JP4130827B2 - Hot water heating system - Google Patents

Description

  The present invention comprises a heat source device having a heat exchanger heated by a burner, and a heating radiator, and hot water heated by the heat exchanger is interposed between the heating radiator and the heat exchanger via a circulation path. The present invention relates to a hot water heating system that circulates.

  Conventionally, in this type of hot water heating system, the circulation path is divided into a forward passage for sending warm water heated by the heat exchanger to the heating radiator, and a return passage for returning the hot water that has passed through the heating radiator to the heat exchanger. The system is constructed, and a cistern and a circulation pump are interposed in the return passage. And by using a variable flow rate pump as the circulation pump and controlling the circulation flow rate of the hot water in the circulation path according to the heating load, the power consumption of the circulation pump can be saved and the heat exchanger in the overload operation can be saved. A device that can prevent the occurrence of condensation is also known (see, for example, Patent Document 1).

By the way, recently, the number of heating radiators installed in homes is increasing, and it is necessary to increase the circulating flow rate of hot water in the circulation path. Here, in order to circulate a large flow rate of hot water through the circulation path via a heat exchanger having a large passage resistance, it is necessary to use a high-lift pump as a circulation pump. However, if a high circulation pump is used to secure a predetermined circulation flow rate in the circulation path, a considerable pressure is applied to the heat exchanger having a large passage resistance, causing a problem in terms of pressure resistance of the heat exchanger. In addition, in the heat exchanger, the flow path area is reduced, and when trying to secure the required circulation flow rate, the flow rate in the heat exchanger becomes very fast, causing an erosion phenomenon and deteriorating the durability of the heat exchanger. . Therefore, it is difficult to sufficiently increase the circulating flow rate of hot water in the circulation path in order to ensure the pressure resistance and durability of the heat exchanger.
JP 11-351589 A (0014-0017, FIG. 1)

  In view of the above, the present invention provides a hot water heating system capable of increasing the circulating flow rate of hot water to a heating radiator without adversely affecting the pressure resistance and durability of the heat exchanger. That is the issue.

In order to solve the above problems, the present invention comprises a heat source device having a heat exchanger heated by a burner, and a heating radiator, and heating water heated by the heat exchanger is passed through a circulation path to the heating radiator. A hot water heating system that circulates between the heat exchanger and the heat exchanger, wherein the circuit is provided with a cistern, and the circulation path is a first circulation path between the heat exchanger and the cistern, The system is divided into a second circulation path between the cistern and the heating radiator, and hot water is circulated through the first and second circulation paths by separate circulation pumps, and the hot water is sent from the heat exchanger to the cistern. The downstream end of the outgoing path of one circulation path and the upstream end of the outgoing path of the second circulation path that sends hot water from the systern to the heating radiator are connected to the systern .

  According to said structure, the amount of heat added to warm water by the heat exchanger in the 1st circuit is transmitted to a heating radiator via a 2nd circuit, and heating is performed. Here, the circulation flow rate of the hot water for the heat exchanger is determined by the flow rate of the circulation pump (first circulation pump) provided in the first circulation path, and the circulation flow rate of the hot water for the heating radiator is provided in the second circulation path. It is determined by the flow rate of the circulation pump (second circulation pump). That is, the circulation flow rate for the heat exchanger and the circulation flow rate for the heating radiator can be determined individually. Therefore, even if the circulation flow rate for the heating radiator is increased, the circulation flow rate for the heat exchanger can be made relatively small so as not to adversely affect the pressure resistance and durability of the heat exchanger. In other words, it is possible to increase the circulation flow rate for the heating radiator without being restricted by the pressure resistance and durability of the heat exchanger, which is advantageous when many heating radiators are installed.

The first circulation path is composed of a forward passage for sending warm water from the heat exchanger to the systole and a return passage for returning hot water from the systern to the heat exchanger, and the second circulation path is warm water from the systern to the heating radiator. And a return passage for returning the hot water from the heating radiator to the cistern. By the way, there is a possibility that the hot water that has flowed into the sys- tern from the outgoing path of the first circulation path flows in a short circuit to the return path of the first circulation path, and the amount of heat added to the hot water by the heat exchanger cannot be transmitted well to the heating radiator. is there. In order to solve such a problem , in the present invention, the downstream end of the forward path of the first circulation path and the upstream end of the forward path of the second circulation path are merged and connected to the systern as described above . According to this, the hot water heated by the heat exchanger flows from the outgoing path of the first circulation path to the heating radiator via the outgoing path of the second circulation path without passing through the systern, and is converted into hot water by the heat exchanger. The added heat is reliably transmitted to the heating radiator.

  In addition, when many heating radiators are installed, the amount of water held in the circulation path including these heating radiators increases, and low temperature water is circulated to the heat exchanger for a relatively long time in the initial stage of operation. The latent heat of the water vapor in the combustion exhaust of the burner is deprived and the dew condensation in the heat exchanger continues for a while. Here, if at least the first circulation pump of both the first and second circulation pumps is constituted by a variable flow rate pump, the circulation flow rate with respect to the heat exchanger in the initial operation can be reduced and condensation can be suppressed. When the circulating water is warmed and no condensation occurs, the circulation flow rate to the heat exchanger can be increased to increase the heating capacity, which is advantageous.

  Referring to FIG. 1, reference numeral 1 denotes a heat source machine, which constitutes a hot water heating system that performs heating by circulating hot water heated by the heat source machine 1 to a heating radiator 2 such as a floor heating panel. The heat source device 1 is provided with a combustion housing 3, and a burner 4 and a heat exchanger 5 heated by the burner 4 are accommodated in the combustion housing 3. Combustion air is supplied into the combustion housing 3 by a combustion fan 6. A gas main valve 4 b and a gas proportional valve 4 c are interposed in the gas passage 4 a for supplying fuel gas to the burner 4.

  The heat exchanger 5 includes a main heat exchanger 5a disposed immediately above the burner 4, and a sub heat exchanger 5b disposed in an exhaust passage through which combustion exhaust gas that has passed through the main heat exchanger 5a flows. The auxiliary heat exchanger 5b is connected in series on the upstream side of the exchanger 5a. In the auxiliary heat exchanger 5b, water vapor in the combustion exhaust is condensed and latent heat is recovered. Then, the condensed water is drained from the drain pipe 5e via the drain receiver 5c and the neutralizer 5d arranged immediately below the auxiliary heat exchanger 5b.

  Further, the heat source device 1 is provided with a cistern 7. Then, the hot water is circulated between the heat exchanger 5 and the cistern 7 via the first circulation path 8, and the hot water is circulated between the cistern 7 and the heating radiator 2 via the second circulation path 9. I have to. A plurality of heating radiators 2 are connected to the second circulation path 9 in parallel via valves 2a such as thermal valves, and when the operation switch of each heating radiator 2 is turned on, Each heating radiator 2 is in a state in which hot water can be circulated by opening the valve 2a.

By the way, when the number of installation of the heat radiator 2 is large, it is necessary to considerably increase the total circulation flow rate of hot water with respect to the heat radiator 2. Here, the circulation path between the heat exchanger 5 and the heating radiator 2 is not divided into the first circulation path 8 and the second circulation path 9 as in the comparative example shown in FIG. In the case where hot water flows through the heat exchanger 5 at a flow rate equal to the circulating flow rate of hot water, the pressure resistance and durability of the heat exchanger 5 are adversely affected if the circulation flow rate is increased. Therefore, in order to ensure the pressure resistance and durability of the heat exchanger 5, the total circulating flow rate of hot water for the heating radiator 2 cannot be increased to the left. In contrast, in the comparative example , the hot water circulation flow rate for the heat exchanger 5 (hot water circulation flow rate in the first circulation path 8) and the hot water circulation flow rate for the heating radiator 2 (hot water circulation flow rate in the second circulation path 9). ) And can be determined individually. Therefore, even if the total circulating flow rate of hot water for the heating radiator 2 is increased, the circulating flow rate of hot water for the heat exchanger 5 is made relatively small so that the pressure resistance and durability of the heat exchanger 5 are not adversely affected. Can be. That is, it becomes possible to increase the total circulating flow rate of hot water to the heating radiator 2 without being restricted by the pressure resistance and durability of the heat exchanger 5.

  Hereinafter, the cistern 7 and the first and second circulation paths 8 and 9 will be described in detail. The cistern 7 is replenished with water through a water supply pipe 7b provided with a water refill valve 7a. Then, two water level electrodes 7c and 7d for detecting the low water level and the high water level are attached to the cistern 7, and when the water level in the cistern 7 becomes lower than the low water level electrode 7c, the refill valve 7a is opened, Water is supplied until the water level electrode 7d is reached. Further, an overflow pipe 7e is connected to the systern 7 so that the water level does not exceed a predetermined upper limit level.

  The first circulation path 8 returns the hot water that has passed through the heat exchanger 5 (main heat exchanger 5a) to the cis turn 7 and the hot water from the cis turn 7 to the heat exchanger 5 (sub heat exchanger 5b). The return passage 8b includes a first circulation pump 10 interposed in the return passage 8b. The second circulation path 9 is composed of a forward passage 9a for sending warm water from the cis turn 7 to the heating radiator 2 and a return passage 9b for returning the warm water from the heating radiator 2 to the cis turn 7, and the second circulation pump is connected to the forward passage 9a. 11 is interposed. Each of the first and second circulation pumps 10 and 11 is composed of a variable flow rate pump driven by a DC motor. The forward passage 8 a of the first circulation path 8 is provided with a thermistor 12 that detects the temperature of the hot water sent from the heat exchanger 5 (heat exchanger outlet hot water temperature), and the return path 8 b of the first circulation path 8. Is provided with a thermistor 13 for detecting the temperature of the hot water returned from the cistern 7 (returning hot water temperature).

  When the operation switch of any of the heating radiators 2 is turned on, the first and second circulation pumps 10 and 11 and the combustion fan 6 are driven, and after detecting the rotation of the combustion fan 6, the gas source valve 4b is opened and spark discharge is performed by a spark plug (not shown) to ignite the burner 4. When the burner 4 is thus burned, the amount of heat added to the hot water by the heat exchanger 5 in the first circulation path 8 is transmitted to the heating radiator 2 via the cistern 7 and the second circulation path 9. The heating is done.

  Here, at the initial stage of operation, the number of rotations of the first circulation pump 10 is lowered, and the hot water circulation flow rate in the first circulation path 8 is decreased so that the hot water temperature at the outlet of the heat exchanger becomes a predetermined temperature (for example, 60 ° C.) or higher. To do. Thereby, dew condensation in the main heat exchanger 5a can be prevented. On the other hand, the rotation speed of the second circulation pump 11 is increased, the hot water circulation flow rate in the second circulation path 9 is increased, and the temperature rise of the heating radiator 2 is accelerated. Then, as the return hot water temperature rises, the rotation speed of the first circulation pump 10 is increased, and the hot water circulation flow rate in the first circulation path 8 is increased to increase the heating capacity. After the return hot water temperature reaches a predetermined set temperature, the combustion amount of the burner 4 is controlled by the gas proportional valve 4c so that the return hot water temperature is maintained at the set hot water temperature. Moreover, the rotation speed of the 2nd circulation pump 11 is controlled, the warm water circulation flow rate in the 2nd circulation path 9 is varied according to the number of operation of the heating radiator 2, and coexistence with heating capability and energy-saving property is aimed at.

By the way, in the comparative example , the forward passage 8a and the return passage 8b of the first circulation path 8 and the forward passage 9a and the return path 9b of the second circulation path 9 are individually connected to the cistern 7. In this configuration, the hot water that has flowed into the cistern 7 from the forward passage 8a of the first circulation path 8 flows in a short-circuited manner into the return passage 8b of the first circulation path 8, and the amount of heat added to the warm water by the heat exchanger 5 is the heat radiation. There is a risk that it will not be transmitted well to the vessel 2.

FIG. 2 shows an embodiment of the present invention in which such a problem is solved. In addition, the same code | symbol as the above is attached | subjected to the member same as the said comparative example . In the present embodiment, a merging passage 14 is provided in which the downstream end of the forward passage 8a of the first circulation path 8 and the upstream end of the forward passage 9a of the second circulation path 9 are joined, and both the first and second circulation paths are provided. The forward passages 8 a and 9 a of the eighth and ninth passages are connected to the systern 7 via the junction passage 14. According to this, when the hot water circulation flow rate in the second circulation path 9 is larger than the hot water circulation flow rate in the first circulation path 8, all of the hot water heated by the heat exchanger 5 causes the cistern 7. Without being routed, the amount of heat supplied to the heating radiator 2 from the outgoing passage 8a of the first circulation path 8 through the outgoing passage 9a of the second circulation path 9 and added to the hot water by the heat exchanger 5 is efficiently heated. It is transmitted to the radiator 2. When the hot water circulation flow rate in the second circulation path 9 is smaller than the hot water circulation flow rate in the first circulation path 8, the hot water circulation flow rate in the second circulation path 9 among the hot water heated by the heat exchanger 5. The portion exceeding the flow amount flows into the cistern 7, and a part of the amount of heat added to the hot water by the heat exchanger 5 is transmitted to the cistern 7. As a result, the temperature of the hot water returned to the heat exchanger 5 (return hot water temperature) rises, the amount of combustion of the burner 4 decreases, and the energy efficiency is maintained well.

In the present embodiment, a bypass passage 9 c that connects the upstream side and the downstream side of the second circulation pump 11 is provided in the second circulation path 9. According to this, even when the flow of hot water from the return passage 9a to the return passage 9b is interrupted due to some abnormality during the operation of the second circulation pump 11, the second circulation pump 11 is connected to the second circulation pump 11 via the bypass passage 9c. The required amount of hot water flows through the circulation of the hot water, and the second circulation pump 11 is protected.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment. For example, in the above embodiment, the heat exchanger 5 is constituted by the main heat exchanger 5a and the sub heat exchanger 5b, but the sub heat exchanger 5b may be omitted. In the above embodiment, both the first and second circulation pumps 10 and 11 are constituted by variable flow rate pumps that are driven by a DC pump. It is also possible to configure with a constant flow pump driven by an AC motor. In the above embodiment, the combustion amount of the burner 4 is controlled so that the return hot water temperature detected by the thermistor 13 provided in the return passage 8b of the first circulation path 8 is maintained at the set temperature. (2) A thermistor may be provided in the forward passage 9a of the circulation path 9, and the combustion amount of the burner 4 may be controlled so that the hot water temperature supplied to the heating radiator 2 detected by the thermistor is maintained at a predetermined set temperature. .

Explanatory drawing which shows the structure of the hot water heating system of a comparative example . Explanatory view showing a configuration of a hot water heating system implementation embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat source machine, 2 ... Heating radiator, 4 ... Burner, 5 ... Heat exchanger, 7 ... Sistern, 8 ... 1st circuit, 8a ... Outbound path of 1st circuit, 9 ... 2nd circuit, 9a ... the second circulation path, 10 ... the first circulation pump, 11 ... the second circulation pump.

Claims (2)

A heat source device having a heat exchanger heated by a burner and a heating radiator are provided so that hot water heated by the heat exchanger is circulated between the heating radiator and the heat exchanger via a circulation path. In a hot water heating system that has a systern in the circulation path,
The circulation path is divided into a first circulation path between the heat exchanger and the cistern and a second circulation path between the cistern and the heating radiator, and each of the first and second circulation paths is divided into While circulating hot water with a circulation pump ,
The downstream end of the outgoing path of the first circulation path that sends warm water from the heat exchanger to the systole and the upstream end of the outgoing path of the second circulation path that sends hot water from the systern to the heating radiator are joined together and connected to the systern. hot water heating system, characterized in that there. Of the first circulation pump that circulates hot water in the first circulation path and the second circulation pump that circulates hot water in the second circulation path, at least the first circulation pump is constituted by a variable flow rate pump. The hot water heating system according to claim 1 .

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