Solar heat collecting system

Abstract

In one embodiment, a solar heat collecting system includes a heat collector configured to heat a heat medium by a sunray, a heating device configured to heat a heat utilizing fluid by heat of the heat medium, and a heat medium flow path configured to circulate the heat medium between the heat collector and the heating device. The system further includes a controller configured to control circulation of the heat medium in the heat collector in accordance with an amount of solar radiation of the sunray, or in accordance with a temperature difference between a first temperature of the heat medium at a first position and a second temperature of the heat medium at a second position located downstream of the first position with respect to the heat medium.

1 . A solar heat collecting system comprising:
 a heat collector configured to heat a heat medium by a sunray;   a heating device configured to heat a heat utilizing fluid by heat of the heat medium;   a heat medium flow path configured to circulate the heat medium between the heat collector and the heating device; and   a controller configured to control circulation of the heat medium in the heat collector in accordance with an amount of solar radiation of the sunray, or in accordance with a temperature difference between a first temperature of the heat medium at a first position and a second temperature of the heat medium at a second position located downstream of the first position with respect to the heat medium.   
     
     
         2 . The system of  claim 1 , wherein the controller stops the circulation of the heat medium in all or part of the heat collector in accordance with the amount of solar radiation or the temperature difference. 
     
     
         3 . The system of  claim 2 , wherein the controller stops the circulation of the heat medium in all or part of the heat collector, when the amount of solar radiation is smaller than a predetermined value, when a time period in which the amount of solar radiation is smaller than the predetermined value lasts longer than predetermined time, when the temperature difference is smaller than a predetermined value, or when a time period in which the temperature difference is smaller than the predetermined value lasts longer than predetermined time. 
     
     
         4 . The system of  claim 1 , wherein the controller restarts the circulation of the heat medium in accordance with the amount of solar radiation or the temperature difference, when the circulation of the heat medium in all or part of the heat collector stops. 
     
     
         5 . The system of  claim 4 , wherein the controller restarts the circulation of the heat medium in the heat collector during the stop of the circulation of the heat medium in all or part of the heat collector, when the amount of solar radiation is larger than a predetermined value, when a time period in which the amount of solar radiation is larger than the predetermined value lasts longer than predetermined time, when the temperature difference is larger than a predetermined value, or when a time period in which the temperature difference is larger than the predetermined value lasts longer than predetermined time. 
     
     
         6 . The system of  claim 1 , wherein
 the heat collector includes a plurality of heat collecting modules, and   the controller controls the circulation of the heat medium in at least one of the heat collecting modules in accordance with the amount of solar radiation or the temperature difference.   
     
     
         7 . The system of  claim 6 , wherein
 the heat collector includes heat collecting modules arranged in parallel with respect to the heat medium, and   the controller stops the circulation of the heat medium in the at least one of the heat collecting modules, when the amount of solar radiation is smaller than a predetermined value, when a time period in which the amount of solar radiation is smaller than the predetermined value lasts longer than predetermined time, when the temperature difference is smaller than a predetermined value, or when a time period in which the temperature difference is smaller than the predetermined value lasts longer than predetermined time.   
     
     
         8 . The system of  claim 6 , wherein
 the heat collector includes heat collecting modules arranged in parallel with respect to the heat medium, and   the controller restarts the circulation of the heat medium in the at least one of the heat collecting modules during stop of the circulation of the heat medium in the at least one of the heat collecting modules, when the amount of solar radiation is larger than a predetermined value, when a time period in which the amount of solar radiation is larger than the predetermined value lasts longer than predetermined time, when the temperature difference is larger than a predetermined value, or when a time period in which the temperature difference is larger than the predetermined value lasts longer than predetermined time.   
     
     
         9 . The system of  claim 6 , wherein
 the heat collector includes heat collecting modules arranged in serial with respect to the heat medium, and   the controller uses a bypass flow path in which the heat medium flows to bypass the at least one of the heat collecting modules, when the amount of solar radiation is smaller than a predetermined value, when a time period in which the amount of solar radiation is smaller than the predetermined value lasts longer than predetermined time, when the temperature difference is smaller than a predetermined value, or when a time period in which the temperature difference is smaller than the predetermined value lasts longer than predetermined time.   
     
     
         10 . The system of  claim 6 , wherein
 the heat collector includes heat collecting modules arranged in serial with respect to the heat medium, and   the controller releases, during use of a bypass flow path in which the heat medium flows to bypass the at least one of the heat collecting modules, the use of the bypass flow path, when the amount of solar radiation is larger than a predetermined value, when a time period in which the amount of solar radiation is larger than the predetermined value lasts longer than predetermined time, when the temperature difference is larger than a predetermined value, or when a time period in which the temperature difference is larger than the predetermined value lasts longer than predetermined time.   
     
     
         11 . The system of  claim 1 , wherein
 the heat collector includes first and second portions that circulate the heat medium, and   when the circulation of the heat medium in the first portion is to be kept and the circulation of the heat medium in the second portion is to be stopped, the controller reduces a flow rate of the heat medium in the heat collector after the stop of the circulation to be lower than a flow rate of the heat medium in the heat collector before the stop of the circulation.   
     
     
         12 . The system of  claim 1 , wherein the heat collector is configured to collect heat by condensing the sunray during stop of the circulation of the heat medium. 
     
     
         13 . The system of  claim 1 , wherein
 the heat collector is configured to collect heat by condensing the sunray,   during stop of the circulation of the heat medium, the heat collector does not condense the sunray to a portion of the heat collector holding the stopped heat medium, and   after restart of the circulation of the heat medium, the heat collector restarts the condensation of the sunray.   
     
     
         14 . The system of  claim 1 , wherein
 the heat collector includes a light condensing panel configured to track an altitude of the sun, and   during stop of the circulation of the heat medium, the heat collector moves the light condensing panel provided in a portion of the heat collector holding the stopped heat medium, to a position at an upstream side of wind from a portion at which heat is collected by condensation of light, and   after restart of the circulation of the heat medium, the heat collector moves the light condensing panel to a light condensing position.   
     
     
         15 . The system of  claim 1 , wherein
 the heat collector includes a light condensing panel configured to track an altitude of the sun, and   during stop of the circulation of the heat medium, the heat collector moves the light condensing panel provided in a portion of the heat collector holding the stopped heat medium, to a position above a portion at which heat is collected by condensation of light, and   after restart of the circulation of the heat medium, the heat collector moves the light condensing panel to a light condensing position.