JP4527647B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply apparatus that performs hot water filling of a bathtub or hot water supply using hot water stored in a hot water storage tank.

Conventionally, in this type, hot water and hot water in the hot water storage tank are mixed with a mixing valve to supply hot water at a set temperature, and the hot water boundary layer in the hot water storage tank after hot water supply is stopped is lower than the mixing valve and mixing If the valve keeps the hot water side and the water side in communication, the hot water in the hot water storage tank will cause direct convection in an attempt to balance and flow into the water supply bypass pipe, causing the hot water temperature to fluctuate greatly during reheating. Therefore, it was intended to prevent this by providing a mixing tank in the water supply bypass pipe. (For example, refer to Patent Document 1.)
Japanese Patent Laid-Open No. 2003-4303

  By the way, in this conventional one, how much hot water temperature is mixed in the feed water bypass pipe, how much hot water temperature is reached, whether it has already cooled down over time, or mixing of hot water has not started yet, It was completely unknown and accurate and good mixing control was not possible.

The present invention pays attention to this point and solves the above-mentioned drawbacks. In particular, the structure is provided in a hot water storage tank for storing hot water heated by heating means, a water supply pipe for supplying water to the hot water storage tank, and an upper portion of the hot water storage tank. It consists of a hot water pipe that taps hot water and a mixing valve that mixes hot water at the tip of the hot water pipe and water from a feed water bypass pipe branched from the feed water pipe to supply hot water at a set temperature. and at what, in response to said remaining hot water position of the hot water in the hot water storage tank, intended to adjust the communication state of the water supply bypass pipe and hot water pipe by mixing valve at the hot water supply is stopped, as the remaining hot water position is higher The hot water outlet side opening is widened .

  According to the present invention, when the hot water is stopped, the downstream convection that causes high temperature water from the hot water storage tank to the hot water supply bypass pipe varies depending on the remaining hot water position in the hot water storage tank. Regardless of the amount of remaining hot water in the hot water storage tank, the same amount of hot water is always held in the water supply bypass pipe, which may cause burns during re-heating, overshoot, There is no undershoot, and a good hot water supply can always be performed regardless of the amount of hot water in the hot water storage tank.

Next, an embodiment of the present invention will be described with reference to the drawings.
1 is a cylindrical hot water storage tank, which uses heating means 2 comprising a heat-pump outdoor unit to boil hot water in the midnight hours when the unit price of contract power by time is low and store hot water at the bottom. A water supply pipe 3 for supplying water is connected, and a hot water discharge pipe 4 for discharging hot water stored in a hot water tap (not shown) or the like is connected to the upper part.

  5 is a mixing valve comprising an electric three-way valve connected to a hot water supply pipe 4 on one side, a water supply bypass pipe 6 branched from the water supply pipe 3 on the other side, and a hot water supply pipe 7 on the center. It is a mixing valve that mixes the feed water from the feed water bypass pipe 6 and feeds it at a set hot water supply temperature. From the hot water temperature, the feed water temperature, and the set temperature, the opening degree of the hot water pipe 4 and the feed water bypass pipe The feed-forward control is performed to adjust the opening of 6, and the mounting position is preferably as close as possible to the upper end of the hot water storage tank 1 in consideration of the heat dissipation loss from the hot water discharge pipe 4, and thus is opposed to the upper part of the hot water storage tank 1. Provided in position.

  A temperature sensor 8 is also provided in the water supply bypass pipe 6 and serves as a water supply thermistor for detecting the temperature of the water supply. When supplying hot water, the temperature sensor 8 detects the temperature of the water supply and adjusts the opening of the mixing valve 5. When the hot water boundary layer serving as a boundary between hot water and water supply is located below the mixing valve 5, hot water supply is stopped and the mixing valve 5 is opened to the degree that the outlet pipe 4 and the water supply bypass pipe 6 communicate with each other. When the high-temperature water in 1 causes downflow convection to flow into the water supply bypass pipe 6, this mixed water temperature is detected, and the water supply bypass pipe 6 side that is the water side at a predetermined temperature or higher is 100%. The mixing valve 5 is driven in an open state, and thereafter, the mixing valve 5 is controlled by the above feedforward control.

Reference numeral 9 denotes a circulation circuit including an outward pipe 10, a return pipe 11, and a circulation pump 12 that connect the hot water storage tank 1 and the heating means 2 so that hot water can be circulated.
Reference numerals 13, 14, 15, and 16 are hot water storage temperature sensors provided above and below the outer peripheral surface of the hot water storage tank 1, 17 is a pressure reducing valve provided in the middle of the water supply pipe 3, and 18 is a pressure provided in the hot water discharge pipe 4. It is a relief valve.

  Reference numeral 19 denotes a control circuit comprising a microcomputer. On the input side, a temperature setting unit 20 of a remote controller (not shown) and a hot water storage temperature sensor 13 at the uppermost position are connected as a hot water temperature sensor, and a temperature sensor 8 is a feed water temperature sensor. And a flow sensor 21 which is connected to the hot water supply pipe 7 and detects the start / stop of hot water supply by detecting the flow of hot water, and is connected to the output side as a step motor of the mixing valve 5. The opening of the mixing valve 5 is adjusted by controlling the driving amount.

  By inputting the detected temperature of the hot water storage tank 1 from the hot water storage temperature sensors 13, 14, 15 and 16 to the control circuit 19, the remaining hot water amount and the remaining hot water amount temperature are calculated and used for various controls, and the remaining hot water amount position is set. Estimate and adjust the opening of the mixing valve 5 on the side of the hot water pipe 4 when the hot water supply is stopped, that is, when the amount of remaining hot water is large and the hot water boundary layer is lower than the mixing valve 5, the downstream convection becomes faster. The 4 side is narrowed to slow down the convection velocity. When the amount of remaining hot water is small and the hot water boundary layer is higher than the mixing valve 5, the convection is slowed down. Thus, the temperature and amount of hot water stored in the water supply bypass pipe 6 when the hot water supply is stopped are made constant by making the downstream convection speed constant regardless of the amount of remaining hot water.

Next, the operation of this embodiment will be described.
If the hot water supply is opened and the hot water supply is started, this is detected by the flow sensor 21, and the control circuit 19 reads the temperature set by the temperature setting unit 20, and the hot water temperature by the temperature sensor 8 and the hot water output by the hot water storage temperature sensor 13 are read. The control circuit 19 calculates the opening degree of the mixing valve 5 according to the temperature, drives the mixing valve 5 to reach this opening degree, and supplies hot water at a set temperature.

  When the hot water boundary layer in the hot water storage tank 1 is below the mixing valve 5, the hot water supply is stopped and the mixing valve 5 is set to an opening degree where the hot water discharge pipe 4 and the water supply bypass pipe 6 communicate with each other. By estimating the remaining hot water amount position based on the temperature detected by the hot water storage temperature sensors 13, 14, and 15 and saying that it is below the mixing valve 5, the opening of the mixing valve 5 on the side of the hot water discharge pipe 4 is made narrower. However, the temperature sensor 8 provided in the water supply bypass pipe 6 detects the mixing temperature of the high-temperature water at this time. .

  When the mixing temperature is detected to reach a predetermined temperature, 55 ° C., the control circuit 19 adjusts the opening degree of the mixing valve 5 so that the feed water bypass pipe 6 side is 100% open and the outlet pipe 4 side is closed. Therefore, when the hot water supply is resumed, the temperature detected by the temperature sensor 8, the tapping temperature of the hot water storage temperature sensor 13, the set temperature, and the like. Then, the opening degree of the mixing valve 5 is determined and adjusted by feedforward control.

  Next, when the amount of remaining hot water is small and the hot water boundary layer in the hot water storage tank 1 is above the mixing valve 5, the hot water supply is stopped and the mixing valve 5 is set to an opening degree at which the outlet pipe 4 and the water supply bypass pipe 6 communicate with each other. The control circuit 19 estimates the remaining hot water amount position based on the temperature detected by the hot water storage temperature sensors 13, 14, 15, 16, and says that it is above the mixing valve 5, thereby opening the outlet pipe 4 side of the mixing valve 5 wider. As described above, the hot water in the hot water storage tank 1 makes the slow downstream convection to be balanced quickly and flows into the water supply bypass pipe 6. At this time, the temperature sensor 8 provided in the water supply bypass pipe 6 Detect the mixing temperature.

  When the mixing temperature is detected to reach a predetermined temperature, 55 ° C., the control circuit 19 adjusts the opening degree of the mixing valve 5 so that the feed water bypass pipe 6 side is 100% open and the outlet pipe 4 side is closed. Therefore, when the hot water supply is resumed, the temperature detected by the temperature sensor 8, the tapping temperature of the hot water storage temperature sensor 13, the set temperature, and the like. Then, the opening degree of the mixing valve 5 is determined and adjusted by feedforward control.

  Therefore, the flow down convection, which is the cause of high temperature water mixing from the hot water storage tank to the water supply bypass pipe when hot water is stopped, varies depending on the position of the remaining hot water in the hot water storage tank. Regardless of the amount of remaining hot water in the hot water storage tank, the same amount of hot water is always retained in the water supply bypass pipe, and there is no concern about burns during re-heating, overshoot or undershoot. The hot water supply is always good regardless of the amount of hot water in the hot water storage tank.

Also, the mixing position of the mixing valve 5 when hot water is stopped is controlled to the optimum position by detecting the mixing temperature of the hot water, so there is no risk of burns, overshooting or undershooting during hot water supply. The hot water supply is always good regardless of the hot water boundary layer.
If the temperature sensor 8 is also used as a water supply thermistor that is originally used, the structure can be easily formed without increasing the number of parts, and it can be provided at a very low cost.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing of the hot water storage type hot water supply apparatus which shows one Embodiment of this invention. The block diagram of the principal part electric circuit. The operation state explanatory view in case the amount of remaining hot water of the mixing valve is large. The operation state explanatory view in case the amount of remaining hot water of the mixing valve is small.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Heating means 3 Water supply pipe 4 Hot water discharge pipe 5 Mixing valve 6 Water supply bypass pipe 8 Temperature sensor 13, 14, 15, 16 Hot water storage temperature sensor 19 Control circuit

Claims (1)

A hot water storage tank for storing hot water heated by the heating means, a water supply pipe for supplying water to the hot water storage tank, a hot water discharge pipe for discharging hot water connected to the upper part of the hot water storage tank, and hot water at the tip of the hot water supply pipe A mixing valve that mixes the water supplied from the water supply bypass pipe branched from the water supply pipe and supplies hot water at a set temperature, depending on the position of the remaining hot water in the hot water storage tank. The hot water storage type hot water supply , which adjusts the state of communication between the hot water pipe and the hot water bypass pipe by the mixing valve when hot water is stopped. The higher the remaining hot water position, the wider the opening of the hot water pipe. apparatus.

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