JP2932160B2 - Hot water level measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the remaining amount of hot water in a bathtub, which is used in a heating and circulating system of a bath water heater having a function of automatically filling a bathtub with a set amount of hot water.

[0002]

2. Description of the Related Art A hot water mat which circulates hot water heated by a heat source as a heat medium, heats hot water in a bathtub through a liquid-liquid type bath heat exchanger, or arranges the hot water under the floor. There is a heating circulation system that heats the floor and heats the floor. On the other hand, when the bath is automatically filled with the set amount of hot water, if there is hot water remaining in the bath, it is necessary to supply the bath with a difference in the amount of hot water from the set hot water amount minus the remaining amount of hot water.
For that purpose, the remaining amount of hot water in the bathtub must be measured. When measuring the remaining amount of hot water, if the amount of heat transferred to the hot water remaining in the bath tub via the bath heat exchanger is constant, the temperature change of the hot water in the upstream part of the bath heat exchanger The remaining amount of hot water can be obtained from the temperature rising speed of hot water obtained by detecting the temperature. However, if a portion of the hot water, which is the heat medium, is also used for floor heating, the amount of hot water circulated through the bath heat exchanger as the heat medium will decrease, and the amount of heat transferred to the hot water will not be constant. The quantity cannot be measured.

[0003]

If the circulating flow rate of hot water to the bath heat exchanger is known, the point in time is determined from the circulating flow rate and the temperature difference between the upstream and downstream temperatures of the bath heat exchanger. The amount of heat transmitted to the hot and cold water at the time can be determined. However, since dust and the like are mixed in the hot and cold water in the bathtub, a mechanical flow sensor such as a water wheel cannot be provided in the circulation path. Therefore, there is no circulation of hot water to heat exchangers such as hot water mats other than the bath heat exchanger, and in a state where all hot water is circulated to the bath heat exchanger, the heat value of the heat source and the efficiency of the heat exchanger Then, the amount of heat transferred to the hot water in the bath tub via the bath heat exchanger is determined, and the circulation flow rate of the hot water is measured based on the temperature rise caused by passing through the bath heat exchanger.

However, as described above, the circulation flow rate cannot be obtained unless all the hot water is circulated through the bath heat exchanger. Therefore, if the operation of the hot water mat or the like cannot be performed immediately after the installation of the equipment and the reheating of the bath cannot be performed alone, the circulation flow rate cannot be obtained until the single operation is performed, and the bathtub is filled with water. A problem arises in that the amount of hot water to be supplied to the bathtub cannot be determined even if it is attempted.

In addition, even if the circulation flow rate is measured once, it may change due to fluctuations in the power supplied to the circulation pump, etc.
Therefore, it is necessary to periodically measure the circulation flow rate and update the circulation flow rate to the latest data. However, if used for many years, the efficiency of the heat exchanger will decrease due to the adhesion of scale and oxidation of the heat exchanger surface, etc., and in order to keep the temperature of hot water as a heat medium constant, it will be the basis for determining the circulation flow rate The calorific value of the heat source must be increased, and the measured circulation flow rate exceeds the actual circulation flow rate. Then, since the remaining amount of hot water in the bathtub is estimated to be larger than the actual remaining amount, there is a problem in that the amount of hot water is not enough even when the hot water is added.

In view of the above problems, the present invention measures the remaining amount of hot water in the bathtub normally even in the initial state where the circulation flow rate has not yet been obtained, or in the state where the efficiency of the heat exchanger is reduced. The purpose is to provide a way to obtain.

[0007]

In order to achieve the above object, the present invention provides a liquid-liquid type one of a plurality of heat exchangers in which a heat medium heated by a heat source is distributed and circulated. Hot and cold water in the bathtub circulated through the circulation path to the bath heat exchanger,
A method for measuring the remaining amount of hot water in a bathtub by detecting the temperature at the upstream and downstream portions of the bath heat exchanger, wherein the heat medium is circulated through the bath heat exchanger, Calculate and store the circulating flow rate from the amount of heat transmitted to the hot and cold water through the bath heat exchanger and the temperature difference between the upstream and downstream portions of the bath heat exchanger, and separately set the circulating flow rate in advance. Every
The amount of heat transferred to the hot water at the measurement time and the upstream portion of the heat exchanger obtained from either one of the two circulation flow rates and the temperature difference between the upstream and downstream portions of the bath heat exchanger at the measurement time The remaining amount of hot water in the bathtub is measured from the temperature change of hot water.

The circulating flow rate is set in advance separately from the circulating flow rate obtained by the calculation. If the circulating flow rate has not yet been calculated in the initial state, or if the circulating flow rate calculated due to aging is larger than the predetermined flow rate. In this case, the remaining amount of hot and cold water in the bathtub is determined based on a preset circulation flow rate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 denotes a bathtub, in which hot and cold water 11 is provided.
Is stretched. The hot and cold water 11 is heated by the burner 2 as a heat source. The water circulated by the heat medium pump 31 is used as a heat medium, and the heat medium is heated by the gas-liquid type heat exchanger 21. To a liquid-liquid type heat exchanger 3 which is a bath heat exchanger. On the other hand, the hot and cold water 11 in the bathtub 1 is configured to circulate in the heat exchanger 3 by the circulation pump 4. The inlet and outlet temperatures of the hot and cold water 11 circulated through the heat exchanger 3 are detected by temperature sensors 41 and 42, respectively. By the way, the heat medium is supplied to the heat exchanger 3 and not only heats the hot water 11 in the bathtub 1 but also branches into a hot water mat 5 for floor heating in the middle of the circulation path and is used for indoor heating. Turning on and off the heating by the hot water mat 5 is performed by an on-off valve 51.
When the valve is opened, the heat medium circulates in the hot water mat 5 to heat the room, and when the on-off valve 51 is closed, the circulation of the heat medium into the hot water mat 5 is stopped. In addition, a hot water filling mechanism 6 is provided between the temperature sensor 42 and the bathtub 1 through an opening / closing valve 61.
When the opening / closing valve 61 is opened, hot water heated by the hot water filling mechanism 6 is supplied to the bathtub 1 and the bathtub 1 is automatically filled with the set hot water.

In the above-mentioned configuration, when the hot water filling mechanism 6 is used to automatically fill the hot water, the hot water filling mechanism 6 determines how much hot water is to be added to the bathtub 1. It is necessary to know how much hot and cold water 11 remains. Incidentally, the amount of heat transmitted to the hot and cold water 11 via the heat exchanger 3 varies depending on the amount of the heat medium branched to the hot water mat 5. For this reason, the circulation flow rate of the hot and cold water 11 described later is measured in a state in which the on-off valve 51 is closed and the heat medium is entirely circulated to the heat exchanger 3, that is, in a state in which the bath is in a reheating operation alone.

Assuming that the amount of heat transmitted to the hot and cold water 11 through the heat exchanger 3 is Q (Kcal / min), Q is the burner 2
From the calorific value Q ₀ (Kcal / min), the efficiency μa of the heat exchanger 21 and the efficiency μb of the heat exchanger 3 by the equation (1).

Q = μa · μb · Q ₀ = μ · Q ₀ (1) (where μ = μa · μb) When Q is obtained in this way, the temperature sensors 4
Based on the detected temperature difference Δt (° C.) of 1.42, the circulation flow rate q (l
/ Min) is determined by the following equation (2). Here, c is the specific heat of the hot water 11 (Kcal / l · ° C.).

Q = Q / (Δt · c) (2) When the heat medium is circulated to the hot water mat 5, the heat quantity Q _{X that} is actually transmitted to the hot and cold water 11 via the heat exchanger 3 is Q Less. Therefore the Q _X by using the circulation flow rate q and the detected temperature difference Delta] t _X of both temperature sensors 41 and 42 at this time (3)
It is obtained by the formula.

Q _X = c · q · Δt _X (3) Next, hot water 1 in the bathtub detected by the temperature sensor 41
Assuming that the temperature rise rate of 1 is Vt (° C./min), the remaining amount W (l (liter)) of the hot and cold water 11 is obtained by the equation (4).

From Q _X = W · Vt W = Q _X / Vt (4) The temperature of the hot and cold water in the bathtub 1 is detected by the temperature sensor 41 provided on the upstream side of the heat exchanger 3 as described above. Therefore, it is not necessary to provide a separate temperature sensor in the bathtub 1.

Incidentally, the remaining amount W has to be obtained when the bath is operated alone as described above. However, when the hot water mat is operated after the installation of the appliance and the bath reheating operation cannot be performed alone, In addition, the circulation flow rate cannot be obtained until the single operation is performed. Therefore, when filling with hot water in such a state, a preset circulation flow rate q _A
Is used to calculate the above equation (3). The circulation flow q _A
Is set to a substantially maximum value within the variation range in consideration of the variation in the actual circulation flow rate due to the difference in the piping condition and the like. When operation using q _A, the remaining amount of the hot water 11 from (3) Q _X becomes larger than the actual value from the formula (4) is calculated is more than the actual remaining capacity. Therefore, the detected remaining amount is always larger than the actual remaining amount under any setting condition, and the hot water 11 does not overflow from the bathtub 1 even if the hot water is added based on the remaining amount.

On the other hand, if the heat exchanger 21 has been used for a long time, the surface of the heat exchanger 21 is oxidized and the efficiency μa is reduced.
In the case where the temperature of the heat medium on the downstream side is detected by a temperature sensor and the amount of gas supply to the burner 2 is controlled so that the detected temperature becomes a constant temperature, the calorific value Q ₀ of the burner 2 must be increased. No. Therefore, the calculated heat quantity Q is equal to the heat exchanger 2
1 becomes larger than the calorific value Q in the normal case, and the circulating flow rate q obtained from the equation (2) becomes larger than the actual value. Then, (3) increasingly heat Q _X obtained from the equation, finally (4) the remaining W obtained by expression is greater than the actual remaining capacity. As described above, when the hot water is added based on the calculation result in which the remaining amount W is larger than the actual remaining amount, the amount of the hot water 11 becomes considerably smaller than the set hot water amount. Therefore, if the amount of hot water is significantly different from the set hot water amount even after the addition of hot water, a predetermined value is selected as the circulating flow rate by selecting means such as a switch, and the remaining amount W is determined using the value. If the determined value is set to a substantially intermediate value within the variation range, a large error does not occur under any installation conditions.

In the above embodiment, a burner is used as a heat source. However, another type such as an electric heater may be used as a heat source.

[0019]

As is clear from the above description, according to the present invention, the remaining amount of hot water in the bathtub can always be known.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bathtub 2 Burner 3 Heat exchanger (liquid-liquid type) 4 Circulation pump 5 Hot water mat 6 Filling mechanism 11 Hot water 41 Temperature sensor 42 Temperature sensor

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroyuki Yamada 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi, Aichi Rinnai Co., Ltd. (56) References JP-A-3-13758 (JP, A) JP-A-3 −204557 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F24H 1/00 602

Claims (3)

(57) [Claims] 1. A heat medium heated by a heat source is circulated through a circulation path to a liquid-liquid type bath heat exchanger which is one of a plurality of heat exchangers distributed and circulated. A method for measuring the remaining amount of hot and cold water in a bathtub by detecting the temperatures of the hot and cold water in the bathtub and the upstream and downstream portions of the bath heat exchanger. In the circulated state, the circulating flow rate is calculated and stored from the amount of heat transmitted to the hot water through the bath heat exchanger and the temperature difference between the upstream and downstream portions of the bath heat exchanger and separately circulated. The flow rate is set in advance, and is transmitted to the hot and cold water at the measurement time obtained from one of the two circulation flow rates and the temperature difference between the upstream and downstream portions of the bath heat exchanger at the measurement time. The feature is to measure the remaining amount of hot water in the bathtub from the amount of heat and the temperature change of hot water in the upstream part of the heat exchanger Hot water remaining amount measurement method. 2. The hot water remaining amount measuring method according to claim 1, wherein the remaining amount of hot water is measured using a preset circulating flow rate when the circulating flow rate obtained by the calculation is not stored. . 3. The method according to claim 1, wherein the circulation flow rate obtained by the calculation and the preset circulation flow rate are selectable, and the remaining amount of the hot water is measured using the selected circulation flow rate. Hot water remaining amount measurement method.