JP4249676B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply device such as a heat pump water heater or an electric water heater.

Conventionally, in this type, a hot water storage tank is installed under the floor, a piping control unit with a mixing valve is installed in a remote location, and a hot water storage temperature sensor attached to the hot water storage tank is used. The mixing ratio of the mixing valve was controlled by the temperature.
(For example, refer to Patent Document 1.)
Japanese Patent Application No. 2003-84213

  By the way, in this conventional type, since the hot water storage temperature sensor attached to the hot water storage tank and the mixing valve controlled by this detected temperature are separated and the piping is long, the hot water temperature detected by the hot water storage temperature sensor at the beginning of hot water supply is Instead, hot water with reduced temperature in the piping is supplied, hot water supply greatly undershoots against the set temperature, and then hot water in the hot water storage tank is supplied, causing overshoot due to a sudden rise in temperature. Also, there was a risk of burns.

The present invention for solving the above problem by focusing on this point, in particular its configuration, the hot water storage tank inlet water pipe and hot water pipe to the hot water storage hot water is connected, a heating means for heating the hot water in the hot water storage tank, the Hot water storage temperature that detects the temperature of hot water in the hot water storage tank in which high temperature water from the hot water pipe and water supply from the water inlet pipe are mixed and a mixing valve that supplies hot water at a set temperature is installed separately. A hot water temperature sensor is provided in the hot water pipe in the vicinity of the mixing valve, and a hot water supply set temperature and a water temperature are set until the temperature difference between the temperature detected by the hot water storage temperature sensor and the temperature detected by the hot water temperature sensor becomes a predetermined temperature or less. feedforward control the mixing ratio of the mixing valve temperature and the hot water temperature sensor of detecting temperature, hot water temperature sensor the temperature difference with the hot water supply pipe reaches below a predetermined temperature, feeding It is for feedback controlling the mixing ratio of the mixing valve so that the set temperature.

According to this invention, when the temperature difference between the hot water temperature in the hot water storage tank and the hot water temperature in the vicinity of the mixing valve becomes equal to or lower than the predetermined temperature, the feed valve is finely controlled, and when the temperature difference reaches the predetermined temperature or lower. The hot water temperature sensor provided in the hot water supply pipe controls the mixing ratio of the mixing valve so that it reaches the set hot water temperature, so there is no concern about undershoot or overshoot, and good hot water can be supplied from the start of hot water supply. Selfish.

Next, an embodiment of the present invention will be described with reference to the drawings.
Reference numeral 1 is a horizontal storage type hot water storage tank unit installed under the floor of the building, 2 is a heating means comprising a heat pump unit, and 3 is a piping unit connecting the hot water storage tank unit 1 and the heating means 2.

The hot water storage tank unit 1 is connected to a horizontally long hot water storage tank 4 for storing hot water, a hot water discharge pipe 5 connected to the upper surface of the hot water storage tank 4 and a return pipe 6 from the heating means 2, and a lower part of the hot water storage tank 4. A water inlet pipe 7 and an outgoing pipe 8 toward the heating means 2 are connected to each other, and a cylindrical water supply auxiliary pipe 9 that communicates with the water inlet pipe 7 and supplies water is provided in the longitudinal direction in the center of the hot water storage tank 4. It extends and is supported by two support legs 10, and the end portion is closed.
A hot water storage temperature sensor 11 for detecting the temperature of the hot water in the hot water storage tank 4 is provided on the outer periphery of the hot water storage tank 4.

  Furthermore, a plurality of water supply holes 12 are provided on the upper side of the water supply auxiliary pipe 9 at equal intervals, and a cross section is provided above the water supply auxiliary pipe 9 facing the water supply hole 12 toward the water supply auxiliary pipe 9. An arc-shaped direction changing means 13 is provided, and the water discharged upward from the water supply hole 12 is once flowed downward and then directed upward. The auxiliary pipe 9 is equal to or larger than the water supply auxiliary pipe 9, and the distance between the hot water storage tank 4 varies depending on the height of the hot water storage tank 4, but is optimal within 20 cm.

  The heating means 2 includes a compressor 14 for compressing refrigerant, a refrigerant-water heat exchanger 15 as a condenser, a decompressor 16, a heat pump circuit 18 including an air heat exchanger 17 as an evaporator, and air heat. A blower 19 that blows air to the exchanger 17, a capacity variable circulation pump 21 provided in the middle of the circulation circuit 20 including the return pipe 6 and the forward pipe 8, and the refrigerant-water heat exchanger 15 inlet side of the circulation circuit 20. A heat exchange inlet temperature sensor 22 for detecting the temperature of the hot water flowing into the refrigerant-water heat exchanger 15 and a refrigerant-water heat exchanger 15 outlet side of the circulation circuit 20; A heat exchange outlet temperature sensor 23 that detects the temperature of hot water flowing out from 15 and a heating controller 24 that controls the heating means 2 are provided.

  The piping unit 3 includes a mixing valve 26 that is driven by a stepping motor (not shown) that mixes high-temperature water from the outlet pipe 5 and low-temperature water from the branch pipe 25 branched from the inlet pipe 7, and the outlet pipe 5. A hot water temperature sensor 27 that detects a hot water temperature immediately before flowing through the mixing valve 26 provided in the middle, a hot water supply pipe 29 having a hot water tap 28 connected downstream of the mixing valve 26, and a hot water supply provided in the hot water supply pipe 29. A temperature sensor 30, a hot water flow rate sensor 31 provided in the hot water supply pipe 29, a hot water pipe 34 branched from the hot water supply pipe 29 and connected to the circulation circuit 33 of the bathtub 32, and the temperature of the bathtub water is maintained in the circulation circuit 33. A heat retention heater 35 and a bath circulation pump 36, a pressure reducing valve 37 for the inlet pipe 7, a water supply temperature sensor 38 and a pressure relief valve 39 for the hot water outlet pipe 5, and a hot water supply control unit 40 for controlling these functional components. The piping and functional parts are concentrated on the piping unit 3 so that the piping work at the time of installation and the maintenance work after the installation can be performed easily and efficiently. This is particularly effective when installed under the floor of a building.

Next, the operation of the embodiment of the present invention will be described.
First, when heating the hot water in the hot water storage tank 4, the heating control unit 24 activates the heat pump circuit 18 and starts driving the circulation pump 21 of the circulation circuit 20. Then, the hot water taken out from the lower part of the hot water storage tank 4 by driving the circulation pump 21 flows into the refrigerant-water heat exchanger 15 of the heating means 2 and is heated, and is returned to the upper part of the hot water storage tank 4 through the circulation circuit 20. As a result, hot water is stored.

  Here, depending on the detected values of the heat exchange inlet temperature sensor 22 and the heat exchange outlet temperature sensor 23, the output of the heat pump circuit 18 and the capacity of the circulation pump 21 are adjusted as appropriate so that the hot water to be heated reaches a predetermined high temperature. It is variable.

  When the hot water storage temperature sensor 11 provided on the side surface of the hot water storage tank 4 detects that a predetermined amount of hot water has been stored, or when the heat exchange inlet temperature sensor 22 detects a predetermined temperature or higher, the hot water supply control is performed. The unit 40 commands the heating control unit 24 to stop the heating operation, and the operations of the heat pump circuit 18 and the circulation pump 21 are stopped.

On the other hand, the hot water stored in the hot water storage tank 4 is controlled by the hot water supply control unit 40 when the hot water tap 28 is opened, and the hot water in the upper part of the hot water storage tank 4 is pushed out to the hot water discharge pipe 5 by the pressure from the inlet pipe 7. The mixing valve 26 mixes the low-temperature water in the branch pipe 25 and the temperature detected by the hot water supply temperature sensor 30 so as to reach a predetermined temperature, and supplies hot water through the hot water supply pipe 29. Is calculated as H = (Th−T1) / (T4−T1),
Th: Hot water supply set temperature
T1: Feed water temperature by feed water temperature sensor 38
T4: Hot water temperature by the hot water temperature sensor 27 and the mixing valve 26 are controlled so that the mixing ratio H is obtained. The hot water temperature T3 in the hot water storage tank 4 detected by the hot water temperature sensor 11 and the hot water temperature sensor The feedforward control is calculated according to the above equation until the temperature difference from the tapping temperature T4 due to 27 falls within a predetermined temperature, here 10 ° C. or less, and the mixing valve 26 is controlled at any time according to this result to 10 ° C. or less. When the temperature reaches, the feedback control is performed to control the mixing ratio H of the mixing valve 26 so that the hot water temperature T2 detected by the hot water temperature sensor 30 on the downstream side of the mixing valve 26 becomes the hot water set temperature Th.

  In addition to this control, feedback control according to the above formula is performed only once at the start of hot water supply, and thereafter the hot water temperature T3 in the hot water storage tank 4 detected by the hot water temperature sensor 11 and the hot water temperature T4 by the hot water temperature sensor 27 are detected. Until the temperature difference is within a predetermined temperature, here 10 ° C. or less, the detected hot water temperature T2 by the hot water temperature sensor 30 is increased in speed of feed forward control for controlling the mixing valve 26 so as to become the hot water supply set temperature Th, When the temperature difference reaches within the predetermined temperature, the control is returned to the original control speed.

  Accordingly, when the hot water storage tank 4 and the piping unit 3 including the mixing valve 26 are separated by these controls and the piping becomes long, the hot water temperature in the hot water storage tank and the hot water temperature in the vicinity of the mixing valve are increased. Since the mixing valve 26 is finely feedback-controlled or feed-forward controlled until the temperature difference from the temperature reaches a predetermined temperature difference, there is no worry of undershoot or overshoot, and good hot water supply can be performed from the start of hot water supply, which is extremely convenient to use. It ’s good.

  Furthermore, in this embodiment, the heat pump type hot water heater has been described. However, the present invention is not limited to this, and an electric water heater using an electric heater as a heating means can provide the same effect.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the hot water storage type hot-water supply apparatus installed under the floor which shows one Embodiment of this invention. The principal part block diagram of the hot-water supply control part.

Explanation of symbols

2 Heating means 4 Hot water storage tank 5 Hot water discharge pipe 7 Water supply pipe 11 Hot water storage temperature sensor 26 Mixing valve 27 Hot water temperature sensor

Claims (1)

A hot water storage tank in which hot water is stored by connecting a water intake pipe and a hot water discharge pipe, heating means for heating the hot water in the hot water storage tank, high temperature water from the hot water discharge pipe, and water supply from the water intake pipe are mixed to obtain a set temperature. A mixing valve that performs hot water supply is provided separately, and includes a hot water storage temperature sensor that detects the hot water temperature in the hot water storage tank, and a hot water pipe near the mixing valve includes a hot water temperature sensor, Until the temperature difference between the temperature detected by the hot water storage temperature sensor and the temperature detected by the hot water temperature sensor falls below a predetermined temperature, the mixing ratio of the mixing valve is feedforward controlled by the hot water set temperature, the hot water temperature, and the detected temperature of the hot water temperature sensor , When the temperature difference reaches a predetermined temperature or less, the hot water temperature sensor provided in the hot water supply pipe feedback controls the mixing ratio of the mixing valve so that the hot water temperature becomes the preset temperature. Hot water storage type water heater, characterized in that that.

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