JP4912986B2 - Control method for hot water heater - Google Patents

Description

  The present invention relates to a method for controlling a hot water heating apparatus that performs heating by circulating hot water heated by a heat source device to a hot water heating terminal in a building.

Conventionally, in this type of hot water heater, a hot water boiler is used so that the hot water going temperature is a constant hot water temperature corresponding to the type of hot water heating terminal (50 ° C for floor heating, 60 ° C for panel convectors, etc.). It is generally performed to control a heat source machine such as.
JP 2007-107862 A

  In such a conventional hot water heater, an excessive amount of heat is supplied compared to the heating load that is actually required on the building side, which is a space to be heated, such as when the heating load is small, and this is wasteful heat dissipation. And inefficient.

  In order to perform efficient heating operation, it is desirable to balance the amount of heat radiated from the hot water heating terminal into the building and the amount of heat radiated from the building to the external environment. For this purpose, hot water heating installed in the building Thermal performance data such as the type and number of terminals, heat dissipation characteristics, the size of the building itself, and the heat loss coefficient are required.

  However, the heat dissipation characteristics of hot water heating terminals depend on the temperature difference between the hot water and the room temperature of the room to be heated, and the calculation conditions become complicated and simple when there are many types of hot water heating terminals. It is difficult to calculate the heat dissipation characteristics by a general calculation, and it is impossible to perform an efficient heating operation in which the heating load and the heat dissipation amount are balanced.

  Therefore, the present invention automatically acquires various condition data of the installation environment of the hot water heating apparatus without requiring high-level specialized knowledge, and enables high-efficiency heating operation that balances the heating load and the heat radiation amount. This is the issue.

  In order to solve the above-described problems, the present invention provides a warm water heating apparatus that performs a heating operation by circulating heating circulating water heated by a heat source device to a warm water heating terminal, and the heating circulating water has a first warm water temperature during a heating trial operation. The heat source device is controlled so as to maintain, and the first actual heating load in the entire building, which is the amount of heat flowing out from the heat source device to the building when the room temperature is stabilized, is measured. The first heat conductance value is calculated from the warm water going temperature and the warm water return temperature in the machine, and then the heat source machine is controlled so that the heating circulating water maintains a second warm water temperature different from the first warm water temperature. Then, the second actual heating load when the room temperature is stabilized is measured, and the second thermal conductance value is calculated from the second actual heating load, the room temperature, the warm water going temperature, and the warm water return temperature, and the heating load and the thermal conductance are calculated. The correlation with During the cell operation, the value of the thermal conductance corresponding to the current required heating load is determined from the correlation, the target hot water temperature is calculated from the thermal conductance value, the desired heating load, and the set room temperature, Heating operation was performed by controlling the heat source unit so that the temperature of the hot water was reached.

  Also, during the trial operation, the total heat loss coefficient of the building is calculated from the actual heating load, room temperature, and outside air temperature, and the required heating load during heating operation is calculated from the total heat loss coefficient and the desired set room temperature and outside air temperature. I tried to do it.

  As described above, according to the present invention, the data for matching the heat radiation amount and the heating load in the hot water heating terminal is automatically acquired without requiring specialized knowledge without knowing the individual types and performance of the hot water heating terminal. Because the target hot water temperature is determined from this data and the current required heating load, the amount of heat released from the hot water heating terminal can be balanced with the heating load, and there is no excess or deficiency. It is possible to perform highly efficient heating operation.

  In addition, even if the thermal performance data related to the building is unknown, the thermal performance data related to the building can be acquired at the same time during the heating trial operation without requiring specialized knowledge. And the heating load can be balanced, and appropriate and highly efficient heating operation can be performed without excess or deficiency.

Next, an embodiment of the present invention will be described with reference to the drawings.
DESCRIPTION OF SYMBOLS 1 is a building as a space to be heated, 2 is a heat source for heating the circulating water, 3 is a hot water heating terminal such as a panel convector provided in the building 1, and 4 is a heat source 2 and hot water heating A hot water circulation circuit 5, which is composed of a hot water forward pipe 4 a and a hot water return pipe 4 b, which connect the terminal device 3 so that heating circulating water can circulate, is a room temperature sensor for detecting the room temperature _Tr in the building 1.

The heat source unit 1 includes a circulation pump 6 that circulates heating circulating water in the hot water circulation circuit 4, a flow rate sensor 7 that detects the warm water flow rate V of the heating circulating water, a heat exchanger 8 that heats the heating circulating water, and a heat exchanger. heating means 9 such as a burner, for heating the 8, outside air temperature sensor 10 for detecting the outside air temperature (the temperature of the building of the external environment) T _a, forward temperature sensor 11 for detecting the hot water forward temperature T ₁ of the hot water circulation circuit 4, the hot water return temperature sensor 12 for detecting the temperature T ₂ back, in which and a control unit 13 for controlling the entire heat source apparatus 1 itself and hot water heating system.

In such a general hot water heating apparatus, the present invention appropriately balances the amount of heat radiated from the hot water heating terminal 3 into the building 1 and the amount of heat radiated from the building 1 to the external environment, and thus highly efficient heating. A control method for measuring the thermal conductance C _{i of the} entire hot water heating terminal 3 to be described later at the time of trial operation and determining the amount of heat supplied from the heat source unit 2 during the heating operation based on the measured thermal conductance C _{i in order} to perform the operation. It is about.

The control method of the present invention will be described in detail below.
First, during the trial operation, the heating operation is performed in advance on the preliminary day to raise the temperature inside the building 1 and stabilize the heating state.

Next, on the first day of the trial operation, the heat source unit 2 is controlled so that the warm water going-out temperature T ₁ is maintained at the first warm water temperature (for example, 45 ° C.) and a constant flow rate V, and the room temperature _{Tr of the} building 1 is stabilized. In this state, the warm water going temperature T ₁ , the warm water return temperature T ₂ , and the warm water flow rate V are measured and stored, and the actual heating load Q _s is calculated from Equation 1 below. At the same time, the outside temperature _Ta and the room temperature _Tr are also measured and stored.

<Formula 1>
_{Q s = c p ρV (T} 1 -T 2) [kW]
c _p : Specific heat of heating circulating water [J / kgK]
ρ: Heating circulating water density [g / cm ² ]

At the same time, the first thermal conductance C _i of the entire hot water heating terminal 3 for the building 1 is calculated from Equation 2 below. This thermal conductance C _i is calculated by a value obtained by dividing the amount of heat Q _s flowing into the building 1 by heating operation by the temperature difference between the room temperature _Tr and the hot water heating terminal 3 and is circulated between the inner surface of the hot water heating terminal 3 and the circulation. It is a coefficient based on a heat transfer rate in consideration of forced convection heat transfer with hot water, heat conduction of the material of the hot water heating terminal 3 itself, and natural convection heat transfer between the outer surface of the hot water heating terminal 3 and room air. In the case where the hot water heating terminal 3 is hot water floor heating, in consideration of the heat transfer rate, in addition to the heat conduction of the hot water heating terminal 3 itself, the heat conduction of the floor material is considered, and further the hot water heating terminal 3 Natural convection heat transfer between the heated floor and room air is considered instead of natural convection heat transfer between the outer surface of the room and room air.

<Formula 2>
C _i = Q _s / {(T ₁ + T ₂ ) / 2−T _r } [kW / K]

Then, the temperature difference from Equation 3 and room temperature T _r and the outside air temperature T _a of the following to calculate the total heat loss coefficient K which is a heating load of the building 1 as a whole per 1 ° C.. Here, a value obtained by dividing the actual heating load Q _s by the temperature difference between inside and outside the building 1 is defined as a total heat loss coefficient K.

<Formula 3>
K = Q _s / (T _r −T _a ) [kW / K]

On the second day of the test run, the heat source device 2 is controlled so as to maintain a second hot water temperature (for example, 40 ° C.) different from the first hot water temperature and a constant flow rate, and the room temperature _{Tr of the} building 1 is In a stable state, the warm water going temperature T ₁ , the warm water return temperature T ₂ , and the warm water flow rate V are measured and stored, and the actual heating load Q _s is calculated from Equation 1. Incidentally, at the same time outside air temperature T _a and the room temperature T _r be measured storage, calculates the total heat loss coefficient K of heating terminal unit 3 side second thermal conductance C _i and buildings 1 from Equation 2 and Equation 3.

On the third day of the test run, the heat source unit 2 is controlled to maintain a third hot water temperature (for example, 35 ° C.) different from the first and second hot water temperatures and a constant flow rate, and the room temperature of the building 1 In a state where _Tr is stable, the hot water going temperature T ₁ , the hot water return temperature T ₂ , and the hot water flow rate V are measured and stored, and the actual heating load Q _s is calculated from Equation 1. Incidentally, at the same time outside air temperature T _a and the room temperature T _r be measured storage, calculates a third thermal conductance C _i and the total heat loss coefficient K building 1 heating terminal unit 3 side from the formula 2 and formula 3.

  Each measured value and each calculated value of each day are shown in Tables 1-3. Here, the measured value at each time in the table is an average value of several measured values near each time, and each value is calculated using this average value.

Then, a correlation shown in FIG. 2 by linear interpolation using the value obtained by averaging the respective each day of the actual heating load Q _s and the first to third thermal conductance C _i. By performing linear interpolation in this way, it is possible to easily derive and store the correlation between the actual heating load Q _s and the thermal conductance C _i , and it can be easily handled even by a microcomputer with low calculation capability. Note that the method of obtaining the correlation is not limited to linear interpolation. For example, an approximate expression may be obtained from each value at each measurement time shown in Tables 1 to 3 by the least square method or the like. Is also good. Such a correlation between the actual heating load Q _s and the thermal conductance C _i is expressed by the following Equation 4.

<Formula 4>
C _i = f (Q _s )

Then, the average value of the total heat loss coefficient K of each day, the temperature difference between the room temperature T _r and the outside air temperature T _a of the entire building 1 is determined as the heating load per 1 ° C.. Here, the value of the total heat loss coefficient K is calculated at the time of trial operation. However, when the heat loss coefficient k [kW / m ² K] which is the thermal performance of the entire building 1 is known in advance. The configuration may be such that the total heat loss coefficient K calculated from the heat loss coefficient k and the total floor area A [m ² ] of the building 1 is manually stored in the control device 13.

Note that such a trial run is preferably performed at night so that each value can be easily calculated without the influence of solar radiation. In addition, the installation conditions of the hot water heating apparatus in this embodiment are a single-family house with a total floor area of 140 m ^2, a plurality of panel convectors having a heat radiation capacity corresponding to the size of the room are installed, and the circulation pump of the heat source unit 2 6 is controlled so that the circulation flow rate is constant, and there is no internal heat generation due to the life of the resident in the building 1 or lighting.

Then, when performing the heating operation, first determine the set room temperature T _{R_set} and air temperature T _a and the temperature difference and the aggregate thermal loss coefficient K from based on Equation 5 below the required heating load Q _r of. When the set room temperature _{Tr_set} is different in a plurality of rooms, the maximum value or the average value may be used.

<Formula 5>
Q _r = K (T _r — _set −T _a ) [kW]

Next, as shown in FIG. 3, the thermal conductance C _i in the current heating operation status is obtained from the obtained required heating load Q _r and Equation 4.

Then, the target hot water going temperature T _{1_set} is obtained from the obtained thermal conductance C _i and the following formula 6, and the heating amount is controlled so that the hot water going temperature T1 in the heat source unit 2 becomes the target hot water going temperature T _{1_set.} Perform heating operation.

<Formula 6>
T ₁ — _set = T _r — _set + Q _s (1 / C _i + ½ c _p ρV) [° C.]

  Thus, since the heat source machine 2 is controlled by calculating an appropriate target hot water temperature at the time when there is a heating request, the amount of heat radiated from the hot water heating terminal 3 into the building 1 and the building 1 radiate to the external environment. The amount of heat can be appropriately balanced, and a highly efficient heating operation with little extra heat dissipation loss can be realized.

Note that calculates a target hot water forward temperature T _{1_Set} as in Equation 6 target hot water temperature, the heating amount of the heat source unit 2 hot water forward temperature T ₁ is to be controlled so that the target hot water forward temperature T _{1_Set,} the heat source equipment However, the present invention is not limited to this. For example, the target warm water return temperature T 2 — _set or the average warm water temperature (T ₁ + T ₂ ) / 2 is calculated, and this is set as the target warm water temperature. The heating amount of the heat source device 2 may be appropriately controlled.

As described above, the thermal conductance C _i which is data for matching the heat radiation amount and the heating load in the hot water heating terminal 3 without requiring specialized knowledge without knowing the individual types and performances of the hot water heating terminal 3. In order to determine the target hot water temperature from the thermal conductance C _i and the current required heating load Q _r , to balance the heat radiation amount in the hot water heating terminal 3 and the heating load Therefore, it is possible to perform an appropriate and highly efficient heating operation without excess or deficiency.

  In addition, even if the thermal performance data related to the building 1 is unknown, the total heat loss coefficient K, which is the thermal performance data related to the building 1, can be obtained at the same time during the heating trial operation without requiring specialized knowledge. In addition, it is possible to balance the heat radiation amount and the heating load in the hot water heating terminal device 3, and it is possible to perform an appropriate and highly efficient heating operation without excess or deficiency.

In the heating trial operation of the above-described embodiment, the measurement was performed by changing the hot water temperature three times over three days. However, if the correlation between the thermal conductance C _i and the actual heating load Q _s can be derived, the hot water is used at least twice. The temperature may be changed, and the temperature of the hot water may be changed on the same day if the room temperature converges immediately after the change of the hot water temperature.

  Further, the heat source device 2 of the above embodiment has been described by taking a combustion-type heating boiler as an example. However, the heat source device 2 is not limited to this. For example, a heat pump type hot water heating device or hot water in a hot water tank heated by midnight power If it is a heat source machine which can supply the requested | required calorie | heat amount to heating circulation water, such as the heat storage type | formula warm water heating apparatus which was used, it will not specifically limit to the kind of heat source.

1 is a system diagram of a hot water heater according to an embodiment of the present invention. Graph showing the correlation between the thermal conductance C _i and heating load Q _s. Diagram for explaining how to determine the thermal conductance C _i from the required heating load Q _r.

Explanation of symbols

1 building 2 heat source machine 3 hot water heating terminal

Claims (2)

In the hot water heating apparatus that performs the heating operation by circulating the heating circulating water heated by the heat source machine to the hot water heating terminal,
During the heating trial operation, the heat source machine is controlled so that the heating circulating water maintains the first hot water temperature, and the first actual heating load in the entire building, which is the amount of heat that has flowed out of the heat source machine when the room temperature is stabilized, is measured. The first heat conductance value is calculated from the first actual heating load, the room temperature in the building, the hot water going temperature at the heat source unit, and the hot water return temperature,
Next, the heat source device is controlled so that the heating circulating water maintains a second hot water temperature different from the first hot water temperature, and the second actual heating load when the heated room temperature is stable is measured. And calculate the value of the second thermal conductance from the room temperature and the warm water return temperature and warm water return temperature,
Find the correlation between these heating load and thermal conductance,
During heating operation, the value of the thermal conductance corresponding to the current required heating load is determined from the above correlation, and the target hot water temperature is calculated from this thermal conductance value, the required heating load, and the set room temperature. A control method for a hot water heating apparatus, wherein a heating operation is performed by controlling a heat source unit so as to be a hot water temperature. During the trial run, calculate the total heat loss coefficient of the building from the actual heating load, room temperature, and outside temperature,
2. The method of controlling a hot water heater according to claim 1, wherein a required heating load during heating operation is calculated from the total heat loss coefficient, a desired set room temperature, and an outside air temperature.

Images