JP6098557B2 - 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 hot water heater has a refrigerant circuit in which a compressor, a water refrigerant heat exchanger that performs heat exchange between refrigerant and water, an expansion valve, and a heat source side heat exchanger are sequentially connected by refrigerant piping. And a hot water supply unit that circulates hot water heated by the water-refrigerant heat exchanger to a heating unit (floor heating panel, bathroom heating device, etc.) or a hot water storage tank by a circulation pump (for example, Patent Document 1).

  In the heat pump type heating / hot water supply apparatus described above, compression is performed so that 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) becomes a predetermined target temperature. The rotation speed of the machine and the opening of the expansion valve are controlled. Here, the target temperature is determined according to the room temperature required by the heating unit and the boiling temperature when boiling the water stored in the hot water storage tank. In the following description, the room temperature and the boiling temperature required for the above-described heating unit are described as the set temperature, unless it is necessary to individually refer to them.

  In the heat pump heating / hot water supply apparatus described above, when the forward temperature reaches the target temperature, control is performed so as to maintain the temperature. Specifically, the rotational speed of the compressor is controlled so that the forward temperature is within a predetermined range with respect to the target temperature (for example, within ± 2 ° C. with respect to the target temperature). When the going-out temperature is within the specified range, the room temperature in the room where the heating unit is installed and the water temperature in the hot water storage tank are close to the set temperature, so the water flows out of the water refrigerant heat exchanger and is heated. The amount of heat released from the heating unit or hot water storage tank flowing into the unit or hot water storage tank is reduced.

  If the amount of heat released from the water-refrigerant heat exchanger is reduced, the forward temperature is stabilized at the target temperature (near), and the condensation temperature in the water-refrigerant heat exchanger hardly changes. At this time, 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 forward temperature is controlled to be within a predetermined range with respect to the target temperature, if the forward temperature is equal to or higher than the upper limit temperature that defines the predetermined range, the rotational speed of the compressor is decreased. It is necessary to lower the back temperature 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 present applicant, when controlling the forward temperature to be within a predetermined range with respect to the target temperature, the rotational speed of the compressor is lower than the minimum rotational speed that is the rotational speed of the compressor at which the COP is the maximum value. If the lower limit rotational speed is lower than the predetermined rotational speed, it is determined whether the forward temperature is equal to or higher than the upper limit temperature that defines a predetermined range. If the forward temperature is higher than the upper limit temperature, the compressor is stopped and the forward temperature is A heat pump type heating and hot water supply apparatus that continues to drive the compressor at the lower limit rotational speed if not higher than the temperature has been previously proposed (Japanese Patent Application No. 2014-14933).

  According to the heat pump type heating / hot water supply apparatus described above, when the forward temperature is lowered toward the target temperature, the compressor is stopped or continuously driven at the lower limit rotational speed, which is caused by deterioration in the operation efficiency of the compressor. It is possible to suppress the deterioration of COP of the heat pump type heating and hot water supply apparatus.

JP-A-2005-274021

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

  However, after restarting the compressor, depending on the heating load of the heating unit (for example, the solar radiation state of the room where the heating unit is installed) and the outside air temperature, the forward temperature is stable at a temperature between the target temperature and the upper limit temperature. There is a case.

  In the above cases, the temperature may be higher than the set temperature in the heating unit or hot water storage tank, and the compressor is continuously operated at the lower limit rotation speed because the forward temperature is not higher than the upper limit temperature. Has been. That is, the heat pump heating / hot water supply apparatus is in a state of being wasted, and if this state continues for a long time, there is a problem that the COP improvement of the heat pump heating / hot water supply apparatus is hindered.

  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 improves the COP by preventing useless operation of the compressor.

  The present invention solves the above-described problems, and the heat pump type heating and hot water supply apparatus of the present invention includes a water-refrigerant heat exchanger that performs heat exchange between the compressor, the refrigerant, and water, a flow rate adjusting unit, and a heat source side heat exchange. A refrigerant circuit formed by sequentially connecting a heater, a hot water supply circuit that circulates hot water between the heating terminal and the water refrigerant heat exchanger by operating a circulation pump, and a forward temperature that is a water temperature that flows out of the water refrigerant heat exchanger And a control means for controlling the compressor. The control means includes a compressor having a maximum COP value in order to keep the forward temperature within a temperature range including a target temperature corresponding to the capacity required by the heating terminal and including an upper limit temperature and a lower limit temperature. When operating at a lower limit rotational speed that is lower than the optimal rotational speed, which is the rotational speed of the engine, it is determined whether or not the forward temperature is equal to or higher than a threshold temperature that is a predetermined temperature between the target temperature and the upper limit temperature. To do. If the forward temperature is equal to or higher than the threshold temperature, the control means measures the threshold temperature excess time, which is the time during which the forward temperature becomes the threshold temperature and is the temperature higher than the threshold temperature and lower than the upper limit temperature. If the excess time is greater than or equal to a predetermined excess limit time, the rotation speed of the compressor is set as the optimum rotation speed. Then, when the compressor is operated at the optimum rotational speed, the compressor is stopped if the forward temperature is equal to or higher than the upper limit temperature.

  The heat pump type heating and hot water supply apparatus of the present invention is a compressor that has a threshold temperature exceeding time that is higher than a threshold temperature and lower than an upper limit temperature that is a predetermined temperature higher than a target temperature, and that is more than a predetermined exceeding limit time. The number of rotations is increased to the optimum number of rotations, and the compressor is stopped when the going-out temperature exceeds the upper limit temperature. Increasing the compressor speed to the optimum speed at which the COP reaches its maximum value speeds up the forward temperature rise, quickly reaches the upper limit temperature, and stops the compressor. It is possible to prevent the compressor from being continuously operated at the above temperature, and to improve the COP of the heat pump type heating hot water supply apparatus.

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, it has a hot water storage tank that is a heating terminal and an indoor unit in the present invention, and heats water by circulating hot water that has been heat-exchanged with a refrigerant in a water-refrigerant heat exchanger to the indoor unit, A heat pump heating and hot water supply apparatus that heats water stored in a hot water storage tank with hot water that has been heat exchanged with the refrigerant in the refrigerant heat exchanger will be described as an example. 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 and 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 that is a flow rate adjusting means, and heat source side heat exchange. The refrigerant circuit 10 is connected to the condenser 5 and the accumulator 6 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.

  An inlet 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. In addition, an outlet 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.

  As shown in FIG. 1, when the heat pump type hot water supply apparatus 100 is operated with the refrigerant circuit 10 as a heating cycle, the refrigerant discharged from the compressor 1 is a four-way valve 2, a water refrigerant heat exchanger 3, an expansion It flows through the valve 4 and the heat source side heat exchanger 5 in this order, flows into the four-way valve 2 again, and is sucked into the compressor 1 through the accumulator 6 (the flow of the refrigerant is indicated by an arrow 80 shown in FIG. 1). When the heat pump type hot water heater 100 is operated using 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.

  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 control means 60 is configured so that the forward temperature detected by the outlet water temperature sensor 57, that is, the temperature of the water heated by the water-refrigerant heat exchanger 3, corresponds to the set temperature of the heating operation set by the user (hereinafter, The compressor 1 is controlled so as to satisfy the target temperature. 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, is further decompressed by the expansion valve 4, and is heated to the outside air and heat in the heat source side heat exchanger 5. The process of evaporating, evaporating, sucking into the compressor 1 and compressing again with the compressor 1 is repeated.

  On the other hand, the hot water heated by the water-refrigerant heat exchanger 3 flows out to the hot water supply pipe 12 a by driving the circulation pump 30, flows through the indoor unit side pipe 12 c through the three-way valve 31, and flows into the indoor 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 outlet water temperature sensor 57 becomes a target temperature corresponding to the set temperature of the heating operation set by the user. In the boiling operation, the compressor 1 is controlled so that the forward temperature detected by the outlet water temperature sensor 57 becomes a target 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 do. 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. The hot water heated by 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, flows through the hot water storage tank side pipe 12b via the three-way valve 31, and flows into the hot water storage tank 70. It flows into the heat exchange part 71 arrange | positioned inside. 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.

  As described above, when the heat pump type heating / hot water supply apparatus 100 performs the heating operation or the heating operation, the forward temperature detected by the outlet water temperature sensor 57 (hereinafter referred to as the forward temperature Tg) is the target temperature (hereinafter referred to as the target temperature). The rotational speed of the compressor 1 is controlled so as to be expressed as Tt), but the value of the COP of the heat pump heating / hot water supply apparatus 100 varies depending on the rotational 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 heating operation and the forward temperature Tg reaches the target temperature Tt, the rotational speed of the compressor 1 is set so that the forward temperature Tg falls within a predetermined range with respect to the target temperature Tt. Be controlled. For example, when the target temperature Tt is 40 ° C., the compressor 1 rotates so that the forward 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 number is controlled.

  If the going-out temperature Tg becomes a temperature near the target 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 vessel 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 forward temperature Tg is stabilized at a temperature near the target 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 operating speed of the refrigerant circuit 10 is maximized when the engine speed is several Rm and the compressor rotational speed R rises or falls below the optimum rotational speed Rm, the operating 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 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 lower 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 higher than the upper limit temperature Tt1, the compressor 1 is operated at the lower limit rotational speed Rd. If the forward temperature Tg is higher than the upper limit temperature Tt1, the compressor 1 is stopped.

  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 the water. However, since the heat capacity of the water is large, the indoor unit 40 can be used even if the compressor 1 is stopped for a short time. In the hot water storage tank 70, the water temperature does not drop rapidly. 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 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.

  A compressor speed table 200 shown in FIG. 3 is stored in a storage unit (not shown) of the control means 60. 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.

  In the compressor rotation speed table 200, the optimum rotation speed Rm at which the COP becomes the maximum value according to the outside air temperature To and the target temperature Tt, and a predetermined ratio (10% in this embodiment) from the optimum rotation speed Rm. A low 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 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 rotation speed Rm is set to 30 rps and the lower limit rotation speed Rd is set to 27 rps when the target temperature Tt is less than 30 ° C., and the target temperature Tt is 30 ° C. or more and 40 Below ℃, 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 temperature Tt is 40 ℃ or higher, the optimum rotational speed Rm is determined to be 40 rps and the lower limit rotational speed Rd is determined to be 36 rps. ing. That is, it is determined that the optimum rotation speed Rm and the lower limit rotation speed Rd increase as the target 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 temperature Tt is 40 ° C. or higher are seen, as described above, the outside air temperature To is less than 5 ° C. The optimum rotational speed Rm is 40 rps and the lower limit rotational speed Rd is 36 rps, whereas the optimum rotational speed Rm is 35 rps and the lower limit rotational speed Rd is 32 rps when the outside air temperature To is 5 ° C. or higher and lower than 10 ° C. When the outside air temperature To is 10 ° C. or higher, the optimum rotational speed Rm is set to 30 rps and the lower limit rotational speed Rd is set to 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 a change in the going temperature Tg. In FIG. 4, in addition to the above-described forward temperature Tg, target temperature Tt, upper limit temperature Tt1, and lower limit temperature Tt2, the threshold temperature is Ts, the threshold temperature excess time is ti, and the excess limit time is te. Further, operation 1 is performed when the compressor 1 is operated at the lower limit rotational speed Rd, and operation 2 is performed when the compressor 1 is operated at the optimum rotational speed Rm. Here, the threshold temperature Ts is a temperature that is equal to or higher than a predetermined target temperature Tt and lower than the upper limit temperature Tt1. For example, when the target temperature Tt is 40 ° C. and the upper limit temperature Tt1 is 42 ° C., the threshold temperature Ts is 41. .5 ° C. Further, the threshold temperature excess time ti is a duration time in which the forward temperature Tg is equal to or higher than the threshold temperature Ts and lower than the upper limit temperature Tt1. The excess limit time te is a predetermined limit time of the threshold temperature excess time ti, and is preferably longer than the continuous operation time (for example, 10 minutes) in which the operation efficiency of the compressor 1 is improved.

  As described above, in the heat pump type heating and hot water supply apparatus 100 of the present invention, when the compressor rotational speed R becomes the lower limit rotational speed Rd, it is determined whether or not the forward temperature Tg is equal to or higher than the upper limit temperature Tt1, and the forward temperature Tg. Is higher than the upper limit temperature Tt1, the compressor 1 is stopped. When the compressor 1 is stopped, if the forward temperature Tg is equal to or lower than the lower limit temperature Tt2, the compressor 1 is restarted at the lower limit rotational speed Rd (operation 1 in FIG. 4). Then, the compressor 1 is restarted at the lower limit rotational speed Rd, the forward temperature Tg rises, and when the forward temperature Tg becomes equal to or higher than the upper limit temperature Tt1, the compressor 1 is stopped.

  For example, when the compressor 1 is restarted at the lower limit rotational speed Rd and the forward temperature Tg is rising, the forward temperature Tg exceeds the threshold temperature Ts (point Q1 in FIG. 4), exceeding the threshold temperature. If the forward temperature Tg becomes equal to or higher than the upper limit temperature Tt1 within a short time Ti1, the time during which the compressor 1 is operated while the forward temperature Tg is higher than the target temperature Tt is short. Therefore, the operating time of the useless heat pump type heating and hot water supply apparatus 100 is shortened and the COP is not deteriorated so much.

  On the other hand, depending on the heating load of the indoor unit 40 (for example, the solar radiation state of the room in which the indoor unit 40 is installed) and the outside air temperature To, the forward temperature Tg exceeds the threshold temperature Ts as shown in FIG. In some cases, the upper limit temperature Tt1 may not be reached even if the threshold temperature excess time Ti2, which is the time from the point Q2), is long. In such a case, there is a possibility that the temperature in the indoor unit 40 or the hot water storage tank 70 is higher than the set temperature, and the forward temperature Tg is not higher than the upper limit temperature Tt1, and therefore the compressor 1 is rotated at the lower limit. Continued operation at several Rd. In other words, the heat pump type heating and hot water supply apparatus 100 is operating in vain, and if this state continues for a long time (in the above example, the threshold temperature excess time Ti2 continues), the COP of the heat pump type heating and hot water supply apparatus 100 is maintained. There was a problem that hindered improvement.

  Therefore, in the heat pump type heating and hot water supply apparatus 100 of the present invention, when the compressor 1 is restarted and the forward temperature Tg reaches the threshold temperature Ts, time measurement is started, and the forward temperature Tg is equal to or higher than the threshold temperature Ts and lower than the upper limit temperature Tt1. Is started, that is, measurement of the threshold temperature excess time Ti is started. If the threshold temperature excess time Ti is equal to or greater than the excess limit time Te (point X in FIG. 4) as the threshold temperature excess time Ti2 shown in FIG. 4, the rotation speed of the compressor 1 is optimized from the lower limit rotation speed Rd. The rotational speed is increased to Rm (switching from operation 1 to operation 2). If the forward temperature Tg is equal to or higher than the upper limit temperature Tt1 when the compressor 1 is operated at the optimum rotational speed Rm, the compressor 1 is stopped. By increasing the rotational speed of the compressor 1 to the optimal rotational speed Rm at which the COP is the maximum value, the increase in the forward temperature Tg is accelerated, and the forward temperature Tg is quickly reached the upper limit temperature Tt1 and the compressor 1 is stopped. Further, it is possible to prevent the compressor 1 from being continuously operated at a temperature equal to or higher than the target temperature Tt, and to improve the COP of the heat pump type heating and hot water supply apparatus 100.

  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 heating and hot water supply apparatus 100 other than the control related to the present invention, such as the control of the compressor 1 and the opening degree control of the expansion valve 4 when raising the going temperature Tg to the target temperature Tt. The illustration and description are omitted for.

  The control means 60 takes the forward temperature Tg detected by the outlet temperature sensor 57 during the heating operation or the boiling operation, is determined according to the set temperature of the heating operation or the heating operation, and is stored in the storage unit. It is determined whether the temperature is equal to or higher than the target temperature Tt (ST1). If the going temperature Tg is not equal to or higher than the target temperature Tt (ST1-No), the control means 60 returns the process to ST1 and maintains the current compressor speed R. Note that until the temperature Tg reaches the target temperature Tt after the heating operation or the boiling operation is started, the control means 60 drives the compressor 1 with the compressor rotational speed R as the rotational speed at startup (for example, 60 rps). doing. 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 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). Note that 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 temperature Tt to compress the compressor speed. The lower limit rotational speed Rd is extracted with reference to the 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 (ST11). Next, the control means 60 determines whether or not the forward temperature Tg is equal to or higher than the threshold temperature Ts (ST12).

  If the going temperature Tg is not equal to or higher than the threshold temperature Ts (ST12-No), the control means 60 returns the process to ST4. If the going temperature Tg is equal to or higher than the threshold temperature Ts (ST12-Yes), the control means 60 starts measuring the threshold temperature excess time ti (ST13).

  Next, the control means 60 determines whether or not the forward temperature Tg is equal to or higher than the threshold temperature Ts and lower than the upper limit temperature Tt1 (ST14). If the going temperature Tg is not less than the threshold temperature Ts and less than the upper limit temperature Tt1 (ST14-No), the control means 60 returns the process to ST4. If the forward temperature Tg is equal to or higher than the threshold temperature Ts and lower than the upper limit temperature Tt1 (ST14-Yes), the control means 60 determines whether or not the threshold temperature excess time ti is equal to or greater than the excess limit time te (ST15).

  If the threshold temperature excess time ti is not longer than the excess limit time te (ST15-No), the control means 60 returns the process to ST14. If the threshold temperature excess time ti is equal to or greater than the excess limit time te (ST15-Yes), the control means 60 resets the timer (ST16) and operates the compressor 1 with the compressor rotational speed R as the optimal rotational speed Rm. (ST17). Note that 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 temperature Tt to compress the compressor speed. The optimum rotational speed Rm is extracted with reference to the table 200.

  Next, the control means 60 determines whether or not the forward temperature Tg when the compressor 1 is operating at the optimum rotational speed Rm is less than the upper limit temperature Tt1 (ST18). If the going-out temperature Tg is less than the upper limit temperature Tt1 (ST18-Yes), the control means 60 returns the process to ST17 and continuously operates the compressor 1 at the optimum rotational speed Rm. If the going temperature Tg is not less than the upper limit temperature Tt1 (ST18-No), the control means 60 advances the process to ST5.

  If the forward temperature Tg is not lower than the upper limit temperature Tt1 in ST4 (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 timer measurement (ST8), and determines whether or not a predetermined time has elapsed from the start of timer measurement, that is, the restart of the compressor 1 (ST9). If the predetermined time 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 predetermined time has elapsed (ST9-Yes), the control means 60 resets the timer (ST10) and returns the process to ST4. Here, the predetermined time in ST9 is a continuous operation time (for example, 10 minutes) in which the operation efficiency of the compressor 1 described above is improved. If the operation time of the compressor 1 is shorter than the predetermined time, the operation efficiency deteriorates. If the time is longer than the predetermined time, the operation efficiency of the compressor 1 is improved.

  As described above, the heat pump type heating and hot water supply apparatus of the present invention has a threshold temperature excess time that is a threshold temperature that is a predetermined temperature higher than a target temperature and less than an upper limit temperature, and a threshold temperature excess time that is a predetermined excess limit time or more. If so, the rotational speed of the compressor is increased to the optimum rotational speed, and the compressor is stopped when the forward temperature is equal to or higher than the upper limit temperature. Increasing the compressor speed to the optimum speed at which the COP reaches its maximum value speeds up the forward temperature rise, quickly reaches the upper limit temperature, and stops the compressor. It is possible to prevent the compressor from being continuously operated at the above temperature, and to improve the COP of the heat pump type heating hot water supply apparatus.

  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 that is the rotational speed of the compressor 1 when the COP reaches the maximum value. The number Rd may be the rotational speed of the compressor 1 corresponding to a COP value that is a predetermined percentage lower than the highest COP value (for example, a COP value that is 5% lower than the highest 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 Outdoor temperature sensor 57 Outlet 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 To outdoor temperature Tt target temperature Tt1 upper limit temperature Tt2 lower limit temperature Tg forward temperature Ts threshold temperature ti, ti1, ti2 threshold temperature excess time te excess limit time R compressor speed Rm optimum speed Rd lower limit speed

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, a flow rate adjusting unit, and a heat source side heat exchanger;
A hot water supply circuit for circulating hot water between a heating terminal and the water refrigerant heat exchanger by operation of a circulation pump;
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
In order to keep the forward temperature within a temperature range including a target temperature corresponding to the capability required by the heating terminal and defined by an upper limit temperature and a lower limit temperature, the compressor having the highest COP value is used. When operating at a lower limit rotational speed that is a predetermined rotational speed lower than the optimal rotational speed that is
Determining whether the forward temperature is equal to or higher than a threshold temperature which is a predetermined temperature between the target temperature and the upper limit temperature;
If the forward temperature is equal to or higher than the threshold temperature, a threshold temperature excess time, which is a time that is equal to or higher than the threshold temperature and lower than the upper limit temperature since the forward temperature becomes the threshold temperature, is measured,
When the threshold temperature excess time is equal to or greater than a predetermined excess limit time, the rotational speed of the compressor is set as the optimal rotational speed, and when the compressor is operated at the optimal rotational speed, the forward temperature is the upper limit. If the temperature is over, stop the compressor,
A heat pump type heating and hot water supply apparatus characterized by that. The control means includes
Until the threshold temperature excess time reaches the excess limit time, the compressor is continuously driven at the lower limit rotational speed,
When operating the compressor at the lower limit rotational speed, if the forward temperature is equal to or higher than the upper limit temperature, the compressor is stopped.
The heat pump type heating and 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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