JP4421497B2 - Waste heat preheating system - Google Patents

Description

  The present invention relates to a waste heat utilization preheating system that preheats a part of water supplied to a hot water supply device using waste heat.

  Attempts have been made to use energy more effectively from the viewpoint of the global environment and the like. As one of the attempts, for example, secondary energy such as electricity and power is generated by primary energy such as gas, and the heat (waste heat) generated when the electricity and power is generated is used. There are systems that make effective use of exhaust heat, such as making steam.

JP 2002-364919 A

  For example, when a private power generation device is provided in a hotel, office building, etc., as an effective utilization method of exhaust heat generated from the private power generation device, for example, it is considered that hot water for hot water supply is created using waste heat. It is done. However, the amount of hot water used in hotels and office buildings is very large, and it is almost impossible to produce hot water for the amount of hot water required for exhaust heat from private power generation devices.

  An object of the present invention is to provide a waste heat utilization preheating system capable of effectively utilizing waste heat in a hot water supply system.

In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, the present invention is a system for preheating a part of water supplied to a main hot water supply device using exhaust heat, and diverts a part of the water supply from a main water supply passage for supplying water to the main hot water supply device. A bypass water supply passage that returns the diversion water to the main water supply passage portion downstream from the diversion position, a pump for introducing a part of the water supply from the main water supply passage into the bypass water supply passage, and a bypass water supply passage A waste water utilization hot water supply device that heats the feed water in the bypass water supply passage using the waste heat generated by the power generation device , and in addition, a water flow stop detection portion that detects a water flow stop in the main water supply passage, A structure comprising a pump stop portion for stopping the pump drive of the bypass water supply passage when the water flow stop detection portion detects that the water flow in the main water supply passage is stopped, or the main water supply Comprises a water flow detection unit for detecting a water flow in the passage, the arrangement, comprising a pump driver for driving the pump bypass water supply passage when it is detected the flow of main water supply passage by the flow detection unit It is characterized by being.

  The exhaust heat utilization preheating system of the present invention has a configuration for preheating a part of the water supplied to the main hot water supply device using the exhaust heat generated in the power generator, and the exhaust heat utilization preheating. By incorporating the system into the hot water supply system, the exhaust heat generated by the power generator can be used effectively, and the main hot water supply device produces hot water by heating the preheated water supply. The amount of energy consumed to create hot water can be reduced.

  In addition, the waste heat utilizing hot water supply apparatus constituting the present invention only needs to preheat (heat) the feed water using the exhaust heat, so that it is not necessary to perform heating amount control and flow rate control of the feed water. For this reason, it is not necessary to provide the sensor etc. required for performing the heating amount control and flow rate control of water supply in an exhaust heat utilization hot water supply apparatus, and can thereby make a waste heat utilization hot water supply apparatus simple.

  Further, in the present invention, a bypass water supply passage is connected to a main water supply passage that supplies water to the main hot water supply device, and an exhaust heat utilizing hot water supply device is provided in the bypass water supply passage. For this reason, the following problems can be solved. For example, if the exhaust heat-use hot water supply apparatus is configured to be directly interposed in the main water supply passage, it may not be used even if a general-purpose exhaust heat use hot water supply apparatus is used. In other words, since the inlet and outlet of the water supply in the general-purpose exhaust heat hot water supply apparatus have a size determined by the standard, the size of the inlet and outlet of the water supply of the exhaust heat hot water supply apparatus However, when it is smaller than the main water supply passage, for example, the general-purpose exhaust heat utilization hot water supply device cannot be directly connected to the main water supply passage. Cannot be used.

  On the other hand, in the configuration of the present invention, a bypass water supply passage is connected to the main water supply passage, and an exhaust heat utilizing hot water supply device is provided in the bypass water supply passage. The flow path diameter of the main water supply passage is determined by, for example, the connection conditions with the main hot water supply device and the degree of design freedom is very low. Compared with the main water supply passage, the diameter of the bypass water supply passage can be set according to the diameters of the water supply inlet and outlet of the hot water supply system using exhaust heat. For this reason, regardless of the flow path diameter of the main water supply passage, it is possible to install a general-purpose exhaust heat-utilizing hot water supply device in the bypass water supply passage, thereby using the general-purpose exhaust heat-utilizing hot water supply device. A preheating system can be easily and inexpensively constructed.

  Further, when the flow passage cross-sectional area of the bypass water supply passage is smaller than the flow passage cross-sectional area of the main water supply passage, the bypass water supply passage is more difficult to flow than the main water supply passage. It is assumed that part of the water supply does not flow well. On the other hand, in this invention, since the pump for introducing a part of the water supply from the main water supply passage to the bypass water supply passage is provided, the flow passage cross-sectional area of the bypass water supply passage is greater than the flow passage cross-sectional area of the main water supply passage. Even if it is small, it is possible to reliably introduce a part of the water supply from the main water supply passage to the bypass water supply passage and to effectively use the exhaust heat.

  Further, a water flow stop detection unit that detects a water flow stop in the main water supply passage is provided, and when the water flow stop detection unit detects a water flow stop in the main water supply passage, a pump stop unit that stops the pump drive of the bypass water supply passage is provided. By providing the configuration provided, or by providing a water flow detection unit that detects the water flow in the main water supply passage, and when the water flow in the main water supply passage is detected by this water flow detection unit, the pump of the bypass water supply passage is driven By providing such a configuration, the pump can be driven when there is a water flow in the main water supply passage, and the pump drive of the bypass water supply passage can be stopped while the water flow in the main water supply passage is stopped. That is, when the water flow in the main water supply passage is stopped, hot water is not produced by the main hot water supply device, so it is not necessary to supply a part of the preheated water from the bypass water supply passage to the main water supply passage. Also, since the water flow in the main water supply passage is stopped, it becomes difficult for water to flow from the bypass water supply passage to the main water supply passage, and a large load is applied to the pump in the bypass water supply passage, so the water flow in the main water supply passage is stopped. Sometimes, the pump driving of the bypass water supply passage can be stopped to suppress the energy consumption for driving the pump. Thereby, the exhaust-heat utilization preheating system which considered energy saving can be provided.

  By the way, when the flow rate of the main water supply passage is much higher than the flow rate of the preheated water (preheated water supply) flowing from the bypass water supply passage to the main water supply passage, Temperature rise is small. For this reason, when there is a water flow in the main water supply passage, the water temperature at any position of the main water supply passage is substantially the same even if the preheated water supply joins from the bypass water supply passage. On the other hand, when the water flow in the main water supply passage stops, the water temperature at the junction of the bypass water supply passage in the main water supply passage starts to rise due to the preheated water flowing from the bypass water supply passage into the main water supply passage. Thus, a temperature difference occurs in the staying water supply in the main water supply passage so that the water temperature in the main water supply passage becomes higher as it approaches the merged portion of the bypass water supply passage. Thus, since the water temperature state of the water supply in the main water supply passage is different between when the water flow is present and when the water flow is stopped, the water flow of the water supply in the main water supply passage is utilized by utilizing the change in the water temperature state. And the stop of the water flow can be detected.

  Paying attention to this, the water temperature detecting means for detecting the water temperature of the main water supply passage upstream from the position where the bypass water supply passage branches, and the main water supply downstream from the position where the bypass water supply passage joins Water temperature detection means for detecting at least one of the water temperature detection means for detecting the water temperature of the passage is provided, and water temperature detection means for detecting the water temperature of the main water supply passage between the branch position and the merge position of the bypass water supply passage is provided. In addition, the water temperature detected by the water temperature detection means is provided with a structure provided with a water flow stop portion for detecting the water flow stop of the main water supply passage, or the water temperature detected by the water temperature detection means. For those equipped with a structure provided with a water flow detection unit that detects the flow of water in the main water supply passage, the water temperature detection means is configured to be attached to the main water supply passage. Since it is a single thing, while preventing complication of the conduit configuration of the main water supply passage, it is possible to detect the presence or absence of water in the main water supply passage.

  Water temperature detecting means for detecting the water temperature of the main water supply passage upstream from the merging position of the bypass water supply passage is provided, and preheating water temperature detecting means for detecting the temperature of the preheated water flowing from the bypass water supply passage into the main water supply passage is provided. In the configuration in which the pump drive of the bypass water supply passage is stopped when the detected water temperature of the preheated water temperature detecting means is lower than the detected water temperature of the water temperature detecting means, or the water flow in the main water supply passage is detected and the preheated water supply When the detected water temperature of the temperature detecting means is equal to or higher than the detected water temperature of the water temperature detecting means, the following effects can be obtained by providing a configuration for driving the pump of the bypass water supply passage. For example, a waste heat utilization hot water supply apparatus is provided with an exhaust heat recovery tank for storing preheated water heated by using exhaust heat, and the preheated water in the exhaust heat recovery tank passes through a bypass water supply passage. In the case of a structure that flows into the water supply passage, for example, when the preheated water in the exhaust heat recovery tank is cooled below the water supply temperature of the main water supply passage, and the cooled preheated water flows into the main water supply passage from the bypass water supply passage There is a risk of lowering the water temperature of the main water supply passage, but by providing the above configuration, when the water supply water temperature lower than the water supply water temperature of the main water supply passage flows into the main water supply passage from the bypass water supply passage, The flow of water supply from the bypass water supply passage can be stopped by stopping driving and stopping the flow of water supply from the bypass water supply passage to the main water supply passage. It is possible to prevent the water temperature decrease in the main water supply passage by the body.

  A circulation passage with a pump is provided to return the liquid after storing the waste heat of the power generation device to the waste heat utilization hot water supply device and transferring the waste heat to the waste heat utilization hot water supply device, and the circulation passage pump. Is driven in synchronization with the on / off operation of the bypass water supply passage pump, and the drive control of the circulation passage pump is simplified. It can be driven only when it is driven and exhaust heat can be efficiently transferred to the water supply in the bypass water supply passage, and the energy consumption of the pump can be suppressed.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 schematically shows a schematic configuration diagram of the exhaust heat utilization preheating system of the first embodiment. This waste heat utilization preheating system 1 includes a bypass water supply passage 4 of a main water supply passage 3 for supplying water to the main hot water supply device 2, a pump 5 and an exhaust heat utilization hot water supply device 6 provided in the bypass water supply passage 4, and a control. Part 7.

  The bypass water supply passage 4 is a passage that diverts a part of the water supply from the main water supply passage 3 and returns the diverted water to the main water supply passage portion downstream of the diversion position. In this first embodiment, the flow passage cross-sectional area of the bypass water supply passage 4 is smaller than the flow passage cross-sectional area of the main water supply passage 3 such as about 1/4 of the flow passage cross-sectional area of the main water supply passage 3. ing.

  The pump 5 is for introducing a part of the water supply from the main water supply passage 3 into the bypass water supply passage 4. In the first embodiment, since the flow passage cross-sectional area of the bypass water supply passage 4 is smaller than the flow passage cross-sectional area of the main water supply passage 3 as described above, the water supply flows from the main water supply passage 3 into the bypass water supply passage 4. Although it is difficult, the pump 5 can reliably feed water from the main water supply passage 3 into the bypass water supply passage 4.

  The waste heat utilization hot water supply device 6 has a configuration in which preheated water is generated by heating the water supply in the bypass water supply passage 4 using the exhaust heat of the power generation device (for example, engine generator) 8. There are various configurations for heating water using exhaust heat, and any configuration may be adopted, but one example is schematically shown in FIG.

  In the example shown in FIG. 2, the exhaust heat utilization hot water supply device 6 includes an exhaust heat recovery tank 10, a heating unit 11, and a water supply passage 12 that connects the bottom of the exhaust heat recovery tank 10 and the heating unit 11. The pump 13 interposed in the water supply passage 12, the water supply passage 14 connecting the top of the exhaust heat recovery tank 10 and the heating unit 11, and the water supply of the bypass water supply passage 4 to the bottom of the exhaust heat recovery tank 10 The water supply introduction passage 15 for guiding to the water supply and the water supply supply passage 16 for supplying the hot water of the exhaust heat recovery tank 10 to the bypass water supply passage 4 are configured.

  The waste heat utilization hot water supply device 6 and the power generation device 8 are connected by a waste heat recovery circulation passage 17. A pump 18 is interposed in the exhaust heat recovery circulation passage 17, and a liquid (for example, water) is circulated through the exhaust heat recovery circulation passage 17 by driving the pump 18. The liquid stores the exhaust heat generated in the power generation device 8 and transmits it to the exhaust heat utilization hot water supply device 6. In the example of FIGS. 1 and 2, the pump 18 is disposed inside the exhaust heat utilization hot water supply apparatus 6, but the pump 18 is a circulation passage portion between the exhaust heat utilization hot water supply apparatus 6 and the power generation apparatus 8. In some cases, it may be disposed.

  In the configuration example of FIG. 2, the heating unit 11 has a water passage 11 a having one end connected to the water supply passage 12 and the other end connected to the water supply passage 14. Through heat exchange between the circulating liquid and the water passing through the water passage 11a, heat storage (exhaust heat) of the circulating liquid in the exhaust heat recovery circulation passage 17 is transferred to the water passing through the water passage 11a to transfer the water. The structure which heats the water flow of 11a is provided. The liquid that has dissipated the exhaust heat in the heating unit 11 returns to the power generator 8 through the exhaust heat recovery circulation passage 17 and stores the exhaust heat again.

  In the waste heat utilization hot water supply apparatus 6 having the above-described configuration, the water supplied from the bypass water supply passage 4 to the water supply introduction passage 15 is supplied to the bottom of the exhaust heat recovery tank 10. Also, by driving the pump 13, water is supplied from the bottom of the exhaust heat recovery tank 10 through the water supply passage 12 to the heating unit 11, and this water supply passes through the water passage 11 a of the heating unit 11 and is discharged from the power generator 8. Heated using heat. The preheated water produced by the heating unit 11 is returned to the exhaust heat recovery tank 10 from the top of the exhaust heat recovery tank 10 through the water supply passage 14. In this example, the waste heat recovery tank 10 stores water before heating on the lower side, and preheated water is stored on the upper side. The preheated water stored in the exhaust heat recovery tank 10 is supplied to the main water supply passage 3 through the water supply supply passage 16 and the bypass water supply passage 4.

  Note that a control unit (not shown) is provided in the exhaust heat utilizing hot water supply apparatus 6, and a pump control unit (not shown) for controlling the driving of the pumps 13 and 18 is provided in this control unit. Is provided. Further, the exhaust heat utilizing hot water supply device 6 is provided with temperature detection means (not shown) for detecting the temperature of the water supplied from the bottom side of the exhaust heat recovery tank 10 to the heating unit 11. The pump control unit of the waste heat utilizing hot water supply apparatus 6 starts the pumps 13 and 18 by, for example, turning on the power. While the pumps 13 and 18 are being driven, the detected temperature of the temperature detecting means is taken in every moment and the detection is taken in. The temperature is compared with a predetermined pump stop determination value (for example, 60 ° C.). The pump controller continues driving the pumps 13 and 18 when it is determined that the detected temperature is equal to or lower than the pump stop determination value, and drives the pumps 13 and 18 when it is determined that the detected temperature exceeds the pump stop determination value. Stop.

  Such drive control of the pumps 13 and 18 is based on the following reasons. That is, the liquid circulating in the exhaust heat recovery circulation passage 17 stores the exhaust heat of the power generation device 8 and transmits it to the exhaust heat utilization hot water supply device 6, and the cooled liquid is the exhaust heat recovery circulation passage 17. Then, it returns to the power generation device 8 and forms cooling water for the power generation device 8. For example, when the feed water supplied from the exhaust heat recovery tank 10 to the heating unit 11 becomes higher than, for example, 60 ° C., the power generation device 8 passes through the exhaust heat recovery circulation passage 17 and reaches the exhaust heat utilization hot water supply device 6. The liquid cannot radiate the exhaust heat of the power generation device 8 to the exhaust heat utilization hot water supply device 6 side, and the liquid that has not been cooled returns from the exhaust heat utilization hot water supply device 6 to the power generation device 8. In such a case, the cooling operation of the power generation device 8 is not performed by the liquid in the exhaust heat recovery circulation passage 17. For this reason, in such a case, the drive of the pumps 13 and 18 is stopped and the exhaust heat recovery operation is stopped. In this case, since the cooling operation is stopped, the power generation operation of the power generation device 8 is also stopped by the control operation of the power generation device 8 for safety.

  The controller 7 of the exhaust heat utilization preheating system 1 is provided with a configuration relating to drive control of the pump 5 of the bypass water supply passage 4. In the first embodiment, the control unit 7 includes a pump driving unit 20, a pump stop unit 21, a water flow stop detection unit 22, and a water temperature comparison unit 23, as shown in FIG. Has been. Further, the main water supply passage 3 detects the water temperature of the main water supply passage portion between the branch position α and the merge position β of the bypass water supply passage 4 as shown in FIG. A water temperature detecting means T1 for detecting the water temperature downstream of the merging position β of the bypass water supply passage 4 is provided.

  The water flow stop detection unit 22 of the control unit 7 uses the water temperature T1 detected by the water temperature detection means T1 and the water temperature T2 detected by the water temperature detection means T2 to detect the water flow stop of the main water supply passage 3. It is a component, and is configured to include a water temperature intake unit 24 and a determination unit 25. That is, in the first embodiment, the water supply flow rate between the branch position α and the merge position β of the main water supply passage 3 is much larger than the water supply flow rate of the bypass water supply passage 4, so that the water flow is in the main water supply passage 3. In some cases, the water supply temperature of the main water supply passage 3 before the preheated water supply in the bypass water supply passage 4 joins (that is, the water temperature T1 detected by the water temperature detecting means T1) is also the value after the preheated water supply in the bypass water supply passage 4 joins. The water supply temperature in the main water supply passage 3 (that is, the water temperature T2 detected by the water temperature detection means T2) is also substantially the same. On the other hand, when the water flow in the main water supply passage 3 is stopped, the water temperature at the junction position β of the bypass water supply passage 4 in the main water supply passage 3 starts to rise due to the preheated water supply from the bypass water supply passage 4. The staying water supply in the passage 3 has a water temperature difference such that the water temperature increases as it approaches the joining position β of the bypass water supply passage 4.

  The water flow stop detection unit 22 detects the water flow stop of the main water supply passage 3 by paying attention to the difference in the water temperature state of the water supply in the main water supply passage 3 depending on the presence or absence of the water flow in the main water supply passage 3 as described above. The configuration as shown is provided. In the first embodiment, the distance from the merge position β of the bypass water supply passage 4 to the water temperature detection position of the water temperature detection means T1, and the merge position β of the bypass water supply passage 4 to the water temperature detection position of the water temperature detection means T2. The water temperature detecting means T1, T2 are arranged so that the distances of the two are different.

  The water temperature capturing section 24 of the water flow stop detecting section 22 captures the water temperature T1 detected by the water temperature detecting means T1 and the water temperature T2 detected by the water temperature detecting means T2 from time to time. The determination unit 25 calculates a difference ΔT between the water temperatures T1 and T2 captured at the same timing. The determination unit 25 is preliminarily given a water flow stop determination value S (for example, 4 ° C.), compares the calculated difference ΔT between the water temperatures T1 and T2 with the water flow stop determination value S, and compares the difference between the water temperatures T1 and T2. It is determined whether or not ΔT is equal to or greater than the water flow stoppage determination value S (ΔT ≧ S). When the determination unit 25 determines that the difference between the water temperatures T1 and T2 is equal to or greater than the water flow stop determination value S, the temperature difference between the water temperatures T1 and T2 is caused by the stop of the water supply water flow in the main water supply passage 3. It judges and outputs a water flow stop detection signal.

  When detecting that the water flow stop detection signal is output from the water flow stop detection unit 22, the pump stop unit 21 outputs the pump stop signal toward the pump drive unit 20. The pump drive unit 20 normally drives the pump 5, but stops the pump drive of the pump 5 when receiving a pump stop signal from the pump stop unit 21. For example, the pump drive unit 20 is predetermined. It is determined whether or not a pump stop signal from the pump stop unit 21 has been received at each given timing, and when it is determined that the pump stop signal has not been received, the drive of the pump 5 is continued and it is determined that the pump stop signal has been received. When this happens, the drive of the pump 5 is stopped. The pump drive unit 20 determines whether or not the pump stop signal is received from the pump stop unit 21 at every predetermined timing while the drive of the pump 5 is stopped, and continues to receive the pump stop signal. When it is determined that the pump 5 is stopped, the drive of the pump 5 is stopped. When it is determined that the pump stop signal is not received, the drive of the pump 5 is restarted.

  In the first embodiment, the pump drive unit 20, the pump stop unit 21, and the water flow stop detection unit 22 stop hot water flow in the main water supply passage 3 (that is, hot water is created in the main hot water supply device 2. When it is not), the driving of the pump 5 is stopped to reduce the energy consumption of the pump 5.

  In the first embodiment, in addition to the water temperature detecting means T1, T2, preheated water temperature detecting means Tt for detecting the temperature of the preheated water flowing from the exhaust heat recovery tank 10 into the main water supply passage 3 via the bypass water supply passage 4. Is provided. The preheated water supply temperature detecting means Tt may be disposed at any position as long as the temperature of the preheated water flowing into the main water supply passage 3 can be detected. The water supply supply passage 16, the bypass water supply passage portion between the exhaust heat utilizing hot water supply device 6 and the main water supply passage 3, the top portion of the exhaust heat recovery tank 10, etc.

  The water temperature comparison unit 23 of the control unit 7 detects the water temperature T1 detected by the water temperature detection means T1 that detects the temperature of the water supply upstream of the joining position β of the bypass water supply passage 4, and the water temperature detected by the preheated water supply temperature detection means Tt. Tt is taken in every moment. Then, the water temperature comparison unit 23 compares the detected detected water temperatures T1 and Tt, and determines whether or not the water temperature Tt is lower than the water temperature T1. When the water temperature comparison unit 23 determines that the water temperature Tt is lower than the water temperature T1, the water temperature of the water supplied from the bypass water supply passage 4 to the main water supply passage 3 is lower than the water supply water temperature of the main water supply passage 3, so that the bypass water supply passage Since there is a concern that the temperature of the water supply in the main water supply passage 3 is lowered by the water supply from 4, the water temperature comparison unit 23 outputs a bypass water temperature decrease signal to the pump stop unit 21. The pump stop unit 21 also outputs a pump stop signal toward the pump drive unit 20 when receiving the bypass water temperature lowering signal. Therefore, the pump drive unit 20 is configured not only when the water supply water flow in the main water supply passage 3 is stopped, but also when the water supply temperature Tt joining the bypass water supply passage 4 to the main water supply passage 3 is higher than the water supply temperature T1 of the main water supply passage 3. Also when the pressure drops, the drive of the pump 5 is stopped.

  In the first embodiment, water temperature detecting means T1, T2 are provided, and the water flow stop detecting unit 22 uses the detected water temperature T1 of the water temperature detecting means T1 and the detected water temperature T2 of the water temperature detecting means T2. The water flow stoppage of the main water supply passage 3 is detected. For example, the water temperature of the main water supply passage 3 upstream of the branch position α of the bypass water supply passage 4 is detected as shown by the dotted line in FIG. The water flow detection means T3 is provided, and the water flow stop detection unit 22 detects the water flow stop of the main water supply passage 3 using the detection water temperature T1 of the water temperature detection means T1 and the detection water temperature T3 of the water temperature detection means T3. It is good. In this case, the water flow stop detection unit 22 takes in the detected water temperature T1 of the water temperature detecting means T1 and the detected water temperature T3 of the water temperature detecting means T3, and calculates the temperature difference between the detected water temperatures T1 and T3. When this temperature difference is compared with a predetermined water flow stop determination value and it is determined that the temperature difference is equal to or greater than the water flow stop determination value, it is determined that the water flow in the main water supply passage 3 is stopped. A water flow stop signal is output toward the pump stop unit 21. In this case, the water temperature detecting means T2 may be omitted.

  Further, water temperature detecting means T1, T2, T3 are provided, and the water flow stop detecting unit 22 uses the water temperatures T1, T2, T3 detected by the water temperature detecting means T1, T2, T3, respectively, in the main water supply passage 3. It is good also as a structure which detects the water flow stop of water supply. In this case, for example, the water flow stop detection unit 22 calculates a temperature difference ΔT12 between the detected water temperature T1 of the captured water temperature detection means T1 and the detection water temperature T2 of the water temperature detection means T2, and detects the temperature difference ΔT12 and the water temperature detection. It is determined whether or not the temperature difference ΔT12 is equal to or greater than the water flow stop determination value S12 (ΔT12 ≧ S12) by comparing a predetermined water flow stop determination value S12 for the set of means T1 and T2. Further, the water flow stop detection unit 22 calculates a temperature difference ΔT13 between the detected water temperature T1 of the fetched water temperature detection means T1 and the detection water temperature T3 of the water temperature detection means T3, and the temperature difference ΔT13 and the water temperature detection means T1, T3. It is determined whether or not the temperature difference ΔT13 is equal to or greater than the water flow stoppage determination value S13 (ΔT13 ≧ S13) by comparing with the waterflow stoppage determination value S13 predetermined for the set. Further, the water flow stop detection unit 22 calculates a temperature difference ΔT23 between the detected water temperature T2 of the fetched water temperature detection means T2 and the detection water temperature T3 of the water temperature detection means T3, and the temperature difference ΔT23 and the water temperature detection means T2, T3. It is determined whether or not the temperature difference ΔT23 is equal to or greater than the water flow stop determination value S23 (ΔT23 ≧ S23) by comparing with a water flow stop determination value S23 determined in advance for the set. The water flow stop detection unit 22 determines that the water flow in the main water supply passage 3 has stopped when it is determined that the temperature difference between the detection temperatures of at least one set of water temperature detection means is equal to or greater than the water flow stop determination value. Outputs a water flow stop detection signal.

  Further, in the first embodiment, the pump stop unit 21 stops the water flow in the main water supply passage 3 or the temperature of the water supplied from the bypass water supply passage 4 to the main water supply passage 3 is the temperature of the main water supply passage 3. When the temperature is lower than the feed water temperature, the pump stop signal is output to stop the driving of the pump 5. For example, the pump stop unit 21 is connected to the heating unit from the exhaust heat recovery tank 10 of the exhaust heat hot water supply device 6. When the temperature of the feed water supplied to 11 becomes higher than a predetermined temperature (for example, 60 ° C.) or when the pump 13 of the exhaust heat utilizing hot water supply device 6 is stopped, the pump is stopped. It is good also as a structure which outputs a signal and stops the drive of the pump 5. FIG.

  In the first embodiment, even if the driving of the pump 5 is stopped by stopping the water flow in the main water supply passage 3, the water supplied from the exhaust heat recovery tank 10 of the exhaust heat utilization hot water supply apparatus 6 to the heating unit 11 is supplied. If the temperature is equal to or lower than a predetermined pump stop determination value (for example, 60 ° C.), the driving of the pump 13 is continued and exhaust heat recovery is continuously performed. For this reason, exhaust heat recovery efficiency can be improved.

  The second embodiment will be described below. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and duplicate descriptions of common portions are omitted.

  In the second embodiment, the water temperature detecting means T2 shown in the first embodiment is omitted, and a water temperature detecting means T3 indicated by a dotted line in FIG. 1 is provided. This water temperature detection means T3 detects the feed water temperature of the main feed water passage portion upstream from the branch position α of the bypass feed water passage 4.

  In the second embodiment, the control unit 7 includes a pump drive unit 26, a water flow detection unit 27, and a water temperature comparison unit 28, as shown in FIG. The water flow detection unit 27 detects that there is water supply in the main water supply passage 3 using the water temperature T1 detected by the water temperature detection means T1 and the water temperature T3 detected by the water temperature detection means T3. A water temperature intake unit 30 and a determination unit 31 are included. The water temperature capturing unit 30 captures the detected water temperature T1 of the water temperature detecting means T1 and the detected water temperature T3 of the water temperature detecting means T3, every moment.

  The determination unit 31 compares the detected water temperatures T1 and T3 captured at the same timing, and determines whether or not the detected water temperatures T1 and T3 match. When the detected water temperatures T1 and T3 match, it is determined that there is a water flow in the main water supply passage 3. Further, when the determination unit 31 determines that the detected water temperatures T1 and T3 do not match, the determination unit 31 calculates the temperature difference ΔT between the detected water temperatures T1 and T3 by subtracting the detected water temperature T3 from the detected water temperature T1. The determination unit 31 compares the calculated temperature difference ΔT with a predetermined allowable range for water flow detection, and determines whether the temperature difference ΔT is a temperature difference within the allowable range for water flow detection. . When the temperature difference ΔT is a temperature difference within an allowable range for water flow detection, the determination unit 31 considers that the detected water temperatures T1 and T3 are substantially the same because the detected water temperatures T1 and T3 are small. Then, it is determined that there is a water flow in the main water supply passage 3. When the determination unit 31 determines that there is a water flow in the main water supply passage 3, the water flow detection unit 27 outputs a water flow detection signal toward the pump drive unit 26.

  Further, when the determination unit 31 determines that the temperature difference ΔT exceeds the allowable range for water flow detection, the water temperature in the main water supply passage 3 is changed from the bypass water supply passage 4 to the main water supply stop by the water flow stop in the main water supply passage 3. By the supply of the preheated water supply to the water supply passage 3, it starts to rise from the joining position β of the bypass water supply passage 4, thereby determining that the water temperature T1 is higher than the water temperature T3. In this case, the water flow detection unit 27 does not output a water flow detection signal.

  The water temperature comparison unit 28 takes in a predetermined one of the water temperature T1 detected by the water temperature detection means T1 and the water temperature T3 detected by the water temperature detection means T3 from time to time, and detects the preheated water supply temperature. The water temperature Tt detected by the means Tt is taken in every moment. And the water temperature comparison part 28 compares the water temperature T1 (T3) taken in at the same timing, and the water temperature Tt, and judges whether the water temperature Tt is more than the water temperature T1 (T3). When the water temperature Tt is equal to or higher than the water temperature T1 (T3), the water temperature comparison unit 28 should not cause a situation in which the temperature of the water supply in the main water supply passage 3 is lowered by the preheated water supplied from the bypass water supply passage 4 to the main water supply passage 3. Judgment is made and a pump drive signal is output toward the pump drive unit 26.

  The pump drive unit 26 drives the pump 5 when receiving the water flow detection signal from the water flow detection unit 27 and detecting that the pump drive signal is received from the water temperature comparison unit 28. When it is detected that one or both of the detection signal and the pump driving signal of the water temperature comparison unit 28 are not received, the driving of the pump 5 is stopped.

  In the second embodiment, water temperature detecting means T1, T3 are provided, and the water flow detecting unit 27 uses the detected water temperature T1 of the water temperature detecting means T1 and the detected water temperature T3 of the water temperature detecting means T3, For example, water temperature detection means T1 and T2 are provided, and the water flow detection unit 27 includes a detection water temperature T1 of the water temperature detection means T1 and a water temperature detection means T2. When the detected water temperature T2 is detected and the detected water temperatures T1 and T2 coincide with each other or it is detected that the temperature difference between the detected water temperatures T1 and T2 is within a predetermined allowable range, The water flow detector 27 may be configured to output a water flow detection signal when it is determined that there is a water flow in the water supply.

  The third embodiment will be described below. In the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and a duplicate description of the common portions is omitted.

In the third embodiment, as shown by the dotted lines in FIGS. 3 and 4, the control unit 7 includes an exhaust heat recovery circulation path pump for controlling the drive of the pump 18 of the exhaust heat recovery circulation path 17. A drive unit 33 is provided. In the third embodiment, the pump control unit provided in the exhaust heat utilizing hot water supply apparatus 6 controls only the pump 18 .

  The exhaust heat recovery circulation passage pump drive unit 33 takes in the operation information of the pump drive unit 20 shown in the first embodiment example or the operation information of the pump drive unit 26 shown in the second embodiment example. The pump 18 is turned on / off in synchronization with the on / off operation.

  In addition, this invention is not limited to the form of each 1st-3rd embodiment, Various embodiments can be taken. For example, in each of the first to third embodiments, the power generation device 8 is an engine engine. However, the power generation device 8 is a fuel cell such as a fixed polymer fuel cell (PEFC). It may be configured.

  In each of the first to third embodiments, the flow passage cross-sectional area of the bypass water supply passage 4 is smaller than the flow passage cross-sectional area of the main water supply passage 3. Depending on the size of the connection port connected to the passage 4, the flow passage cross-sectional area of the bypass water supply passage 4 may be equal to the flow passage cross-sectional area of the main water supply passage 3.

  Further, in each of the first to third embodiments, the presence or absence of water flow in the main water supply passage 3 is detected using the water temperature detecting means for detecting the water temperature of the main water supply passage 3. The main water supply passage 3 is provided with a water flow sensor capable of detecting the water flow and the flow rate detection means, and the water flow detection unit or the water flow stop detection unit uses the outputs of the water flow sensor and the flow rate detection means to generate the main water supply passage. It is good also as a structure which judges the presence or absence of 3 water flows.

  Furthermore, in the first embodiment, the water temperature comparison unit 23 detects a water temperature T1 of the water temperature detection means T1 that detects the water temperature in the main water supply passage portion upstream of the joining position β of the bypass water supply passage 4, and the preheated water supply temperature. The detected water temperature Tt of the detection means Tt is compared, and the pump stop unit 21 is based on the comparison operation of the water temperature comparison unit 23 as well as when the water flow stop detection unit 22 detects the water flow stop of the main water supply passage 3. Even when it is detected that the detected water temperature Tt of the preheated water supply temperature detecting means Tt is lower than the detected water temperature T1 of the water temperature detecting means T1, the driving of the pump 5 of the bypass water supply passage 4 is stopped. If it is assumed that the temperature of the water supplied from the bypass water supply passage 4 to the main water supply passage 3 is hardly lower than the water temperature of the main water supply passage 3, the water temperature comparison unit 23 is omitted. In addition, the pump stop unit 21 may be configured to control the drive stop of the pump 5 in the bypass water supply passage 4 regardless of the temperature of the water supplied from the bypass water supply passage 4 to the main water supply passage 3. In this case, the preheating water supply temperature detecting means Tt may be omitted.

  Furthermore, in the second embodiment, the detected water temperature T1 (T3) of the water temperature detecting means T1 (T3) for detecting the water temperature in the main water supply passage portion upstream of the joining position β of the bypass water supply passage 4 by the water temperature comparison unit 28. ) And the detected water temperature Tt of the preheated water supply temperature detecting means Tt, and the pump drive unit 26 detects the water flow in the main water supply passage 3 and also performs preheating based on the comparison operation of the water temperature comparison unit 28. The pump 5 was driven when it was detected that the detected water temperature Tt of the water supply temperature detecting means Tt was equal to or higher than the detected water temperature T1 (T3) of the water temperature detecting means T1 (T3). 4, when it is assumed that the temperature of the feed water that joins the main feed water passage 3 hardly falls below the water temperature of the main feed water passage 3, the water temperature comparison unit 28 is omitted, and the pump drive unit 26 , Vipa The pump 5 may be driven when the water flow in the main water supply passage 3 is detected regardless of the temperature of the water supply that joins the main water supply passage 3 from the water supply passage 4.

It is the schematic block diagram which showed one example of embodiment of the exhaust-heat utilization preheating system of this invention. It is a model figure for demonstrating one structural example of the waste heat utilization hot water supply apparatus which comprises a waste heat utilization preheating system. It is a block diagram for demonstrating the structural example of the control part which comprises the waste heat utilization preheating system of 1st Embodiment. It is a block diagram for demonstrating the structural example of the control part which comprises the exhaust-heat utilization preheating system of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Waste heat utilization preheating system 2 Main hot water supply device 3 Main water supply passage 4 Bypass water supply passage 5,13 Pump 6 Waste heat utilization hot water supply device 8 Electric power generation device 10 Waste heat recovery tank 11 Heating part 17 Circulation path 20, 26 Pump drive part 21 Pump Stop part 22 Water flow stop detection part 23, 28
27 Water Flow Detection Unit 33 Waste Heat Recovery Circulation Path Pump Drive Unit T1, T2, T3, Water Temperature Detection Means Tt Preheating Water Supply Temperature Detection Means

Claims (7)

This system preheats a part of the water supplied to the main hot water supply device using exhaust heat, and diverts a part of the water supply from the main water supply passage that supplies the main hot water supply device to the downstream of the diversion position. A bypass water supply passage that returns the diverted water to the main water supply passage portion on the side, a pump for introducing a part of the water supply from the main water supply passage to the bypass water supply passage, and generated in the power generator installed in the bypass water supply passage A wastewater-use hot water supply device that uses exhaust heat to heat the water supply in the bypass water supply passage , and in addition, a water flow stop detection portion that detects a water flow stop in the main water supply passage, and the water flow stop detection portion A structure comprising a pump stop unit that stops the pump drive of the bypass water supply passage when it is detected that the water flow in the water supply passage has stopped, or the water flow in the main water supply passage is detected. Discharge of the water flow detection unit, characterized by having a structure, comprising a pump driver for driving the pump bypass water supply passage when it is detected the flow of main water supply passage by the flow detection unit Heat preheating system. This system preheats a part of the water supplied to the main hot water supply device using exhaust heat, and diverts a part of the water supply from the main water supply passage that supplies the main hot water supply device to the downstream of the diversion position. A bypass water supply passage that returns the diverted water to the main water supply passage portion on the side, a pump for introducing a part of the water supply from the main water supply passage to the bypass water supply passage, and generated in the power generator installed in the bypass water supply passage A wastewater-use hot water supply device that uses exhaust heat to heat the water supply in the bypass water supply passage, a water flow stop detection portion that detects a water flow stop in the main water supply passage, and the water flow stop detection portion water flow has a pump stop unit stopping the pump drive of the bypass water supply passage is provided when it is detected that has stopped, further, the bypass water supply passage is branched At least one of water temperature detection means for detecting the water temperature of the main water supply passage upstream from the position and water temperature detection means for detecting the water temperature of the main water supply passage downstream of the position where the bypass water supply passage joins And a water temperature detecting means for detecting the water temperature of the main water supply passage portion between the branch position and the merge position of the bypass water supply passage is provided, and the water flow stop detection unit is detected by each of the water temperature detection means. The water flow in the main water supply passage is stopped when it is detected that a temperature difference equal to or greater than a predetermined water flow stoppage determination value is generated between at least one set of water temperature detection means by comparing the water temperatures. The pump stop unit receives the water flow stop detection signal and stops the pump drive of the bypass water supply passage. Waste heat utilization preheating system that is characterized in that. A water flow stop detection unit that detects a water flow stop in the main water supply passage, and a pump stop unit that stops the pump drive of the bypass water supply passage when the water flow stop detection unit detects that the water flow in the main water supply passage has stopped. In the hot water supply system using waste heat , there is a heating unit that uses the exhaust heat of the power generator to heat the feed water in the bypass water supply passage to create preheated water, and waste heat that stores the preheated water supplied by the heating unit A recovery tank is provided, and the preheat water supply of the exhaust heat recovery tank is supplied to the main water supply passage through the bypass water supply passage, and the main water supply passage on the upstream side of the position where the bypass water supply passage joins is provided. A water temperature detecting means for detecting the water temperature and a preheated water temperature detecting means for detecting the temperature of the preheated water supplied to the main water supply passage are provided. A water temperature comparison unit for taking in and comparing the water temperatures detected by the hot water supply temperature detection means is provided, and the pump stop unit is based on the comparison operation of the water temperature comparison unit, and the detected water temperature by the preheating water supply temperature detection means is the water temperature detection means. claim 1 or claim 2 exhaust heat utilization preheating system according even when it is detected that is lower than the detection temperature, characterized in that to stop the pump drive of the bypass water supply passage by. A water flow detection unit that detects a water flow in the main water supply passage, and a pump drive unit that drives the pump of the bypass water supply passage when the water flow detection unit detects the water flow in the main water supply passage, Water temperature detecting means for detecting the water temperature of the main water supply passage upstream from the position where the water supply passage branches, and water temperature detection for detecting the water temperature of the main water supply passage downstream of the position where the bypass water supply passage joins And a water temperature detecting means for detecting the water temperature of the main water supply passage portion between the branching position and the merge position of the bypass water supply passage, and the water flow detection unit The water temperatures detected by the detection means are taken in, and the water temperatures are compared to make sure that all the water temperatures are the same or all the water temperature detection means. When it is detected that the temperature difference is within an allowable range given in advance, it is determined that there is a water flow in the main water supply passage, and a water flow detection signal is output. waste heat utilization preheating system according to claim 1, wherein the driving the pump bypass water supply passage receives. The waste heat utilization hot water supply device is provided with a heating unit that uses the waste heat of the power generation device to heat the feed water in the bypass water supply passage to produce preheated water, and a waste heat recovery tank that stores the preheated water supplied by the heating unit. Water temperature detection for detecting the water temperature of the main water supply passage upstream from the position where the bypass water supply passage joins, with a configuration in which the preheat water supply of the exhaust heat recovery tank is supplied to the main water supply passage through the bypass water supply passage And a preheating water temperature detecting means for detecting the temperature of the preheated water supplied to the main water supply passage, and comparing the water temperatures detected by the water temperature detecting means and the preheated water temperature detecting means, respectively. A water temperature comparison unit is provided, and the pump drive unit detects the water flow in the main water supply passage by the water flow detection means and performs preheating based on the comparison operation of the water temperature comparison unit. When the detection temperature by the water temperature detecting means is detecting that the detected coolant temperature or higher by the water temperature detecting means, waste heat utilization preheating system according to claim 4, wherein the driving the pump bypass water supply passage. The waste heat utilization preheating system according to any one of claims 1 to 5, wherein a flow passage cross-sectional area of the bypass water supply passage is smaller than a flow passage cross-sectional area of the main water supply passage. A circulation passage with a pump is provided to return the liquid after storing the waste heat of the power generation device to the waste heat utilization hot water supply device and transferring the waste heat to the waste heat utilization hot water supply device. to any one of claims 1 to 6, characterized in that the exhaust heat recovery circulating passage pump drive unit for driving in synchronization the pump on and off operation of the pump in the bypass water supply passage is provided The exhaust heat preheating system described.

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