JP2013096678A - Closed hot water storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a closed hot water storage tank which prevents freezing and keeps water hot by energizing an electric heater with a connection pipe for connecting a plurality of tank units with each other at an appropriate timing.SOLUTION: The closed hot water storage tank includes a plurality of tank units 20 and 21 connected with each other through a connection pipe 22, an electric heater 25 provided in the connection pipe 22, and an energizing means which responds to a hot water temperature at the upper side of one tank unit 20 and that at a position of the connection pipe 22 to energize the electric heater 25 when the hot water temperature at the position of the connection pipe 22 is lower than a predetermined freezing prevention temperature or when the hot water temperature of the upper side of one tank unit 20 is higher than a predetermined first set temperature to check the presence of hot water and the hot water temperature at the position of the connection pipe 22 is lower than a predetermined second set temperature which requires heat retention of hot water.

Description

  The present invention relates to a sealed hot water storage tank used in a hot water supply system that stores hot water produced by a heat source device (hot water supply device) in a hot water storage tank and appropriately supplies it to a required location.

  In a sealed hot water storage tank used for a hot water supply system in which hot water produced by a heat source device (hot water heater) such as a heat pump, a boiler, a solar heat collector, etc. is stored in a hot water storage tank and appropriately supplied to a required location, generally, a plurality of tanks are used. The unit is not allowed to be connected and used, or it is only allowed to be connected with a very short pipe of about several tens of centimeters. This is because when the connection pipe becomes longer, hot water (hot water) is cooled in the connection pipe part, and not only the amount of hot water that can be used is reduced, but also a phenomenon in which hot water and cold water remain in the hot water storage tank may occur. This is considered to be a problem during hot water supply.

  In addition, at the timing when hot water in the hot water storage tank is consumed, there is a case where unboiled water is present in the connection pipe. In this case, if heating is continued with an electric heater or the like focusing only on heat retention, the electric heater This can cause water to boil, which can significantly reduce energy consumption efficiency. In addition, as a technique for preventing the freezing of the pipe, Patent Document 1 discloses that a heating element including a pipe sensing thermostat for sensing the pipe temperature and a heat generating part connected to the thermostat is attached to the pipe. The thing which prevented the freezing of piping is shown.

JP-A-8-17553

  However, in the one shown in Patent Document 1, even if it is possible to prevent water from freezing in the connecting pipe part at low outside air temperature, it is possible to prevent a temperature drop due to heat radiation of the hot water in the connecting pipe part. Have difficulty. On the other hand, in a hot water supply system, there is a need to use a plurality of tank units connected by connecting pipes in order to increase the capacity of a hot water storage tank. In this case, in order to increase the degree of freedom when installing a plurality of tank units. The key point is that the length of the connecting pipe can be increased.

  In particular, when the connecting pipe becomes long, it is possible to eliminate the risk of water freezing in the connecting pipe part, but it is necessary to prevent the temperature from decreasing due to heat radiation from the connecting pipe part. Therefore, how to keep warm is an issue. In addition, at the timing when hot water in the hot water storage tank is consumed, there is a case where unboiled water exists in the connection pipe. Therefore, paying attention only to warm water warming, it is heated and heated by an electric heater or the like. In such a case, water may be boiled with an electric heater, and solving this problem is one of important issues.

  The present invention has been made in view of such circumstances, and is in a sealed hot water storage tank having a configuration in which a plurality of tank units are connected by a connecting pipe, and an electric heater provided in the connecting pipe has an appropriate timing. An object of the present invention is to provide a sealed hot water storage tank capable of realizing both freezing prevention and warm water insulation by energization.

In order to solve the above-described problems, the sealed hot water storage tank of the present invention employs the following means.
That is, a sealed hot water storage tank according to the present invention is a sealed hot water storage tank used in a hot water supply system for storing hot water produced by a heat source machine in a hot water storage tank and supplying hot water to a required location as appropriate. The other tank unit bottom is connected in series via a connecting pipe, the one tank unit is connected to the water supply side to the heat source unit, and the other tank unit is connected to the hot water side from the heat source unit. A plurality of tank units, an electric heater provided in the connecting pipe, a hot water temperature at the top of the one tank unit, and the one tank at the time of storing hot water in the connecting pipe connected to the bottom of the other tank unit Responding to the hot water temperature at the outlet to the unit and the inlet to the other tank unit at the time of hot water, the hot water temperature at the position of the connecting pipe is preset When the temperature is lower than the prevention temperature, or when the hot water temperature at the upper part of the one tank unit is higher than the first preset temperature set in advance to confirm the presence or absence of hot water, the hot water temperature at the connecting pipe position needs to be kept warm. And a means for energizing the electric heater when the temperature is equal to or lower than a preset second set temperature.

  According to the present invention, a plurality of tank units are connected in series by a connecting pipe, and an electric heater is provided in the connecting pipe, and the hot water temperature at the top of one tank unit and the bottom of another tank unit with respect to the electric heater. In response to the hot water temperature at a position that serves as an outlet to one tank unit when hot water is stored in the connecting pipe connected to, and an inlet to another tank unit when hot water is discharged, the hot water temperature at the position of the connecting pipe is preset. When the temperature is below the freezing prevention temperature, or when the hot water temperature at the upper part of one tank unit is higher than the first preset temperature set in advance to confirm the presence or absence of the hot water, the hot water temperature at the connecting pipe position needs to be kept warm. Since a means for energizing is provided when the temperature is equal to or lower than a preset second set temperature, a plurality of tank units must be connected via a relatively long connecting pipe. Even if the hot water storage tank structure cannot be obtained, it is confirmed that the hot water temperature at the upper part of one tank unit is equal to or higher than the first set temperature and that there is hot water at the upper part of one tank unit. When the temperature is equal to or lower than the second set temperature that requires heat retention, the electric pipe is energized to heat the connecting pipe, thereby preventing a decrease in hot water temperature due to heat dissipation in the connecting pipe portion. When the front and back of the connection pipe are water and the outside air temperature is low, when the temperature of the connection pipe is below the preset freezing prevention temperature, the connection pipe is heated by energizing the electric heater to heat the connection pipe. Can prevent the water from freezing. Accordingly, the degree of freedom of installation of the tank unit when increasing the capacity of the hot water storage tank can be increased, and a phenomenon in which hot water and water whose temperature has decreased remains in the hot water storage tank due to heat radiation in the connecting pipe portion occurs. The possibility of accidents such as breakage of connecting pipes due to the possibility or freezing of water can be solved. In addition, at the timing when hot water in the hot water storage tank is consumed, there may be a case where unboiled water exists in the connection pipe. In this case, if heating is continued with an electric heater while focusing only on keeping warm water, However, such a situation can also be prevented.

  Furthermore, the sealed hot water storage tank of the present invention is the above-described sealed hot water storage tank, wherein the means for energizing the electric heater is installed in the upper part of the one tank unit, and the first setting is used to confirm the presence or absence of hot water. A first thermostat that is turned on at a temperature higher than the temperature, and a first thermostat that is installed at the connecting pipe position and that is turned on at a temperature equal to or lower than the second set temperature that requires heat retention higher than the first set temperature. 2 thermostats and a third thermostat that is installed at the position of the connecting pipe and that is turned on at a temperature lower than the first set temperature and below the freeze prevention temperature, and the power circuit of the electric heater includes the A configuration in which a circuit in which the first thermostat and the second thermostat are connected in series and a parallel circuit in which the third thermostat is connected in parallel is provided. The features.

  According to the present invention, the energizing means for the electric heater is installed in the upper part of one tank unit, and the first thermostat that is turned on at a temperature equal to or higher than the first set temperature in order to confirm the presence or absence of hot water, and the position of the connecting pipe And a second thermostat that is turned on at a temperature equal to or lower than the second set temperature that requires heat retention higher than the first set temperature, and is installed at the connecting pipe position and is lower than the first set temperature. A third thermostat that is turned ON at a temperature equal to or lower than the anti-freezing temperature, and a parallel circuit in which a first thermostat and a second thermostat are connected in series to a power circuit of the electric heater and a third thermostat is connected in parallel Since the circuit is provided, the temperature of the connecting pipe position becomes a temperature below the anti-freezing temperature at which the third thermostat is turned on, or The temperature of the hot water at the top of the tank unit is equal to or higher than the first set temperature at which the first thermostat is turned on, and the temperature at the connecting pipe position is equal to or lower than the second set temperature at which the second thermostat is turned on. When the temperature is reached, the connecting pipe can be heated by energizing the electric heater. Therefore, it is easy to prevent the temperature drop of hot water due to heat dissipation in the connecting pipe when heat insulation is necessary, and the prevention of water freezing in the connecting pipe by simply adding an electric circuit that combines the three first to third thermostats. Therefore, it is possible to improve the function and reliability of the sealed hot water storage tank.

  Furthermore, the sealed hot water storage tank of the present invention is configured such that the first thermostat, the second thermostat, and the third thermostat are each OFF-operated with an appropriate width of temperature hysteresis in the above-described sealed hot water storage tank. It is characterized by that.

  According to the present invention, the first thermostat, the second thermostat, and the third thermostat are each configured to be turned off with a temperature hysteresis of a suitable width, so that each thermostat can be prevented from being disturbed and hunting, Electric power consumption due to unnecessary energization of the electric heater can be prevented. Accordingly, it is possible to stabilize the operation of each thermostat and reduce the power consumption while improving the temperature drop prevention and freezing prevention functions in the sealed hot water storage tank.

  Furthermore, the sealed hot water storage tank of the present invention is the above-described sealed hot water storage tank, wherein the energizing means for the electric heater is installed at an upper position of the one tank unit and detects the hot water temperature at the position. Based on a temperature sensor, a second temperature sensor that is installed at the connecting pipe position and detects the temperature of the hot water at the position, and the detected temperature of the first temperature sensor and the second temperature sensor, the second temperature sensor Detects a temperature lower than the anti-freezing temperature, or the first temperature sensor detects a temperature equal to or higher than a first set temperature for checking the presence or absence of hot water in the upper part of the one tank unit, and the second temperature. And a control unit that energizes the electric heater when the sensor detects a temperature equal to or lower than a second set temperature that requires heat retention.

  According to the present invention, the means for energizing the electric heater is installed at the upper position of the one tank unit, and is installed at the first temperature sensor for detecting the hot water temperature at the position and the connecting pipe position. Based on the second temperature sensor for detecting the hot water temperature and the detected temperatures of the first temperature sensor and the second temperature sensor, when the second temperature sensor detects a temperature not higher than the freezing prevention temperature, or the first temperature sensor is When the temperature above the first set temperature for checking the presence or absence of hot water is detected at the upper part of the tank unit, and the second temperature sensor detects the temperature below the second set temperature that needs to be kept warm, the electric heater And a control unit that energizes the first, the second temperature sensor detects a temperature that is equal to or lower than the anti-freezing temperature, or the first temperature sensor detects a temperature that is equal to or higher than the first set temperature, and the second Temperature sensor Upon detecting the second setting temperature below the temperature, it is possible to heat the connection pipe by energizing the electric heater. Therefore, it is possible to prevent the temperature of hot water from decreasing due to heat dissipation in the connecting pipe when heat retention is necessary, and to prevent the water from freezing in the connecting pipe, etc. by combining the two temperature sensors and the control unit. The function and reliability of the hot water storage tank can be improved.

  According to the present invention, even in the case of a hot water storage tank structure in which a plurality of tank units must be connected via a relatively long connecting pipe, the hot water temperature at the top of one tank unit is equal to or higher than the first set temperature, When it is confirmed that there is hot water in the upper part of one tank unit, when the hot water temperature at the position of the connecting pipe is lower than the second set temperature that requires heat retention, the electric heater is energized to heat the connecting pipe. By doing so, it is possible to prevent a decrease in hot water temperature due to heat dissipation in the connecting pipe part, and when the front and rear of the connecting pipe are water and the outside air temperature is low, the hot water temperature at the connecting pipe position is set in advance to the freezing prevention temperature. In the following cases, by energizing the electric heater and heating the connecting pipe, it is possible to prevent water from freezing in the connecting pipe part. In addition to increasing the degree of freedom of installation, there is a possibility that hot water and water with reduced temperature may remain in the hot water storage tank due to heat dissipation in the connection pipe part, and damage to the connection pipe due to water freezing. Can be resolved. In addition, at the timing when hot water in the hot water storage tank is consumed, there may be a case where unboiled water exists in the connection pipe. In this case, if heating is continued with an electric heater while focusing only on keeping warm water, However, such a situation can also be prevented.

1 is a schematic configuration diagram of a hot water supply system using a sealed hot water storage tank according to a first embodiment of the present invention. It is an electric circuit diagram with respect to the electric heater provided in the connection piping of the sealed hot water storage tank shown in FIG. It is operation | movement explanatory drawing of the 1st thru | or 3rd thermostat which turns ON / OFF the electric heater shown in FIG. It is a control circuit diagram with respect to the electric heater provided in the connection piping of the enclosed hot water storage tank which concerns on 2nd Embodiment of this invention.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 shows a schematic configuration diagram of a hot water supply system using a sealed hot water storage tank according to the first embodiment of the present invention, and FIG. 2 shows an electric heater provided in a connection pipe of the sealed hot water storage tank. It is an electric circuit diagram.
The hot water supply system 1 includes a heat source device (hot water supply device) 2 that produces hot water, and a sealed hot water storage tank 3 that stores the hot water produced by the heat source device 2 and can appropriately supply hot water to a required location. ing.

  As the heat source device 2, a heat pump, a boiler, a solar heat collector, or a heat source device combining them can be used. In this embodiment, an example using the heat pump 4 will be described. The heat pump 4 comprises a compressor 5, a refrigerant / water heat exchanger 6, an expansion valve 7, and an air heat exchanger 8 functioning as an evaporator connected by a refrigerant pipe 9 to constitute a closed cycle refrigeration cycle. This heat pump 4 is configured such that high-temperature and high-pressure refrigerant gas compressed by a compressor 5 is radiated by a refrigerant / water heat exchanger 6 and water is heated by the heat to produce hot water. A water supply pipe 10 and a water supply pump 11 for supplying water from the sealed hot water storage tank 3 side to the heat exchanger 6 and a hot water supply pipe 12 for discharging hot water produced by the refrigerant / water heat exchanger 6 are provided. I have.

  A sealed hot water storage tank 3 for storing hot water produced by the heat pump 4 and appropriately supplying it to a required hot water supply location includes a plurality of first tank units (one tank unit) 20 and second tank units (other tanks). Tank unit) 21, which is connected in series by a connecting pipe 22. One end of the connecting pipe 22 is connected to the upper part of the first tank unit 20 and the other end is connected to the bottom part of the second tank unit 21. The water supply pipe 10 for the heat source unit 2 and the hot water pipe from the heat source unit 2 are connected. 12, a plurality of first tank units 20 and second tank units 21 are connected in series.

  A water supply pipe 10 for the heat source unit 2 is connected to the bottom of the first tank unit 20 connected to the water supply side of the heat source unit 2, and tap water or the like is supplied to the first tank unit 20. A water supply pipe 23 is connected. Moreover, the hot water supply pipe 12 from the heat source device 2 is connected to the upper part of the second tank unit 21 connected to the hot water side of the heat source device 2.

  By setting it as such a water piping structure, water, such as a tap water, can be supplied to the 1st tank unit 20 via the water supply pipe 23 from the bottom part. As shown by the solid line arrows, hot water can be produced by supplying the refrigerant / water heat exchanger 6 of the heat pump 4 through the water supply pipe 10 and the water supply pump 11 and heating with high-temperature and high-pressure refrigerant. The hot water produced in this way is introduced into the tank unit from the upper part of the second tank unit 21 via the hot water supply pipe 12, whereby hot water and cold water are mixed into the plurality of second tank units 21 and the first tank unit 20. A temperature boundary layer is formed, and a required amount of hot water can be stored in the tank units 20 and 21 sequentially while moving the temperature boundary layer.

  On the other hand, when hot hot water stored in the first tank unit 20 and the second tank unit 21 is used by supplying hot water to a required location, the second water pressure is applied to the first tank unit 20 by using the supply water pressure. The hot water stored in the tank unit 21 is sequentially sent from the upper part of the second tank unit 21 to the hot water discharge pipe 24 as indicated by the broken line arrows, so that it can be used at a required hot water supply location. It is like that.

  Further, in the above-described sealed hot water storage tank 3, an electric heater 25 is provided on the outer periphery of the connecting pipe 22 connecting the plurality of first tank units 20 and the second tank units 21 along the length direction thereof. It has been. Further, in order to turn on / off the electric heater 25, a first thermostat 26 is installed at an upper position of the first tank unit 20, and the outlet to the first tank unit 20 is stored when hot water is stored in the connecting pipe 22, and the second thermostat 26 is discharged when hot water is discharged. A second thermostat 27 and a third thermostat 28 are installed at a position serving as an inlet to the tank unit 21.

  The first thermostat 26 is for confirming whether or not there is hot water in the upper part of the first tank unit 20, and the first thermostat 26 is turned on at, for example, 50 ° C., as shown in FIG. The thermostat is turned off at 40 ° C. This is because when the temperature of the hot water in the first tank unit 20 is 40 ° C. or lower, only freezing prevention is performed without keeping the temperature.

  Further, the second thermostat 27 determines whether or not it is necessary to keep the warm water when the first thermostat 26 is turned on and it is confirmed that there is warm water of 50 ° C. or more in the upper part of the first tank unit 20. This second thermostat 27 is, for example, a thermostat that is turned on at 70 ° C. and turned off at 80 ° C., as shown in FIG. This is an example in the case where it is desired to keep the temperature of the hot water at 70 ° C. or higher, and can be changed according to the temperature to be kept warm.

Further, the third thermostat 28 is for preventing water from freezing in the connecting pipe 22 at a low outside air temperature. The third thermostat 28 is, for example, 5 ° C. as shown in FIG. The thermostat is turned on at 10 ° C and turned off at 10 ° C. This is an example in the case where it is desired to prevent freezing when the temperature of water becomes 5 ° C. or less, and can be changed as necessary.
In addition, the first thermostat 26, the second thermostat 27, and the third thermostat 28 are each provided with a temperature hysteresis as described above, but this temperature hysteresis may be set with an appropriate width, It is not limited to the temperature range.

  The three thermostats of the first thermostat 26, the second thermostat 27, and the third thermostat 28, as shown in FIG. 2, in the electric circuit 30 that supplies electricity from the power source 29 to the electric heater 25, the first thermostat. A parallel circuit formed by connecting a third thermostat 28 in parallel to a circuit connected 26 and the second thermostat 27 in series constitutes an electric circuit connected in series to the electric heater 25. When the temperature of the water in the connection pipe 22 is lowered to 5 ° C. or less by the electric circuit 30, the third thermostat 28 senses the temperature and performs an ON operation, so that the electric heater 25 can be energized. As a result, the connecting pipe 22 can be heated by the electric heater 25, and water freezing in the connecting pipe 22 can be prevented.

  The electric circuit 30 is a temperature when the first thermostat 26 confirms that hot water is present in the upper part of the first tank unit 20, and the temperature of the hot water in the connecting pipe 22 is a temperature that requires heat retention, that is, When the second thermostat 27 senses that the temperature has decreased to 70 ° C. or lower, that is, when both the first thermostat 26 and the second thermostat 27 are turned on, the electric heater 25 can be energized. It can be configured. As a result, when it is confirmed that there is hot water in the upper part of the first tank unit 20 and the temperature of the hot water in the connecting pipe 22 is a temperature that needs to be kept warm, the electric heater 25 is energized to connect the connecting pipe. 22 can be heated and the temperature of the hot water in the tank unit can be kept at the required temperature.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
In the hot water supply system 1, when hot water is stored in the plurality of first tank units 20 and second tank units 21 constituting the sealed hot water storage tank 3, the heat pump 4 and the water supply pump 11 are operated as is well known. Hot water can be produced by heating water with a high-temperature and high-pressure refrigerant in the refrigerant / water heat exchanger 6. By introducing this hot water into the first tank unit 20 and the second tank unit 21 through the hot water supply pipe 12 and storing them, a required amount of hot water can be stored. Moreover, the hot water can be used at the hot water supply location by discharging the hot water from the upper part of the second tank unit 21 to the required hot water supply location via the hot water discharge pipe 24.

  During this time, in the connection pipe 22 connecting the first tank unit 20 and the second tank unit 21, when hot water is stored in the first tank unit 20 and the second tank unit 21, the connection pipe As the heat is radiated from 22, the temperature of the hot water is assumed to decrease. Moreover, when warm water is not stored and the front and back of the connecting pipe 22 are water, it is assumed that water may freeze in the connecting pipe 22 at a low outside air temperature.

  However, in this embodiment, the electric heater 25 is provided on the outer periphery of the connection pipe 22, and the first thermostat 26 installed on the upper part of the first tank unit 20 and the hot water of the connection pipe 22 are stored with respect to the electric heater 25. The water in the connection pipe 22 is frozen at a low outside temperature through the second thermostat 27 and the third thermostat 28 installed at the outlet to the first tank unit 20 and the inlet to the second tank unit 21 when the hot water is discharged. If there is a risk of heating, or if there is hot water at the top of the first tank unit 20 and the temperature of the hot water in the connecting pipe 22 has dropped to a temperature that requires heat retention, The connecting pipe 22 can be heated.

  That is, in the present embodiment, the first thermostat 26 is ON at 50 ° C., the thermostat is OFF at 40 ° C., the second thermostat 27 is ON at 70 ° C., the thermostat is OFF at 80 ° C., and the third thermostat 28 is 5 The thermostat operates ON at 10 ° C. and OFF at 10 ° C., and the thermostats 26, 27, and 28 are connected to a circuit in which a first thermostat 26 and a second thermostat 27 are connected in series as shown in FIG. The third thermostat 28 is connected in parallel to form a parallel circuit, and the parallel circuit is connected to the power supply circuit of the electric heater 25 in series with the electric heater 25.

  Therefore, when the third thermostat 28 installed in the connecting pipe 22 senses a temperature of 5 ° C. or less and is turned on, or when the first thermostat 26 installed on the upper part of the first tank unit 20 is 50 When the second thermostat 27 installed in the connecting pipe 22 senses a temperature of 70 ° C. or less and is turned on in a state where the temperature is higher than 0 ° C., the electric heater 25 is energized. Thus, the connecting pipe 22 can be heated.

  As a result, even when a hot water storage tank structure in which a plurality of tank units 20 and 21 are inevitably connected via a relatively long connecting pipe 22 is used, the hot water temperature at the upper part of the first tank unit 20 is set to a set temperature (here In the case where it is confirmed that there is hot water at the upper part of the first tank unit 20, the temperature of the hot water in the connecting pipe 22 is equal to or lower than a set temperature (70 ° C. in this case) that needs to be kept warm. When the electric heater 25 is energized and the connecting pipe 22 is heated, a decrease in the hot water temperature due to heat radiation from the connecting pipe 22 can be prevented. In addition, when the front and back of the connection pipe 22 are water and the outside air temperature is low, when the hot water temperature of the connection pipe 22 is equal to or lower than a preset anti-freezing temperature (here, 5 ° C.), the electric heater 25 is energized to connect the connection pipe 22. By heating 22, it is possible to prevent freezing of water in the connecting pipe portion.

  Thus, according to the present embodiment, the degree of freedom of installation of the plurality of tank units 20, 21 that are installed when the capacity of the hot water storage tank 3 is increased can be increased, and the tank unit 20 is radiated by the connection pipe 22. , 21 can solve the problems such as the possibility that the hot water and the water whose temperature has been lowered remain in the spots, and the accident that the connecting pipe 22 is damaged due to water freezing. Further, at the timing when the hot water in the tank units 20 and 21 is consumed, there may be a case where unboiled water exists in the connection pipe 22, and in this case, the heating is performed by the electric heater 25 while paying attention only to the warm water retention. If it continues, it will become a situation where water is boiled with the electric heater 25, but such a situation can also be prevented.

  Also, the three first to third thermostats 26 and 27 installed at the above positions are used to prevent the temperature of the hot water from being lowered due to heat radiation in the connecting pipe 22 when heat insulation is necessary, and to prevent the water from freezing in the connecting pipe 22. , 28 can be easily realized by a simple configuration in which the parallel circuit combined with the electric circuit 30 of the electric heater 25 is incorporated, and the function and reliability of the sealed hot water storage tank 3 can be improved. .

  Further, since the three first, second, and third thermostats 26, 27, and 28 are each provided with a temperature hysteresis set with an appropriate temperature range, the turbulence of each thermostat 26, 27, and 28 is provided. And hunting can be prevented, and power consumption due to unnecessary energization of the electric heater 25 can be prevented. Therefore, it is possible to stabilize the operation of each thermostat 26, 27, 28 and reduce the power consumption while improving the temperature drop prevention and freezing prevention functions in the sealed hot water storage tank 3.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
In this embodiment, instead of the thermostats 26, 27, 28 and the electric circuit 30 in the first embodiment described above, the first and second temperature sensors 40, 41 and the energization control unit 42 for the electric heater 25 are provided. Is different. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, as shown in FIG. 1, a first temperature sensor 40 is provided at an upper position of the first tank unit 20, and the outlet to the first tank unit 20 is stored when hot water is stored in the connecting pipe 22. A second temperature sensor 41 is provided at a position serving as an inlet to the two tank unit 21, and energization is performed for ON / OFF control of energization to the electric heater 25 based on detection values of the first and second temperature sensors 40 and 41. The control unit 42 is provided (see FIG. 4).

  As shown in FIG. 3, the energization control unit 42 is configured such that when the second temperature sensor 41 detects a temperature equal to or lower than the freezing prevention temperature (here, 5 ° C.) or the first temperature sensor 40 is the first temperature sensor 40. When a temperature equal to or higher than the set temperature (here, 50 ° C.) is detected and the second temperature sensor 41 detects a temperature equal to or lower than the second set temperature (here, 70 ° C.), the respective contact points of the power supply circuit of the electric heater 25 43 has the function of turning on and energizing the electric heater 25.

As described above, according to the present embodiment, when the second temperature sensor 41 detects a temperature equal to or lower than the freezing prevention temperature (5 ° C.), or the first temperature sensor 40 exceeds the first set temperature (50 ° C.). When the temperature is detected and the second temperature sensor 41 detects a temperature equal to or lower than the second set temperature (70 ° C.), the electric pipe 25 can be energized to heat the connecting pipe 22.
Therefore, the combination of the two temperature sensors 40 and 41 and the energization control unit 42 realizes prevention of temperature drop of the hot water due to heat radiation in the connection pipe 22 when heat insulation is necessary and prevention of water freezing in the connection pipe 22. Thus, the same effect as in the first embodiment can be obtained, and the function and reliability of the sealed hot water storage tank 3 can be improved.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, the configuration of the sealed hot water storage tank 3 and the heat pump 4 is not limited to the configuration of the embodiment shown in FIG. 1 described above, and various modifications are possible. In particular, the first tank unit 20 and the second tank unit 21 are shown as one large tank, but each tank unit may be configured by connecting a plurality of small-capacity tanks. .

DESCRIPTION OF SYMBOLS 1 Hot water supply system 2 Heat source machine 3 Sealed hot water storage tank 20 1st tank unit (one tank unit)
21 Second tank unit (other tank units)
22 connecting pipe 25 electric heater 26 first thermostat 27 second thermostat 28 third thermostat 29 power supply 30 electric circuit 40 first temperature sensor 41 second temperature sensor 42 energization control unit 43 contact

Claims (4)

An enclosed hot water storage tank used in a hot water supply system for storing hot water produced by a heat source machine in a hot water storage tank and supplying hot water to a required location as appropriate.
The upper part of one tank unit and the bottom part of the other tank unit are connected in series via a connecting pipe, the one tank unit is on the water supply side to the heat source unit, and the other tank unit is connected from the heat source unit. A plurality of tank units connected to the hot water side;
An electric heater provided in the connecting pipe;
The position of the hot water temperature at the top of the one tank unit and the outlet to the one tank unit when storing hot water in the connecting pipe connected to the bottom of the other tank unit, and the inlet to the other tank unit when discharging hot water In response to the hot water temperature, when the hot water temperature at the connecting pipe position is equal to or lower than a preset anti-freezing temperature, or when the hot water temperature at the upper part of the one tank unit is set in order to confirm the presence or absence of hot water, And a means for energizing the electric heater when the temperature of the hot water at the connecting pipe position is equal to or higher than a preset second preset temperature that needs to be kept warm. Sealed hot water storage tank. The energizing means to the electric heater is
A first thermostat installed at the upper part of the one tank unit and operated to be turned on at a temperature equal to or higher than the first set temperature in order to confirm the presence or absence of hot water;
A second thermostat that is installed at the connection pipe position and that is ON-operated at a temperature equal to or lower than the second set temperature that requires heat retention higher than the first set temperature;
A third thermostat installed at the connecting pipe position and operating ON at a temperature lower than the anti-freezing temperature lower than the first set temperature;
The power supply circuit of the electric heater is configured to include a parallel circuit in which a circuit in which the first thermostat and the second thermostat are connected in series and a third thermostat are connected in parallel. Item 2. A sealed hot water storage tank according to item 1.   The hermetic hot water storage tank according to claim 2, wherein each of the first thermostat, the second thermostat, and the third thermostat is configured to perform an OFF operation with a temperature hysteresis having an appropriate width. The energizing means to the electric heater is
A first temperature sensor installed at an upper position of the one tank unit and detecting a hot water temperature at the position;
A second temperature sensor installed at the connecting pipe position and detecting the temperature of the hot water at the position;
When the second temperature sensor detects a temperature not higher than the anti-freezing temperature based on the detected temperatures of the first temperature sensor and the second temperature sensor, or the first temperature sensor is located above the one tank unit. The electric heater is energized when a temperature equal to or higher than a first set temperature for confirming the presence or absence of hot water is detected and the second temperature sensor detects a temperature equal to or lower than a second set temperature that requires heat retention. A sealed hot water storage tank according to claim 1, further comprising a control unit.

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