JPS589335B2 - Control method in heat pump - Google Patents

Description

[Detailed Description of the Invention] The present invention... The present invention relates to a method of controlling the operation of a heat pump system used for air conditioning and heating, particularly a double handle heat pump as a heat recovery type heat pump.

Generally, heat pumps rely on air, well water, or heat recovery for low heat sources. This low heat source is used as a high heat source by a heat pump to obtain the specified hot water, but when there is a cooling load and a heating load at the same time. Conventionally, a refrigerator with multiple condensers is used, and the hot water increases from the condenser connected to the load side. A method is adopted in which excess heat is radiated to a condenser connected to the cooling system.

In other words, operate the cooling water pump and hot water pump. In order to maintain the hot water outlet temperature at a predetermined temperature, excess heat was radiated to a condenser connected to the cooling system according to increases and decreases in the hot water load.

However, when the hot water outlet temperature reaches a predetermined temperature, it is desirable to stop the hot water pump to save energy.

At this time, when the hot water bomb is stopped, the cooling water control valve cannot follow the flow, causing the cooling water outlet temperature to rise suddenly, causing the condensation pressure switch of the refrigerator to operate, causing the refrigerator to stop.

Therefore, usually. Do not stop the hot water pump, or stop the refrigerator once. Since the restart method was used, it forced inefficient and wasteful operation, resulting in high power consumption, which not only did not result in energy savings, but also made operation management complicated.

The present invention aims to accurately eliminate these conventional drawbacks by recovering heat, greatly improving cycle efficiency, making it easier to ensure energy savings, and enabling stable operation that improves operational safety. The purpose of this invention is to provide a control method for controlling

The present invention is. After confirming that the hot water temperature has reached the specified temperature, switch the control signal of the condenser cooling water temperature control valve to a temperature signal lower than the control signal when operating the hot water pump, lower the condensing pressure, and then stop the hot water pump. It is characterized by the following.

An embodiment of the present invention will be described with reference to the drawings for a double-handle heat bomb type refrigerator A. A compressor 2 is driven by a motor to circulate refrigerant between a condenser 3:3' and an evaporator 1.

The condenser 3 is connected to a circuit 8 consisting of a heat storage tank 9 serving as a heating load or hot water tank, a hot water pump 18, and a three-way control valve 20, and the condenser 3' is connected to a cooling tower 5. A cooling system circuit 4 consisting of a cooling water bomb 14 and a three-way control valve 1γ is in communication.

In addition, the evaporator 1 has a heat storage tank γ that serves as a cooling load or a cold water tank.
, a cold water pump 16, and a three-way control valve 22 are connected to each other by a circuit 6. in this case. There is a heat pump in which the refrigerator is equipped with a heat storage tank consisting of a cold water tank and a hot water tank.
It functions effectively even without this heat storage tank, and two two-way valves can be used in place of the three-way control valve to enable switching operations.

Here, when cooling load > heating load - 0 (that is, for example, in midsummer), the heating load is stopped and the cooling system including the cooling tower and the cooling load system are operated.

In addition, when there is a cooling load>heating load, the condensing pressure increases (hot water temperature increases), so the hot water temperature is detected and the cooling system is used to adjust the condensing pressure to a predetermined condensing pressure (or predetermined hot water) using the three-way control valve 17. Controls cooling water bypass flow rate.

That is, when operating the heat recovery method, evaporator 1. The compressor 2, condenser 3, condenser 3', and cooling tower 5 are operated.

The refrigerator A has a capacity control mechanism 21 like a suction vane control device, and is controlled so that the temperature in the outlet pipe of the chilled water circuit 6 or the current value of the main motor is constant.

Also, the temperature in the hot water circuit 8 or the heat storage tank (hot water tank high temperature section)
Excess heat of the hot water is discharged to the condenser 3' while maintaining the temperature in the hot water at a predetermined temperature.

In other words, the surplus heat of the hot water is transferred to the cooling water circuit 4 by the temperature controller 2 with a detection part inserted into the hot water outlet piping of the hot water circuit 8 or the temperature controller 13 in the heat storage tank with the detection part inserted into the high temperature part of the hot water heat storage tank 9. Three-way control valve 1 in piping
Hot water circuit 8 by adjusting γ. The temperature of the heat storage tank 9 is controlled.

In order to make the temperature distribution inside the heat storage tank uniform, a three-way control valve 22 is installed at the inlet of the cold water pump 16 and the hot water pump 18.
20 is inserted, but in this state, if the temperature in the hot water heat storage tank 9, for example the temperature of the temperature thermostat 11 or the temperature in the hot water inlet pipe 19 rises to a predetermined temperature, the detection part is activated. Thermostat 11,1 inserted in these parts
0 etc. is activated.

Then, temperature controller 1 sends a signal to three-way control valve 1T.
2 or 13 to the temperature controller 15, which has a lower temperature setting value than the temperature controller 12 or 13. After opening and closing the three-way control valve 1γ in the direction of lowering the condensing pressure for a certain period of time via a timer, the hot water pump is switched on by this time signal. 1
8 is stopped.

In the specific example shown in Fig. 2, the detection part of the hot water controller 12 of the three-way cooling water control valve 11 is installed on the cooling water side when the hot water pump is in operation, and in this case, the detection part of the hot water controller 12 is installed on the cooling water side when the hot water pump is stopped. The detection units for both the thermostat and the thermostat of the temperature controller 12 during operation are inserted into the cooling water circuit 4.

In addition, in the case of a screw refrigerator or a reciprocating refrigerator, as a means to reduce the condensing pressure, the capacity control mechanism 21 of the refrigerator is set to the low capacity side, that is, when the hot water thermostat 10 or 11 is activated, first in the case of a screw refrigerator In the case of a slide vane or reciprocating refrigerator, it is effective to operate the unloader mechanism to the low capacity side to reduce the load on the condenser and lower the condensing pressure before stopping the hot water pump 18.

In addition, this method can function effectively in the case of a centrifugal chiller and in cases where surging is difficult to occur. It is reasonable to close the door at the door and then stop the hot water pump.

Other suitable examples of means for lowering the condensing pressure include: An operation that opens the valve 23 in the bypass path 4' provided in the cooling water circuit 4 also functions effectively.

In the figure, 24 is a hot gas bypass valve, and 25 is a thermostat for detecting cold water temperature.

According to the present invention, when the hot water temperature reaches a predetermined temperature during the operation cycle in which the cold water pump for the evaporator, the cooling water pump for the condenser, and the hot water pump for the condenser are operating. This is because the hot water cylinder was shut down after measures were taken to lower the condensing pressure. When the hot water temperature in the heat storage tank reaches a predetermined temperature, or when the hot water load is removed and the temperature in the hot water outlet or inlet piping reaches a predetermined temperature, the hot water cylinder is stopped, allowing energy-saving operation control. The condensing pressure increases due to a transient phenomenon caused by stopping the hot water pump, allowing continuous operation without stopping the refrigerator.When the hot water pump is not operating, the condensing pressure is kept low because it is controlled by the temperature controller. Since the refrigerator can be operated with high efficiency, it is also possible to easily reduce the capacity of the double-bundle heat pump refrigerator depending on the heating and cooling capacity ratio. It is also possible to reduce the load on the cooling tower and reduce the output of the double-bundle heat pump chiller, eliminate the need for an auxiliary heat source for heating, significantly increase the coefficient of performance, and increase the Not only is it possible to operate the heat pump economically with the best efficiency at all times, but it also improves operational safety and ensures proper operation of the heat pump. It has features such as easy operation management.

[Brief explanation of drawings]

The drawing is a system explanatory diagram showing an embodiment of the present invention. FIG. 2 is a system explanatory diagram of another embodiment. A... Refrigerator, 1... Evaporator, 2... Compressor, 3, 3'
...Condenser, 4...Cooling water circuit. 4'...Bypass path,
5... Cooling tower, 6... Chilled water circuit, γ... Heat storage tank, 8...
Hot water circuit. 9... Hot water heat storage tank, 10, 11, 25... Thermostat, 12, 13, 15... Temperature controller, 14... Cooling water pump, 16... Cold water pump, 17,
2022...Three-way control valve, 18...Hot water pump, 19...
...Hot water inlet piping, 21...Capacity control mechanism. 23... Valve,
24...Hot gas bypass valve.

Claims (1)

[Claims] 1. Evaporator. In a heat pump having a plurality of condensers, a condenser connected to a compressor and a cooling system, and a condenser connected to a load or a heat storage tank, the chilled water pump for the evaporator, the chilled water pump for the condenser, and A heat pump characterized in that when the temperature of hot water reaches a predetermined temperature during an operation cycle in which a hot water pump for a condenser is operating, a method is taken to lower the condensing pressure and then the hot water pump is stopped. Control method. 2. The control method for a heat pump according to claim 1, wherein the hot water pump is stopped after the capacity control of the front heat pump is set to a low capacity side. 3. In a heat pump having multiple condensers: an evaporator, a compressor, and a condenser connected to the cooling system, and a condenser connected to a load or heat storage tank, a cold water pump for the evaporator and a cold water pump for the condenser are used. During the operation cycle in which the cooling water pump and the hot water pump for the condenser are operating, when the hot water temperature reaches a predetermined temperature, the condensing pressure is lowered when the hot water bomb is stopped after taking measures to lower the condensing pressure. 1. A control method for a heat pump, characterized in that a timer is used to set a time limit between when a measure is taken and when the hot water pump is stopped, and then the hot water pump is stopped.