KR20030005000A - Water heating system - Google Patents

Abstract

PURPOSE: A hot water system is provided to control water temperature of a second hot water line, preventing drain of a first heat exchanger and evaporation of a first hot water line. CONSTITUTION: A hot water system comprises a burner(1), a first hot water line(10), a first heat exchanger(11), a second hot water line(20), a second heat exchanger(21), a controlling member(30). The first heat exchanger raises water temperature of the first hot water line by heat exchange with an exhaust gas of the burner. The second heat exchanger raises water temperature of the second hot water line by heat exchange with the hot water of the first hot water line. The controlling member controls water temperature of the second hot water line by controlling the burning of the burner and the water temperature of the first hot water line. The controlling member stores data about lower limit of water temperature of the second hot water line corresponding to the first hot water line to prevent dewing, and upper limit of water temperature of the second hot water line corresponding to the first hot water line to prevent evaporating.

Description

Hot Water System {WATER HEATING SYSTEM}

The present invention provides a heat exchanger comprising: a first heat exchanger for heating a water in a first hot water furnace by heat exchange between a burner, a first hot water furnace, and a burner exhaust gas, and a hot water; And a second heat exchanger for heating the water in the second hot water furnace by the heat exchanger to control the water temperature in the second hot water furnace by controlling the combustion amount of the burner and controlling the water temperature in the first hot water furnace. Relates to a hot water system.

According to the conventional hot water system, hot water generated by heating through the first heat exchanger by the burner flows through the first hot water path, and heats the water to the second hot water path through the second heat exchanger to form hot water. In addition, in order to obtain hot water at a target temperature in the second hot water furnace, the burn amount of the burner is controlled based on the water temperature in the second hot water furnace. Then, hot water generated in the second hot water path is supplied to the outside.

However, if the difference between the temperature of the water supplied to the second hot water path and the target temperature is small and the flow rate of the second hot water path is small, the water in the first hot water path does not need to be heated in the first heat exchanger, so that the burner The combustion amount of is controlled to be small. Therefore, when the water temperature in the first hot water furnace is low, the temperature of the fin portion of the first heat exchanger does not become a high temperature, so that the water vapor contained in the combustion exhaust of the burner together with the components of the combustion exhaust is applied to the fin portion of the first heat exchanger. Condensation If the condensation and evaporation of condensed water are repeated, the fin portion of the first heat exchanger may be corroded, thereby degrading its heat exchange efficiency. In addition, if the fin portion of the first heat exchanger is blocked, the flow of the combustion exhaust of the burner may be disturbed, so that a good combustion state of the burner may not be maintained.

On the other hand, if the difference between the temperature of the water supplied to the second hot water path and the target temperature is large and the flow rate of the second hot water path is large, it is necessary to greatly heat the water in the first hot water path in the first heat exchanger. Therefore, there is a possibility that the water temperature in the first hot water furnace becomes excessively high, and eventually boils and the water temperature in the second hot water furnace cannot be controlled.

Here, conventionally, when there is a possibility that drainage occurs due to low water temperature in the first hot water furnace, the combustion amount of the burner controlled based on the water temperature in the second hot water furnace as described above is based on the water temperature in the first hot water furnace. The control to prevent the lowering of the temperature of the water to the first hot water furnace is adopted. Moreover, even when there is a possibility that the water temperature in a 1st warm water heater may become high and it may boil, the action which controls the temperature rise of a 1st warm water heater by controlling the combustion amount of a burner based on the water temperature of a 1st warm water heater is also employ | adopted.

However, when the combustion amount control of the burner is switched from the control based on the water temperature of the second hot water furnace to the control based on the water temperature of the first hot water furnace, the combustion amount of the burner changes rapidly, so that the control of the water temperature of the second warm water furnace May become unstable. In addition, since such control is executed after the change in the water temperature of the first hot water furnace is detected, the water temperature of the first hot water furnace decreases until the drain occurs in the first heat exchanger or rises to a boiling point due to time delay or the like. It takes some time to stabilize the water temperature in the second hot water furnace.

The present invention provides a hot water system capable of stably controlling the water temperature in the second hot water furnace while preventing the generation of a drain in the first heat exchanger and the boiling of the water into the first hot water furnace.

1 is an explanatory diagram of a configuration of a hot water system of the present embodiment.

Explanation of symbols on the main parts of the drawings

1-Burner 10-1st hot water furnace

11-First Heat Exchanger 20-Second Hot Water Furnace

21-Second heat exchanger 30-Controller

33-Memory

The hot water system of the present invention for solving the above problems, "the control means is a second corresponding to the water temperature of the first hot water furnace is determined based on the amount of heat transferred from the hot water of the first hot water furnace to the water of the second hot water furnace; The water temperature or flow rate of the second hot water furnace corresponding to the water temperature of the first hot water furnace when condensation in the first heat exchanger of water vapor contained in the combustion exhaust of the burner is prevented as the water temperature or the flow of water of the burner is the lower limit water temperature or And a storage means for storing as the lower limit water flow rate and storing the water temperature or the flow rate of the second warm water furnace corresponding to the water temperature of the first warm water furnace when the boiling of the water to the first warm water passage is prevented as the upper limit water temperature or the upper limit flow rate, The water temperature or flow rate of the second hot water furnace is controlled to be higher than or equal to the lower limit water temperature or the lower limit flow rate stored in the storage means, and the upper limit water temperature or the upper limit stored in the storage means. Controlling to less than one flow rate ".

According to the present invention, the lower limit water temperature / flow rate and the upper limit water temperature / flow rate of the water temperature or flow rate (hereinafter referred to as “water temperature / flow rate”) of the second warm water path stored in the storage means are the second warm water to the second warm water. It is determined based on the amount of heat transferred to the water of the furnace.

Therefore, since the water temperature / flow rate of the second hot water path is controlled to be equal to or higher than the lower limit water temperature / flow rate, the water temperature of the first hot water path is maintained at a high temperature such that drain generation in the first heat exchanger is prevented. It is possible to reliably prevent the occurrence of drains. In addition, since the water temperature / flow rate of the second hot water furnace is controlled to be below the upper limit water temperature / flow rate, the water temperature of the first hot water furnace is controlled at a low temperature such that boiling is prevented, so that boiling of water to the first hot water furnace is prevented reliably. can do. In addition, the water temperature in a 2nd warm water path means the water temperature of a 2nd warm water path downstream of a 2nd heat exchanger.

In the hot water system, the storage means stores the lower limit water temperature and the upper limit water flow rate, and the control means controls the water temperature of the second hot water furnace to be higher than or equal to the lower limit water temperature, and controls the flow rate of the second hot water furnace to be below the upper limit flow rate. It is preferable.

When the water temperature in the second hot water furnace is relatively low, it is unlikely that the user is likely to use a large amount of hot water in the second hot water furnace, that is, preventing drainage of the first heat exchanger due to a large increase in the flow rate of the second hot water furnace. Probability is high. Therefore, by controlling the water temperature of the second hot water path to the lower limit water temperature, it is possible to reliably prevent the occurrence of drain in the first heat exchanger even when the flow rate of the second hot water path is close to the maximum.

On the other hand, when the water temperature in the second hot water furnace is relatively high, the user is likely to feel dissatisfaction due to the likelihood that such high temperature hot water is desired, that is, the drop in the water temperature in the second hot water furnace. Accordingly, by controlling the flow rate of the second hot water path to the upper limit flow rate, it is possible to reliably prevent boiling of the water in the first hot water path even when the temperature of the second hot water path is high.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Embodiment which concerns on the hot water system of this invention is described using drawing. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the structure of the hot water system of this embodiment.

The hot water system of this embodiment shown in FIG. 1 heats the water of the 1st hot water path 10 by the heat exchange with the burner 1, the 1st hot water path 10, and the combustion exhaust of the burner 1, The water in the second hot water path 20 is heated to form hot water by heat exchange between the first heat exchanger 11, the second hot water path 20, and the hot water path of the first hot water path 10. Controller (control means) 30 which controls the water temperature of the second hot water heater 20 by controlling the combustion temperature of the second heat exchanger 21 and the burner 1 to control the water temperature of the first hot water heater 10. Equipped with.

The burner 1 is supplied with gas from the gas supply path 2, the gas is ignited through the spark plug 4 by the igniter 3, and combustion air is supplied by the combustion fan 5. do. The combustion state of the burner 1 is detected through the flame rod 6. The gas supply passage 2 is provided with a main gas solenoid valve 7, a gas proportional valve 8, and a gas solenoid valve 9 sequentially from the upstream side.

The water temperature sensor 12 is installed in the first hot water path 10 downstream of the first heat exchanger 11, and the pump 13 upstream of the first heat exchanger 11 and downstream of the second heat exchanger 21. ) Is installed. Moreover, the 1st hot water path 10 branches downstream of the 1st heat exchanger 11 and upstream of the 2nd heat exchanger 21, and is downstream of the 2nd heat exchanger 21 via the heating apparatus which is not shown in figure. It is connected to the heating hot water furnace 14 joined. The hot water generated in the first heat exchanger 11 is switched to the second heat exchanger 21 or the heating hot water passage 14 at the branched position of the first hot water passage 10 and the heating hot water passage 14. The three-way valve 15 is provided. In addition, the first hot water path 10 is connected to the cistern (tank) 16 downstream of the second heat exchanger 21.

The water supply temperature sensor 22 and the hot water supply temperature sensor 23 are respectively installed in the second hot water path 20 upstream and downstream of the second heat exchanger 21. In addition, a flow rate sensor 24 and a quantity servo 25 are provided upstream of the second heat exchanger 21. In addition, the second hot water path 20 is provided through the water supply path 28 having the manual water supply valve 26 and the water supply solenoid valve 27 upstream of the second heat exchanger 21. )

The controller 30 controls the amount of combustion of the burner 1 and the like on the basis of the operation setting by the operation panel 31 or the remote controller 32. The controller 30 further includes a lower limit temperature and an upper limit flow rate of the second warm water path 20 determined based on the heat transfer amount from the warm water of the first warm water path 10 to the water of the second warm water path 20. ) Is provided with a storage means (33) for storing.

The function of the hot water system which consists of said structure is demonstrated.

In the hot water supply operation, first, the combustion fan 5 starts to operate under the control of the controller 30 and is ignited by the igniter 3 through the ignition plug 4. The main gas solenoid valve 7 and the gas solenoid valve 9 are opened, and the gas is supplied from the gas supply path 2 to the burner 1 so that the burner 1 starts combustion. The controller 30 controls the combustion amount of the burner 1 by controlling the opening degree of the gas proportional valve 8 and the rotation speed of the combustion fan 5 based on the set hot water temperature in the operation panel 31 or the like.

In addition, the three-way valve 15 connects the first hot water path 10 to the second heat exchanger 21, and the pump 13 starts operation. As a result, the hot water of the first hot water path 10 generated by being heated by heat exchange with the combustion exhaust of the burner 1 in the first heat exchanger 11 is transferred from the second heat exchanger 21 to the second hot water path ( Heat exchanged with running water. Then, hot water generated by heat exchange in the second heat exchanger 21 is supplied from the second hot water path 20.

In the heating operation, on the other hand, the burner 1 is burned under the control of the controller 30 as in the hot water operation. In addition, the three-way valve 15 connects the first hot water path 10 to the heating hot water path 14. Thereby, the hot water of the 1st hot water path 10 produced | generated by the 1st heat exchanger 11 is supplied to the heating apparatus not shown through the heating hot water path 14, and heating is performed by this heating apparatus. .

Here, how the lower limit temperature Tmin and the upper limit flow rate Wmax of the second hot water path 20 stored in the storage means 33 are determined will be described.

Hereinafter, the water temperature in the upstream of the 1st heat exchanger 11 of the 1st warm water path 10 is represented by Θin, the water temperature in the downstream is Θout, and the flow rate of water is represented by W '. In addition, the water temperature (hereinafter referred to as 'water supply temperature') upstream of the second heat exchanger 21 of the second hot water path 20 is referred to as Tin, and the water temperature in the downstream (hereinafter referred to as 'water supply temperature'). Tout, the flow rate is represented by W.

First, the coefficient which shows the heat exchange characteristic of the 2nd heat exchanger 21 is set to H ([kPa / s * degreeC]). This coefficient H is determined experimentally as described later. In addition, the amount of heat transferred from the hot water of the first warm water path 10 to the water of the second warm water path 20 is equal to the coefficient H and the average water temperature of the first warm water path 10 ((Θout + Θin) / 2). ) And the difference between the average water temperature ((Tout + Tin) / 2) of the second warm water path 20. In addition, it is assumed that the amount of heat absorbed by the second heat exchanger 21 by the water in the second hot water heater 20 is equal to the amount of heat of movement in the second heat exchanger 21. In this way, the following relational expression ① is obtained.

W (Tout-Tin) = (H / 2) {(Θout + Θin)-(Tout + Tin)}... … ①

In the second heat exchanger 21, it is assumed that the heat loss of the hot water of the first warm water path 10 is equal to the heat gain of the water of the second warm water path 20. The heat loss amount of the hot water in the first hot water path 10 includes the heat capacity of water (= 1 [㎉ / l · ° C.]), the flow rate W 'of the first hot water path 10, and the upstream of the first heat exchanger 11. Is approximated by the product of the water temperature difference (Θout-Θin) downstream. In addition, the acquired calorific value of the water in the second warm water path 20 is approximately represented by the product of the heat capacity of the water, the flow of water W in the second warm water path 20, and the difference between the hot water supply temperature and the water supply temperature (Tout-Tin). Thus, the following relational expression ② is obtained.

W (Tout-Tin) = W '(Θout-Θin)... … ②

When the water temperature Θin is eliminated using the relations 1 and 2, the following relation 3 is obtained.

H = 2WW '(Tout-Tin) / {2W'Θout- (W + W') Tout + (W-W ') Tin}... … ③

The coefficient H is determined experimentally based on the relational expression ③. That is, the water temperature Θout in the downstream of the first heat exchanger 11 of the first warm water path 10 is measured by the water temperature sensor 12. In addition, the water supply temperature Tin, the hot water supply temperature Tout, and the water flow amount W of the second hot water path 20 are measured by the water supply temperature sensor 22, the hot water supply temperature sensor 23, and the water flow rate sensor 24, respectively. do. In addition, the flow-rate W 'of the first warm water path 10 is determined based on the capacity of the pump 13. The coefficient H is determined by substituting these measured values into the relational expression ③.

Here, by changing the relational expression ③, the following relational expressions ④ and ⑤ are obtained.

Tout = {2HW'Θout + (W (2W '+ H) -HW') Tin} / {W (2W '+ H) + HW'}... … ④

W = HW '(2Θout-Tout-Tin) / (2W' + H) (Tout-Tin)... … ⑤

When the water temperature θout of the first warm water path 10 downstream of the first heat exchanger 11 falls and falls below Θmin (˜42 ° C.), drainage occurs in the first heat exchanger 11. Therefore, the lower limit temperature Tmin of the hot water supply temperature Tout is determined by the following equation (6).

Tmin = {2HW'Θmin + (W (2W '+ H) -HW') Tin} / {W (2W '+ H) + HW'}... … ⑥

On the other hand, if the water temperature Θout of the first warm water passage 10 downstream of the first heat exchanger 11 rises and exceeds Θ max (˜85 ° C.), the water of the first warm water passage 10 may boil. Most likely. Therefore, the upper limit flow-rate Wmax of the flow-rate W of the 2nd warm water path 20 is determined by following Formula (7).

Wmax = HW '(2Θmax-Tout-Tin) / (2W' + H) (Tout-Tin)... … ⑦

In the hot water system having the above configuration, the gas proportional valve 8 is controlled by the controller 30 so that the hot water temperature Tout measured by the hot water temperature sensor 23 does not fall below the lower limit temperature Tmin of the equation ⑥. The amount of combustion of the burner 1 is controlled through the opening degree of the engine and the rotation speed of the combustion fan 5. In addition, the flow rate is controlled by the controller 30 through the water quantity feeder 25 so that the flow rate W of the second warm water path 20 measured by the flow rate sensor 24 does not exceed the upper limit flow rate Wmax. do.

According to the hot water system of the present embodiment, the lower limit water temperature Tmin and the upper limit flow rate Wmax of the second warm water path 20 stored in the storage means 33 are the second from the warm water of the first warm water path 10. It is determined based on the relational expressions ① and ② indicating the amount of heat transferred to the water of the hot water furnace 20.

Therefore, since the hot water temperature Tout of the second hot water path 20 is controlled to be equal to or higher than the lower limit water temperature Tmin, the water temperature θout of the first hot water path 10 is maintained at a high temperature, so that the first heat exchanger ( Drain generation in 11) can be reliably prevented. In addition, since the water temperature θout of the first hot water passage 10 is controlled to a low temperature by controlling the flow rate W of the second hot water passage 20 to be equal to or less than the upper limit flow rate Wmax, the first hot water passage 10 The boiling of water of) can be prevented reliably.

Moreover, when the water temperature of the 2nd warm water path 20 is comparatively low, the probability that a user is using the warm water of the 2nd warm water path 20 in large quantities, ie, the large flow volume W of the 2nd warm water path 20 is large. The probability of preventing drain generation of the first heat exchanger 11 due to increase is high. Therefore, the hot water supply temperature Tout of the second hot water path 20 is controlled by the lower limit water temperature Tmin, so that even if the flow rate W of the second hot water path 20 is close to its maximum, the first water supply temperature Tout is the first. Drain generation in the heat exchanger 11 can be reliably prevented.

On the other hand, when the hot water supply temperature Tout of the second hot water heater 20 is relatively high, the user is likely to feel such high temperature hot water, that is, the probability of feeling dissatisfaction due to the drop in the water temperature of the second hot water heater 20. This is high. Therefore, the flow rate W of the second hot water passage 20 is controlled to be equal to or lower than the upper limit flow rate Wmax, so that the boiling water of the first hot water passage 10 can be boiled even when the hot water supply temperature Tout is at a high temperature. Can be prevented.

Moreover, in the state which added each characteristic of the 2nd heat exchanger 21, the coefficient H is experimentally determined based on the real hot water system. Therefore, drain generation and boiling can be reliably prevented through the control of the hot water supply temperature Tout or the flow of water W of the second hot water path 20.

In addition, in this embodiment, the hot water supply temperature Tout is controlled as a preventive measure of drain generation in the first heat exchanger 11, and the flow rate of the second hot water passage 20 as a measure to prevent boiling of the water in the first hot water passage 10. Although (W) was controlled, as another embodiment, as a preventive measure of drain generation in the first heat exchanger 11, the flow rate W of the second warm water passage 20 is controlled, and the water of the first warm water passage 10 is controlled. The hot water supply temperature Tout may be controlled as a boiling prevention measure.

In the present embodiment, the coefficient H has been determined experimentally. As another embodiment, the heat exchange rate η of the second heat exchanger 21 is experimentally determined from the relation that W (Tout-Tin) = η (Θout-Θin). It may be determined. In this case, the hot water supply temperature Tout and the flow rate W of the second hot water path 20 are represented by the following equations ⑧ and ⑨, respectively.

Tout = Tin + η (W '/ W) (Θout-Θin). … ⑧

W = ηW '(Θout-Θin) / (Tout-Tin)... … ⑨

And as a preventive measure of drain generation in the 1st heat exchanger 11, and the preventive boiling of the water of the 1st warm water path 10, the hot water temperature Tout or the 2nd warm water path 20 shown by said Formula (8) and (9) is mentioned. The flow rate W may be controlled.

In the present embodiment, the coefficient H is determined experimentally based on the water temperature Θout of the first warm water path 10 downstream of the first heat exchanger 11, but as another embodiment, the first heat exchanger ( The coefficient H may be determined experimentally based on the water temperature Θin of the first warm water path 10 in the upstream of 11) or the water temperatures Θout and Θin in the upstream and downstream.

As described above, according to the present invention, it is possible to stably control the water temperature in the second hot water passage while preventing the generation of a drain in the first heat exchanger and the boiling of the water in the first hot water passage.

Claims (2)

The first heat exchanger which heats up the water in a 1st hot water furnace by heat exchange with a burner, a 1st hot water furnace, and the combustion exhaust of a burner, and heat-exchanges with the 2nd hot water furnace, and the hot water of a 1st hot water passage And a second heat exchanger for heating the water in the second hot water furnace to make hot water, and a control means for controlling the water temperature of the burner by controlling the combustion amount of the burner to control the water temperature in the second hot water furnace. In The control means includes the combustion temperature of the burner as a water temperature or flow rate of the second hot water furnace corresponding to the water temperature of the first hot water furnace determined based on the amount of heat transferred from the hot water of the first hot water passage to the water of the second hot water passage. The water temperature or flow rate of the second hot water furnace corresponding to the water temperature of the first hot water furnace when the condensation in the first heat exchanger of the steam to be prevented is stored as the lower limit water temperature or the lower limit flow rate, and the boiling of the water into the first warm water passage is And a storage means for storing the water temperature or the flow rate of the second hot water passage corresponding to the water temperature of the first hot water passage when being prevented as the upper limit water temperature or the upper limit flow rate, A hot water system characterized by controlling the water temperature or flow rate of the second hot water furnace to be equal to or higher than the lower limit water temperature or the lower limit flow rate stored in the storage means, and to control the water temperature or flow rate below the upper limit water temperature or the upper limit flow rate stored in the storage means. The method according to claim 1, The memory means memorizes the lower limit water temperature and the upper limit flow rate, The control means controls the water temperature of the second hot water path to the lower limit water temperature or more, and controls the flow of water of the second hot water path to below the upper limit water amount.