JP5887230B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water heater that circulates hot water in a hot water storage tank to a primary side of a hot water supply external heat exchanger and heats flowing water flowing on a secondary side to supply hot water.

  Conventionally, in a hot water storage type water heater having an external heat exchanger of this type, as in Patent Document 1, a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, and a primary side A hot water supply external heat exchanger that heats and supplies hot water flowing from the hot water in the hot water storage tank circulating through the hot water tank, and a primary side connecting the upper part of the hot water storage tank and the primary inlet of the hot water supply external heat exchanger A side return pipe, a primary return pipe connecting the primary outlet of the hot water supply external heat exchanger and the hot water storage tank, and a hot water in the hot water storage tank provided outside the hot water supply provided in the middle of the primary return pipe. A primary side pump that circulates to the primary side of the heat exchanger, a water supply pipe connected to the secondary side inlet of the hot water supply external heat exchanger, and a hot water supply pipe connected to the secondary side outlet of the hot water supply external heat exchanger There was something with.

JP 2012-107843 A

  However, in such a conventional apparatus, a primary side outlet and a secondary side inlet are provided below the hot water supply external heat exchanger, and a primary side inlet and a secondary side outlet are provided above the hot water supply external heat exchanger. Because it is provided, hot water remains on the upper part of the primary side of the hot water external heat exchanger after hot water is stopped, and hot water on the secondary side of the upper part of the hot water external heat exchanger is also overheated, resulting in post boiling. There was a problem that an overshoot occurred in which the hot water temperature greatly exceeded the hot water set temperature at the beginning of the next hot water supply.

Therefore, in order to solve the above-described problems, the present invention provides a hot water storage tank for storing hot water, heating means for heating the hot water in the hot water storage tank, and hot water in the hot water storage tank circulating in the primary side as a heat source as a secondary source. A hot water external heat exchanger composed of a plate heat exchanger that heats and supplies hot water on the side, and a primary forward pipe that connects the upper part of the hot water storage tank and a primary inlet of the hot water external heat exchanger; A primary side return pipe connecting the primary outlet of the hot water supply external heat exchanger and the hot water storage tank, and provided in the middle of either the primary side forward pipe or the primary side return pipe in the hot water storage tank A primary side pump for circulating hot water to the primary side of the hot water supply external heat exchanger, a water supply pipe connected to a secondary side inlet of the hot water supply external heat exchanger, and a secondary side outlet of the hot water supply external heat exchanger A hot water supply pipe connected to the hot water supply outside heat exchange It is arranged closer fixed upright posture, the bottom of the secondary side outlet and the primary inlet fed-Yugai heat exchanger, and the primary outlet and the secondary inlet fed-Yugainetsu It was assumed that it was provided in the upper part of the exchanger.

  According to the present invention, after the hot water supply is stopped, the heat of the hot water remaining near the primary inlet and the secondary outlet located below the hot water external heat exchanger is the temperature remaining on the hot water external heat exchanger. Heat transfer quickly to low hot water, and no boiling occurs after hot water on the secondary side of the hot water heat exchanger is overheated, preventing overshoot from occurring at the beginning of the next hot water supply. it can.

Schematic configuration diagram of one embodiment of the present invention The perspective view of the hot water supply external heat exchanger of the same embodiment

Next, a hot water storage type water heater according to an embodiment of the present invention will be described with reference to the drawings.
1 is a tank unit having a hot water storage tank 2 for storing hot water, 3 is a hot water external heat exchanger composed of a plate heat exchanger for heating the hot water in the hot water tank 2 as a heat source, and 4 is a hot water tank 2. The primary side circulation circuit 4 circulates the hot water inside the hot water supply outside heat exchanger 3 to the primary side, and the primary side circulation circuit 4 connects the one side inlet 3 a of the hot water supply outside heat exchanger 3 and the upper part of the hot water storage tank 2. The primary side return pipe 5 is composed of a primary side return pipe 6 that connects the primary side outlet 3b of the hot water supply external heat exchanger 3 and the lower part of the hot water storage tank 2. A primary pump 7 is provided for circulating the hot water taken out from the primary side of the hot water supply external heat exchanger 3.

  8 is a water supply pipe connected to the secondary side inlet 3 c of the hot water supply external heat exchanger 3, and 9 is a hot water supply pipe connecting the secondary side outlet 3 d of the hot water supply external heat exchanger 3 and the hot water tap 10. Here, the water supply pipe 8 is directly connected from the city water to the hot water supply external heat exchanger 3 without going through the pressure reducing valve.

  Here, the hot water supply external heat exchanger 3 is arranged and fixed in the tank unit 1 in a posture in which a known plate type heat exchanger is set up, and a primary side inlet 3a and a secondary side outlet are provided at the lower part of one end plate. 3d is arranged, and a primary side outlet 3b and a secondary side inlet 3c are arranged on the same surface of the end plate. Even if the primary side inlet 3a and the secondary side outlet 3d are arranged at the lower part of the end plate on the one surface side, and the primary side outlet 3b and the secondary side inlet 3c are arranged at the upper part of the end plate on the other side. Good.

  11 is a heat pump unit as a heating means for heating the hot water in the hot water storage tank 2, and 12 is a heating circulation circuit for circulating the hot water in the hot water storage tank 2 to the heat pump unit 11, which is connected to the inlet of the heat pump unit 11. And a heating return pipe 14 connecting the outlet side of the heat pump unit 11 and the upper part of the hot water storage tank 2. The hot water storage tank 13 is located in the middle of the heating forward pipe 13. 2 A heating circulation pump 16 for circulating hot water taken out from the lower part to the water side of the refrigerant water heat exchanger 15 of the heat pump unit 11 is provided.

  17 is a compressor that compresses refrigerant, 18 is an expansion valve that decompresses and expands the pressure of the refrigerant, 19 is an evaporator that evaporates liquid refrigerant, 20 is a blower that blows outside air as a heat source to the evaporator 19, and 21 is refrigerant water. An incoming water temperature sensor 22 detects the temperature of hot water from the hot water storage tank 2 that flows into the water side of the heat exchanger 15, and 22 is the temperature of hot water boiled up by the heat pump unit 11 that flows out from the water side of the refrigerant water heat exchanger 15. The boiling temperature sensor 23 detects the outside air temperature, and the outside air temperature sensor 23 detects the outside air temperature. The heat pump unit 11 compresses the refrigerant absorbed by the evaporator 19 by the compressor 17 and supplies water via the refrigerant water heat exchanger 15. It is intended to be heated.

  Reference numeral 24 denotes a heating branch pipe branched from the middle of the heating return pipe 14 and connected to the primary return pipe 6, and 25 is provided at a branch point between the heating return pipe 14 and the heating branch pipe 24. This is a heating switching valve that switches between returning to the upper part of the hot water storage tank 2 or returning to the lower part of the hot water storage tank 2 via the heating branch pipe 24 and the primary return pipe 6.

  26 is a supplementary water pipe branched from the hot water supply pipe 9 and connected between the primary side pump 7 of the primary side return pipe 6 and the connection point of the heating branch pipe 24, and 27 is provided in the middle of the supplementary water pipe 26 to control the supply water pressure. A pressure reducing valve 28 for reducing the pressure is an overpressure relief valve that is connected in the middle of the primary side outgoing pipe 5 and releases the overpressure in the hot water storage tank 2.

  29 is a water supply temperature sensor that is provided in the middle of the water supply pipe 8 to detect the water supply temperature, 30 is a hot water supply temperature sensor that is provided in the middle of the hot water supply pipe 9 to detect the hot water supply temperature, and 31 is a water supply temperature sensor that is provided in the middle of the hot water supply pipe 9. The hot water supply flow sensor 32 detects the temperature of hot water as a heat source that is provided in the primary side forward pipe 5 and flows into the hot water external heat exchanger 3, and 33 is in the middle of the primary return pipe 6. A plurality of primary outlet temperature sensors 34 are provided on the upper and lower sides of the hot water storage tank 2 to detect the temperature of the hot water stored in the hot water tank.

  Reference numeral 35 denotes a remote controller including an operation switch for setting a desired hot water supply set temperature and a display unit for displaying the hot water set temperature.

  Reference numeral 36 denotes an incoming water temperature sensor 21, a boiling temperature sensor 22, an outside air temperature sensor 23, a feed water temperature sensor 29, a hot water supply temperature sensor 30, a hot water supply flow rate sensor 31, a primary inlet temperature sensor 32, a primary outlet temperature sensor 33, and a hot water storage temperature sensor 34. The detection value is input, and the operation of the primary pump 7, the heat pump unit 11, the heating circulation pump 16, the compressor 17, the expansion valve 18, the blower 20, and the heating switching valve 25 is controlled and connected to the remote control 35 so as to be communicable. Control means. The control means 36 stores a program for controlling the operation of the water heater in advance, and has a calculation, comparison, storage function, and clock function.

<Boiling operation>
At the start time of a predetermined time zone (midnight time zone) at which the power unit price is cheap, the control means 36 drives the heat pump unit 11 and the heating circulation pump 16 so as to start boiling the hot water amount corresponding to the hot water supply load amount so far. The hot water taken out from the lower part of the hot water storage tank 2 is started and heated to the set temperature.

  At this time, the control means 36 keeps the heating switching valve 25 on the heating branch pipe 24 side while the boiling temperature detected by the boiling temperature sensor 22 is lower than a predetermined temperature lower than the boiling setting temperature, and the temperature is low. When hot water is prevented from flowing in from the upper part of the hot water storage tank 2 to lower the hot water storage temperature, and the boiling temperature reaches a predetermined temperature lower than the boiling temperature, the heating switching valve 25 is placed on the upper side of the hot water tank 2. The hot water that has been boiled so as to communicate with each other is returned to the upper part of the hot water storage tank 2, and hot water at the boiling set temperature is stored in a stacked manner from the upper part of the hot water storage tank 2.

  When the lowest hot water storage temperature sensor 34 detects a predetermined boiling end determination temperature, the control unit 36 stops driving the heat pump unit 11 and the heating circulation pump 16 and ends the boiling operation.

  At this time, the hot water stored in the hot water storage tank 2 expands as the temperature of the hot water in the hot water tank 2 rises, and when the pressure in the hot water storage tank 2 exceeds the set pressure of the overpressure relief valve 28, the overpressure relief valve 28 opens. When the expanded water is drained and the pressure in the hot water storage tank 2 falls below the set pressure of the overpressure relief valve 28, the overpressure relief valve 28 closes and the drainage stops, so that the hot water tank 2 is maintained at an appropriate pressure. Yes.

  Then, the hot water stored in the hot water storage tank 2 contracts due to the natural heat dissipation of the hot water in the hot water storage tank 2 over time and the temperature drop of the hot water in the hot water storage tank 2 due to the hot water supply described later, and the pressure in the hot water storage tank 2 is reduced. When the pressure falls below the set pressure of 27, the city water flows into the hot water storage tank 2 from the supplementary water pipe 25 via the pressure reducing valve 27, and when the pressure in the hot water storage tank 2 exceeds the set pressure of the pressure reducing valve 28, The inflow of water stops and the hot water storage tank 2 is kept in a full water state at an appropriate pressure.

<Hot-water supply operation>
Next, the hot water supply operation will be described. When the hot water tap 10 is opened, city water flows into the secondary side of the hot water supply external heat exchanger 3 from the water supply pipe 8 and passes through the secondary side of the hot water supply external heat exchanger 3. The discharged hot water flows out from the hot water supply pipe 9 toward the hot water tap 10. At this time, when the hot water supply flow sensor 31 detects a predetermined minimum working water amount or more, the control means 36 supplies the hot water temperature detected by the hot water temperature sensor 29, the hot water set temperature set by the remote controller 35, and the hot water flow sensor. The hot water required heat quantity is calculated from the hot water supply flow rate detected at 31, and the primary side pump 7 is started to drive at a rotational speed corresponding to the hot water storage temperature detected by the hot water storage temperature sensor 34 and the calculated hot water required heat quantity. .

  Then, the number of revolutions of the primary pump 7 is feedback-controlled so that the hot water temperature detected by the hot water temperature sensor 30 matches the hot water set temperature set by the remote controller 35 to perform hot water supply at the hot water set temperature.

  When the hot water supply flow rate detected by the hot water supply flow rate sensor 31 decreases to less than the minimum working water amount, for example, when the hot water tap 10 is closed, the control unit 36 stops the operation of the primary pump 7 and ends the hot water supply.

<Waiting for hot water supply>
During the hot water supply standby after the hot water supply is stopped, the hot water flowing from the upper part of the hot water storage tank 2 remains in the vicinity of the primary side inlet 3a of the hot water external heat exchanger 3, and the secondary side near the secondary side outlet 3d remains. Although the hot water is heated, the primary side inlet 3a and the secondary side outlet 3d are located in the lower part of the hot water supply external heat exchanger 3, so that hot water near the primary side inlet 3a is not supplied from the hot water supply external heat exchanger 3. The heat is conducted to the hot water on the primary side and the secondary side having a low temperature on the upper side of the hot water, and the specific gravity difference between the hot water on the primary side and the secondary side having a low temperature on the upper side of the hot water supply heat exchanger 3 is also upward. The hot water in the vicinity of the primary side inlet 3a of the hot water supply external heat exchanger 3 quickly drops in temperature, and boiling occurs after the hot water on the secondary side of the hot water supply external heat exchanger 3 is overheated. Absent.

  In this way, since no secondary boiling occurs in the hot water on the secondary side in the hot water supply external heat exchanger 3 during standby for hot water supply, it is possible to prevent the occurrence of overshooting of the hot water temperature at the beginning of the next hot water supply. it can.

The present invention is not limited to the above embodiment, Ru der capable modifications without departing from the scope of the invention.

  Further, the heating means is not limited to the heat pump unit 11, and for example, exhaust heat by cogeneration, solar heat, or an electric heater may be used as the heating means.

DESCRIPTION OF SYMBOLS 2 Hot water storage tank 3 Hot water supply external heat exchanger 3a Primary side inlet 3b Primary side outlet 3c Secondary side inlet 3d Secondary side outlet 5 Primary side outgoing pipe 6 Primary side return pipe 7 Primary side pump 8 Water supply pipe 9 Hot water supply pipe 11 Heat pump unit (Heating means)

Claims (1)

A hot water storage tank for storing hot water, heating means for heating the hot water in the hot water storage tank, and plate-type heat exchange for heating and supplying hot water in the secondary side using hot water in the hot water tank circulating in the primary side as a heat source A hot water external heat exchanger composed of a heater, a primary side forward pipe connecting the upper part of the hot water storage tank and the primary inlet of the hot water external heat exchanger, a primary outlet of the hot water external heat exchanger, and the hot water storage A primary return pipe connecting the tank, and provided in the middle of either the primary forward pipe or the primary return pipe, the hot water in the hot water storage tank is circulated to the primary side of the hot water supply external heat exchanger A primary water pump, a hot water supply pipe connected to a secondary inlet of the hot water supply external heat exchanger, and a hot water supply pipe connected to a secondary outlet of the hot water supply external heat exchanger. exchanger is arranged closer fixed upright posture And wherein the secondary side outlet and the primary inlet in the lower portion of the fed-Yugai heat exchanger, and the primary outlet and the secondary inlet is provided above the fed-Yugai heat exchanger Hot water storage water heater.

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