JP6331996B2 - Heat pump type hot water heater - Google Patents

Description

  The present invention relates to a heat pump type heating and hot water supply apparatus that performs heat exchange between a refrigerant and water.

  2. Description of the Related Art Conventionally, there is known a heat pump type heating and hot water supply apparatus that performs heating and hot water supply using hot water generated by performing heat exchange between a refrigerant and water. This heat pump type heating hot water supply apparatus is formed by sequentially connecting a compressor, a four-way valve, a water refrigerant heat exchanger for exchanging heat between the refrigerant and water, an expansion valve, and a heat source side heat exchanger through refrigerant piping. A water supply circuit comprising a refrigerant circuit, a water refrigerant heat exchanger, a circulation pump, a heating terminal (floor heating panel, bathroom heating device, etc.) and a hot water supply terminal (hot water storage tank, hot water faucet, etc.) connected by a hot water supply pipe, Hot water heated by a refrigerant in a water-refrigerant heat exchanger is circulated to a heating terminal or a hot water supply terminal by driving a circulation pump to perform a heating operation or a hot water supply operation (for example, see Patent Document 1).

  In the heat pump heating and hot water supply apparatus described in Patent Document 1, the temperature of hot water that is heated by exchanging heat with the refrigerant and flows out of the water-refrigerant heat exchanger (hereinafter referred to as the forward temperature) is a predetermined target forward temperature. Thus, the rotation speed of the compressor is controlled. Here, the target forward temperature is determined according to the room temperature required at the heating terminal or the hot water supply temperature required at the hot water supply terminal. In the following description, the room temperature required for the heating terminal and the hot water supply temperature required for the hot water supply terminal are described as the set temperature, unless otherwise mentioned individually.

  In the heat pump type hot water supply apparatus described above, when the going temperature reaches the target going temperature, the temperature is controlled to be maintained. Specifically, if the forward temperature is a predetermined range determined by the upper limit temperature and the lower limit temperature with respect to the target forward temperature (for example, if the upper limit temperature is the target forward temperature + 2 ° C and the lower limit temperature is the target forward temperature -2 ° C, the target forward temperature is The rotational speed of the compressor is controlled so that the temperature is within ± 2 ° C. When the going-out temperature is within a predetermined range, the room temperature and the hot water supply temperature are close to the set temperature, so the hot water heating terminal flowing out from the water-refrigerant heat exchanger and flowing into the heating terminal and hot water supply terminal The amount of heat released at the hot water supply terminal is reduced.

  If the amount of heat released from the water-refrigerant heat exchanger is reduced, the forward temperature is stabilized at the target forward temperature (near), and therefore the condensation temperature in the water-refrigerant heat exchanger hardly changes. That is, among the four processes (compression process / condensation process / expansion process / evaporation process) in the heat pump unit, the efficiency of the three processes excluding the compression process hardly changes.

  On the other hand, the operating efficiency of the compressor varies depending on the type of compressor and the outside air temperature, but it is designed to maximize the operating efficiency at a predetermined rotational speed, and the rotational speed is higher than this rotational speed. Or if it falls, the operating efficiency of a compressor will deteriorate, ie, the efficiency of the compression process of the four processes in the heat pump unit mentioned above will deteriorate. This is due to the characteristics of the motor mounted on the compressor. Therefore, the efficiency of the heat pump unit is greatly influenced by the operation efficiency of the compressor when the condensation temperature hardly changes, and the efficiency of the heat pump unit is maximized when the rotation speed of the compressor is the predetermined rotation speed. When the rotational speed of the compressor is increased or decreased from the rotational speed, the efficiency of the heat pump unit is deteriorated.

  When the above-mentioned forward temperature is controlled to be within a predetermined range with respect to the target forward temperature, if the forward temperature is equal to or higher than the upper limit temperature, the rotational temperature is reduced by reducing the rotational speed of the compressor. It is necessary to lower it to the target temperature. At this time, if the rotational speed of the compressor is lowered below the rotational speed at which the operation efficiency of the compressor becomes the maximum value, the efficiency of the heat pump unit deteriorates, so that the COP of the heat pump heating / hot water supply device may deteriorate.

  Therefore, the applicant of the present invention, when controlling the forward temperature to be within a predetermined range with respect to the target forward temperature, the compressor rotational speed is the optimal rotational speed that is the rotational speed of the compressor with the highest COP. If the lower limit rotational speed is lower than the predetermined rotational speed, it is determined whether the forward temperature is higher than the upper limit temperature. If the forward temperature is higher than the upper limit temperature, the compressor is stopped, and the forward temperature must be higher than the upper limit temperature. For example, a heat pump type heating and hot water supply apparatus that continues to drive the compressor at the lower limit rotational speed has been previously proposed (Japanese Patent Application No. 2014-14933).

  According to the above heat pump type heating and hot water supply apparatus, when the outgoing temperature is lowered toward the target outgoing temperature, the compressor is stopped or continuously driven at the lower limit rotational speed, so that the operating efficiency of the compressor is deteriorated. The resulting deterioration of the COP of the heat pump type heating and hot water supply apparatus can be suppressed.

JP-A-2005-274021

  In the heat pump type heating and hot water supply apparatus previously proposed by the present applicant, when the compressor is stopped and the forward temperature is lower than the lower limit temperature, the compressor is restarted at the lower limit frequency. And if the going-out temperature rises by restarting a compressor and becomes more than upper limit temperature, a compressor will be stopped again.

  Incidentally, the operating efficiency of the compressor varies depending on the time during which the compressor is continuously driven, in addition to the above-described difference depending on the rotational speed. Specifically, when the continuous operation time of the compressor is shorter than the continuous operation time unique to the compressor (for example, 10 minutes, hereinafter referred to as the minimum compressor operation time), the operation efficiency deteriorates, and the compressor If it becomes longer than the minimum operation time, the operation efficiency is improved.

  Therefore, when the forward temperature becomes lower than the lower limit temperature and the compressor is restarted, it is preferable that the compressor is continuously operated for the minimum compressor operation time regardless of the forward temperature. However, if the forward temperature is higher than the upper limit temperature after the compressor restarts and the minimum compressor operating time elapses, the compressor The operation was wasted (in a state where water was heated more than necessary), which hindered the COP improvement of the heat pump type heating and hot water supply apparatus.

  An object of the present invention is to solve the above-described problems and to provide a heat pump type heating and hot water supply apparatus that suppresses deterioration of COP when the compressor is restarted in order to keep the going temperature within a predetermined temperature range.

  The present invention solves the above-described problems, and the heat pump type heating and hot water supply apparatus of the present invention sequentially includes a water-refrigerant heat exchanger that performs heat exchange between the compressor, the refrigerant, and water, and a heat source side heat exchanger. A refrigerant circuit connected, a hot water supply circuit for circulating hot water between a heating terminal and / or a hot water supply terminal and a water refrigerant heat exchanger by operation of a circulation pump, and a water temperature flowing out of the water refrigerant heat exchanger It has a forward temperature detection means for detecting the temperature and a control means for controlling the compressor. The control means captures the forward temperature detected by the forward temperature detection means at a predetermined interval. In addition, the control means COPs the compressor in order to keep the forward temperature within a temperature range including the target forward temperature according to the capability required at the heating terminal and / or the hot water supply terminal and determined by the upper limit temperature and the lower limit temperature. When operating at a lower limit rotational speed that is lower than the rotational speed of the compressor that is the maximum value, determine whether or not a predetermined compressor minimum operating time has elapsed since starting the compressor, If the minimum compressor operating time has elapsed, it is determined whether or not the forward temperature when the minimum compressor operating time has elapsed is equal to or higher than the upper limit temperature. And the excess heat amount, which is the amount of heat from the time when the upper limit temperature is reached to the time when the compressor is stopped when the forward temperature is rising, is calculated. When the controller stops the compressor, if the forward temperature decreases and falls below the lower limit temperature, the point when the forward temperature becomes the lower limit temperature every time the forward temperature is taken in from the forward temperature detection means. The loss heat amount, which is the amount of heat up to the time the take-in temperature is taken in, is calculated, and when the loss heat amount becomes the same as the excess heat amount, the compressor is restarted at the lower limit rotational speed.

  Since the heat pump type heating and hot water supply apparatus of the present invention restarts the compressor when the amount of heat loss is the same as the excess heat amount calculated previously, until the minimum operation time of the compressor has elapsed after restarting the compressor It is possible to suppress the going-up temperature from reaching the upper limit temperature during the period, and to improve the heat pump type hot water supply apparatus COP.

It is a block diagram of the heat pump type heating hot-water supply apparatus in embodiment of this invention. It is drawing explaining the relationship between compressor rotation speed and COP in embodiment of this invention. It is a compressor rotation speed table in embodiment of this invention. It is a time chart showing the change of the operating state of a compressor and the going temperature in the embodiment of the present invention. It is a flowchart explaining the process performed by the control means in embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, the present invention has an indoor unit that is a heating terminal and a hot water storage tank that is a hot water supply terminal in the present invention, and circulates hot water that has exchanged heat with refrigerant in a water-refrigerant heat exchanger to the indoor unit for heating operation. An example of a heat pump heating and hot water supply apparatus that performs hot water supply operation (hereinafter referred to as boiling operation) that heats the water stored in the hot water storage tank with hot water that has been exchanged with the refrigerant in the water refrigerant heat exchanger. Will be described. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  FIG. 1 shows a configuration of a heat pump type heating and hot water supply apparatus according to the present invention. This heat pump type heating hot water supply apparatus 100 includes a variable capacity compressor 1, a four-way valve 2, a water refrigerant heat exchanger 3 that performs heat exchange between refrigerant and water, an expansion valve 4, a heat source side heat exchanger 5, and an accumulator 6. The refrigerant circuit 10 is connected by the refrigerant pipe 11 in order, and the circulation direction of the refrigerant can be switched by switching the four-way valve 2.

  In this refrigerant circuit 10, a refrigerant pipe 11 near the refrigerant outlet of the compressor 1 is provided with a discharge temperature sensor 51 for detecting the temperature of the refrigerant discharged from the compressor 1. Further, the refrigerant pipe 11 between the water refrigerant heat exchanger 3 and the expansion valve 4 has a temperature of the refrigerant flowing out of the water refrigerant heat exchanger 3 when the water refrigerant heat exchanger 3 functions as a condenser. Or a refrigerant temperature sensor 53 for detecting the temperature of the refrigerant flowing into the water refrigerant heat exchanger 3 when the water refrigerant heat exchanger 3 functions as an evaporator. The refrigerant pipe 11 between the expansion valve 4 and the heat source side heat exchanger 5 has a temperature of the refrigerant flowing into the heat source side heat exchanger 5 when the heat source side heat exchanger 5 functions as an evaporator. Or a heat exchange temperature sensor 54 for detecting the temperature of the refrigerant flowing out of the heat source side heat exchanger 5 when the heat source side heat exchanger 5 functions as a condenser. Furthermore, a pressure sensor 50 is provided in the refrigerant pipe 11 on the discharge side of the compressor 1 (between the four-way valve 2 and the water refrigerant heat exchanger 3). In addition, an outside air temperature sensor 52 is provided in the vicinity of the heat source side heat exchanger 5.

  In the vicinity of the heat source side heat exchanger 5, a fan 7 is disposed that takes outside air into a housing (not shown) of the heat pump heating and hot water supply apparatus 100 and distributes the outside air to the heat source side heat exchanger 5. The fan 7 is attached to an output shaft (rotary shaft) of a motor that can vary the rotational speed (not shown). Further, the expansion valve 4 uses a stepping motor to enable pulse control of the opening degree of the valve.

  A refrigerant pipe 11 and a hot water supply pipe 12a are connected to the water-refrigerant heat exchanger 3. As shown in FIG. 1, one end of the hot water supply pipe 12a is connected to a three-way valve 31, and one end of an indoor unit side pipe 12c and one end of a hot water storage tank side pipe 12b are connected to the three-way valve 31, respectively. . Further, the other end of the indoor unit side pipe 12c and the other end of the hot water storage tank side pipe 12b are connected to the other end of the hot water supply pipe 12a. In FIG. 1, a connection point of a hot water supply pipe 12 a, a hot water storage tank side pipe 12 b, and an indoor unit side pipe 12 c is a connection point 13. The indoor unit side pipe 12c is provided with an indoor unit 40 such as a floor heating device or a radiator, and the hot water storage tank side pipe 12b is provided with a hot water storage tank 70.

  A heat exchanging portion 71 formed in a spiral shape is provided below the hot water storage tank 70. Both ends of the heat exchanging part 71 are connected to the hot water tank side pipe 12b, and hot water flowing through the hot water tank side pipe 12b flows to the heat exchanging part 71. A hot water supply port 73 for supplying hot water stored in the hot water storage tank 70 to a bathtub, a washbasin faucet or the like is provided at the upper part of the hot water storage tank 70. In addition, a water inlet 72 for supplying water to the hot water storage tank 70 is provided below the hot water storage tank 70, and a water pipe (not shown) is directly connected to the water inlet 72.

  Between the connection point 13 and the water-refrigerant heat exchanger 3, a variable capacity circulation pump 30 is provided. By driving the circulation pump 30, the water heat-exchanged with the refrigerant in the water-refrigerant heat exchanger 3 circulates in the direction of the arrow 90 shown in FIG. The water flowing out of the water-refrigerant heat exchanger 3 flows into the indoor unit side pipe 12c and flows into the indoor unit 40 according to the switching of the three-way valve 31, or flows into the hot water tank side pipe 12b and flows into the hot water storage tank 70. Flow into. And the water which flowed out from the indoor unit 40 or the hot water storage tank 70 flows into the water-refrigerant heat exchanger 3 through the connection point 13.

  As described above, the water-refrigerant heat exchanger 3, the circulation pump 30, the indoor unit 40, and the hot water storage tank 70 are connected to each other by the hot water supply pipe 12a, the hot water storage tank side pipe 12b, and the indoor unit side pipe 12c. A hot water supply circuit 12 of the hot water supply apparatus 100 is configured.

  A return temperature sensor 56 that detects a return temperature that is the temperature of the water flowing into the water refrigerant heat exchanger 3 is provided on the water inlet side of the water refrigerant heat exchanger 3 in the hot water supply pipe 12a. Further, a forward temperature sensor 57 serving as a forward temperature detecting means for detecting a forward temperature, which is a temperature of water flowing out of the water / refrigerant heat exchanger 3, is provided on the water outlet side of the water / refrigerant heat exchanger 3 in the hot water supply pipe 12. Is provided. Further, a hot water storage tank temperature sensor 58 for detecting the temperature of the hot water staying in the hot water storage tank 70 is provided at a substantially central portion in the vertical direction inside the hot water storage tank 70.

  In addition to the configuration described above, the heat pump type heating and hot water supply apparatus 100 has a control means 60. The control means 60 takes in the temperature detected by each temperature sensor and the refrigerant pressure detected by the pressure sensor 50, or takes in an operation request from a user by a remote controller (not shown), and the compressor 1 and the fan 7 according to these. Various controls relating to the operation of the heat pump heating / hot water supply device 100 such as drive control of the circulation pump 30, switching control of the four-way valve 2, opening control of the expansion valve 4, switching control of the three-way valve 31, and the like are performed. In addition, although illustration is abbreviate | omitted, the control means 60 has a memory | storage part which memorize | stores the timer part which measures time, the value detected with various sensors, the control program of the heat pump type heating hot-water supply apparatus 100, etc.

  Next, operation | movement of the refrigerant circuit 10 and the hot water supply circuit 12 in the heat pump type heating hot water supply apparatus 100 of this invention is demonstrated. In the following description, the refrigerant circuit 10 of the heat pump type heating and hot water supply apparatus 100 is operated as a heating cycle, and the indoor unit 40 is driven to perform the heating operation, and the hot water storage tank 70 stores the refrigerant. A case where a boiling operation for heating water to a predetermined temperature is performed will be described as an example.

  First, the case where a heating operation is performed will be described. When the user operates the remote control or the like of the indoor unit 40 to turn on the switch and instruct to start the heating operation, the control means 60 starts the circulation pump 30 at a predetermined number of revolutions and supplies hot water to the indoor unit side pipe 12c. The three-way valve 31 is switched so that flows. Thereby, warm water circulates between the water refrigerant heat exchanger 3 and the indoor unit 40.

  Moreover, the control means 60 switches the four-way valve 2 so that the refrigerant circuit 10 becomes a heating cycle. Specifically, the control means 60 is connected so that the discharge side of the compressor 1 and the water refrigerant heat exchanger 3 are connected, and the suction side of the compressor 1 and the heat source side heat exchanger 5 are connected. The four-way valve 2 is switched as described above. Thereby, the water refrigerant heat exchanger 3 functions as a condenser, and the heat source side heat exchanger 5 functions as an evaporator.

  Next, the control means 60 starts the compressor 1 and the fan 7, and starts the heating operation of the heat pump type heating hot water supply apparatus 100. The controller 60 detects the water temperature (hereinafter, the temperature of water heated by the water / refrigerant heat exchanger 3 corresponds to the set temperature of the heating operation set by the user, that is, the forward temperature detected by the forward temperature sensor 57. The compressor 1 is controlled so as to be the target going-out temperature. Specifically, the control means 60 obtains the temperature difference between the forward temperature detected by the forward temperature sensor 57 and the target forward temperature, and calculates the temperature difference stored in advance in the storage unit and the rotation speed of the compressor 1. The rotational speed of the compressor 1 is determined with reference to the associated table, and the compressor 1 is driven at this rotational speed.

  As indicated by an arrow 80 in FIG. 1, the refrigerant discharged from the compressor 1 passes through the four-way valve 2, condenses by exchanging heat with water in the water refrigerant heat exchanger 3, and further decompressed by the expansion valve 4. The heat source side heat exchanger 5 exchanges heat with the outside air to evaporate, repeats the process of being sucked into the compressor 1 and compressed by the compressor 1 again.

  On the other hand, the hot water heated by exchanging heat with the refrigerant in the water / refrigerant heat exchanger 3 flows out to the hot water supply pipe 12a by driving of the circulation pump 30, flows through the indoor unit side pipe 12c via the three-way valve 31, and flows indoors. It flows into the unit 40. The room in which the indoor unit 40 is installed is heated by the heat radiation of the hot water flowing through the indoor unit 40. Hot water that has flowed out of the indoor unit 40 flows into the water-refrigerant heat exchanger 3 via the connection point 13 and the circulation pump 30, and is heated by exchanging heat with the refrigerant again.

  Next, the case where the boiling operation is performed will be described. In the heating operation, the control unit 60 performs drive control of the compressor 1 so that the forward temperature detected by the forward temperature sensor 57 becomes the target forward temperature corresponding to the set temperature of the heating operation set by the user. In the boiling operation, the compressor 1 is set so that the forward temperature detected by the forward temperature sensor 57 becomes the target forward temperature corresponding to the boiling temperature that is a target value of the water temperature stored in the hot water storage tank 70 described later. To control. In addition, since control of the refrigerant circuit 10 during the boiling operation is the same as that during the heating operation described above, a detailed description thereof will be omitted below.

  The hot water stored in the hot water storage tank 70 decreases by flowing out from the hot water supply port 73. Since the water pipe is directly connected to the water inlet 72 as described above, water is supplied from the water inlet 72 to the hot water storage tank 70 by a reduced amount due to the water pressure of the tap water. Thereby, the temperature of the hot water stored in the hot water storage tank 70 is lowered.

  The control means 60 constantly monitors the hot water storage tank temperature detected by the hot water storage tank temperature sensor 58 as the temperature of the hot water stored in the hot water storage tank 70, and the hot water storage tank temperature taken in is determined in advance from the boiling temperature. If the temperature is equal to or lower than the boiling start temperature that is a predetermined temperature (for example, 5 ° C.), the boiling operation is started to set the temperature of the hot water stored in the hot water storage tank 70 to the boiling temperature.

  The control means 60 starts the circulation pump 30 at a predetermined number of revolutions and switches the three-way valve 31 so that water flows through the hot water storage tank side pipe 12b. Thereby, hot water circulates between the water-refrigerant heat exchanger 3 and the hot water storage tank 70. Hot water heated by exchanging heat with the refrigerant in the water / refrigerant heat exchanger 3 flows out of the water / refrigerant heat exchanger 3 to the hot water supply pipe 12a by the operation of the circulation pump 30, and is connected to the hot water tank side pipe through the three-way valve 31. It flows through 12b and flows into the heat exchanging portion 71 disposed in the hot water storage tank 70. The water stored in the hot water storage tank 70 is heated by the hot water flowing through the heat exchange unit 71. The hot water flowing out from the heat exchanging unit 71 flows into the water / refrigerant heat exchanger 3 through the connection point 13 and the circulation pump 30, and is again heated by exchanging heat with the refrigerant.

  When the heat pump type hot water supply apparatus 100 is operated with the refrigerant circuit 10 as a cooling cycle, the refrigerant discharged from the compressor 1 is the four-way valve 2, the heat source side heat exchanger 5, the expansion valve 4, and the water refrigerant heat exchange. It flows in the direction of the vessel 3 and flows into the four-way valve 2 again, and is sucked into the compressor 1 through the accumulator 6, so that it flows in the opposite direction as when operating as a heating cycle (in the direction of arrow 80), In FIG. 1, the description of the refrigerant flow direction in this case is omitted.

  As described above, when the heat pump heating / hot water supply apparatus 100 performs the heating operation or the heating operation, the forward temperature (hereinafter referred to as the forward temperature Tg) detected by the forward temperature sensor 57 is the target temperature (hereinafter, the target forward). The rotation speed of the compressor 1 is controlled so that the temperature becomes Tt), but the value of the COP of the heat pump heating / hot water supply apparatus 100 varies depending on the rotation speed of the compressor 1. The relationship between the rotation speed of the compressor 1 and the COP will be described in detail with reference to FIG.

  FIG. 2 is a diagram showing the relationship between the rotational speed of the compressor 1 (hereinafter referred to as “compressor rotational speed R”) and the COP. The vertical axis represents the COP value, and the horizontal axis represents the compressor rotational speed R ( (Unit: rps). In FIG. 2, the relationship between the compressor rotational speed R and the COP when the outside air temperature is To and the different outside air temperatures To1 and To2 (To1> To2) is illustrated as an example.

  When the heat pump heating / hot water supply apparatus 100 performs a heating operation or a boiling operation and the forward temperature Tg reaches the target forward temperature Tt, the rotation of the compressor 1 is performed so that the forward temperature Tg falls within a predetermined range with respect to the target forward temperature Tt. The number is controlled. For example, when the target going temperature Tt is 40 ° C., the going temperature Tg is 38 ° C. (hereinafter referred to as the lower limit temperature Tt 2) or more and less than 42 ° C. (hereinafter referred to as the upper limit temperature Tt 1). The rotation speed is controlled.

  If the going-out temperature Tg becomes a temperature near the target going-out temperature Tt, the temperature of the room in which the indoor unit 40 is installed and the water temperature in the hot water storage tank 70 are close to the respective set temperatures. The amount of heat dissipated from the hot water flowing out of the exchanger 3 and flowing into the indoor unit 40 or the hot water storage tank 70 is reduced. If the amount of heat released from the water-refrigerant heat exchanger 3 is reduced, the outgoing temperature Tg is stabilized at a temperature near the target outgoing temperature Tt, so that the condensation temperature in the water-refrigerant heat exchanger 3 hardly changes. That is, among the four processes (compression process / condensation process / expansion process / evaporation process) in the refrigerant circuit 10, the efficiency of the three processes excluding the compression process hardly changes.

  On the other hand, the operating efficiency of the compressor 1 varies depending on the type of the compressor 1 and the outside air temperature To, but it is designed so that the operating efficiency at the optimum rotation speed Rm is maximized, and the rotation efficiency is higher than the optimum rotation speed Rm. When the number increases or decreases, the operating efficiency of the compressor 1 deteriorates. That is, the efficiency of the compression process among the four processes (compression process / condensation process / expansion process / evaporation process) in the refrigerant circuit 10 described above deteriorates. This is due to the operating efficiency characteristics of the motor mounted on the compressor 1. Therefore, the efficiency in the refrigerant circuit 10 of the heat pump type hot water supply apparatus 100 is greatly influenced by the operation efficiency of the compressor 1 when the condensation temperature in the water refrigerant heat exchanger 3 hardly changes, and the compressor rotational speed R is optimal. When the number is Rm, the efficiency of the refrigerant circuit 10 is maximized, and when the compressor rotational speed R rises or falls below the optimum rotational speed Rm, the efficiency of the refrigerant circuit 10 deteriorates.

  When the forward temperature Tg is controlled to be a temperature between the upper limit temperature Tt1 and the lower limit temperature Tt2, and the forward temperature Tg is equal to or higher than the upper limit temperature Tt1, It is necessary to lower R and reduce the going temperature Tg to the target going temperature Tt. At this time, if the compressor rotational speed R is decreased to the optimum rotational speed Rm or less, the efficiency of the refrigerant circuit 10 is deteriorated, so that the COP of the heat pump heating / hot water supply apparatus 100 is deteriorated.

  From the above, as shown in FIG. 2, at each outside air temperature To1, To2, there is a compressor speed R at which the COP becomes the maximum value, that is, an optimum speed Rm at which the operating efficiency of the compressor 1 is maximized. When the outside air temperature is To1, the COP becomes the maximum value C1 at the optimum rotational speed Rm1, and when the outside air temperature is To2, the COP becomes the maximum value C2 at the optimum rotational speed Rm2. Here, Rm1 <Rm2, C1> C2, and the higher the outside air temperature To, the higher the COP at the lower compressor speed R. The COP at each of the outside air temperatures To1 and To2 deteriorates even when the compressor rotational speed R is lower than the optimal rotational speeds Rm1 and Rm2.

  In order to solve the problems described above, when the compressor rotational speed R is decreased in order to decrease the going temperature Tg, the compressor rotational speed R is lower by a predetermined percentage than the optimum rotational speed Rm. (Hereinafter referred to as the lower limit rotational speed Rd), it is determined whether or not the forward temperature Tg is higher than the upper limit temperature Tt1, and if the forward temperature Tg is not higher than the upper limit temperature Tt1, the compressor 1 is set at the lower limit rotational speed Rd. The compressor 1 is stopped if the operation continues and the forward temperature Tg is higher than the upper limit temperature Tt1.

  For example, as shown in FIG. 2, if the compressor rotational speed R is decreased to the lower limit rotational speeds Rd1 and Rd2 that are 10% lower than the optimal rotational speeds Rm1 and Rm2 at the respective outside air temperatures To1 and To2 (points in FIG. 2). If the forward temperature Tg is higher than the upper limit temperature Tt1, it is determined whether or not the forward temperature Tg is higher than the upper limit temperature Tt1, and the compressor 1 is continuously operated at the lower limit rotational speeds Rd1 and Rd2. If the forward temperature Tg is higher than the upper limit temperature Tt1, the compressor 1 is stopped.

  Thereby, the deterioration of COP of the heat pump type heating hot water supply apparatus 100 resulting from the rotation speed reduction of the compressor rotation speed R can be suppressed while lowering the going temperature Tg to a temperature between the upper limit temperature Tt1 and the lower limit temperature Tt2. While the compressor 1 is stopped, the water / refrigerant heat exchanger 3 does not heat water, but the water temperature rapidly decreases in the indoor unit 40 and the hot water storage tank 70 due to the large heat capacity of water. There is nothing. Therefore, even if this invention is implemented, a user does not feel uncomfortable.

  When the control means 60 controls the compressor 1 in order to set the above-described forward temperature Tg to a temperature between the upper limit temperature Tt1 and the lower limit temperature Tt2, the outside air temperature is used using the compressor rotation speed table 200 shown in FIG. A lower limit rotational speed Rd corresponding to the outside air temperature To (unit: ° C.) detected by the sensor 52 and the target going temperature Tt is extracted. Then, the control means 60 determines whether or not the forward temperature Tg is higher than the upper limit temperature Tt1 if the lower limit rotational speed Rd is reached when the compressor rotational speed R is being decreased, and the forward temperature Tg is determined to be the upper limit temperature Tt1. If it is not higher, the compressor 1 is continuously operated at the lower limit rotational speed Rd, and if the forward temperature Tg is higher than the upper limit temperature Tt1, the compressor 1 is stopped. In addition, if the going-out temperature Tg falls and becomes lower than lower limit temperature Tt2 by having stopped the compressor 1, the control means 60 will restart the compressor 1 with the minimum rotation speed Rd.

  The storage unit of the control means 60 stores a compressor rotation speed table 200 shown in FIG. The compressor rotation speed table 200 is created based on the results of tests performed in advance and is stored in the control means 60.

  The compressor rotation speed table 200 has an optimum rotation speed Rm at which the COP becomes the maximum value and a predetermined ratio from the optimum rotation speed Rm according to the outside air temperature To and the target going-out temperature Tt (in this embodiment, 10%). Thus, a lower limit rotational speed Rd is determined.

  As shown in FIG. 3, the outside air temperature To is divided into three temperature ranges of less than 5 ° C., 5 ° C. or more, less than 10 ° C., and 10 ° C. or more. Further, for each of the three temperature ranges of the outside air temperature To, the target forward temperature Tt is divided and assigned to three temperature ranges of less than 30 ° C., 30 ° C. or more and less than 40 ° C., and 40 ° C. or more.

  For example, when the outside air temperature To is less than 5 ° C., the optimum rotational speed Rm is set to 30 rps and the lower limit rotational speed Rd is set to 27 rps when the target forward temperature Tt is less than 30 ° C., and the target forward temperature Tt is 30 ° C. Above 40 ° C., the optimum rotational speed Rm is determined to be 35 rps and the lower limit rotational speed Rd is determined to be 32 rps. When the target forward temperature Tt is 40 ° C. or higher, the optimum rotational speed Rm is 40 rps, and the lower limit rotational speed Rd is 36 rps. It is stipulated. That is, it is determined that the optimum rotational speed Rm and the lower limit rotational speed Rd increase as the target forward temperature Tt increases.

  Further, when the optimum rotational speed Rm and the lower limit rotational speed Rd of the temperature range difference of the outside air temperature To when the target going-out temperature Tt is 40 ° C. or higher, the case where the outside air temperature To is less than 5 ° C. is as described above. The optimum rotational speed Rm is 40 rps and the lower limit rotational speed Rd is 36 rps. On the other hand, when the outside air temperature To is 5 ° C. or higher and lower than 10 ° C., the optimal rotational speed Rm is 35 rps and the lower limit rotational speed Rd is 32 rps. When the outside air temperature To is 10 ° C. or higher, the optimum rotational speed Rm is 30 rps and the lower limit rotational speed Rd is 27 rps. That is, the optimum rotational speed Rm and the lower limit rotational speed Rd are determined to decrease as the outside air temperature To increases.

  Next, a problem that occurs when the compressor 1 is controlled using the compressor rotation speed table 200 and an operation of the present invention that solves this problem will be described with reference to FIG. FIG. 4 is a timing chart showing the operation / stop of the compressor 1 and the change in the going temperature Tg. FIG. 4A shows the case where the conventional control is performed, and FIG. 4B shows the control of the present invention. Each case is shown.

  Conventionally, as shown in FIG. 4A, when the compressor 1 is stopped, the forward temperature Tg decreases, and when the forward temperature Tg becomes the lower limit temperature Tt2 at time ts1, the compressor 1 is restarted at the lower limit rotational speed Rd. It was running. At this time, since the outdoor temperature To is high, the return temperature Tg from the indoor unit 40 or the hot water storage tank 70 to the water / refrigerant heat exchanger 3 is high, etc. The temperature may rise to the upper limit temperature Tt1 in a short time (point Pu1 in FIG. 4A).

  On the other hand, the operating efficiency of the compressor 1 varies depending on the time during which the compressor 1 is continuously driven, in addition to the difference depending on the compressor rotational speed R. Specifically, when the operation time of the compressor 1 is shorter than the continuous operation time unique to the compressor 1 (for example, 10 minutes, hereinafter referred to as the compressor minimum operation time tcm), the operation efficiency deteriorates. If it becomes longer than the minimum compressor operation time tcm, the operation efficiency is improved.

  From the above, after the compressor 1 is restarted at the lower limit rotational speed Rd, the compressor 1 is not stopped until the compressor minimum operation time tcm elapses after the compressor 1 is restarted. It is desirable to keep driving. However, as shown in FIG. 4A, the forward temperature Tg becomes higher than the upper limit temperature Tt1 between the restart of the compressor 1 at time ts1 and the time te1 when the compressor minimum operation time tcm elapses. In this case, the compressor 1 continues to operate from the time (point Pu1) when the going temperature Tg becomes higher than the upper limit temperature Tt1 to the time te1 when the compressor minimum operation time tcm elapses.

  As a result, the forward temperature Tg at time te1 when the compressor minimum operation time tcm has elapsed and the compressor 1 is stopped becomes higher by ΔT1 ° C. (excess temperature ΔT1) than the upper limit temperature Tt1. That is, as shown in FIG. 4A, at the point Pu1, the hot water is heated by the water / refrigerant heat exchanger 3 more than necessary until the time te1 at which the compressor 1 stops after the forward temperature Tg reaches the upper limit temperature Tt1. Will be.

  Further, when the compressor 1 is stopped at the time te1, the forward temperature Tg decreases, and at the time ts2, the forward temperature Tg becomes the lower limit temperature Tt2, and the compressor 1 is restarted at the lower limit rotational speed Rd. If there is no change in the temperature To or the return temperature, the return temperature Tg again exceeds the upper limit temperature Tt1 at the point Pu2 between the restart of the compressor 1 and the elapse of the minimum compressor operation time tcm. However, the hot water is heated by the water / refrigerant heat exchanger 3 more than necessary until it stops at time te2 after the minimum compressor operating time tcm has elapsed.

  As described above, when conventional control is performed, the state in which hot water is heated by the water / refrigerant heat exchanger 3 more than necessary may continue to hinder the COP improvement of the heat pump heating / hot water supply apparatus 100. there were. Further, as shown in FIG. 4A, in the conventional control, the time during which the forward temperature Tg is equal to or higher than the upper limit temperature Tt1 becomes longer, so the average forward temperature Tga, which is the time average value of the forward temperature Tg, is the target forward. There is a possibility that the temperature becomes higher than the temperature Tt, and there is a fear that the control may be uncomfortable for the user, such as excessive heating resulting in an increase in the room temperature or an increase in the hot water supply temperature.

  Therefore, in the heat pump type heating and hot water supply apparatus 100 of the present invention, when the going temperature Tg becomes equal to or higher than the upper limit temperature Tt1 after the compressor 1 is restarted until the compressor minimum operation time tcm elapses, An excess heat quantity Qu, which is the amount of heat that heats the hot water between the time when the temperature Tg exceeds the upper limit temperature Tt1 and the time when the compressor 1 is stopped, is calculated and obtained. After the compressor 1 stops, the forward temperature Tg becomes the lower limit temperature Tt2. After that, the compressor 1 is restarted at the timing when the loss heat quantity Qd, which is the heat quantity lost when the hot water is reduced, becomes the same value as the previously calculated excess heat quantity Qu.

  Specifically, as shown in FIG. 4B, the compressor 1 is restarted at time ts1, and the going-out temperature Tg increases between time ts1 and time te1 when the minimum compressor operation time tcm elapses. When the upper limit temperature Tt1 is reached at time t1 (point Pu1a), the excess heat amount Qu1 from time t1 to time te1 (point Pu1b) at which the compressor 1 stops is calculated. Next, when the going temperature Tg decreases and reaches the lower limit temperature Tt2 at time t2 (point Pd1a), the going temperature Tg is fetched from the going temperature sensor 57 every predetermined time (for example, 30 seconds) from time t2. The amount of heat loss Qd1 is obtained. Then, the compressor 1 is restarted at time ts2 when the excess heat quantity Qu1 = loss heat quantity Qd1.

  The above control is repeated after the compressor 1 is restarted at time ts2, and the compressor 1 is stopped after the minimum compressor operating time tcm has elapsed from time t3 (point Pu2a) when the forward temperature Tg becomes the upper limit temperature Tt1. The amount of excess heat Qu2 up to time te2 (point Pu2b) is obtained, and the amount of heat loss Qd2 from the time t4 (point Pd2a) at which the forward temperature Tg becomes the lower limit temperature Tt2 until the compressor 1 is restarted becomes equal to the amount of excess heat Qu2. The compressor 1 is restarted at ts3.

  Thus, by always restarting the compressor 1 at the timing when the excess heat quantity Qu and the loss heat quantity Qd become equal, as shown in FIG. 4B, the excess heat quantity Qu2 can be made smaller than the previous excess heat quantity Qu1. That is, the time from when the compressor 1 is restarted until the outgoing temperature Tg exceeds the upper limit temperature Tt1 until the minimum compressor operating time tcm elapses can be shortened, and the water-refrigerant heat exchanger 3 is more than necessary. Heating the hot water can be suppressed.

  In addition, by restarting the compressor 1 at the timing when the excess heat quantity Qu and the loss heat quantity Qd become equal, the time during which the going temperature Tg is lower than the lower limit temperature Tt2 becomes longer, so the average going temperature Tga becomes the target going temperature. The temperature is near Tt. Thereby, it can suppress that it becomes control which a user feels unpleasant, such as heating becomes excessive heating, room temperature rises, and hot water supply temperature becomes high.

  Next, control of the compressor 1 performed by the control means 60 during heating operation or heating operation will be described using the above-described compressor rotation speed table 200 with reference to the flowchart shown in FIG. The flowchart shown in FIG. 5 is used when the compressor 1 is controlled so that the forward temperature Tg falls between the upper limit temperature Tt1 and the lower limit temperature Tt2 when the heat pump heating / hot water supply apparatus 100 performs the heating operation or the heating operation. The flow of processing is shown, ST represents a step, and the number following this represents a step number. In FIG. 5, the control of the heat pump type heating and hot water supply apparatus 100 other than the control related to the present invention, such as the opening control of the expansion valve 4 and the drive control of the fan 7 when the forward temperature Tg is raised to the target forward temperature Tt. The illustration and description are omitted for.

  When the heating operation or the heating operation is started, the control means 60 takes in the forward temperature Tg detected by the forward temperature sensor 57, and the acquired forward temperature Tg is determined according to the set temperature of the heating operation or the boiling operation. It is determined whether or not the temperature is equal to or higher than the target forward temperature Tt stored in the storage unit (ST1). If the going temperature Tg is not equal to or higher than the target going temperature Tt (ST1-No), the control means 60 returns the process to ST1 and maintains the current compressor speed R. The control means 60 sets the compressor speed R at the start-up speed (for example, 60 rps) until the temperature Tg reaches the target temperature Tt after the heating operation or the heating operation is started. Is driving. Moreover, the control means 60 takes in the going-out temperature Tg every predetermined time (for example, every 30 seconds).

  In ST1, if the forward temperature Tg is equal to or higher than the target forward temperature Tt (ST1-Yes), the control means 60 reduces the compressor rotational speed R (ST2). The control means 60 decreases the compressor rotational speed R at a predetermined speed, for example, 2 rps / 30 seconds.

  Next, the control means 60 determines whether or not the compressor rotational speed R has become equal to or lower than the lower limit rotational speed Rd (ST3). The control means 60 takes in the outside air temperature To detected by the outside air temperature sensor 52 every predetermined time (for example, every 30 seconds), and uses this and the stored target air temperature Tt to rotate the compressor. The lower limit rotation speed Rd is extracted with reference to the number table 200.

  If the compressor rotation speed R is not less than the lower limit rotation speed Rd (ST3-No), the control means 60 returns the process to ST2 and continues to decrease the compressor rotation speed R. If the compressor speed R is equal to or lower than the lower limit speed Rd (ST3-Yes), the control means 60 determines whether or not the forward temperature Tg is lower than the upper limit temperature Tt1 (ST4).

  If the going-out temperature Tg is lower than the upper limit temperature Tt1 (ST4-Yes), the control means 60 continuously operates the compressor 1 at the minimum rotational speed Rd (ST18), and returns the process to ST4. If the going temperature Tg is not less than the upper limit temperature Tt1 (ST4-No), the control means 60 stops the compressor 1 (ST5).

  Next, control means 60 determines whether or not forward temperature Tg is lower than or equal to lower limit temperature Tt2 (ST6). If the going temperature Tg is not lower than the lower limit temperature Tt2 (ST6-No), the control means 60 returns the process to ST5 and keeps the compressor 1 stopped. If the going temperature Tg is equal to or lower than the lower limit temperature Tt2 (ST6-Yes), the control means 60 restarts the compressor 1 at the minimum rotational speed Rd (ST7).

  Next, the control means 60 starts the timer measurement (ST8), and the minimum operation time tcm of the compressor is changed from the start of the timer measurement, that is, the restart of the compressor 1 (time ts1, time ts2, etc. shown in FIG. 4B). It is determined whether or not it has elapsed (ST9). If the minimum compressor operating time tcm has not elapsed (ST9-No), the control means 60 returns the process to ST9 and continues to drive the compressor 1 at the minimum rotational speed Rd. If the minimum compressor operation time tcm has elapsed (ST9-Yes), the control means 60 resets the timer (ST10).

  Then, the control means 60 again determines whether or not the forward temperature Tg is lower than the upper limit temperature Tt1 (ST11). If the going-out temperature Tg is lower than the upper limit temperature Tt1 (ST11-Yes), the control means 60 continuously operates the compressor 1 at the lower limit rotational speed Rd (ST17), and returns the process to ST11. If the going temperature Tg is not less than the upper limit temperature Tt1 (ST11-No), the control means 60 stops the compressor 1 (ST12).

  Next, the control means 60 calculates the excess heat quantity Qu (ST13). The control means 60 starts the timer measurement at ST8 and then the time when the going temperature Tg becomes the upper limit temperature Tt1 (time t1 and time t3 shown in FIG. 4B) and the time when the compressor 1 is stopped at ST12. (Time te1 and time te2 shown in FIG. 4B) are stored, and the excess heat amount Qu from the time when the forward temperature Tg becomes the upper limit temperature Tt1 to the time when the compressor 1 stops is integrated or added. Calculate using the method. The control means 60 stores the calculated excess heat quantity Qu in the storage unit.

  Next, the control means 60 determines whether or not the forward temperature Tg is lower than the lower limit temperature Tt2 (ST14). If the going temperature Tg is not lower than the lower limit temperature Tt2 (ST14-No), the control means 60 returns the process to ST14 and keeps the compressor 1 stopped. If the going temperature Tg is equal to or lower than the lower limit temperature Tt2 (ST14-Yes), the control means 60 starts from the time when the going temperature Tg becomes the lower limit temperature Tt2 (for example, time t2 or time t4 shown in FIG. 4B). The amount of heat loss Qd is calculated (ST15). As described above, the control means 60 captures the forward temperature Tg every predetermined time, and every time the forward temperature Tg is captured, the control means 60 takes the forward temperature Tg from the lower limit temperature Tt2 to the time when the forward temperature Tg is captured. The amount of heat loss Qd is calculated.

  Next, the control means 60 determines whether or not the calculated heat loss Qd is equal to the stored excess heat Qu (ST16). If the loss heat quantity Qd is not equal to the excess heat quantity Qu (ST16-No), the control means 60 calculates the loss heat quantity Qd every time the process returns to ST15 and the forward temperature Tg is taken. If the loss heat quantity Qd is equal to the excess heat quantity Qu (ST16-Yes), the control means 60 restarts the compressor 1 at the lower limit rotational speed Rd (ST17), and returns the process to ST8.

  As described above, in the heat pump type heating and hot water supply apparatus 100 according to the present invention, when the heating operation or the heating operation is performed, the temperature at which the going temperature Tg includes the target going temperature Tt and is determined by the upper limit temperature Tt1 and the lower limit temperature Tt2. The compressor 1 is controlled so as to be within the range. Then, the loss of heat Qd when the forward temperature Tg is lowered to be lower than the lower limit temperature Tt2 by stopping the compressor 1 is from when the forward temperature Tg becomes higher than the upper limit temperature Tt1 while the forward temperature Tg is increasing. The compressor 1 is restarted when the compressor 1 is stopped and becomes the same as the excess heat quantity Qu until the forward temperature Tg decreases and becomes equal to or lower than the upper limit temperature Tt1. Thereby, it is possible to suppress the forward temperature Tg from exceeding the upper limit temperature Tt1 between the restart of the compressor 1 and the elapse of the minimum compressor operation time tcm, and the COP of the heat pump heating and hot water supply apparatus 100 is improved. can do.

  In the embodiment described above, the lower limit rotational speed Rd is set to a rotational speed that is a predetermined rate lower than the optimal rotational speed Rm, which is the rotational speed of the compressor 1 when the COP reaches the maximum value. The rotational speed Rd may be the rotational speed of the compressor 1 corresponding to a COP value that is a predetermined percentage lower than the maximum COP value (for example, a COP value that is 5% lower than the maximum COP value).

DESCRIPTION OF SYMBOLS 1 Compressor 3 Water refrigerant | coolant heat exchanger 10 Refrigerant circuit 12 Hot water supply circuit 40 Indoor unit 55 Outside temperature sensor 57 Outward temperature sensor 60 Control means 70 Hot water storage tank 100 Heat pump type heating hot water supply apparatus 200 Compressor rotation speed table C1 Maximum value of COP C2 Maximum value of COP Tg Outbound temperature Tga Average outbound temperature To Outside temperature Tt Target temperature Tt1 Upper limit temperature Tt2 Lower limit temperature te Compressor stop time ts Compressor start-up time tcm Compressor minimum operation time R Compressor speed Rm, Rm1, Rm2 Optimal Rotational speed Rd, Rd1, Rd2 Lower limit rotational speed Qu, Qu1, Qu2 Excess heat quantity Qd, Qd1, Qd2 Loss heat quantity

Claims (3)

A refrigerant circuit formed by sequentially connecting a compressor, a water refrigerant heat exchanger that performs heat exchange between the refrigerant and water, and a heat source side heat exchanger;
A hot water supply circuit for circulating hot water by operation of a circulation pump between a heating terminal and / or a hot water supply terminal and the water refrigerant heat exchanger;
A forward temperature detecting means for detecting a forward temperature which is a water temperature flowing out of the water refrigerant heat exchanger;
Control means for controlling the compressor;
A heat pump type heating and hot water supply apparatus having
The control means includes
The forward temperature detected by the forward temperature detection means is captured at predetermined intervals,
In order for the forward temperature to fall within a temperature range including a target forward temperature according to the capacity required by the heating terminal and / or the hot water supply terminal and determined by an upper limit temperature and a lower limit temperature, the COP is connected to the compressor. When operating at a lower limit rotational speed that is a predetermined rotational speed lower than the rotational speed of the compressor that is the maximum value,
Determining whether a predetermined compressor minimum operating time has elapsed since starting the compressor;
If the compressor minimum operation time has elapsed, determine whether the forward temperature at the time when the compressor minimum operation time has elapsed is equal to or higher than the upper limit temperature,
When the forward temperature is equal to or higher than the upper limit temperature, the compressor is stopped, and the amount of heat from the time when the upper temperature is reached to the time when the compressor is stopped when the forward temperature is rising. Calculate excess heat,
When the compressor temperature is stopped, if the forward temperature is reduced to be equal to or lower than the lower limit temperature, the forward temperature becomes the lower limit temperature every time the forward temperature is taken in from the forward temperature detection means. Calculate the amount of heat loss that is the amount of heat from the time to the time when the previous temperature was taken in,
At the time when the heat loss is the same as the excess heat, the compressor is restarted at the lower limit rotational speed.
A heat pump type heating and hot water supply apparatus characterized by that. The control means, after restarting the compressor at the lower limit rotational speed, until the minimum operation time of the compressor elapses from the time when the compressor is restarted, Maintaining the speed ,
The heat pump type heating / hot water supply apparatus according to claim 1. 3. The heat pump type heating and hot water supply apparatus according to claim 1, wherein the lower limit rotation speed is a rotation speed of the compressor corresponding to a COP value that is lower by a predetermined percentage than a maximum value of COP.

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