JP7079608B2 - Heating system - Google Patents

Description

The techniques disclosed herein relate to heating systems.

Patent Document 1 describes a heat pump that heats a heat medium by using heat absorbed from the outside air, a combustor that heats the heat medium by using the heat of burning fuel, and heat of the heat medium. A heating system including a heater for heating and a control device is disclosed. When the temperature of the heat medium supplied to the heater drops to a predetermined ignition temperature, the control device operates the combustor to start heating the heat medium, and the temperature of the heat medium supplied to the heater extinguishes the fire. When the temperature rises to the temperature, the operation of the combustor is stopped. Further, the control device raises the target heating temperature of the heat pump when the combustor is operated to start heating the heat medium. This makes it possible to quickly raise the temperature of the heat medium supplied to the heater to the fire extinguishing temperature when the amount of heat dissipated in the heater decreases, and to quickly end the heating of the heat medium by the combustor. , The heating of the heat medium by the combustor is suppressed to the minimum necessary.

Japanese Unexamined Patent Publication No. 2012-13245

In the technique of Patent Document 1, it is considered to minimize the amount of heating by the combustor, but the operation content that can maximize the primary energy efficiency of the entire heating system is not considered. In a heating system equipped with two types of heat sources, a heat pump and a combustor, it is required to provide a technique that can maximize the primary energy efficiency of the entire system.

This specification provides a technique that can maximize the primary energy efficiency of the entire system in a heating system having two types of heat sources, a heat pump and a combustor.

The heating system disclosed in the present specification utilizes a heat medium circulation path for circulating a heat medium, a heat pump that heats the heat medium by using heat absorbed from the outside air, and heat obtained by burning fuel. A combustor for heating the heat medium, a heater for heating by using the heat of the heat medium, and a control device are provided. The combustor includes a plurality of burners. Each of the plurality of burners can burn the fuel. The plurality of burners are arranged in series with the heat medium circulation path. When the heat medium should be heated by using both the heat pump and the combustor, the control device operates only a part of the burners of the combustor to operate the burner. Let the heat medium heat up. When the control device should use the combustor to heat the heat medium without using the heat pump, the control device operates all the plurality of burners of the combustor to heat the heat medium. Let me do it.

As a result of diligent research by the inventor and others, when the heat medium should be heated using both the heat pump and the combustor, the case where all the burners of the combustor are operated (hereinafter referred to as "total combustion"). It has been found that the primary energy efficiency of the entire system is improved by operating only a part of the burners of a plurality of burners (hereinafter sometimes referred to as "partial combustion") as compared with (there is). The reason is as follows.

If the heat medium should be heated using both the heat pump and the combustor, and if the combustor is completely burned to heat the heat medium, the minimum amount of fuel to be supplied to the combustor is assumed. Even if it is reduced to (that is, even if the thermal power is reduced to the minimum), the amount of heat that the combustor applies to the heat medium per unit time increases. Therefore, when the combustor is completely burned, the heat medium reaches the threshold temperature at which the combustor should be stopped (so-called fire extinguishing temperature) in a short time. Therefore, the combustor is stopped immediately after a short operation. As a result, there is a high possibility that the combustor will be started and stopped frequently in order to maintain the heat medium at the set temperature required for heating. Even while the combustor is stopped (that is, all burners are stopped), the heat medium is heated by the heat pump, so that the temperature of the heat medium is suppressed from dropping sharply, and the heat medium is stopped. It takes a relatively long period of time for the temperature of the combustor to fall below the threshold temperature (so-called ignition temperature) at which the operation of the combustor should be started. That is, the period during which the combustor is not operating becomes longer. While the combustor is not operating (ie, while the combustor is not heating the heat medium), the heat medium dissipates heat as it passes through the combustor. As described above, when the heat medium should be heated using both the heat pump and the combustor, the heat medium is heated by the combustor even when the combustor is completely burned to heat the heat medium. If only efficiency is focused, there is not much difference compared to the case where the combustor is partially burned to heat the heat medium.

However, when the combustor is completely burned, the combustor may be started and stopped frequently as described above. Therefore, the temperature of the heat medium introduced into the heat pump changes significantly, and the temperature of the heat medium introduced into the heat pump becomes unstable. That is, with the frequent start and stop of the combustor, the change in the amount of heat that the heat pump can heat the heat medium (so-called heating width) becomes large. For example, during the operation of the combustor and immediately after the stop, the temperature of the heat medium introduced into the heat pump becomes relatively high, so that the heating width by the heat pump becomes small. As a result, the heating efficiency (specifically, COP (Coefficient Of Performance)) of the heat pump during that period deteriorates. Further, for example, when the combustor is stopped for a long period of time, the temperature of the heat medium introduced into the heat pump becomes relatively low, so that the heating width of the heat pump becomes large. During that time, the heating efficiency of the heat pump becomes relatively good. In this way, when the heat medium should be heated using both the heat pump and the combustor, if the combustor is fully burned, the heating width of the heat pump will not be stable, and the heating efficiency of the heat pump for the entire period will be averaged. Will be low.

For the above reasons, when the heat medium should be heated using both the heat pump and the combustor, if the combustor is fully burned, the heating efficiency of the heat pump will be low, and the primary energy of the entire system will be reduced. It is less efficient.

On the other hand, when the heat medium should be heated using both the heat pump and the combustor, if the combustor is partially burned to heat the heat medium, the combustor will heat the heat medium per unit time. The amount of heat applied to is reduced. Therefore, when the combustor is partially burned, the temperature of the heat medium is set to the set temperature required for heating by adjusting the amount of fuel supplied to the combustor (that is, by adjusting the thermal power of the operating burner). It will be easier to maintain. That is, it is less likely that the combustor will be started and stopped frequently. When the combustor is partially combusted, the combustor can be continuously operated for a long time as compared with the case where the combustor is fully combusted. However, when the combustor is partially burned, a part of the plurality of burners does not operate, so that the heat medium dissipates heat while passing through the non-operating burner portion. Therefore, as described above, when the heat pump and the combustor are operated at the same time to heat the heat medium, when the combustor is partially combusted to heat the heat medium, only the heating efficiency of the heat medium by the combustor is used. If we pay attention to it, there is not much difference compared to the case where the combustor is completely burned to heat the heat medium.

However, when the combustor is partially combusted, the frequency of starting and stopping the combustor is low as described above. Therefore, the change in the temperature of the heat medium introduced into the heat pump becomes small, and the temperature of the heat medium introduced into the heat pump becomes stable. Therefore, the change in the heating width due to the heat pump becomes small. As a result, the heating efficiency of the entire period by the heat pump is higher on average than in the case where the combustor is fully combusted.

For the above reasons, when the heat medium should be heated using both the heat pump and the combustor, partial combustion of the combustor increases the heating efficiency of the heat pump, resulting in higher primary energy of the entire system. Higher efficiency.

According to the above configuration, when the heat medium should be heated by utilizing both the heat pump and the combustor, the control device operates only a part of the burners of the combustor to generate heat. Let the medium heat up. As a result, when the heat medium should be heated using both the heat pump and the combustor, the primary energy of the entire system is compared with the case where all the burners of the combustor are operated to heat the heat medium. Efficiency can be increased. Therefore, according to the above configuration, in a heating system including two types of heat sources, a heat pump and a combustor, the primary energy efficiency of the entire system can be maximized.

As a result of diligent research by the inventors, if the heat medium should be heated using a combustor instead of using a heat pump (for example, if the heat pump is used for heating applications other than heating), the combustor should be fully used. It has also been found that burning is more efficient than partial burning of the combustor. That is, in the case where the heat medium is heated by using the combustor without using the heat pump, when the combustor is partially combusted, the heat medium causes the non-operating burner part among the plurality of burners of the combustor. Heat is dissipated while passing through, and the heating efficiency of the heat medium is reduced. In particular, when the fan in the combustor operates as in the case of total combustion, the amount of heat dissipated in the non-operating burner portion becomes larger. On the other hand, when the combustor is completely burned, the heat dissipation as described above is not performed and the heat loss is reduced. However, since the amount of heat applied to the heat medium by the combustor per unit time is large, it is highly possible that the combustor is frequently started and stopped in order to maintain the heat medium at the set temperature required for heating. However, since the heat medium is not heated by the heat pump while the combustor is stopped, the temperature of the heat medium falls below the ignition temperature relatively early after the combustor is stopped, and the combustor is operating. The period during which there is no heat (that is, the period during which the combustor does not heat the heat medium) can be shortened. Therefore, when the heat medium should be heated by using a combustor instead of using a heat pump, the heating efficiency is higher when the combustor is fully combusted than when the combustor is partially combusted. According to the above configuration, the primary energy efficiency of the entire system can be maximized even when the heat medium should be heated by using a combustor instead of using a heat pump.

The figure which shows typically the operation of the hot water supply heating system 2 at the time of a heat storage operation and a hot water supply operation. The figure which shows typically the operation of the hot water supply heating system 2 at the time of combined heating operation. A flowchart showing heat pump temperature control. A flowchart showing burner temperature control. The graph which shows the temperature change of the detection temperature of the thermistor 78 in each case of the case of full combustion and the case of partial combustion of the burner heating device 82 in the combined heating operation. The graph which shows the relationship between the combustion load of a burner heating device 82 and the average combustion efficiency of a burner heating device 82 at the time of combined heating operation. The graph which shows the relationship between the combustion load of a burner heating apparatus 82 and COP of a heat pump 50 at the time of combined heating operation. The graph which shows the relationship between the combustion load of the burner heating apparatus 82 and the primary energy efficiency of the whole system at the time of combined heating operation. The figure which shows typically the operation of the hot water supply heating system 2 at the time of a single heating operation. The graph which shows the relationship between the combustion load of a burner heating device 82 and the average combustion efficiency of a burner heating device 82 at the time of a single heating operation.

(Example)
As shown in FIG. 1, the hot water supply / heating system 2 according to the present embodiment includes a hot water supply system 104, a heat pump system 106, a heating system 108, and a control device 100.

The heat pump system 106 includes a heat pump 50. The heat pump 50 includes a refrigerant circulation path 52 for circulating a refrigerant (for example, Freon gas R410A, etc.), a heat exchanger (evaporator) 54, a fan 56, a compressor 62, and a three-fluid heat exchanger (condenser). ) 58 and an expansion valve 60. The heat exchanger 54, the compressor 62, the three-fluid heat exchanger 58, and the expansion valve 60 are installed in the refrigerant circulation path 52. By operating the heat pump 50 having such a configuration, the high-temperature and high-pressure refrigerant can be sent into the refrigerant circulation path 52 passing through the three-fluid heat exchanger 58.

The hot water supply system 104 includes a tank 10, a tank water circulation path 20, a tap water introduction path 24, a supply path 36, and a burner heating device 81.

The tank 10 stores hot water heated by the heat pump 50. The tank 10 is a closed type, and the outside is covered with a heat insulating material. Water is stored in the tank 10 until it is full. Thermistors 12, 14, 16 and 18 are attached to the tank 10 at substantially equal intervals in the height direction of the tank 10. Each thermistor 12, 14, 16 and 18 measures the temperature of the water at its mounting position.

The tank water circulation path 20 has an upstream end connected to the lower part of the tank 10 and a downstream end connected to the upper part of the tank 10. A circulation pump 22 is interposed in the tank water circulation path 20. The circulation pump 22 sends out the water in the tank water circulation path 20 from the upstream side to the downstream side. Further, as described above, the tank water circulation path 20 passes through the three-fluid heat exchanger 58. Therefore, when the heat pump 50 is operated, the water in the tank water circulation path 20 is heated by the three-fluid heat exchanger 58. Therefore, when the circulation pump 22 and the heat pump 50 are operated, the water in the lower part of the tank 10 is sent to the three-fluid heat exchanger 58 to be heated, and the heated water is returned to the upper part of the tank 10. The tank water circulation channel 20 is a water channel for storing heat in the tank 10.

The upstream end of the tap water introduction path 24 is connected to the tap water supply source 32. The downstream side of the tap water introduction path 24 is branched into a first introduction path 24a and a second introduction path 24b. The downstream end of the first introduction path 24a is connected to the lower part of the tank 10. The downstream end of the second introduction path 24b is connected in the middle of the supply path 36. A mixing valve 36a that adjusts the ratio of the flow rate of water flowing through the first introduction path 24a (that is, the flow rate of water flowing from the tank 10 to the supply path 36) and the flow rate of water flowing through the second introduction path 24b is arranged at the connection portion. Has been done. A check valve 26 is interposed in the first introduction path 24a. A check valve 28 and a water amount sensor 30 are interposed in the second introduction path 24b. The water amount sensor 30 detects the flow rate of tap water flowing in the second introduction path 24b.

The upstream end of the supply path 36 is connected to the upper part of the tank 10. As described above, the second introduction path 24b of the tap water introduction path 24 is connected in the middle of the supply path 36. A water amount sensor 34 is interposed in the supply path 36 on the upstream side of the connection portion with the second introduction path 24b. The water amount sensor 34 detects the flow rate of water flowing from the tank 10 to the supply path 36. A burner heating device 81 is interposed in the supply path 36 on the downstream side of the connection portion with the second introduction path 24b. The burner heating device 81 includes a burner 81a capable of burning gas. The burner heating device 81 heats the water in the supply path 36 by operating the burner 81a to burn the gas. The downstream end of the supply path 36 is connected to the hot water tap 38. The supply path 36 is provided with a bypass path 36b, which is a flow path that bypasses the burner heating device 81. Further, the bypass path 36b is interposed with a bypass control valve 36c for adjusting the opening degree of the bypass path 36b.

The heating system 108 includes a systurn 70, a heating medium circulation path 71, a burner heating device 82, and a heater 76. The heating heat medium circulation path 71 includes a heating outward path 72, a heating return path 84, a regulating valve 90, a heat recovery path 88, a bypass path 94, and a circulation channel 96. The heating heat medium circulation path 71 is a flow path for circulating the heat medium (specifically, water or antifreeze) in the systurn 70. The heat medium in the heating heat medium circulation path 71 is heated by the burner heating device 82 and the three-fluid heat exchanger 58.

The cistern 70 is a container whose upper part is open, and stores a heat medium for heating (that is, water or antifreeze) inside. The downstream end of the circulation flow path 96 and the upstream end of the heating outbound route 72 are connected to the systurn 70. A heat medium flows into the cisturn 70 from the circulation flow path 96. The heat medium in the systurn 70 is introduced into the heating outbound route 72.

The upstream end of the heating outbound route 72 is connected to the systurn 70, and the downstream end is connected to the outbound port of the heater 76. A circulation pump 74 is interposed in the heating outbound route 72. The circulation pump 74 is a pump that sends out the heat medium in the heating outward path 72 to the downstream side. A burner heating device 82 is interposed in the heating outbound path 72 on the upstream side of the heater 76. The burner heating device 82 heats the heat medium in the heating outbound path 72. In this embodiment, the burner heating device 82 includes four burners 82a to 82d. The burners 82a to 82d can each burn gas. The burner heating device 82 heats the heat medium in the heating outbound path 72 by operating a part or all of the burners 82a to 82d to burn the gas. The operation of the burner heating device 82 is shown in FIGS. 2 and 9. In the example of FIG. 2, only one burner 82a is operating, and in the example of FIG. 9, all the burners 82a to 82d are operating. Further, the burner heating device 82 also includes a fan (not shown) that operates during the operation of the burner (one burner 82a or all the burners 82a to 82d) to blow air. The burner heating device 82 has a higher ability to heat the heat medium than the heat pump 50. In other words, the burner heating device 82 has a larger heating amount per unit time than the heat pump 50. The heat medium heated by the burner heating device 82 is supplied to the heater 76. Further, a thermistor 78 is interposed on the downstream side of the burner heating device 82 of the heating outbound route 72. The thermistor 78 measures the temperature of the heat medium in the heating outbound path 72 after passing through the burner heating device 82.

The heater 76 is a terminal that heats a living room by using the heat of a heat medium supplied from the heating outbound route 72. When the heat medium supplied from the heating outbound route 72 is used for heating, the heat is taken away and the temperature becomes relatively low. The relatively low temperature heat medium after being used for heating is introduced into the heating return path 84.

The upstream end of the heating return path 84 is connected to the return port of the heater 76, and the downstream end is connected to the upstream end of the bypass path 94 and the upstream end of the heat recovery path 88. A thermistor 86 is interposed in the heating return path 84. The thermistor 86 measures the temperature of the heat medium in the heating return path 84 (that is, the temperature of the heat medium sent to the three-fluid heat exchanger 58).

The upstream end of the heat recovery path 88 is connected to the upstream end of the bypass path 94 and the downstream end of the heating return path 84, and the downstream end is connected to the downstream end of the bypass path 94 and the upstream end of the circulation flow path 96. The heat recovery path 88 passes through the three-fluid heat exchanger 58. Therefore, when the heat pump 50 is operated, the heat medium in the heat recovery path 88 is heated by the three-fluid heat exchanger 58. A thermistor 92 is interposed on the downstream side of the three-fluid heat exchanger 58 of the heat recovery path 88. The thermistor 92 measures the temperature of the heat medium in the heat recovery path 88 after passing through the three-fluid heat exchanger 58.

The upstream end of the bypass path 94 is connected to the downstream end of the heating return path 84 and the upstream end of the heat recovery path 88, and the downstream end is connected to the downstream end of the heat recovery path 88 and the upstream end of the circulation flow path 96. That is, the bypass path 94 bypasses the upstream side and the downstream side of the three-fluid heat exchanger 58.

The regulating valve 90 is attached to a connection portion between the downstream end of the heating return path 84, the upstream end of the heat recovery path 88, and the upstream end of the bypass path 94. By changing the opening degree of the regulating valve 90, the flow rate of the heat medium passing through the heat recovery path 88 (the flow rate of the heat medium passing through the three-fluid heat exchanger 58) and the heat medium passing through the bypass path 94. The ratio with the flow rate of can be changed. For the regulating valve 90 of this embodiment, for example, a three-way valve is used.

The upstream end of the circulation flow path 96 is connected to the downstream end of the heat recovery path 88 and the downstream end of the bypass path 94, and the downstream end is connected to the systurn 70. A thermistor 98 is interposed in the circulation flow path 96. The thermistor 98 measures the temperature of the heat medium in the circulation flow path 96.

The control device 100 is electrically connected to the hot water supply system 104, the heat pump system 106, and the heating system 108, and controls the operation of each component.

(Operation of hot water supply and heating system)
Next, the operation of the hot water supply / heating system 2 of this embodiment will be described. The hot water supply heating system 2 can execute each of the heat storage operation, the hot water supply operation, the combined heating operation, and the single heating operation. Hereinafter, each operation will be described.

(Heat storage operation)
The heat storage operation is an operation in which the water in the tank 10 is heated by the heat generated by the heat pump 50. The solid arrow in FIG. 1 indicates the flow of the refrigerant in the heat pump 50 and the flow of water in the tank 10 during the heat storage operation. When the control device 100 instructs the execution of the heat storage operation, the heat pump 50 starts operation and the circulation pump 22 rotates.

When the heat pump 50 operates, the refrigerant in the refrigerant circulation path 52 passing through the three-fluid heat exchanger 58 becomes a high-temperature and high-pressure gas state. Further, when the circulation pump 22 rotates, the water in the tank 10 circulates in the tank water circulation path 20. That is, the water existing in the lower part of the tank 10 is introduced into the tank water circulation path 20, and when the introduced water passes through the three-fluid heat exchanger 58, it is heated by the heat of the refrigerant in the refrigerant circulation path 52. The heated water is returned to the top of the tank 10. As a result, hot water is stored in the tank 10. A layer of hot water is formed in the upper part of the tank 10, and a layer of cold water is formed in the lower part.

(Hot water supply operation)
The hot water supply operation is an operation of supplying the water in the tank 10 to the hot water supply tap 38. The broken line arrow in FIG. 1 indicates the flow of water in the tank 10 during the hot water supply operation. The hot water supply operation can also be executed during the above heat storage operation. When the water heater 38 is opened, the control device 100 opens the mixing valve 36a. Then, due to the water pressure from the tap water supply source 32, tap water flows into the lower part of the tank 10 from the tap water introduction path 24 (first introduction path 24a). At the same time, the hot water in the upper part of the tank 10 is supplied to the hot water tap 38 via the supply path 36.

When the temperature of the water supplied from the tank 10 to the supply path 36 (that is, the detection temperature of the thermistor 12) is higher than the hot water supply set temperature, the control device 100 adjusts the mixing valve 36a to adjust the second introduction path. Tap water is introduced from 24b into the supply channel 36. Therefore, the water supplied from the tank 10 and the tap water supplied from the second introduction path 24b are mixed in the supply path 36. The control device 100 adjusts the opening ratio of the mixing valve 36a so that the temperature of the water supplied to the hot water supply plug 38 matches the hot water supply set temperature. On the other hand, the control device 100 operates the burner heating device 81 when the temperature of the water supplied from the tank 10 to the supply path 36 is lower than the hot water supply set temperature. Therefore, the water passing through the supply path 36 is heated by the burner heating device 81. The heated water is mixed with water from the bypass path 36b whose opening degree is adjusted by the bypass control valve 36c and is supplied to the hot water supply tap 38. The control device 100 controls the output of the burner heating device 81 so that the temperature of the water supplied to the hot water tap 38 matches the set temperature of the hot water supply.

(Combined heating operation)
In the combined heating operation, both the heat pump 50 and the burner heating device 82 are operated to heat the heat medium in the heating heat medium circulation path 71, and the heat of the heated heat medium is dissipated by the heater 76 in the living room. It is a heating operation to heat. In the situation where the combined heating operation should be performed, for example, when the heating operation should be performed while the heat storage operation and the hot water supply operation are not performed, both the heat pump 50 and the burner heating device 82 are heat sources for heating. It is a situation where the execution of heating operation is instructed when it is available as. The solid line arrow in FIG. 2 indicates the flow of the refrigerant of the heat pump 50 and the flow of the heat medium in the heat medium circulation path 71 for heating during the combined heating operation.

When the user is instructed to execute the heating operation, first, the control device 100 adjusts the opening degree of the adjusting valve 90 according to the heating load in the heater 76. As a result, the heat medium in the cisturn 70 passes from the cisturn 70 through the heating outward path 72, the heater 76, the heating return path 84, the heat recovery path 88, and the circulation flow path 96 in this order, and returns to the cisturn 70. Is formed (see FIG. 2). Further, depending on the opening degree of the regulating valve 90, a path through which a part of the heat medium flowing through the heat recovery path 88 passes through the bypass path 94 and is introduced into the circulation flow path 96 is also formed (not shown).

Next, the control device 100 sets the heating set temperature, which is the temperature of the heat medium to be supplied to the heater 76, based on the operating temperature set by the user. The control device 100 calculates and sets the heating set temperature using a predetermined formula. Next, the control device 100 operates the circulation pump 74 at a predetermined rotation speed. By operating the circulation pump 74, the heat medium circulates in the above path.

Next, the control device 100 starts the heat pump temperature control in FIG. 3 and the burner temperature control in FIG. 4. The contents of the heat pump temperature control and the burner temperature control will be described in detail later. After starting the heat pump temperature control and the burner temperature control, the control device 100 continuously executes the heat pump temperature control and the burner temperature control until the user instructs the end of the heating operation. ..

The heat pump temperature control is described with reference to FIG. The heat pump temperature control is a control executed by the control device 100 in order to heat the heat medium to a predetermined target hot water temperature by the heat pump 50. The target hot water temperature is the target temperature of the heat medium after being heated by the three-fluid heat exchanger 58. As shown in FIG. 3, when the heat pump temperature control is started, first, in S10, the control device 100 determines the heating set temperature and the bypass ratio of the control valve 90 (of the heat medium flowing in the heat medium circulation path 71 for heating). , The ratio of the heat medium flowing through the bypass path 94) and the detected temperature of the thermista 86 (the temperature of the heat medium sent to the three-fluid heat exchanger 58), the target hot water discharge temperature is calculated.

Next, in S12, in the control device 100, the detection temperature of the thermistor 92 (the temperature of the heat medium sent out from the three-fluid heat exchanger 58) is lower than the operation start temperature which is higher than the target hot water discharge temperature by a predetermined temperature α1 (for example, 1 ° C.). Monitor that. The value of α1 may be changed depending on the target hot water temperature. In another example, the operation start temperature may be a temperature lower than the target hot water discharge temperature by a predetermined temperature α1. When the detected temperature of the thermistor 92 is lower than the above-mentioned operation start temperature, the control device 100 determines YES in S12 and proceeds to S14.

In S14, the control device 100 starts the operation of the heat pump 50. By operating the heat pump 50, the heat medium passing through the heat recovery path 88 is heated by the heat of the refrigerant in the refrigerant circulation path 52 in the three-fluid heat exchanger 58.

Next, in S16, the control device 100 monitors that the detected temperature of the thermistor 92 becomes equal to or higher than the stop temperature by a predetermined temperature α2 (for example, 15 ° C.) higher than the target hot water discharge temperature. When the detection temperature of the thermistor 86 is equal to or higher than the stop temperature, the control device 100 determines YES in S16 and proceeds to S18. When the detection temperature of the thermista 92 is equal to or higher than the stop temperature, the temperature of the refrigerant in the refrigerant circulation path 52 passing through the three-fluid heat exchanger 58 and the temperature in the heat recovery path 88 passing through the three-fluid heat exchanger 58. The difference in temperature of the heat medium becomes small, and the heating efficiency of the heat pump 50 decreases.

In S18, the control device 100 stops the heat pump 50. As a result, the heat medium passing through the heat recovery path 88 is not heated by the heat of the refrigerant in the refrigerant circulation path 52 in the three-fluid heat exchanger 58.

After finishing S18, the control device 100 returns to S10. In this way, the control device 100 repeatedly executes each process of S10 to S18 until the user instructs the end of the heating operation.

Next, the burner temperature control is described with reference to FIG. The burner temperature control is a control executed by the control device 100 in order to operate the burner heating device 82 and set the temperature of the heat medium supplied to the heater 76 to the heating set temperature.

First, in S30, in the control device 100, the detection temperature of the thermistor 78 (that is, the temperature of the water supplied to the heater 76) is lower than the ignition temperature by a predetermined temperature β (for example, 5 ° C.) from the heating set temperature. To monitor. The value of β may be changed according to the heating set temperature. If the detected temperature of the thermistor 78 is lower than the ignition temperature, the control device 100 determines YES in S30 and proceeds to S32.

In S32, the control device 100 starts the operation of the burner heating device 82. The content of S32 differs depending on whether the hot water supply heating system 2 is performing the combined heating operation or the single heating operation (described later). In this case, in the hot water supply heating system 2, the combined heating operation is performed (that is, the control device 100 also executes the heat pump temperature control (FIG. 3) in parallel). Therefore, in S32, the control device 100 burns the gas using only a part of the burners (for example, the burner 82a) of the burners 82a to 82d of the burner heating device 82. Such an operation of the burner heating device 82 may be referred to as "partial combustion" below. When the burner heating device 82 starts partial combustion, the heat medium is heated by the burner heating device 82.

When the operation of the burner heating device 82 is started in S32, the control device 100 changes the flow rate of the gas supplied to the burner heating device 82 (in this case, the burner 82a) so that the detection temperature of the thermistor 78 stabilizes at the heating set temperature. adjust. Specifically, the control device 100 reduces the gas flow rate when the detected temperature of the thermistor 78 exceeds the heating set temperature, and increases the gas flow rate when the detected temperature of the thermistor 78 is lower than the heating set temperature. be able to. The thermal power of the burner 82a increases or decreases as the gas flow rate increases or decreases.

Next, in S34, the control device 100 monitors that the detected temperature of the thermistor 78 becomes equal to or higher than the fire extinguishing temperature which is higher than the heating set temperature by a predetermined temperature γ (for example, 5 ° C.). The value of γ may be changed according to the heating set temperature. When the detected temperature of the thermistor 78 becomes equal to or higher than the fire extinguishing temperature, the control device 100 determines YES in S34 and proceeds to S36.

In S36, the control device 100 stops the burner heating device 82. That is, the control device 100 extinguishes the burning burner 82a. As a result, the heat medium is not heated by the burner heating device 82.

After finishing S36, the control device 100 returns to S30. In this way, the control device 100 repeatedly executes each process of S30 to S36 until the user instructs the end of the heating operation.

The heat pump temperature control (FIG. 3) and the burner temperature control (FIG. 4) have been described above. As described above, when the user instructs the end of the heating operation during the execution of the heat pump temperature control and the burner temperature control, the control device 100 sets the heat pump 50, the burner heating device 82, and the burner heating device 82 which are in operation at that time. , All the circulation pumps 74 are stopped. In that case, the combined heating operation ends.

As described above, in the combined heating operation, the control device 100 performs partial combustion in which only the burner 82a is operated when the burner heating device 82 is operated (see S32 in FIG. 4). When operating the burner heating device 82 in the combined heating operation, the case where partial combustion is performed as described above is compared with the case where "total combustion" is performed to operate all the burners 82a to 82d, and the system as a whole is operated. High primary energy efficiency. The reason will be described below.

FIG. 5 shows the thermistor 78 in each of the cases where the burner heating device 82 is fully burned (see (a)) and partially burned as described above (see (b)) during the combined heating operation. It is a graph which shows the temperature change of the detection temperature. In the example of FIG. 5, the heating set temperature is 40 ° C., the ignition temperature is 35 ° C., and the fire extinguishing temperature is 45 ° C.

As shown in FIG. 5A, when the burner heating device 82 is fully burned, the burner heating device 82 operates once even when the flow rate of the gas supplied to each of the burners 82a to 82d is reduced to the minimum value. Then, the amount of heat applied to the water in the heating outbound route 72 per unit time increases (for example, at least 10000 kcal / h). Therefore, as shown in FIG. 5A, the detection temperature of the thermistor 78 reaches the fire extinguishing temperature (45 ° C.) in a short time. Therefore, the burner heating device 82 is stopped immediately after being operated for a short time. Therefore, in order to keep the heat medium at the heating set temperature, the burner heating device 82 is likely to be started and stopped frequently.

On the other hand, as shown in (b) in FIG. 5, when the burner heating device 82 is partially burned, the gas is burned only by the burner 82a. Therefore, when the gas flow rate is reduced to the minimum value, per unit time. The amount of heat applied to the water in the heating outbound route 72 can be reduced (for example, 2500 kcal / h at the minimum). Therefore, as shown in FIG. 5B, by adjusting the flow rate of the gas supplied to the burner heating device 82, it becomes easy to maintain the detected temperature of the thermistor 78 at a value near the heating set temperature. That is, in order to maintain the temperature of the water in the heating outbound route 72 at a value close to the heating set temperature, it is unlikely that the burner heating device 82 is frequently started and stopped. When the burner heating device 82 is partially burned, the burner heating device 82 can be continuously operated for a long time as compared with the case where the burner heating device 82 is fully burned.

FIG. 6 shows the relationship between the combustion load of the burner heating device 82 and the average combustion efficiency of the burner heating device 82 during the combined heating operation. Here, the "average combustion efficiency" indicates a value obtained by averaging the combustion efficiency during the period when the burner heating device 82 is operating and the combustion efficiency during the period when the burner heating device 82 is stopped. In FIG. 6, E1 represents the relationship when the burner heating device 82 is fully burned, and E2 represents the relationship when the burner heating device 82 is partially burned. As shown in E2, when the burner heating device 82 is partially burned, the maximum combustion load is 7 kW. Hereinafter, the same applies to FIGS. 7, 8 and 10. As shown by E1 and E2, there is no big difference in the average combustion efficiency between the case where the burner heating device 82 is fully burned and the case where the burner heating device 82 is partially burned.

As described above, when the burner heating device 82 is completely burned during the combined heating operation, there is a high possibility that the burner heating device 82 is frequently started and stopped (see (a) in FIG. 5). Even while the burner heating device 82 is stopped (that is, the operations of all the burners 82a to 82d are stopped), the heat medium in the heating heat medium circulation path 71 is heated by the heat pump 50, so that heat is generated. It is suppressed that the temperature of the medium drops sharply, and it takes a relatively long period of time for the temperature of the heat medium to drop to the ignition temperature of the burner heating device 82. That is, the period during which the burner heating device 82 is not operating becomes long. While the burner heating device 82 is not operating, the heat medium exchanges natural convective heat with the air while passing through the burner heating device 82 (that is, with the air while the fan of the burner heating device 82 is stopped). Heat exchange) causes heat dissipation. The term "heat dissipation" as used herein means that the temperature of the heat medium introduced into the burner heating device 82 is the temperature detected by the thermistor 78 (that is, the heat after passing through the burner heating device 82 and before being introduced into the heater 76. It means heat dissipation in a period higher than the temperature of the medium). As described above, when the combined heating operation is performed, the heat medium is heated by the heat pump 50 even while the burner heating device 82 is stopped. However, when calculating the average combustion efficiency in FIG. 6, the burner heating device 82 is used. The calculation is performed after considering the amount of heat radiated by the burner heating device 82 (heat radiating amount) as the amount of heat radiated by the burner heating device 82 while the burner heating device 82 is stopped.

Further, as described above, when the burner heating device 82 is partially burned during the combined heating operation, the possibility that the burner heating device 82 is frequently started and stopped is reduced, and the burner heating device 82 is continuously operated for a long time. (See (b) in FIG. 5). However, when the burner heating device 82 is partially burned, the heat medium exchanges forced convection heat with air while passing through the non-operating burner 82b to 82d portions (that is, the fan of the burner heating device 82 operates. Heat exchange with the air that accompanies it) dissipates heat.

Therefore, as described above, if only the average heating efficiency of the burner heating device 82 is focused on, there is a large difference between the case where the burner heating device 82 is fully burned and the case where the burner heating device 82 is partially burned during the combined heating operation. It disappears (see E1 and E2 in FIG. 6).

However, there is a large difference in the heating efficiency of the heat pump 50 between the case where the burner heating device 82 is fully burned and the case where the burner heating device 82 is partially burned during the combined heating operation. FIG. 7 shows the relationship between the combustion load of the burner heating device 82 and the COP of the heat pump 50 during the combined heating operation. In FIG. 7, E11 represents the relationship when the burner heating device 82 is fully burned, and E12 represents the relationship when the burner heating device 82 is partially burned. As shown by E11 and E12, the COP of the heat pump 50 when the burner heating device 82 is partially burned is higher than the COP of the heat pump 50 when the burner heating device 82 is fully burned.

As described above, when the burner heating device 82 is fully burned during the combined heating operation, the burner heating device 82 is frequently started and stopped (see (a) in FIG. 5). Therefore, the temperature of the heat medium introduced into the heat pump 50 changes significantly, and the temperature of the heat medium introduced into the heat pump 50 becomes unstable. That is, as the burner heating device 82 is frequently started and stopped, the amount of heat that the heat pump 50 can heat the heat medium (so-called heating width) changes significantly. For example, during the operation of the burner heating device 82 and immediately after the stop, the temperature of the heat medium introduced into the heat pump 50 becomes relatively high, so that the heating width by the heat pump 50 becomes small. As a result, the COP of the heat pump during that period deteriorates. Further, for example, when the burner heating device 82 is stopped and a long period of time elapses, the temperature of the heat medium introduced into the heat pump 50 becomes relatively low, so that the heating width of the heat pump 50 becomes large. During that time, the COP of the heat pump 50 becomes relatively good. As described above, when the burner heating device 82 is completely burned during the combined heating operation, the heating width by the heat pump 50 is not stable, and the COP of the heat pump 50 becomes low on average (see E11 in FIG. 7).

On the other hand, when the burner heating device 82 is partially burned during the combined heating operation, the frequency of starting and stopping of the burner heating device 82 is low as described above (see (b) in FIG. 5). Therefore, the change in the temperature of the heat medium introduced into the heat pump 50 becomes small, and the temperature of the heat medium introduced into the heat pump 50 becomes stable. Therefore, the change in the heating width due to the heat pump 50 becomes small. As a result, the COP of the heat pump 50 is higher on average than in the case of total combustion (see E12 in FIG. 7).

Due to this, as shown in FIG. 8, when the burner heating device 82 is partially burned during the combined heating operation, the primary energy efficiency of the entire system is higher than when the burner heating device 82 is fully burned. FIG. 8 shows the relationship between the combustion load of the burner heating device 82 during the combined heating operation and the primary energy efficiency of the entire hot water supply heating system 2. In FIG. 8, E21 represents the relationship when the burner heating device 82 is fully burned, and E22 represents the relationship when the burner heating device 82 is partially burned. As shown by E21 and E22, the primary energy efficiency in the case of partial combustion of the burner heating device 82 is higher than the primary energy efficiency in the case of full combustion.

(Independent heating operation)
In the single heating operation, the heat medium in the heat medium circulation path 71 for heating is heated using only the burner heating device 82 as a heat source, and the heat of the heated heat medium is used to heat the living room by the heater 76. be. The situation where the single heating operation should be performed requires that the heat pump 50 be used as a heat source for heating the hot water in the tank 10, for example, when the heating operation should be performed while the heat storage operation is being performed. In this situation, when only the burner heating device 82 can be used as a heat source for heating, the execution of the heating operation is instructed. The solid line arrow in FIG. 9 indicates the flow of the refrigerant of the heat pump 50 and the flow of the heat medium in the heating heat medium circulation path 71 during the combined heating operation.

Also in this case, when the user instructs to execute the heating operation, the control device 100 first adjusts the opening degree of the adjusting valve 90, and all of the heat medium flowing through the heating return path 84 passes through the bypass path 94. (Bypassing the heat recovery path 88) so that it can be introduced into the circulation flow path 96. That is, a path that bypasses the three-fluid heat exchanger 58 is formed. As a result, the heat medium in the cisturn 70 passes from the cisturn 70 through the heating outward path 72, the heater 76, the heating return path 84, the bypass path 94, and the circulation flow path 96 in this order, and returns to the cisturn 70. It is formed (see FIG. 9).

Next, the control device 100 sets the heating set temperature, which is the temperature of the heat medium to be supplied to the heater 76, based on the operating temperature set by the user. Next, the control device 100 operates the circulation pump 74 at a predetermined rotation speed to circulate the heat medium in the above path.

Next, the control device 100 starts burner temperature control (see FIG. 4). In this case, since the heat pump 50 is already operating for another purpose (for example, heating of water in the tank 10), the control device 100 does not perform heat pump temperature control (see FIG. 3). After starting the burner temperature control, the control device 100 continuously executes the burner temperature control until the user instructs the end of the heating operation.

The content of the burner temperature control (FIG. 4) in the case of the single heating operation is basically the same as the burner temperature control in the case of the combined heating operation. However, in the case of the single heating operation, in S32, the control device 100 burns the gas (that is, completely burns) using all the burners 82a to 82d of the burner heating device 82. When the burner heating device 82 starts full combustion, the heat medium is heated by the burner heating device 82. In the case of the single heating operation as well, the control device 100 adjusts the flow rate of the gas supplied to the burner heating device 82 (in this case, the burners 82a to 82d) as necessary, as in the case of the combined heating operation. As the gas flow rate increases or decreases, the thermal power of the burners 82a to 82d increases or decreases.

When the user instructs the end of the heating operation during the execution of the burner temperature control, the control device 100 stops all the burner heating devices 82 and the circulation pump 74 that are in operation at that time. In that case, the single heating operation ends.

As described above, in the single heating operation, when the burner heating device 82 is operated (see S32 in FIG. 4), the control device 100 performs total combustion in which all the burners 82a to 82d are operated. When operating the burner heating device 82 in the single heating operation, unlike the case of the combined heating operation, the primary energy efficiency of the entire system is higher in the case of performing full combustion than in the case of performing partial combustion. The reason will be described below.

FIG. 10 shows the relationship between the combustion load of the burner heating device 82 and the average combustion efficiency of the burner heating device 82 during the single heating operation. In FIG. 10, E31 represents the relationship when the burner heating device 82 is fully burned, and E32 represents the relationship when the burner heating device 82 is partially burned. As shown by E31 and E32, the average combustion efficiency in the case of full combustion of the burner heating device 82 is higher than the average combustion efficiency in the case of partial combustion, regardless of the magnitude of the combustion load.

In the case of a single heating operation, the heat pump 50 has already been used for purposes other than heating, and only the burner heating device 82 is used as a heat source for heating. At this time, if the burner heating device 82 is partially burned, heat is dissipated while the heat medium passes through the non-operating burners 82b to 82d of the burners 82a to 82d of the burner heating device 82. , The heating efficiency of the heat medium is lowered (see E32 in FIG. 10). In particular, when the fan (not shown) in the burner heating device 82 operates as in the case of total combustion, the amount of heat radiated from the non-operating burners 82b to 82d becomes even larger. On the other hand, when the burner heating device 82 is fully burned, the heat dissipation as described above is not performed and the heat loss is reduced. However, since the amount of heat applied to the heat medium by the burner heating device 82 per unit time is large, it is highly possible that the burner heating device 82 is frequently started and stopped in order to maintain the heat medium at the heating set temperature. .. However, since the heat medium is not heated by the heat pump 50 while the burner heating device 82 is stopped, the temperature of the heat medium falls below the ignition temperature relatively early after the burner heating device 82 is stopped (). YES in S30 of FIG. 4), the period during which the burner heating device 82 is not operating (that is, the period during which the burner heating device 82 does not heat the heat medium) can be shortened. Therefore, during the single heating operation, the heating efficiency is higher when the burner heating device 82 is completely burned than when the burner heating device 82 is partially burned. Therefore, in the case of the single heating operation, the primary energy efficiency of the entire system is higher in the case where the burner heating device 82 is fully burned than in the case where the burner heating device 82 is partially burned.

The contents of each operation of the hot water supply / heating system 2 (heat storage operation, hot water supply operation, combined heating operation, single heating operation) have been described above. If the heat pump 50 is used for a purpose other than heating (for example, the heat storage operation is started) during the combined heating operation, the control device 100 changes the operation content from the combined heating operation to the independent heating operation. Switch to. At that time, the control device 100 ends the heat pump temperature control (FIG. 3). Then, the control device 100 switches the burner heating device 82 in operation from partial combustion to full combustion, and then continues the burner temperature control (FIG. 4).

On the contrary, when the heat pump 50 shifts to a state where it can be used as a heat source for heating (for example, the executed heat storage operation ends) during the execution of the single heating operation, the control device 100 operates. Is switched from the single heating operation to the combined heating operation. At that time, the control device 100 starts the heat pump temperature control (FIG. 3). Then, the control device 100 switches the burner heating device 82 in operation from full combustion to partial combustion, and then continues the burner temperature control (FIG. 4).

The configuration and operation of the hot water supply / heating system 2 of this embodiment have been described above. As described above, in the present embodiment, the control device 100 partially burns the burner heating device 82 when the combined heating operation is executed (S32 in FIG. 4). Thereby, when the heat medium should be heated by using both the heat pump 50 and the burner heating device 82, the primary energy efficiency of the entire system can be improved as compared with the case where the burner heating device 82 is completely burned. Therefore, according to this embodiment, in the hot water supply heating system 2 provided with two types of heat sources, the heat pump 50 and the burner heating device 82, the primary energy efficiency of the entire system can be maximized.

Further, in this embodiment, the control device 100 completely burns the burner heating device 82 when the independent heating operation is executed (S32 in FIG. 4). As described above, when the single heating operation is executed, the combustion efficiency is higher when the burner heating device 82 is fully burned than when it is partially burned. According to this embodiment, even when the heat medium should be heated by using the burner heating device 82 without using the heat pump 50, the primary energy efficiency of the entire system can be maximized.

The correspondence between this embodiment and the description of the claims will be described. The burner heating device 82 is an example of a “combustor”. The case of performing combined heating operation is an example of "when the heat medium should be heated by using both the heat pump and the combustor". The case of performing a single heating operation is an example of "a case where the heat medium should be heated by using a combustor without using a heat pump".

Although the examples have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

(Modification 1) In the above embodiment, when the burner heating device 82 is partially burned, only one burner 82a is operated. However, the number of burners to be operated when the burner heating device 82 is partially burned is not limited to one, and may be two or three. Generally speaking, only a part of the burners of the combustor may be operated to heat the heat medium.

(Modification 2) In the above embodiment, the burner heating device 82 includes four burners 82a to 82d. However, the number of burners included in the burner heating device 82 is not limited to four, and may be another number (for example, three, five or more, etc.). Generally speaking, the combustor may be equipped with a plurality of burners.

(Modification 3) In the above embodiment, in the burner temperature control (FIG. 4), the control device 100 uses the detected temperature of the thermistor 78 (that is, the temperature of the heat medium supplied to the heater 76) as a reference. The operation of the burner heating device 82 is switched between starting and stopping. However, the control device 100 is not limited to the above criteria, and may switch the start and stop of the operation of the burner heating device 82 based on any reference. For example, the control device 100 may switch the start and stop of the operation of the burner heating device 82 based on the detection temperature of the thermistor 98 (the temperature of the heat medium in the circulation flow path 96).

The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

2: Hot water supply and heating system 10: Tank 12, 14, 16, 18: Thermista 20: Tank water circulation path 22: Circulation pump 24: Tap water introduction path 24a: First introduction path 24b: Second introduction path 26: Check valve 28 : Check valve 30: Water volume sensor 32: Tap water supply source 34: Water volume sensor 36: Supply path 36a: Mixing valve 36b: Bypass path 36c: Bypass control valve 38: Hot water tap 50: Heat pump 52: Refrigerator circulation path 54: Heat Exchanger 56: Fan 58: Three-fluid heat exchanger 60: Expansion valve 62: Compressor 70: Systurn 71: Heat medium circulation path for heating 72: Heating outbound path 74: Circulation pump 76: Heater 78: Thermista 81: Burner heating Device 81a: Burner 82: Burner heating device 82a, 82b, 82c, 82d: Burner 84: Heating return path 86: Thermista 88: Heat recovery path 90: Adjustment valve 92: Thermista 94: Bypass path 96: Circulation flow path 98: Thermista 100 : Control device 104: Hot water supply system 106: Heat pump system 108: Heating system

Claims (1)

It ’s a heating system.
A heat medium circulation path for circulating the heat medium,
A heat pump that heats the heat medium using the heat absorbed from the outside air,
A combustor that heats the heat medium using the heat generated by burning fuel, and
A heater that heats using the heat of the heat medium and
Equipped with a control device,
The combustor includes a plurality of burners.
Each of the plurality of burners can burn the fuel.
The plurality of burners are arranged in series with the heat medium circulation path.
When the heat medium should be heated by using both the heat pump and the combustor, the control device operates only a part of the burners of the combustor to operate the burner. Let the heat medium heat up ,
When the control device should heat the heat medium by using the combustor without using the heat pump, the control device operates all the plurality of burners of the combustor to heat the heat medium. To do ,
Heating system.

Images