11, and a condensation heat exchanger 12 capable of heating water, on a circulation flow path of a refrigerant such as CO ₂ . And the expansion valve 13 is provided. The condensing heat exchanger 12 can heat the hot water supplied from the lower part of the hot water storage tank 2 through the pipe 34 by driving the pump P, and the water supplied from the water supply pipe 31 through the pipe 34. The heated hot water can be sent into the hot water storage tank 2 through the pipe 37 and stored.

  The defrosting bypass passage 18 bypass-connects the downstream side of the compressor 11 of the refrigeration cycle 1 and the downstream side of the expansion valve 13 and has an on-off valve V3. By opening the on-off valve V3 and allowing the refrigerant to flow through the defrosting bypass path 18, a high-temperature refrigerant can be supplied to the evaporating heat exchanger 10, whereby defrosting from the evaporating heat exchanger 10 is prevented. It is possible.

  The heat pump device H includes an outside air temperature sensor Sa for detecting the outside air temperature, a refrigerant outlet side temperature sensor Sb for detecting the refrigerant outlet side temperature of the evaporating heat exchanger 10, and the water temperature entering the condensing heat exchanger 12. An incoming water temperature sensor Sc is also provided. The evaporative heat exchanger 10 is provided with a fan 10 a attached thereto, and this fan 10 a causes the outside air flowing into the housing 19 of the heat pump apparatus H to act on the evaporative heat exchanger 10. In FIG. 1, although the outside air temperature sensor Sa is disposed in the housing 19, the outside air temperature sensor Sa is configured to measure the temperature before the outside air that has flowed into the housing 19 is blown to the evaporative heat exchanger 10. It is provided so as to detect, and the outside air temperature can be detected appropriately.

  The auxiliary control unit 4A is configured using a microcomputer or the like as the main control unit 4 and executes data communication with the main control unit 4 and according to an instruction from the main control unit 4 or the like. Operation control of each part of the heat pump device H is executed. The operation control performed in the heat pump device H includes operation control for determining the presence or absence of frost formation on the evaporative heat exchanger 10, operation control of the defrosting operation, and the like, which will be described later.

  Next, the operation of the hot water supply device WH and an example of an operation processing procedure executed in the heat pump device H will be described with reference to the flowcharts shown in FIGS.

  First, during the operation of the heat pump device H, the temperature difference α (α = Ta−Tb) between the outside air temperature Ta and the refrigerant outlet side temperature Tb of the evaporative heat exchanger 10 is calculated constantly or periodically (S1). . Next, a first threshold TH1 for determining whether or not there is frost formation in the evaporative heat exchanger 10 is determined in accordance with the outside air temperature Ta and the temperature Tc entering the condensing heat exchanger 12 (S2) ). In this case, as in the specific example shown in FIG. 3, the first threshold value TH1 is set to a lower value as the outside air temperature Ta is lower, and to a lower value as the incoming water temperature Tc is higher. In FIG. 3, for example, when the outside air temperature Ta is -3 ° C and the incoming water temperature Tc is 25 ° C, the first threshold TH1 is 8 ° C, but the outside air temperature Ta decreases to -7 ° C, and the incoming water When the temperature Tc rises to 50 ° C. or more, the first threshold TH1 is set to 5 ° C.

However, FIG. 3 only shows a part of the first threshold value TH1 in a scattered manner, and the first threshold value TH1 can not be appropriately determined only by the contents shown in the figure. In practice, the first threshold value TH1 is calculated by using the outside air temperature Ta and the incoming water temperature Tc as variables, and using an arithmetic expression that is predetermined so that an appropriate value can be calculated as the first threshold value TH1. Desired. Of course, instead of this, data of a table closely showing the correspondence between the outside air temperature Ta and the incoming water temperature Tc and the first threshold value TH1, or linear data continuously showing the correspondence are shown in the auxiliary control unit 4A etc. The first threshold value TH1 may be determined based on this data.

  Thereafter, the temperature difference α between the outside air temperature Ta and the refrigerant outlet temperature Tb is compared with the first threshold TH1, and if the temperature difference α is the first threshold TH1 or more, frost is formed on the evaporative heat exchanger 10 The defrosting operation is started (S3: YES, S4). The defrosting operation is performed by opening the on-off valve V3 and feeding the high-temperature refrigerant into the evaporative heat exchanger 10. Although omitted in the drawing, the defrosting operation is terminated when, for example, the refrigerant outlet side temperature Tb is equal to or higher than a predetermined temperature (for example, 4 ° C.). On the other hand, unlike the above, when the temperature difference α is not the first threshold TH1 or more, the defrosting operation is not started, and the calculation processing of the temperature difference α continues thereafter and the first threshold TH1 A determination is made, and the presence or absence of frost formation is determined (S3: NO, S1 to S3).

According to the above-described series of operation control, the following operation can be obtained.
That is, as described in the "Summary of the Invention" section, when frost is formed on the evaporative heat exchanger 10, the temperature of the outside air temperature Ta and the refrigerant outlet temperature Tb of the evaporative heat exchanger 10 Although the difference α becomes larger, the lower the outside air temperature Ta, and the higher the temperature Tc entering the condensing heat exchanger 12, the smaller the temperature difference α in the case where frost formation occurs in the evaporative heat exchanger 10 Tend. On the other hand, in the above-described series of operation procedures, the first threshold TH1 is set to a lower value as the outside air temperature Ta is lower, and to a lower value as the inflow water temperature Tc is higher. And, even when frost formation occurs under conditions where the incoming water temperature Tc is high and the temperature difference α becomes a rather small value, it can be appropriately detected that frost formation is occurring. Therefore, the determination accuracy of the presence or absence of frost formation is enhanced, and the problem that the heat pump apparatus H is continuously operated as it is without the defrosting operation being performed despite the frost formation is avoided. Is possible.

  In the heat pump apparatus H, the following operation control is also performed in parallel with the above-described series of operation control.

That is, the heat pump apparatus H shifts to a predetermined steady operation after an appropriate time has elapsed since the start of the operation. After the transition to such a steady operation, the outside air temperature Ta, the incoming water temperature Tc, and the refrigerant outlet side temperature Tb in the initial stage of the steady operation are measured, and these are used as the reference outside air temperature Ta ₀ and incoming water temperature Tc _0. And the refrigerant outlet side temperature Tb ₀ , and the temperature difference α between the outside air temperature Ta and the refrigerant outlet side temperature Tb at that time is stored as the temperature difference α ₀ as the reference thereafter (S10 : YES, S11). Preferably, the values of the outside air temperature Ta ₀ , the incoming water temperature Tc ₀ , and the refrigerant outlet side temperature Tb ₀ are an average value or a median value of values measured a plurality of times in an appropriate span after the transition to the steady operation. Etc. are used. Similarly, as the temperature difference α ₀ , an average value or a median value of the temperature differences α calculated a plurality of times in an appropriate span after the transition to the steady operation is used.

Thereafter, it continues executing processing for calculating a temperature difference alpha at the current time, calculation of the change value Δα of the temperature difference alpha with respect to the temperature difference alpha ₀ as a reference is also continuously executed (S12). In addition to this, the evaporative heat exchange is made to correspond to the change values ΔTa, ΔTc of the outside air temperature Ta and the inflow water temperature Tc (which are change values with respect to the outside air temperature Ta _{0 at} the start of steady operation start and the inflow water temperature Tc ₀ ) A second threshold value TH2 for determining whether or not the vessel 10 has frost formation is determined (S13). In this case, as in the specific example shown in FIG. 5, the second threshold value TH2 is set to a lower value as the change value ΔTa of the outside air temperature Ta is smaller, and is higher as the change value ΔTc of the incoming water temperature Tc is larger. Value. In FIG. 5, for example, when change value ΔTa of outside air temperature and change value ΔTc of inflow water temperature are both zero, second threshold value TH2 is 4 ° C., but change value ΔTa is −5 ° C. When the value ΔTc reaches + 50 ° C., the second threshold value TH2 is set to 2.5 ° C.

  However, FIG. 5 shows only a part of the second threshold value TH2 in a dotted manner, as in the case of FIG. Actually, the process for obtaining the second threshold value TH2 is performed using an arithmetic expression in the same manner as in the case of obtaining the first threshold value TH1. The arithmetic expression in this case uses the change values ΔTa and ΔTc as variables. However, instead of this, the second threshold value TH2 may be determined by using data in a table indicating the correlation between the change values ΔTa and ΔTc and the second threshold value TH2 or linear data. is there.

  Thereafter, the change value Δα of the temperature difference α is compared with the second threshold TH2, and if the change value Δα is equal to or greater than the second threshold TH2, it is determined that the evaporation heat exchanger 10 has frost. The defrosting operation is started (S14: YES, S15). The method of the defrosting operation and the conditions for ending the defrosting operation are the same as those described above. On the other hand, when the change value Δα is not greater than or equal to the second threshold value TH2, the defrosting operation is not started and the calculation process of the change value Δα and the determination of the second threshold value TH2 are continuously performed. The presence or absence of frost is determined (S14: NO, S12 to S14).

  According to the series of operation control described above, the second threshold value TH2 is determined in correspondence with the change value ΔTa of the outside air temperature and the change value ΔTc of the incoming water temperature. For example, the change value ΔTa of the outside air temperature is small. To be a value means that the outside air temperature Ta is lower than the initial state of steady operation of the heat pump device H, and in this case, the second threshold TH2 is lowered. Therefore, in the operation control shown in FIG. 2, threshold selection is performed that approximates the lowering of the first threshold TH1 as the outside air temperature Ta is lower. Similarly, the fact that the change value ΔTc of the incoming water temperature is a large value means that the incoming water temperature Tc has become higher than in the initial stage of steady operation. In this case, the second threshold value TH2 is lowered. Therefore, in the operation control shown in FIG. 2 as well, threshold selection that approximates the lowering of the first threshold TH1 as the incoming water temperature Tc is higher is performed. From such a thing, the presence or absence of frost formation to the evaporative heat exchanger 10 is correctly judged also by operation control shown in FIG. 4, and when there is frost formation, defrost operation is appropriately started. .

  In the heat pump device H, the defrosting operation is performed when it is determined that the evaporative heat exchanger 10 has frost in at least one of the two operation controls shown in FIGS. 2 and 4. . Therefore, it is possible to more thoroughly prevent the normal operation of the heat pump apparatus H from being continued even though the determination of the presence or absence of frost is performed with higher accuracy and the frost is generated. It is.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the heat pump device and the hot water supply device according to the present invention can be variously modified within the range intended by the present invention.

In the embodiment described above, the two operation controls shown in FIG. 2 and FIG. 4 are configured to be executed, but only one of the two operation controls is executed. It may be configured. Even in such a case, it is possible to improve the determination accuracy of the presence or absence of frost formation as compared with the prior art.
The threshold value does not necessarily have to be determined based on both the outside air temperature Ta and the incoming water temperature Tc. For example, without considering the external air temperature Ta, it may determine the threshold based only on the incoming water temperature Tc.
The defrosting operation is not limited to the means using the defrosting bypass path 18, and for example, means such as heating the evaporative heat exchanger using a heater can be employed, and the specific contents thereof are not limited.

WH Water heater H Heat pump unit U Heat storage unit Sa External air temperature sensor Sb Refrigerant outlet side temperature sensor Sc Water temperature sensor 1 Refrigeration cycle 10 Evaporative heat exchanger 12 Condensation heat exchanger 18 Defrosting bypass 4A Auxiliary control unit (control means )

Claims (3)

A condensing heat exchanger capable of hot water heating using a refrigerant, and a refrigeration cycle having an evaporating heat exchanger capable of absorbing heat from outside air;
A temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger is detected, and when this temperature difference becomes equal to or more than a predetermined first threshold, or when a predetermined steady operation of the refrigeration cycle is started. Control means for performing operation control for starting a defrosting operation for the evaporative heat exchanger when a change value of the temperature difference as a reference is equal to or greater than a predetermined second threshold;
A heat pump apparatus,
The first and second threshold values are configured to be changed according to a change in the incoming water temperature so as to have a lower value as the incoming temperature of hot water to the condensing heat exchanger becomes higher. A heat pump device. A condensing heat exchanger capable of hot water heating using a refrigerant, and a refrigeration cycle having an evaporating heat exchanger capable of absorbing heat from outside air;
A temperature difference between the outside air temperature and the refrigerant outlet side temperature of the evaporative heat exchanger is detected, and when this temperature difference becomes equal to or more than a predetermined first threshold, or when a predetermined steady operation of the refrigeration cycle is started. Control means for performing operation control for starting a defrosting operation for the evaporative heat exchanger when a change value of the temperature difference as a reference is equal to or greater than a predetermined second threshold;
A heat pump apparatus,
The first and second thresholds are set to be lower as the outside air temperature is lower and to be lower as the temperature of the water entering the condensation heat exchanger is higher. It is comprised so that it may change according to each change of, The heat pump apparatus characterized by the above-mentioned. A hot water supply apparatus comprising the heat pump apparatus according to claim 1 or 2, wherein hot water heating for hot water supply is enabled by the heat pump apparatus.

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