Solar water heating system

Abstract

The present invention relates to a solar water heating system including: a solar collector to which solar heat is collected; a solar collector circulation pipe adapted to circulate an operating medium on which the solar heat collected by the solar collector is accumulated therealong; a thermal storage tank in which the operating medium and the water used for living are heat-exchanged; a hot water circulation pipe communicating with the thermal storage tank; a freezing prevention valve located on one side of the hot water circulation pipe and adapted to be open and closed to allow the water in the thermal storage tank to selectively flow along the hot water circulation pipe; and a controller adapted to control the operation of the freezing prevention valve, thereby preventing the hot water circulation pipe from being frozen and destructed.

1 . A solar water heating system comprising:
 a solar collector to which solar heat is collected;   a solar collector circulation pipe connected to the solar collector and adapted to circulate an operating medium on which the solar heat collected by the solar collector is accumulated therealong;   a thermal storage tank in which the operating medium and the water used for living are heat-exchanged;   a hot water circulation pipe communicating with the thermal storage tank, to which the water is supplied;   a freezing prevention valve located on one side of the hot water circulation pipe and adapted to be selectively open and closed to allow the water in the thermal storage tank to selectively flow along the hot water circulation pipe; and   a controller adapted to control the operation of the freezing prevention valve in accordance with the variation of at least one or more of a temperature T 1  of a given portion of the hot water circulation pipe and a temperature T 2  of the water in the thermal storage tank, thereby preventing the hot water circulation pipe from being frozen and destructed.   
     
     
         2 . The solar water heating system according to  claim 1 , wherein if the temperature T 1  of a given portion of the hot water circulation pipe is below Ta (wherein 1° C≦Ta≦6° C.), the freezing prevention valve is open by means of the controller, and if the temperature T 1  of the given portion of the hot water circulation pipe is above Tc (wherein 9° C≦Tc≦11° C.), the freezing prevention valve is closed by means of the controller. 
     
     
         3 . The solar water heating system according to  claim 1 , wherein if the temperature T 1  of a given portion of the hot water circulation pipe is below Ta (wherein 3° C≦Ta≦6° C.), the freezing prevention valve is open by means of the controller, and if the temperature T 1  of the given portion of the hot water circulation pipe and the temperature T 2  of the water of the thermal storage tank satisfy the condition (1), T2>Tb, T1>Tc and the condition (2), T2≦Tb, T1>T2−dT (wherein 11° C<Tb≦14° C., 9° C≦Tc≦11° C., 1° C≦dT≦3° C.), the freezing prevention valve is closed by means of the controller. 
     
     
         4 . The solar water heating system according to  claim 2  or  3 , wherein the Ta is 4° C., the Tb is 12° C., the Tc is 10° C., and the dT is 2° C. 
     
     
         5 . A solar water heating system comprising:
 a solar collector to which solar heat is collected;   a solar collector circulation pipe connected to the solar collector and adapted to circulate an operating medium on which the solar heat collected by the solar collector is accumulated therealong;   a thermal storage tank in which the operating medium and the water used for living are heat-exchanged;   a hot water circulation pipe communicating with the thermal storage tank and having a hot water intake pipe through which the water is supplied to the thermal storage tank and a hot water discharge pipe through which the water is discharged from the thermal storage tank;   a connection pipe adapted to allow the hot water intake pipe and the hot water discharge pipe to communicate with each other;   a check valve mounted on the connection pipe and adapted to selectively open and close the connection pipe;   a circulation pump mounted on the connection pipe and adapted to allow the water in the thermal storage tank to be circulated along the hot water intake pipe and the hot water discharge pipe through the connection pipe; and   a controller adapted to control the operation of the circulation pump in accordance with the variation of at least one or more of a temperature T 1  of a given portion of the hot water circulation pipe and a temperature T 2  of the water in the thermal storage tank, thereby preventing the hot water circulation pipe from being frozen and destructed.   
     
     
         6 . The solar water heating system according to  claim 5 , wherein if the temperature T 1  of a given portion of the hot water circulation pipe is below Ta (wherein  1 ° C≦Ta≦ 6 ° C.), the circulation pump is operated by means of the controller, and if the temperature T 1  of the given portion of the hot water circulation pipe and the temperature T 2  of the water of the thermal storage tank satisfy the condition (1), T2>Tb, T1>Tc and the condition (2), T2≦Tb, T1>T2−dT (wherein 11° C<Tb≦14° C., 9° C≦Tc≦11° C., 1° C≦dT≦3° C.), the operation of the circulation pump stops by means of the controller. 
     
     
         7 . The solar water heating system according to  claim 6 , wherein the Ta is 2° C., the Tb is 12° C., the Tc is 10° C., and the dT is 2° C. 
     
     
         8 . The solar water heating system according to  claim 6 , further comprising a freezing prevention heater adapted to adjust the temperature of the water in the thermal storage tank under the control of the controller, wherein if the temperature T 2  of the water of the thermal storage tank is below 12° C., the freezing prevention heater is operated by means of the controller, and if the temperature T 2  of the water of the thermal storage tank is above 14° C., the operation of the freezing prevention heater stops by means of the controller. 
     
     
         9 . The solar water heating system according to  claim 5  or  6 , further comprising a freezing prevention heater adapted to adjust the temperature of the water in the thermal storage tank under the control of the controller, wherein if the temperature T 2  of the water of the thermal storage tank is below 6° C., the freezing prevention heater is operated by means of the controller, and if the temperature T 2  of the water of the thermal storage tank is above 8° C., the operation of the freezing prevention heater stops by means of the controller. 
     
     
         10 . A solar water heating system comprising:
 a solar collector to which solar heat is collected;   a solar collector circulation pipe connected to the solar collector and adapted to circulate an operating medium on which the solar heat collected by the solar collector is accumulated therealong;   a thermal storage tank having an outside tank communicating with the solar collector circulation pipe and an inside tank located inside the outside tank in such a manner as to be isolated from the outside tank;   a hot water circulation pipe communicating with the inside tank, to which the water is supplied;   one or more freezing prevention valves adapted to be open and closed if a given portion of the hot water circulation pipe reaches an opening temperature, to allow the water in the inside tank to be discharged to the outside from the hot water circulation pipe and adapted to be open and closed if the given portion of the hot water circulation pipe reaches a closing temperature, to prevent the water in the inside tank from being discharged to the outside from the hot water circulation pipe; and   a controller adapted to control the opening/closing of the one or more freezing prevention valves in accordance with the variation of the temperature of the given portion of the hot water circulation pipe, thereby preventing the hot water circulation pipe from being frozen and destructed.   
     
     
         11 . The solar water heating system according to  claim 10 , wherein the hot water is residential water, the hot water circulation pipe has a hot water intake pipe through which the residential water is introduced into the inside tank and a hot water discharge pipe through which the residential water heated in the inside tank is discharged, the hot water discharge pipe being partially contacted with the hot water intake pipe, the given portion of the hot water circulation pipe is a portion of the hot water discharge pipe, on which a sensor measuring the temperature of the given portion is mounted, the hot water discharge pipe having an outflow pipe mounted on one side thereof to discharge the hot water to the outside of the hot water circulation pipe, and the freezing prevention valve is mounted on the outflow pipe to open and close the outflow pipe. 
     
     
         12 . The solar water heating system according to  claim 11 , further comprising a heat insulation material adapted to be surrounded along the contacted portion between the hot water intake pipe and the hot water discharge pipe. 
     
     
         13 . The solar water heating system according to  claim 10 , wherein the hot water is residential water, the hot water circulation pipe has a hot water intake pipe through which the residential water is introduced into the inside tank and a hot water discharge pipe through which the residential water heated in the inside tank is discharged, the hot water intake pipe and the hot water discharge pipe having first and second outflow pipes mounted on one sides thereof to discharge the hot water to the outside of the hot water circulation pipe, and the freezing prevention valves are composed of a first freezing prevention valve mounted on the first outflow pipe to open and close the first outflow pipe, a second freezing prevention valve mounted on the second outflow pipe to open and close the second outflow pip, and a third freezing prevention valve mounted on the hot water intake pipe in such a manner as to be closed if the first freezing prevention valve is open and to be open if the first freezing prevention valve is closed. 
     
     
         14 . The solar water heating system according to  claim 11  or  13 , further comprising a freezing prevention heater disposed at the inside tank to raise the temperature of the hot water in the inside tank, the freezing prevention heater being operated by means of the controller if the given portion of the hot water circulation pipe reaches the opening temperature and the operation of the freezing prevention heater being stopped by means of the controller if the given portion of the hot water circulation pipe reaches the closing temperature. 
     
     
         15 . A solar water heating system comprising:
 a solar collector to which solar heat is collected;   a solar collector circulation pipe connected to the solar collector and adapted to circulate an operating medium on which the solar heat collected by the solar collector is accumulated therealong;   a thermal storage tank having an outside tank communicating with the solar collector circulation pipe and an inside tank located inside the outside tank in such a manner as to be isolated from the outside tank;   a hot water circulation pipe communicating with the inside tank and having a hot water intake pipe through which residential water is introduced into the inside tank and a hot water discharge pipe through which the residential water heated in the inside tank is discharged, the hot water discharge pipe being partially contacted with the hot water intake pipe;   an outflow pipe mounted on one side of the hot water discharge pipe to discharge the hot water to the outside of the hot water circulation pipe; and   a freezing prevention valve having a sensor mounted thereon to measure a temperature in such a manner as to open and close the outflow pipe in accordance with the temperature sensed by the sensor.   
     
     
         16 . A solar water heating system comprising:
 a thermal storage tank in which residential water introduced thereinto is stored;   a circulation pump adapted to circulate the residential water existing in the lower portion of the thermal storage tank having a lower temperature by 10° C. to 15° C. than the residential water existing in the upper portion of the thermal storage tank therethrough;   a solar collector to which solar heat is collected to heat the residential water supplied by the circulation pump;   a solar collector circulation pipe adapted to connect the solar collector and the thermal storage tank with each other and adapted to provide a passage through which the residential water heated by the solar collector is discharged to the thermal storage tank;   a thermal storage tank circulation pipe connected to the thermal storage tank and adapted to provide passages through which the residential water is introduced into the lower portion of the thermal storage tank and the residential water existing in the upper portion of the thermal storage tank is discharged;   a first temperature sensor mounted on the thermal storage tank circulation pipe to detect the temperature thereon; and   a controller adapted to operate the circulation pump if the temperature detected by the first temperature sensor is below a first reference temperature,   wherein the thermal storage tank and the thermal storage tank circulation pipe are located indoors, and the circulation pump, the solar collector and the first temperature sensor are located outdoors.   
     
     
         17 . The solar water heating system according to  claim 16 , wherein the solar collector circulation pipe comprises a solar collector intake pipe adapted to provide a passage through which the residential water stored in the thermal storage tank is introduced into the solar collector and a solar collector discharge pipe adapted to provide the passage through which the residential water heated by the solar collector is discharged to the thermal storage tank, and the first temperature sensor is mounted on the solar collector intake pipe in vicinity of the solar collector. 
     
     
         18 . The solar water heating system according to  claim 17 , further comprising a second temperature sensor mounted on the solar collector discharge pipe in vicinity of the solar collector, and the circulation pump is operated by means of the controller if the temperature detected by the second temperature sensor is above a second reference temperature. 
     
     
         19 . The solar water heating system according to  claim 18 , wherein the operation of the circulation pump stops by means of the controller if the temperature detected by the first temperature sensor or the second temperature sensor is above a first set temperature or below a second set temperature. 
     
     
         20 . The solar water heating system according to  claim 16 , wherein a flow rate of the circulation pump is in a range between 6 l/hr and 9 l/hr per area (1 m 2 ) of the solar collector. 
     
     
         21 . The solar water heating system according to  claim 18 , wherein the circulation pump is operated by means of the controller in accordance with the difference between the temperatures detected by the first temperature sensor and the second temperature sensor.