Patent Publication Number: US-8117998-B2

Title: Hot water supplying system

Description:
TECHNICAL FIELD 
     The present invention relates to a hot water supplying system, particularly a hot water supplying system for heating cold water flowing into an inlet to a temperature set by a user and then supplying the heated water through an outlet, which includes a preheating-circulating system that maximally reduces the time to attain the set temperature, and is designed to use a portion of preheating energy for heating and prevents pipelines from freezing and bursting during the winter by circulating the preheated water. 
     BACKGROUND ART 
     In general, a hot water supplying system is designed to heat water to a temperature set by a user in a short time and then supply the heated water, and in a hot water supplying system, important factors to determine the performance of the system are how long it takes to heat the water to the temperature set by the user and whether to be able to supply the water with the temperature maintained at the set level even if the amount of water that is used changes. 
       FIG. 1  is a view showing the configuration of a hot water supplying system in the prior art. 
     According to the configuration of a hot water supplying system  10  in the prior art, as water flowing into an inlet  11  passes through a heat exchanger  15 , it is heated by a heating device (burner) provided in the heat exchanger  15 , such that hot water is supplied through an outlet  17  to a user. 
     A flow sensor  14 , an inflow temperature sensor  13 , and an outflow temperature sensor  16  that detect the flow and temperature of water are disposed in the pipeline from the inlet  11  to the outlet  17 . 
     A controller  18  compares a temperature detected by the sensors with a temperature set by a user using a temperature setting device  19  and maintains the water at the set temperature by determining the combustion intensity of the heating device in the heat exchanger  15 , depending on the compared results. 
     DISCLOSURE 
     Technical Problem 
     Even though the hot water supplying system  10  in the prior art supplies hot water that is heated at a set temperature in a short time by instantaneously providing much heat energy through heating by the heat exchanger  15 , water flowing into the inlet  11  is at a low temperature when the outdoor temperature is low such as during winter, and therefore there is a limit in reducing the time that is taken to supply high-temperature water by heating the low-temperature water in the heat exchanger  15 . 
     Further, if the pause state of the hot water supplying system  10  is maintained for a long time in the winter, the pipelines may be frozen and burst. When a separate heating device is provided to prevent the pipelines from bursting, additional loss of energy is correspondingly generated. 
     Technical Solution 
     The present invention has been invented to overcome the above problems and it is an object of the invention to provide a hot water supplying system that has a preheating-circulating system for maximally reducing the time to attain a temperature set by a user and can use heat energy of flowing hot water for heating, by changing the path of water flowing in the preheating-circulating system on the basis of whether the hot water is used or not. 
     In order to achieve the objects, the present invention provides a hot water supplying system that heats low-temperature water flowing into an inlet to a high temperature and supplies hot water through an outlet, and the hot water supplying system comprises a water tank for storing water flowed into the inlet; a heat exchanger for heating the water flowed therein; a controller that compares a temperature measured by a temperature sensor with a predetermined preheating temperature and controls the operation of the heat exchanger, the temperature sensor being disposed at a predetermined position in a pipeline through which water flows; and a pump that is disposed on a pipeline connecting a first node with a second node, wherein the first node is disposed on a pipeline connecting the heat exchanger with the outlet, and the second node is disposed on a pipeline connecting the inlet with the water tank. 
     Further, a check valve is further provided on a pipeline connecting the pump with the second node. 
     Further, a third node is disposed on a pipeline connecting the first node with the outlet, and a three-way valve is provided between the first node with the pump such that the preheated water passes through a radiator disposed in a separate pipeline connecting the third node with the three-way valve. 
     Advantageous Effects 
     As described above, according to a hot water supplying system of the invention, since a water tank storing a predetermined amount of water is provided with the hot water supplying system, and water stored in the water tank and remaining in the pipelines is preheated even when the hot water is not used, it is possible to supply hot water heated to a set temperature in the shortest time whenever a user wants to use the hot water, and to prevent the pipelines from freezing and bursting in the winter. 
     Further, since the flow path of water in the preheating-circulating process is controlled such that the water passes through a radiator at the outside by manually operating a three-way valve, it is possible to use the hot water supplying system as a heating device, in addition to preheating the water remaining in the hot water supplying system, by using only one inner pump. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing the configuration of a hot water supplying system in the prior art; 
         FIG. 2  is a view showing the configuration of a hot water supplying system according to a first embodiment of the invention; 
         FIG. 3  is a view showing a flow path of water while preheating according to a first embodiment of the invention; 
         FIG. 4  is a view showing a flow path of water while using hot water according to a first embodiment of the invention; 
         FIG. 5  is a view showing the configuration of a hot water supplying system according to a second embodiment of the invention; 
         FIG. 6  is a view showing a flow path of water while preheating according to a second embodiment of the invention; and 
         FIG. 7  is a view showing a flow path of water while using hot water according to a second embodiment of the invention. 
     
    
    
     BEST MODE 
     Configurations and operations of preferred embodiments of the invention are described hereafter in detail with reference to the accompanying drawings. 
       FIG. 2  is a view showing the configuration of a hot water supplying system according to a first embodiment of the invention,  FIG. 3  is a view showing a flow path of water while preheating, and  FIG. 4  is a view showing a flow path of water while using hot water. 
     As shown in  FIG. 2 , a hot water supplying system  20  according to a first embodiment of the invention includes a water tank  22  for storing water flowing into an inlet  21 , a heat exchanger  25  for heating the water, a temperature sensor  23  and a flow sensor  24  that are disposed on a pipeline connecting the water tank  22  with the heat exchanger  25 , a pump  28  that is disposed on a pipeline connecting a first node  41 , which is disposed on a pipeline connecting the heat exchanger  25  with an outlet  32 , with a second node  42 , which is disposed on a pipeline connecting the inlet  21  with the water tank  22 , and a check valve  29  for preventing a backward flow. 
     The hot water supplying system  20  according to the first embodiment has a closed inner circular path of the pipeline connecting the inlet  21  with the outlet  32 . Accordingly, since water remaining in the hot water supplying system  20  is preheated while a user does not use the hot water, the water can be heated at a temperature set by the user within a short time when the user starts to use hot water. 
     About 2 l of water is stored in the water tank  22 , which flows into the inlet  21 . The water stored in the water tank  22  and the water remaining in the inner pipeline of the hot water supplying system  20  are preheated while the user does not use hot water such that the preheated water can reach a desired high temperature within a short time at the time the user starts to use hot water. 
       FIG. 3  is a view showing a flow path of water in which water is being preheated while the user does not use the hot water. While the hot water is not being used, the outlet  32  is closed and water is preheated, flowing through the path indicated by a thick line by the pump  28 . 
     The temperature sensor  23  is disposed in the pipeline connecting the water tank  22  with the heat exchanger  25 , and during preheating, the controller  30  connected with the temperature sensor  23  compares a temperature measured by the temperature sensor  23  with a predetermined preheating temperature set by the user. For example, if the preheating temperature is set at 40° C. by the user, the controller  30  controls to stop heating in the heat exchanger  25  when the temperature measured by the temperature sensor  23  is +5° C. or more higher than the set preheating temperature, and controls to start heating in the heat exchanger  25  when the temperature measured by the temperature sensor  23  is −5° C. or more lower than the set preheating temperature. It is apparent to those skilled in the art that the above set temperature and the temperature range can be changed by the user. 
     Further, the temperature sensor  23  may be disposed anywhere in the pipeline through which the water flows, but it may be preferable to dispose the temperature sensor  23  at a position in the pipeline right after the water tank  22  having large heat capacity and set a temperature measured at the position as a reference temperature of the water. 
       FIG. 4  is a view showing a water flow path while using hot water, in which the water flowing into the inlet  21  passes through the water tank  22  and is heated by the heat exchanger  25 . Then, the water is discharged through the outlet  32  and supplied to the user. 
     When the user opens a valve at the outlet  32  to use the hot water, all of the water which reaches the first node  41 , is discharged through the outlet  32  by the pressure difference, and the inner circulation as shown in  FIG. 3  is no longer made. 
     The flow sensor  24  is disposed in the pipeline connecting the water tank  22  with the heat exchanger  25 , such that when water flow is detected, the flow sensor  24  sends a detection signal to the controller  30  and the controller  30  actuates the heat exchanger  25 . 
     It is possible to obtain the functional effect of preventing the pipelines from freezing and bursting during the winter, by the preheating configuration according to the first embodiment. 
       FIG. 5  is a view showing the configuration of a hot water supplying system according to a second embodiment of the invention,  FIG. 6  is a view showing a flow path of water while preheating, and  FIG. 7  is a view showing a flow path of water while using hot water. 
     As show in  FIG. 5 , the configuration of the hot water supplying system  20  according to the second embodiment of the invention is additionally provided with a three-way valve  27  disposed on the pipeline connecting the first node  41  with the second node  42 , including the configuration according to the first embodiment. Further, a third node  43  is disposed on a pipeline connecting the first node  41  with the outlet  32 , and a radiator  26  is disposed on a separate pipeline connecting the third node  43  with the three-way valve  27 . The three-way valve  27  has two inlets  27   a ,  27   b  and one outlet  27   c  and can change the flow path of water. 
     As shown in  FIG. 6 , in a preheating-circulating process according to the second embodiment, when a user does not use hot water, the first inlet  27   a  of the three-way valve  27  and the outlet  32  are closed, and the second inlet  27   b  and the outlet  27   c  of the three-way valve  27  are open, such that inner circulation of water is created by the path as shown in the figure. 
     It is possible to prevent pipelines from freezing and bursting at temperatures below zero during the winter, using the configuration of the hot water supplying system  20 . Further, the hot water supplying system  20  can be used as a heating device by transferring heat of the hot water to the radiator  26 . 
     The invention is also characterized in that it is possible to supply hot water and achieve outside-heating by circulating the water, using only one pump  28 , as shown in  FIG. 6 .  FIG. 7  is a view showing a flow path of water when a user uses hot water, which is the same as in the first embodiment shown in  FIG. 4 . 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, it is provided a hot water supplying system that includes a preheating-circulating system which enables to maximally reduce the time to attain a temperature set by a user, and is designed to use a portion of preheating energy for heating, preventing pipelines from freezing and bursting in winter with preheating-circulating.