JP2006336939A - Hot water heating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a circulation flow rate of hot water with respect to a heating radiator without adversely affecting pressure tightness and durability of a heat exchanger, and to prevent energy loss due to heat dissipation in the heat exchanger in a hot water heating system provided with a heat source machine 1 having the heat exchanger heated by a burner 4, and the heating radiator 2, and circulating hot water heated by the heat exchanger between the heating radiator and the heat exchanger via a circulation passage. <P>SOLUTION: The circulation passage is divided into a first circulation passage 8 between the heat exchanger 5 and a cistern 7, and a second circulation passage 9 between the cistern 7 and the heating radiator 2, and hot water is circulated through each of the first and second circulation passages by individual pumps 10 and 11. When a temperature of the hot water supplied to the heating radiator 2 is raised to an extinction temperature, combustion of the burner 4 is stopped, and then, after waiting for a delay necessary for preventing after-boiling in the heat exchanger 5, the pump 10 for the first circulation passage is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

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. Moreover, 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.

  In addition, the conventional hot water heating system is provided with a temperature sensor for detecting the temperature of the hot water flowing in the outgoing passage of the circulation path, and the gas proportional valve is used to maintain the detected temperature of the temperature sensor at a predetermined set temperature. Temperature control is performed to control the amount of combustion. However, if the heating load is reduced due to a decrease in the number of operating heat radiators or the like, the detected temperature of the temperature sensor may be higher than the set temperature even if the combustion amount of the burner is minimized. In this case, when the temperature detected by the temperature sensor rises to a fire extinguishing temperature that is set about 10 ° C. higher than the set temperature, combustion of the burner is stopped while the operation of the circulation pump is continued, and the temperature detected by the temperature sensor is The combustion of the burner is resumed when the ignition temperature is lowered to about 10 ° C. lower than the set temperature.

However, if such control is performed, the heat of the hot water is dissipated by the heat exchanger due to the circulation of the hot water while the burner is stopped from burning, resulting in energy loss due to the heat dissipation, which is contrary to the demand for energy saving. .
JP 11-351589 A (0014-0017, FIG. 1)

  In view of the above points, the present invention makes it possible to increase the circulating flow rate of hot water to a heating radiator without adversely affecting the pressure resistance and durability of the heat exchanger, and to dissipate heat in the heat exchanger. The problem is to provide a hot water heating system that can also prevent energy loss due to heat.

  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 circulation path includes a cistern, and the circulation path includes a first circulation path between the heat exchanger and the cistern, A first circulation pump that is divided into a second circulation path between the systern and the heating radiator and circulates hot water in the first circulation path, and a second circulation pump that circulates hot water in the second circulation path, and The temperature detected by the temperature sensor for the second circulation path that detects the temperature of the hot water flowing in the outgoing path of the second circulation path that sends warm water from the systern to the heating radiator has risen to a fire extinguishing temperature that is set higher than a predetermined set temperature. Sometimes the second circulation pump is in operation Ignition in which the combustion of the burner is stopped while continuing, the operation of the first circulation pump is stopped by delaying the combustion for a predetermined time, and the temperature detected by the temperature sensor for the second circulation path is set lower than the set temperature. Control means for restarting operation of the first circulation pump and combustion of the burner when the temperature is lowered is provided.

  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 first circulation pump, and the circulation flow rate of the warm water for the heating radiator is determined by the flow rate of the 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.

  When the temperature detected by the second circulation path temperature sensor rises to the fire extinguishing temperature, not only combustion of the burner is stopped, but also the operation of the first circulation pump is stopped. Therefore, warm water is not circulated through the first circulation path, and energy loss due to heat radiation of the warm water by the heat exchanger is prevented.

  When the temperature detected by the second circulation path temperature sensor rises to the fire extinguishing temperature, if the operation of the first circulation pump is stopped simultaneously with the combustion of the burner, the after-boiling in the heat exchanger (residual heat of the heat exchanger) This causes a phenomenon that hot water staying in the heat exchanger boils). Therefore, it is desirable to stop the operation of the first circulation pump with a predetermined time delay from the combustion stop of the burner. According to this, after-boiling in the heat exchanger can be prevented, and the remaining heat of the heat exchanger can be absorbed in the hot water between the combustion stop of the burner and the operation of the first circulation pump stopped, and energy efficiency is improved. improves.

  By the way, when the temperature of the hot water in the first circulation path rises excessively, it is necessary to stop the combustion of the burner and circulate the hot water in the first circulation path to prevent boiling in the heat exchanger. . Therefore, the control means detects the temperature of the temperature sensor for the first circulation path that detects the temperature of the hot water flowing in the outgoing path of the first circulation path that sends the warm water from the heat exchanger to the systole to prevent boiling in the heat exchanger. When the temperature rises to a predetermined combustion prohibition temperature, the combustion of the burner is stopped while the operation of the first circulation pump and the second circulation pump is continued, and the detection temperature of the first circulation path temperature sensor is combusted. It is desirable that the combustion of the burner is restarted when the combustion permission temperature is set lower than the prohibited temperature.

  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 41 and a gas proportional valve 42 are interposed in the gas passage 40 for supplying fuel gas to the burner 4. The burner 4 is composed of a plurality of unit burners 4a. These unit burners 4a are divided into a plurality of sets, the gas passage 40 is branched downstream of the gas proportional valve 42 for each set of unit burners 4a, and fuel gas is supplied to each set of unit burners 4a in each branch path. A capacity switching valve 43 is provided. Thus, the combustion amount of the burner 4 can be varied over a wide range by combining the control of the capacity switching valve 43 and the control of the gas proportional valve 42.

  The heat exchanger 5 includes a main heat exchanger 51 disposed immediately above the burner 4 and a sub heat exchanger 52 disposed in an exhaust passage through which combustion exhaust gas that has passed through the main heat exchanger 51 flows. A sub heat exchanger 52 is connected in series on the upstream side of the exchanger 51. In the auxiliary heat exchanger 52, water vapor in the combustion exhaust is condensed and latent heat is recovered. Then, the condensed water is drained from the drain pipe 52c via the drain receiver 52a and the neutralizer 52b arranged immediately below the auxiliary heat exchanger 52.

  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 this embodiment, and hot water for the heating radiator 2 is not divided. When hot water flows through the heat exchanger 5 at a flow rate equal to the circulation flow rate, if the circulation flow rate is increased, the pressure resistance and durability of the heat exchanger 5 are adversely affected. Therefore, in order to ensure the pressure resistance and durability of the heat exchanger 5, the total circulating flow rate of hot water with respect to the heating radiator 2 cannot be increased so much. On the other hand, in this embodiment, 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 in the second circulation path 9). Flow rate) 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 70 provided with a water refill valve 71. Then, two water level electrodes 72 and 73 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 equal to or lower than the low water level electrode 72, the water refill valve 71 is opened, and the water level is high. Water is supplied until the water level electrode 73 is reached. Further, an overflow pipe 74 is connected to the cistern 7 so that the water level does not exceed a predetermined upper limit level.

  The first circulation path 8 returns the warm water from the cis turn 7 to the heat exchanger 5 (sub heat exchanger 52) and the forward passage 8a that sends the warm water that has passed through the heat exchanger 5 (main heat exchanger 51) to the cis turn 7. 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. Further, a bypass passage 9 c that connects the upstream side and the downstream side of the second circulation pump 11 is provided in the forward passage 9 a of 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. Each of the first and second circulation pumps 10 and 11 is a variable flow rate pump driven by a DC motor.

  In the cis turn 7, in order to prevent the low temperature hot water returned to the cis turn 7 from the return passage 9 b of the second circulation path 9 from flowing into the forward passage 9 a of the second circulation path 9, the second circulation path 9 A baffle plate 75 is provided between the connecting portion of the forward passage 9a and the connecting portion of the return passage 9b. Further, in the present embodiment, the downstream end of the forward passage 8 a of the first circulation path 8 and the upstream end of the forward passage 9 a of the second circulation path 9 are joined and connected to the cistern 7. Therefore, 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 does not pass through the cistern 7. Furthermore, 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 increased. Is transmitted to. 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 rises, the amount of combustion of the burner 4 decreases, and energy efficiency is maintained favorably. In addition, 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 individually connected to the cis turn 7, and the hot water heated by the heat exchanger 5 is passed through the cis turn 7. It is also possible to flow to the forward passage 9a of the second circulation path 9 via the route.

  The first circulation path 8 is provided with a first circulation path temperature sensor 12 for detecting the temperature of the hot water sent from the heat exchanger 5, and the second circulation path 9 has a forward path 9 a. A second circulation path temperature sensor 13 for detecting the temperature of the hot water supplied to the heating radiator 5 is provided.

  The heat source unit 1 is provided with a controller 14 as control means, and when the operation switch of any of the heating radiators 2 is turned on, the heating operation control shown in FIG. In FIG. 2, YT1H is a combustion prohibition temperature (for example, 90 ° C.) set to prevent boiling in the heat exchanger 5, and YT1L is a combustion permission temperature set lower than the combustion prohibition temperature. YT2H is a fire extinguishing temperature set about 10 ° C higher than the set temperature of hot water to be supplied to the heating radiator 2, and YT2L is hot water to be supplied to the heating radiator 2. The ignition temperature is set to be about 10 ° C. lower than the set temperature.

  In the heating operation control, first, the operation of the second circulation pump 11 is started in step S1, and the operation of the first circulation pump 10 is started in step S2. Next, in step S3, it is determined whether or not the detected temperature T1 of the first circulation path temperature sensor 12 is equal to or higher than the combustion prohibition temperature YT1H. At first, since T1 <YT1H, step S4 and S5 described later are skipped and the process proceeds to step S6, where combustion of the burner 4 is started. When starting combustion, first, the combustion fan 6 is driven, the rotation of the combustion fan 6 is detected, the gas source valve 41 is opened, spark discharge is performed with a spark plug (not shown), and the burner 4 is ignited. To do.

  When combustion of the burner 4 is started, temperature control is then performed in step S7. In the temperature control, the gas proportional valve 42 and capacity switching are performed based on the detected temperature T2 of the second circulation path temperature sensor 13 so that the detected temperature T2 of the second circulation path temperature sensor 13 is maintained at the set temperature. The combustion amount of the burner 4 is controlled by the valve 43. In addition, at the initial stage of the heating operation, the first circulation path 8 is reduced by reducing the rotation speed of the first circulation pump 10 so that the detected temperature T1 of the first circulation path temperature sensor 12 is equal to or higher than a predetermined temperature (for example, 60 ° C.). The hot water circulation flow rate is reduced in order to prevent condensation in the main heat exchanger 5a. Moreover, the rotation speed of the 2nd circulation pump 11 is controlled so that the warm water circulation flow rate in the 2nd circulation path 9 changes according to the driving | running number of the heating radiator 2. FIG.

  By the way, when the heating load is reduced due to a decrease in the number of operating heat radiators 2 or the like, the second circulation path temperature sensor 13 is set even if the combustion amount of the burner 4 is minimized (minimum combustion amount necessary for preventing misfire). The detected temperature T2 may be higher than the set temperature. Therefore, it is determined in step S8 whether or not the detected temperature T2 of the second circulation path temperature sensor 13 is equal to or higher than the fire extinguishing temperature YT2H. If T2 ≧ YT2H, the gas source valve 41 is switched in step S9. The valve is closed and combustion of the burner 4 is stopped. Then, when it is determined in step S10 that a predetermined time has elapsed since the combustion stop, the operation of the first circulation pump 10 is stopped in step S11. Next, in step S12, it is determined whether or not the detected temperature T2 of the second circulation path temperature sensor 13 has become equal to or lower than the ignition temperature YT2L. When T2 ≦ YT2L, the process returns to step S2 and returns to the first. The operation of the circulation pump 10 is resumed. In this case, the detected temperature T1 of the first circulation path temperature sensor 12 is lower than the combustion prohibition temperature YT1H. Therefore, the process proceeds from step S3 to step S6, and combustion of the burner 4 is resumed.

  Thus, when the detected temperature T2 of the second circulation path temperature sensor 13 rises to the fire extinguishing temperature YT2H, the combustion of the burner 4 is first stopped, and then the operation of the first circulation pump 10 is stopped when a predetermined time has elapsed. Thereafter, the first circulation pump 10 is maintained in the operation stop state until the detected temperature T2 of the second circulation path temperature sensor 13 decreases to the ignition temperature YT2L. Here, the operation of the second circulation pump 11 is continued, and the heat of the warm water is radiated in the heating radiator 2 by the circulation of the warm water in the second circulation path 9, but the operation of the first circulation pump 10 is stopped. Since hot water is no longer circulated through the first circulation path 8, heat of the hot water is not radiated by the heat exchanger 5, and energy loss is prevented. The predetermined time is a time (for example, 5 seconds) necessary and sufficient for preventing post-boiling in the heat exchanger 5 (a phenomenon in which hot water staying in the heat exchanger 5 is boiled due to residual heat of the heat exchanger 5). ) Is set. Therefore, even if the operation stop of the first circulation pump 10 is delayed with respect to the combustion stop of the burner 4, heat of the hot water in the heat exchanger 5 is not dissipated, but the remaining heat of the heat exchanger 5 can be absorbed into the hot water. Energy efficiency is improved.

  When it is determined in step S8 that the detected temperature T2 of the second circulation path temperature sensor 13 is lower than the fire extinguishing temperature YT2H, the process returns to step S3. Usually, the process of returning from the step S3 to the step S3 through the step S6, the step S7, and the step S8 is repeated. However, when the detected temperature T1 of the first circulation path temperature sensor 12 becomes equal to or higher than the combustion prohibition temperature YT1H for some reason, the process proceeds from step S3 to step S4 and combustion of the burner 4 is stopped. In this case, the operation of the first circulation pump 10 is not stopped. Therefore, the heat exchanger 5 dissipates the hot water, and the danger of boiling is quickly avoided. Moreover, the 2nd circulation pump 11 is also continuously operated and the heating by the heating radiator 2 is not interrupted. Thereafter, when it is determined in step S5 that the detected temperature T1 of the first circulation path temperature sensor 12 has fallen below the combustion permission temperature YT1L, the combustion of the burner 4 is restarted in step S6.

  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 includes the main heat exchanger 51 and the sub heat exchanger 52, but the sub heat exchanger 52 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.

Explanatory drawing which shows the structure of the hot water heating system of embodiment of this invention. The flowchart which shows the content of the heating operation control performed with the hot water heating system of embodiment.

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 DESCRIPTION OF SYMBOLS ... Outward passage of 2nd circulation path, 10 ... 1st circulation pump, 11 ... 2nd circulation pump, 12 ... Temperature sensor for 1st circulation paths, 13 ... Temperature sensor for 2nd circulation paths, 14 ... Controller (control means) , T1 ... detected temperature of the first circulation path temperature sensor, T2 ... detected temperature of the second circulation path temperature sensor, YT1H ... combustion prohibited temperature, YT1L ... combustion permission temperature, YT2H ... fire extinguishing temperature, YT2L ... ignition temperature.

Claims (3)

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,
A first circulation pump for circulating hot water in the first circulation path and a second circulation pump for circulating hot water in the second circulation path;
When the temperature detected by the temperature sensor for the second circulation path that detects the temperature of the hot water flowing in the outgoing path of the second circulation path that sends warm water from the systern to the heating radiator rises to a fire extinguishing temperature that is set higher than a predetermined set temperature In addition, the combustion of the burner is stopped while the operation of the second circulation pump is continued, the operation of the first circulation pump is stopped, and the detected temperature of the second circulation path temperature sensor is set lower than the set temperature. A hot water heating system comprising control means for restarting the operation of the first circulation pump and the combustion of the burner when the ignition temperature is reduced to the ignition temperature.   The operation of the first circulation pump is stopped after a predetermined time delay from the combustion stop of the burner when the temperature detected by the second circulation path temperature sensor rises to the fire extinguishing temperature. Hot water heating system.   The control means detects the temperature of the hot water flowing in the outgoing path of the first circulation path that sends warm water from the heat exchanger to the cistern, and the temperature detected by the temperature sensor for the first circulation path prevents boiling in the heat exchanger. When the temperature rises to a predetermined combustion prohibition temperature set for the purpose, the combustion of the burner is stopped while the operation of the first circulation pump and the second circulation pump is continued, and the first circulation path temperature sensor 3. The hot water heating system according to claim 1, wherein the combustion of the burner is resumed when the detected temperature of the gas falls to a combustion permission temperature set lower than the combustion inhibition temperature.

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