JP5845397B2 - Hot water heater - Google Patents

Description

  The present invention relates to a hot water heater that performs heating by circulating hot water generated using a heat source device to a heating terminal using a circulation pump.

  A conventional open or semi-enclosed hot water heater has a tank inside the main body in order to absorb expansion and contraction of circulating water for heating.

  This tank has a tank cap structure for the open type, and the tank cap has a negative pressure / pressurized valve structure for the semi-sealed type. When the internal pressure changes, these valves Opens and communicates with the atmosphere.

  Due to the structure as described above, in any method, the circulating water for heating evaporates and decreases with long-term use. And if it decreases by a certain amount, supplementation of the circulating water for heating will be needed (for example, refer patent document 1).

  In order to notify the user of this replenishment time, each company has a structure in which a water level detection means such as a water electrode is provided in the tank so that a decrease in the water level is constantly monitored.

  In general, two levels of water level detection means are provided, and when the level falls below the first level, a display prompting “water supply” is displayed on the display unit of the remote controller or the like, and when the level falls below the second level, the operation is stopped. In many cases, a warning is displayed on the display.

JP 2009-121765 A

  However, in the configuration of the above-mentioned conventional hot water heater, naturally, two or two pairs of water level electrodes are required independently in order to detect two levels of water level. Similarly, two detection circuits are required, which complicates the circuit and increases the cost.

  This invention solves the said subject, and it aims at providing the hot water heater with the high usability which can respond when heating circulation water decreases only by having one system of water electrode circuits.

In order to solve the above-described conventional problems, a hot water heater of the present invention includes a circulation pump that circulates hot water heated by a heat exchanger via a circulation pipe connected to each heating terminal, and the circulation pipe. A water tank disposed in the water tank, a water electrode for detecting a water storage state in the water tank, and a control unit. Until the water electrode detects that there is no water in the water tank, the circulation pump The drive signal to the circulation pump is changed so that the rotation speed becomes the target rotation speed, and for a predetermined time after the water electrode detects that there is no water in the water tank, a notification to that effect is given to the user. The operation is stopped when the drive signal to the circulation pump is fixed and the predetermined time has elapsed, or when the rotation speed of the circulation pump rises to a predetermined value or more within the predetermined time. It is what.

ADVANTAGE OF THE INVENTION According to this invention, a hot water heater with high usability which can respond when heating circulation water reduces can be provided only by having one system of water electrode circuits.

Overall configuration diagram of hot water heater in Embodiment 1 of the present invention Front view of remote controller of same hot water heater External view of the hot water heater Configuration diagram of the water tank of the hot water heater Control block diagram of the same hot water heater The figure showing the remote control screen of the water supply notice display of the hot water heater The figure showing the remote control screen of the water supply warning display of the same hot water heater The figure showing the remote control screen of circulation pump rotation speed abnormality display of the same hot water heater Control block diagram of hot water heater in Embodiment 2 of the present invention Control block diagram of hot water heater in Embodiment 3 of the present invention Timing chart of scan signal of same hot water heater

According to a first aspect of the present invention, there is provided a circulation pump for circulating hot water heated by a heat exchanger through a circulation pipe connected to each heating terminal, a water tank disposed in the circulation pipe, and the water tank A water electrode for detecting a water storage state in the water tank and a control unit, and the circulation pump is configured so that the rotation speed of the circulation pump becomes a target rotation speed until the water electrode detects that there is no water in the water tank. Change the drive signal to the pump, the predetermined time after the water electrode detects that there is no water in the water tank, inform the user to that effect, and fix the drive signal to the circulation pump, The hot water heater is characterized in that the operation is stopped when the predetermined time elapses or when the rotational speed of the circulation pump rises to a predetermined value or more within the predetermined time.

  As a result, when there is only one water electrode circuit, when the circulating water for heating decreases, a notification that prompts the user to "water supply" is given for a certain period of time. It is possible to perform operations in two stages, such as stopping and performing a “warning”.

In addition, when the water level decreases quickly due to inadvertent water leakage or the like, the circulating pump is idled, and the rotational speed increases abnormally. Since this rotational speed is constantly checked, in such a case, the operation can be stopped immediately without stopping the pump without damaging the pump, and the water electrode can deteriorate over time. It can be minimized. In particular, by fixing the drive signal to the circulation pump, it is possible to easily determine an increase in the number of rotations during the idling operation of the circulation pump, and to stop the circulation pump reliably and safely.

  The second invention is characterized in that the energization to the water electrode is intermittent energization, the amount of hydrogen gas generated by energizing the water electrode can be reduced to a minimum, and the residence The dangerous situation of explosion of hydrogen gas can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that this implementation is not limited.

(Embodiment 1)
FIG. 1 is an external view of a hot water heater according to Embodiment 1 of the present invention. First, the structure of the hot water heater in this Embodiment is demonstrated using FIG.

  The hot water heater of the present embodiment is a heat pump hot water heater using a heat pump as a heating source. In the figure, the right side is a refrigerant circuit, and the left side is a water circuit. In the water / refrigerant heat exchanger 1 located in the middle, the refrigerant warmed in the refrigerant circuit and the circulating water are heat-exchanged.

  The configuration on the refrigerant circuit side includes a compressor 2 that compresses the refrigerant and discharges the high-temperature refrigerant, a water-refrigerant heat exchanger 1 that generates heat by exchanging heat between water and the high-temperature refrigerant, and a refrigerant that flows in the pipe. An expansion valve 3 for adjusting the amount, an air heat exchanger 4 that performs heat exchange between air and a refrigerant, and a blower 5 that causes air to flow through the air heat exchanger are provided.

  And the compressor 2, the water refrigerant | coolant heat exchanger 1, the expansion valve 3, and the air heat exchanger 4 are connected cyclically | annularly with refrigerant | coolant piping, and the refrigerant circuit is comprised. In addition, as a form of the water-refrigerant heat exchanger 1, there is no problem even if it is either a plate type or a double pipe type.

  On the other hand, the configuration on the water circuit side receives the warm water returned from the floor heating panels 27a and 27b by the return header 6, stores the hot water in the water tank 7, expels the air, and then sends it out downstream by the circulation pump 8. The water-refrigerant heat exchanger 1 is disposed downstream, and after being reheated while passing through it, the water-refrigerant heat exchanger 1 is sent out through the forward header 9 and sent to the floor heating panels 27a and 27b.

  In the present embodiment, the return header 6 and the forward header 9 are for four systems so that the heating pipe can be divided into four systems. The forward header 9 is provided with thermal valves 10a to 10d so that the four systems can be opened and closed independently. Furthermore, in order to control the temperature of circulating water, the incoming water temperature sensor 11 and the tapping temperature sensor 12 are arrange | positioned at the upstream and the downstream of the water-refrigerant heat exchanger 1, respectively.

  Further, in order to detect the water level of the water tank 7, a water electrode 13 is provided in the water tank 7, and a voltage is applied when necessary to detect a decrease in water. 28 is a remote control.

  FIG. 2 is a front view of the remote controller 28. The remote controller 28 is connected to the outdoor hot water heater by wire, and is installed indoors such as in a living room to operate the hot water heater and adjust the temperature of the circulating water. The display related to it is performed.

  FIG. 3 is an external view of the main body of the hot water heater. The basic configuration is based on an outdoor unit of an air conditioner. In addition, a water tank 7 and a circulation pump 8 are accommodated in a back box 14 and added. Yes.

  Further, the forward header 9 and the return header 6 incorporating the thermal valves 10a to 10d are accommodated in a connection box 15 on the left side. At the time of installation of the product, the construction contractor performs construction for connecting the heating pipes connected to the required floor heating panels to the forward header 9 and the return header 6, respectively.

  FIG. 4 is a structural diagram of the water tank 7. The total volume is set to about 3 L, and is calculated so that the amount of water to evaporate can be secured for about two years by normal operation. The cap 16 has a structure in which a gap communicating with the atmosphere is provided between the mouth of the water tank 7 and forms an open system.

  17 is a filter. When water is reduced and water is supplied with the cap 16 removed, mixing of dust and the like is eliminated, and the upper limit of the amount of water is adjusted to match the lower surface of the filter. It is also used as a measure of quantity.

Reference numerals 18 and 19 denote a water supply port and a water discharge port provided in the lower part, and are connected to the circulation pump 8. The water electrode 13 is inserted from the upper part to a position about 0.3 L below the tank in order to detect that the water level of the water tank 7 has dropped.

  FIG. 5 is a control block diagram. In the figure, 20 is a water electrode determination circuit that is connected to the water electrode 13 and detects the presence or absence of water in the water tank 7, 21 is a circulation pump drive circuit that drives the circulation pump 8, and a DC pump is adopted in this embodiment. The rotation speed is controlled.

  22 is a circulation pump rotation detection circuit for detecting the number of rotations of the circulation pump 8, 23 is a control unit that receives these pieces of information and performs overall operation control, and 24 is connected to the control unit 23 to control the remote controller. It is a remote control circuit.

  In the heat pump type hot water heater configured as described above, the operation of the heat pump type hot water heater will be described below.

  First, normal heating operation will be described.

  When the user wants to start heating, when the “heating off / on” SW of the remote control 28 is operated, the LED is turned on and a display as shown in FIG. 2 appears on the liquid crystal display unit, and the heating operation is started.

  This information is transmitted from the remote control circuit 24 to the control unit 23. First, among the four circuits of the thermal valve 10, a thermal valve corresponding to a preset circuit is energized to open the circuit. In the case of this example, as shown in FIG. 2, the floor heating operation in the “living room” area is instructed, and the corresponding thermal valve 10 is opened.

  After a while, a drive signal is given from the control unit 23 to the circulation pump 8 through the circulation pump drive circuit 21 so as to reach the determined rotation speed, and circulation is started in the circulation water circuit. Thereafter, the rotational speed data is fed back to the control unit 23 via the circulation pump rotation detection circuit 22, and the control unit 23 changes the drive signal supplied from the circulation pump drive circuit 21 to see the target rotation. Keep the number.

  Furthermore, about 3 minutes after the start of operation, the compressor 2, the blower 5, and the expansion valve 3 start to operate, and heat collection begins on the refrigerant circuit side. The water / refrigerant heat exchanger 1 exchanges heat between the refrigerant circuit and the water circuit, and the circulating water is heated to become hot water and supplied to the floor heating laid in the living room through the forward header 9. The temperature of the heating panel surface rises.

  The surface temperature can be set by changing the “temperature control” setting of the remote controller in FIG. 2, and in this case, the operation can be performed in 10 steps from “high” to “low” by operating the button. In the present embodiment, “5” is set, the supplied hot water temperature is about 40 ° C., and the surface temperature of the floor heating panel is about 28 ° C. Further, the amount of water in the water tank 7 is described in the construction manual and the instruction manual so that the water is placed up to the lower surface position of the filter 17 (the state shown in FIG. 4), which is the upper limit at the time of product installation.

  Accordingly, in this state, since the water electrode 13 is sufficiently immersed in water, the water electrode determination circuit 20 detects “there is water” and the heating operation is continued. During the heating operation, the volume of the circulating water increases because the temperature of the circulating water increases. The expanded portion appears as an increase in the water level in the water tank 7, and the volume of air in the tank decreases.

Then, that amount of air is pushed out of the tank from the gap of the cap 16. In the case of the present embodiment, the maximum hot water temperature that can be boiled with a heat pump is 55 ° C., and therefore the expansion rate when the temperature is raised from 5 ° C. is about 1.5%. Moreover, since the total amount of system water is limited to 30 L at the maximum, the volume of water increased by expansion is 30 L × 1.5% = 0.45 L.

  In this embodiment, since the amount from the upper limit of the water tank 7 to the full water is about 1 L, the expansion can be absorbed sufficiently. Therefore, the circulating water does not overflow outside the water tank 7. Further, when the heating operation is stopped and the temperature of the circulating water cools, the volume contracts and the water level decreases in the water tank 7, and air is sucked from the gap of the cap 16 contrary to the expansion. Become.

  Next, the operation when the circulating water naturally decreases due to evaporation will be described.

  As mentioned before, the total capacity of the water tank 7 is about 3L, the volume of the air part above the upper limit of the water level is about 1L, so the amount of water in the tank is set to about 2L. is there. The amount of water when the water electrode 13 is completely exposed is about 0.3 L. Therefore, when 1.7 L of water is reduced, the water electrode 13 is exposed.

  On the other hand, the amount of water evaporation after one season (one year) in normal use is known to be about 0.6 L by experiment, and 1.7 L of water evaporates when calculated from this. Will take at least about two seasons (two years) or more.

  In such a state, the water electrode 13 is exposed to the air and the current flowing through the water electrode determination circuit 20 does not flow, and the determination circuit detects this. When this is detected, the information is first sent from the control unit 23 to the remote control circuit 24, and a "water supply notice display" as shown in FIG. 6 is performed on the display unit of the remote control.

  At this time, considering the convenience of the user, the heating operation is not stopped, only the display is performed, and the supply of circulating water is requested. At this point, about 0.3 L of water still remains in the water tank, and there is no urgency to stop the operation immediately. Further, since 0.3L corresponds to the amount of evaporation for half a year, during that time, sufficient time may be taken to appeal the “water supply notice” to the user.

  In fact, in this embodiment, when the user has not yet supplied water, the “water supply notice” can be temporarily turned off by pressing the “OK” button on the remote control 28 in FIG. 2, and the normal heating operation is continued. it can. In this embodiment, when the “water supply notice” is turned off without “water supply”, the “water supply notice” is displayed again at the start of operation on the next day.

  In this way, consideration is given to allowing the user to perform “water supply” while repeating the “water supply notice” every day.

  However, if “water supply” is not repeated even after repeated “water supply notice”, this state is counted by the control unit 23, and when 7 days have passed, this time, the remote controller “water supply” as shown in FIG. Warning display "is performed to stop the heating operation.

  The above is the operation when the circulating water is normally evaporated and reduced.

  Next, the operation when there is some abnormality in the equipment and the circulating water is suddenly lost due to water leakage or the like will be described.

First, the circulating water decreases, and the water electrode 13 is exposed to the air, and this is detected. At this time, similarly to the decrease due to evaporation, the operation of the heating operation is continued without stopping the operation of the heating operation and displaying the “water supply notice” on the remote controller. After that, even if there is no normal water supply by the user, 7
The operation continues by repeating the “water supply notice” for a day, but if the cause of the decrease in the circulating water is due to water leakage, there will be a situation where the circulating water is completely lost during this period.

  In such a case, the idling state is entered despite the circulation pump 8 being driven. In idling operation, it is known that the rotational speed of the pump increases rapidly because the load on the pump becomes extremely light.

  Therefore, if the number of revolutions detected by the circulation pump rotation detection circuit 22 rises above a predetermined threshold value in the “water supply notice” state, the heating operation is stopped as “circulated water has run out”. The circulation pump rotational speed abnormality is displayed on the remote controller 28. FIG. 8 shows the display contents of the remote control at that time. Further, the rotational speed abnormality determination of the circulation pump 8 is performed at 5000 rpm.

  In order to detect the idling of the circulation pump 8 more reliably, it is effective to stop the “rotational speed feedback” that is normally performed and set the drive signal output from the circulation pump drive circuit 21 to a fixed value. It is. For this reason, a method is described in which the drive signal is changed to a fixed value after the “water supply notice” is detected.

(Embodiment 2)
FIG. 9 is a control block diagram according to the second embodiment of this invention. Here, a bias circuit 25 is provided before the water electrode determination circuit 20. This function is to limit the timing at which the determination is made by biasing the water electrode 13.

  As described above, in order to determine the presence / absence of circulating water with the water electrode 13, it is necessary to pass a current through the circulating water and determine the value thereof, in which case hydrogen gas is generated by electrolysis of the circulating water. To do. From the viewpoint of safety, we want to keep the amount of hydrogen gas generated as small as possible.

  At the same time, the water electrode 13 deteriorates in proportion to the detection time. In order to suppress these risks as much as possible, the operation mode in which detection is performed by the bias circuit 25 is limited. In the present embodiment, the bias circuit 25 is turned on only when the heating operation is stopped. Thus, at least the bias application time can be made half or less of the energization time.

(Embodiment 3)
FIG. 10 is a control block diagram according to the third embodiment of this invention. Here, a scan circuit 26 is provided in front of the water electrode determination circuit 20. This function is to change the voltage applied to the water electrode 13 to an intermittent voltage and further suppress the generation amount of hydrogen gas and the progress of deterioration of the water electrode 13.

  An actual scan signal timing chart is shown in FIG. As can be seen from the figure, the water electrode 13 is biased for a period of 150 us in 120 ms. By doing so, the bias application time can be reduced to 1/800 of the normal time.

  As described above, the hot water heater of the present invention has a single water electrode circuit, and when the circulating water for heating decreases, performs a notification for prompting “water supply” to the user for a certain period of time. When the water is not supplied, the operation can be performed in two stages, such as stopping the operation and issuing a “warning”, so that the present invention can be applied to a domestic or commercial hot water heater.

DESCRIPTION OF SYMBOLS 1 Water refrigerant heat exchanger 2 Compressor 3 Expansion valve 4 Air heat exchanger 5 Blower 6 Return header 7 Water tank 8 Circulation pump 9 Outflow header 10a-d Thermal valve 11 Inlet temperature sensor 12 Hot water temperature sensor 13 Water electrode 14 Back surface Box 15 Connection box 16 Cap 17 Filter 18 Water supply port 19 Water outlet 20 Water electrode determination circuit 21 Circulation pump drive circuit 22 Circulation pump rotation detection circuit 23 Control unit 24 Remote control circuit 25 Bias circuit 26 Scan circuit 27a, b Floor heating panel 28 Remote control

Claims (2)

A circulating pump that circulates hot water heated by a heat exchanger via a circulation pipe connected to each heating terminal, a water tank disposed in the circulation pipe, and a water storage state in the water tank are detected. Until the water electrode detects that there is no water in the water tank, and sends a drive signal to the circulation pump so that the rotation speed of the circulation pump becomes the target rotation speed. The predetermined time after the water electrode detects that there is no water in the water tank is notified to the user and the drive signal to the circulation pump is fixed, and the predetermined time has passed. In the case, or when the rotational speed of the circulating pump rises to a predetermined value or more within the predetermined time, the hot water heater is stopped. The hot water heater according to claim 1, wherein the water electrode is intermittently energized.