JPS6261852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, with the deterioration of the energy situation, energy saving in consumer electronics is becoming recognized as an urgent social issue. On the other hand, as social standards of living improve, the demand for hot water supply in general life is on the rise.

The present invention is based on this situation and aims to achieve energy saving in water heaters, which have a large impact on the energy consumption of consumer appliances. More specifically, the present invention relates to an operation control sequence that achieves the minimum energy consumption when a heat pump heating principle is adopted as a heating device of a water heater and is further combined with an auxiliary heating device.

A more detailed explanation will be given below with reference to the figures. 1st
The figure shows an example of the configuration of a conventionally known heat pump type water heater, in which a compressor 1, a natural convection heat exchanger 2, an expansion mechanism 3, and an evaporator 4 are sequentially connected via refrigerant piping to constitute a heat pump heating section. . The natural convection heat exchanger 2 is inserted into a heat storage tank 6 surrounded by a heat insulating material 5, heats water from below the tank 6, and gradually heats the water in the tank while keeping it at a uniform temperature. . 7 is the water supply port, city water pipe 8 and pressure reducing check valve 9
The heat storage tank 6 is connected to the lower part of the heat storage tank 6 via the heat storage tank 6 and the like. Reference numeral 10 denotes a hot water supply port provided at the upper part of the heat storage tank 6, which is connected to a hot water tap 12 via a hot water supply pipe 11.

To further explain the operation of the conventional example shown in FIG. 1 above, the heat exchanger 2 uniformly heats the inside of the heat storage tank 6 from below. Therefore, it is clear that the condensing temperature of the heat pump cycle needs to be set higher than the internal temperature of the heat storage tank 6, that is, the hot water supply temperature.

FIG. 2 shows an embodiment of the heat pump water heater of the present invention. In the figure, reference numeral 13 denotes a forced circulation counterflow type heating heat exchanger, and a circulation water supply port 14 and a water channel 1 are provided below the heat storage tank 6 by a circulation pump 21.
After water is supplied and heated by 5, it is transferred to a heat storage tank 6.
A circulation waterway is constructed such that hot water is stored in the upper part of the tank from a pipe line 17 connected to the upper part of the tank. Reference numeral 16 denotes a temperature flow rate adjusting device disposed at the outlet of the heating heat exchanger 13, which adjusts the amount of circulating water in the circulation waterway so that the temperature of the hot water at the outlet of the heating heat exchanger 13 remains approximately constant.
Note that the same components as in FIG. 1 are given the same reference numerals.

By arranging the circulation waterway, the heating heat exchanger 13, and the temperature flow rate adjustment device 16 in this way, it becomes possible to obtain hot water at a higher temperature than the condensation temperature of the heat pump cycle. That is, as shown in FIG. 3, when comparing the conventional example and the embodiment of the present invention under the same condensing temperature conditions, in the conventional example, the temperature inside the heat storage tank shown in the figure is the boiling limit temperature, whereas in the present invention, the temperature inside the heat storage tank in the figure is the boiling limit temperature. In the embodiment of the invention, as shown in the water temperature at the outlet of the heating heat exchanger, it is possible to obtain a temperature as high as ΔT shown in the figure. This means that the embodiments of the present invention can obtain hot water at the same condensing temperature (that is, the same outdoor conditions and the same power consumption).

In Figure 2, the solid arrow (→) indicates the flow direction of refrigerant gas during heat pump heating, and the dashed arrow (〓)
Similarly, the white arrow () indicates the flow direction of water during hot water supply. As is clear from FIG. 2, the heat storage tank 6 has a two-layer structure when heated by the heat pump, with a hot water layer at the top and a water layer at the bottom, separated by a hot water boundary layer 18 shown by a dashed line in the figure. . This boundary layer 18 moves downward in accordance with the heat pump heating operation and upward in accordance with the hot water supply operation. Therefore, the heat pump heating operation ends when the boundary layer 18 reaches the circulating water supply port 14.

In addition, 19 is a late-night power auxiliary heater which is an auxiliary heating device, 20 is a safety valve, 21 is a circulation pump for heat pump heating, 22 is an outdoor fan, 28 is a pressure switch, and 27b and 27a are temperature thermostats.

Adding a more detailed explanation to the above-mentioned embodiment of the heat pump water heater according to the present invention, when it is put to practical use as a water heater, bath water supply is the main hot water supply, except in the summer when showering and laundry are the main hot water supply. In winter, it is necessary to store heat at a high temperature of 85°C like a normal electric water heater or boiler.
In particular, in late-night power water heaters that need to secure an amount of heat storage to meet the daily hot water supply load during low-cost late-night power hours, high-temperature heat storage is required with the limited heat storage layer capacity. To explain a little further, the hot water supply load throughout the year changes depending on the amount of hot water used and the temperature of the water supply in each season, but usually has a pattern of being low in the summer and high in the winter, as shown in FIG. In other words, if the heat storage tank capacity is constant, it is reasonable to store heat at a low temperature in the summer to reduce heat retention loss, and to store heat at a high temperature in the winter to ensure hot water supply capacity.

Therefore, by making the boiling temperature variable in a thermal storage water heater that uses late-night electricity and setting the boiling temperature at any time according to the seasonal hot water supply load, it is possible to save energy by reducing heat retention loss and remaining hot water. It can be achieved.

As a result, in the heat pump water heater of the present invention, the contribution rate of the highly efficient heat pump cycle can be increased throughout the year by increasing the boiling temperature of the heat pump device.

If the entire hot water supply load can be met by heat pump heating alone, especially during the summer, significant energy savings can be achieved. Furthermore, by increasing the heat pump boiling temperature, it is possible to extend the heat pump sole heating time throughout the year and achieve further energy savings. It has already been shown that in the embodiment of the present invention, a higher boiling temperature can be obtained than in the conventional system, as shown in FIGS. 1 to 3.

In the present invention, the late-night power heater 1
9 to save energy regarding the auxiliary heating effect. That is, it relates to sequence control of the heat pump heating device and the late-night power heater 19, which is an auxiliary heating device.

In the sequence control of the heater 19 and the heat pump device, there are three modes: (i) simultaneous operation of the heat pump and heater, (ii) first heater operation, then heat pump operation, (iii) first heat pump operation, then heater operation. can be mentioned. First, in method (i), as shown in FIG. 5, the operating time of the heat pump (the dotted area in the figure) is short, and the power generated immediately after the start of late-night power is excessive, causing problems during the night-time power peak. There are problems such as a relatively short boiling time and a decrease in heat retention efficiency, so the energy saving effect is low. Method (ii) has little energy-saving effect because heater heating is performed in a low temperature range throughout the year. Normal heat pump cycles are not very effective because it is difficult to heat up to 85℃. Method (iii), as shown by the solid line in Figure 6, operates the heat pump immediately after power is turned on at night to raise the temperature from low to medium (approximately 60°C), and in the summer, this temperature can satisfy the hot water supply load. It is possible, and the operation will end at this point, but in the winter, a heater will be used to further raise the temperature to a high temperature (approximately 85 degrees Celsius).
In other words, by adopting method (iii), it is possible to reduce power peaks immediately after the start of late-night power hours, the boiling time is relatively long and heat retention efficiency is high, and the annual operation time of the heat pump is the longest, resulting in energy saving effects. It has great effects, such as being the largest. The broken line in FIG. 6 is a diagram assuming that a heater is added to the conventional example shown in FIG. 1, and it can be seen that the total power consumption required for boiling is large because the heat pump boiling temperature is low. Note that when the heat pump is in operation as shown in the dotted lines in Figure 6, the inside of the heat storage tank is divided into an upper hot water layer and a lower water layer.For convenience, the average temperature in the tank is shown in Figure 6.

Based on the above points, the present invention relates to switching control between heat pump operation and heater operation, the details of which are shown in FIG. In the figure, 1 is a compressor;
22 is an outdoor fan motor, 21 is a circulation pump, 2
3 is an earth leakage breaker connected to the late-night power supply;
24 is a power relay of 2a 1b, 19 is a late-night power heater, and 25 is a thermometer whose temperature setting can be changed as necessary to detect the water temperature near the heater 19. A first thermostat 26 controls the operation of the heat pump and detects, for example, the outside temperature. 27 is a second contact for controlling the operation of the heat pump; 28 and 29 are pressure detection contacts and overfire prevention contacts connected in parallel to the safety circuit of the earth leakage breaker 23; and 30 is an antifreeze thermostat connected to a common 100V power supply as shown in the figure. Connected.

Next, to explain the operation of the device of the present invention in more detail, if the outside temperature is high enough to operate the heat pump when the late-night electric power of 1φ200V is applied, the first thermo 26 contact will close, so the second thermo
The relay 24 is excited in response to the closing operation of the contact 27. As a result, the compressor 1, outdoor fan 22 and
The circulation pumps 21 connected to the 100V circuit are each energized and driven to perform heat pump heating operation. When the second contact 27 detects the end of the heat pump heating and operates to open, the relay 24 returns and the back contact contacts to energize the heater 19. When the boiling thermometer 25 connected in series with the heater 19 is set to a boiling temperature higher than the heat pump heating, the heater 19 is heated with electricity to boil the water to a predetermined temperature. 28 cuts off the 200V circuit when the high pressure of the heat pump cycle rises abnormally for some reason (for example, poor water circulation due to a failure of the pump 21), and 29 cuts off the 200V circuit when the temperature of the heater 19 rises abnormally. Protect the equipment by disconnecting the 200V circuit. The thermometer 30 is normally used to prevent the water circuit from freezing by closing when the water circuit is about to freeze and forcing the pump 21 to operate.
Connected to 100V power supply.

The present invention employs a circulating water temperature detection thermometer 27a installed near the circulating water supply port 14 or the water channel 15 as the second contact point 27 for switching from heat pump cycle heating to heater heating operation. A more detailed explanation will be added below. As clearly shown in FIG. 2, in the present invention, the hot water boiling method is a single water circulation system in which hot water is separated into upper and lower parts, and when the water in the heat storage tank 6 passes through the heating heat exchanger 13, ℃). Therefore, the hot water boundary layer 18 gradually moves downward as the heat pump operates.
As a result, the heat pump heating is completed by replacing almost all of the inside of the heat storage tank 6 with hot water.
As shown in the figure. As is clear from the figure, when the boundary layer 18 in the heat storage tank 6 descends to the vicinity of the circulating water supply port 14, the temperature of the circulating water in the water channel 15 rises rapidly.
That is, by detecting this temperature rise with the water temperature detection thermometer 27a, when the inside of the heat storage tank 6 uniformly rises to the heat pump heating temperature, the heat pump cycle heating device is stopped and the heat pump heating operation is switched to the heater heating operation. In addition, by reducing the required temperature rise due to heater heating operation, there is less need for heater heating operation with poor heating efficiency, and the overall ratio of highly efficient heat pump heating operation increases. This makes it possible to achieve energy-saving operation throughout the year, which has great effects such as saving on electricity costs. In particular, when the inlet water temperature of the heating heat exchanger 13 rises, the high pressure force increases as a characteristic of the heat pump cycle and the heating efficiency COP decreases. Since it is possible to achieve high efficiency operation, the present invention is groundbreaking in that it can directly detect rapid temperature changes in the water channel 15 and perform efficient and reliable switching control. It is something. In the embodiment, the temperature of the water at the inlet of the heat exchanger 13 is detected by the thermometer 27a installed near the water channel 15. It is clear that the thermostat 27b also has a similar mechanism.

The temperature adjustment device 16 may be a wax type temperature flow rate adjustment valve using paraffin wax pellets, or an electronic control mechanism that controls the capacity of the pump 21 using a thermistor element at the outlet of the heat exchanger. It is clear that it performs the following functions.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional heat pump water heater, Fig. 2 is a block diagram of an embodiment of a heat pump device according to the present invention, and Fig. 3 is an explanatory diagram of the heat pump heating principle shown in Figs. Figure 4 is an explanatory diagram of the annual hot water supply load, Figure 5 is a diagram of the power consumption pattern when operating a heat pump device that is not based on the present invention,
FIG. 6 is a power pattern diagram during operation of the heat pump device of the present invention, FIG. 7 is a circuit diagram of an embodiment of the control circuit of the present invention, and FIG. 8 is a diagram showing temporal changes in the water temperature at the inlet of the heat exchanger in the present invention. 1...Compressor, 4...Evaporator, 13...Heat exchanger, 3...Expansion mechanism, 6...Heat storage tank, 19...
...Auxiliary heating device, 16...Temperature adjustment mechanism.

Claims (1)

[Claims] 1. Hot water supply consisting of a heat pump cycle heating device that combines a compressor, evaporator, heating heat exchanger, and expansion mechanism through an annular refrigerant piping line, a heat storage tank, and an auxiliary heating device that heats the water in the heat storage tank. In the apparatus, the heating heat exchanger is a forced circulation heat exchanger, a temperature adjustment mechanism is provided to keep the hot water temperature at the outlet of the heating heat exchanger constant, and water is supplied from the bottom of the heat storage tank to the heating heat exchanger by a circulation pump. A circulation waterway is configured such that the water is supplied, heated to a constant temperature in a heating heat exchanger, and then returned to the upper part of the heat storage tank, and when the water temperature at the inlet of the heating heat exchanger reaches a predetermined value or higher, the heat pump cycle heating device is stopped. A heat pump type water heater characterized by being equipped with a thermo device that switches to an auxiliary heating device.