JPH0517463B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water heater using a heat pump and an auxiliary heater.

Configuration of conventional example and its problems An example of a heat pump water heater having an auxiliary heater is shown in FIG. A condenser 2 of a heat pump consisting of a compressor 1, a condenser 2, a throttling mechanism 3, and an evaporator 4 is connected to a hot water storage tank 7 through a water circulation circuit 8, and an auxiliary device is provided downstream of the condenser 2 in the water circulation circuit 8. Heater 10
The hot water temperature detector 13 controls the amount of circulating water so that the hot water temperature flowing into the hot water tank 7 is kept constant by the hot water temperature detector 13, and stores hot water at a higher temperature from the upper part of the hot water tank 7. The heat pump and the auxiliary heater 10 are stopped by the detector 14. In this type of heat pump water heater, in order to increase the temperature of the hot water flowing into the hot water storage tank 7, the condenser 2 is used to keep the condensing temperature of the heat pump almost constant at a relatively high location.
When the inlet water temperature is low, the amount of circulating water is controlled to be small, and as the inlet water temperature becomes high, the amount of circulating water is controlled to be large. However, there is a limit to the control range for the amount of circulating water, so if the inlet water temperature of the condenser 2 exceeds a certain level, the condensing pressure cannot be kept constant even if the amount of circulating water is maximized, and eventually the pressure will rise to the operating limit of the heat pump. There is a risk of Therefore, the operation of the heat pump and auxiliary heater 10 is stopped at a point where the inlet water temperature is relatively low. In this kind of control, when the hot water in the hot water storage tank 7 is used up completely and then boiled, the temperature of the water in the hot water storage tank 7 is boiled to a completely uniform high temperature from the top to the bottom as shown in Figure 2. However, the hot water in the hot water storage tank 7 is rarely used up completely every day, and there is usually residual hot water in most cases. For example, if 1/3 of the hot water remains every day, new high-temperature hot water is replenished from the upper part of the hot water tank 7, and the remaining hot water is pushed back to the lower part of the hot water tank 7, and the inlet water temperature of the condenser 2 reaches the set temperature _T14. When the temperature rises to this point, boiling is completed.At this time, the temperature of the remaining hot water is sufficiently higher than the above set temperature, so the temperature remains in the hot water storage tank 7.
The shape will remain at the bottom. If this operation pattern continues for several days, the temperature of the remaining hot water will gradually drop due to heat radiation, and as shown in Figure 3, the upper two-thirds will be hot water and the lower one-third will be medium- or low-temperature hot water. 1/3 of them were hardly used anymore, and when a large amount of hot water was needed, there was a problem of running out of hot water.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the conventional system, and aims to provide a structure that allows hot water to be drawn quickly, and also achieves both an energy saving effect and a guaranteed hot water supply.

Structure of the Invention To achieve this object, the present invention provides a compressor,
The condenser of a heat pump consisting of a condenser, a throttle mechanism, and an evaporator is connected to a hot water storage tank through a water circulation circuit, and an auxiliary heater is disposed downstream of the condenser in the water circuit, and the auxiliary heating A hot water temperature sensor is installed downstream of the water tank, and a circulating water flow rate control mechanism is installed to keep the temperature of hot water flowing into the hot water storage tank constant during both parallel operation and individual operation of the auxiliary heater and the heat pump, as well as an outside temperature sensor and , a condenser inlet water temperature sensor having a first set value of a low temperature and a second set value of a high temperature is provided, the outside air temperature is lower than a predetermined value, and the condenser inlet water temperature is lower than the first set value. Sometimes, the auxiliary heater and heat pump are operated in parallel, and when the outside air temperature is higher than a predetermined value and the condenser inlet water temperature is lower than the first set value, the heat pump is operated independently, and the condenser inlet water temperature is lower than the first set value. Up to the second set value, a control circuit is configured to operate the auxiliary heater independently.

With this configuration, the auxiliary heater and heat pump can be operated in parallel when the outside temperature is low and the water temperature at the condenser inlet is low and more heating capacity is required. The inlet water temperature is not affected by the auxiliary heater, allowing effective operation. Additionally, when the first set value is reached, the heat pump stops and the auxiliary heater is operated to heat up to the second set value, so the water temperature in the hot water storage tank is completely uniform from top to bottom. , guaranteeing hot water supply.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below using the system configuration shown in FIG. 4 and the control circuit shown in FIG. 5. Fourth
In the figure, 1 is a compressor, 2 is a condenser, 3 is an expansion valve, 4 is an evaporator, 5 is a fan, and 6 is an accumulator, which constitute the refrigerant circuit of the air source heat pump. On the other hand, 7 is a hot water tank, 8
is a water circulation circuit between the condenser 2, 9 is a pump, 1
0 is an auxiliary heater installed downstream of condenser 2, 1
1 is a hot water supply pipe; 12 is a water supply pipe; these constitute the water circulation between the hot water tank 7, the condenser 2, and the auxiliary heater 10, and the function of discharging hot water from the hot water tank 7 to the hot water supply pipe 11 by supplying water from the water supply pipe 12. are doing. 1 more
Reference numeral 3 denotes a temperature sensor for hot water flowing into the hot water storage tank 7, which controls the amount of circulating water by manipulating the number of revolutions of the pump, and flows into the hot water storage tank 7 both when the heat pump and the auxiliary heater 10 are operated in parallel and when each is operated individually. Hot water is stored at a constant inflow temperature. Further, 14' is a condenser inlet water temperature detector, which has a first set value for a constant temperature and a second set value for a high temperature. This stops the operation of the heater.

In FIG. 5, 15 is the compressor 1 and the fan 5.
16 is a second relay that turns the auxiliary heater 10 on and off. 17 is a contact that is activated by the first set value of the low temperature of the condenser inlet water temperature detector 14'; when the temperature is below the set value, it switches to the first relay 15; when it is above the set value, it switches to the second relay 16. be. Reference numeral 18 denotes a contact which is activated by the second set value of the high temperature of the condenser inlet water temperature detector 14', and is closed when the set value is lower than the set value and opened when the set value is higher than the set value. Reference numeral 19 is a contact point of the outside air temperature sensor, which has a characteristic of being open when the outside temperature is high and closed when the outside temperature is low. Each operation will be explained using the above system and control circuit.

First, the outside air temperature is high and the condenser inlet water temperature is the first.
If it is below the set value, the contact 17 is connected to the first relay 15 for the compressor and fan, the contact 18 is closed, and the contact 19 is open, so the compressor 1 fan 5 operates and the auxiliary heater 10 The heat pump is in independent operation, and a certain amount of high-temperature hot water is stored from the upper part of the hot water tank 7 by the hot water temperature detector 13.
Here, if there is no hot water remaining at the beginning of operation, a slight boundary layer is formed between the lower temperature water in the lower part of the hot water storage tank 7 and a certain amount of high temperature hot water is stored from the upper part, and the boundary layer forms in the hot water storage tank 7. As it reaches the bottom, the condenser inlet water temperature rises and when it reaches the first set value, the contact 17 moves to the auxiliary heater side, the heat pump operation is stopped, and the auxiliary heater 10 is operated. . At this time, the hot water temperature distribution in the hot water storage tank 7 is as shown in Figure 2.
Since the temperature is high all the way to the bottom, the condenser inlet water temperature quickly rises to the second set value, and contact 1
8 is opened and the operation of the auxiliary heater is completed in a very short time. In addition, if there is residual hot water at the beginning of operation, the temperature of the residual hot water is usually lower than it was at the beginning of boiling, and therefore there is a slight boundary layer between the medium-temperature residual hot water in the upper part and the low-temperature water in the lower part. has been formed. When heating operation is performed in this state, high-temperature hot water is supplied from the upper part of the hot water storage tank 7, separated into three layers: high-temperature water in the upper part, medium-temperature water in the middle, and low-temperature water in the lower part, and is pushed down to the lower part. As the boundary layer between the lower low-temperature water and medium-temperature water reaches the lower part of the hot water storage tank 7, the condenser inlet water temperature rises to the first set value, and the contact point 17
changes, the heat pump operation stops, and the auxiliary heater 10 starts operating. At this point, the hot water temperature distribution in the hot water storage tank 7 is as shown by the broken line in FIG. 6, and the lower part is at a medium temperature. From this state, the hot water at a medium temperature in the lower part is heated by the auxiliary heater 10, becomes a constant high water temperature, is stored from the upper part of the hot water tank 7, and is finally heated uniformly to the bottom of the hot water tank as shown by the solid line in Figure 6. . In the above explanation, we have explained the case where the outside temperature is high, but when the outside temperature is low, the heating capacity of the heat pump decreases, so in order to secure the necessary amount of hot water within a predetermined time, it is necessary to use the auxiliary heater 10. It is necessary to drive in parallel. When the outside temperature is low, the outside temperature detector 19 is closed, and the heat pump and auxiliary heater 10 operate simultaneously. In this case, the process up to the final boiling is the same as described above, and uniform high-temperature hot water is always ensured all the way to the bottom of the hot water storage tank 7. In addition, even if the heat pump is operated in parallel with the auxiliary heater, the condenser 2 is connected to the auxiliary heater 10.
Since the condenser 2 can be operated at a relatively low inlet/outlet water temperature, there is an advantage that the operating efficiency of the heat pump can be maintained at a high level.

Effects of the Invention As explained above, the condenser of a heat pump consisting of a compressor, a condenser, a throttle mechanism, and an evaporator is connected to a hot water storage tank through a water circulation circuit, and auxiliary heating is performed downstream of the condenser in the water circuit. A hot water temperature sensor installed on the downstream side of the auxiliary heater measures the amount of environmental water so that the temperature of the hot water flowing into the hot water tank remains constant during both the parallel operation of the auxiliary heater and the heat pump, and each individual operation. In addition to providing a control mechanism, an outside temperature sensor, a first set value for low temperature and a second set value for high temperature are provided.
A condenser inlet water temperature detector having a set value of When the condenser inlet water temperature is higher than a predetermined value and lower than the first set value, the heat pump is operated independently, and when the condenser inlet water temperature is from the first set value to the second set value, the auxiliary heater is operated independently. By configuring the circuit, a certain amount of high-temperature hot water is stored from the top of the hot water storage tank, so hot water can be taken quickly. Also, since the outside temperature is low and the water temperature at the condenser inlet is low, a large amount of heating capacity is required. When the auxiliary heater and heat pump are operated in parallel, it is possible to secure sufficient heating capacity, quickly obtain the required amount of hot water, and even when the auxiliary heater and heat pump are operated in parallel, it is possible to Since the heat pump condenser is located in In both cases, the condenser inlet water temperature detector, which has a first set value of low temperature and a second set value of high temperature, operates the heat pump at the first set value of low temperature and then turns the auxiliary heater up to the second set value. In order to operate the heat pump, it is possible to ensure operation within the operating limits of the heat pump, and to ensure uniform high-temperature hot water in the hot water storage tank all the way to the bottom.Furthermore, the heat pump can be stopped and the auxiliary heater can be stopped only by using the condenser inlet water temperature detector. Because of the configuration, there is only one detector for stop control, which has great effects such as simplifying the configuration and reducing costs.

[Brief explanation of the drawing]

Figure 1 is a diagram of the conventional system configuration, Figure 2 is a diagram of the hot water temperature distribution in the hot water storage tank when the water is heated up from the state with no residual water in the conventional system, and Figure 3 is the diagram of the water temperature distribution in the conventional system with hot water remaining. Figure 4 is a configuration diagram showing an example of the system configuration of the present invention, Figure 5 is a control circuit diagram of the main parts, and Figure 6 is the final boiling state. FIG. 2 is a hot water temperature distribution map in a hot water storage tank. 1... Compressor, 2... Condenser, 3... Throttle mechanism, 4... Evaporator, 7... Hot water storage tank, 8... Water circulation circuit, 10... Auxiliary heater, 13... Hot water temperature detector , 14'...Condenser inlet water temperature detector, 19...
...Outside temperature detector.

Claims (1)

[Claims] 1. The condenser of a heat pump consisting of a compressor, a condenser, a throttle mechanism, and an evaporator is connected to a hot water storage tank through a water circulation circuit, and an auxiliary heater is disposed downstream of the condenser in the water circulation circuit. , a circulating water amount control mechanism is provided so that the temperature of the hot water flowing into the hot water storage tank is kept constant by a hot water detector provided downstream of the auxiliary heater, both when the auxiliary heater and the heat pump are operated in parallel and when the heat pump is operated individually; together with an outside temperature sensor, a first setpoint for low temperature and a second setpoint for high temperature.
A condenser inlet water temperature detector having a set value of When the condenser inlet water temperature is higher than a predetermined value and lower than the first set temperature, the heat pump operates independently, and when the condenser inlet water temperature falls from the first set value to the second set value, the auxiliary heater operates independently. A heat pump water heater with a control circuit.