Describir: Solar heating design by f chart method

           _    _     _____     ______   _    _      ___              
  ____    | || | ||  / ____||  /_   _// | \  / ||   / _ \\      ___   
 |    \\  | || | || / //---`'   -| ||-  |  \/  ||  / //\ \\    /   || 
 | [] ||  | \\_/ || \ \\___     _| ||_  | .  . || |  ___  ||  | [] || 
 |  __//   \____//   \_____||  /_____// |_|\/|_|| |_||  |_||   \__ || 
 |_|`-`     `---`     `----`   `-----`  `-`  `-`  `-`   `-`     -|_|| 
 `-`                                                             `-`  
   ___    
  / _ \\  
 | / \ || 
 | \_/ || 
  \___//  
  `---`