Efficiency restoration in a photovoltaic cell

Abstract

The electrical output efficiency of a photovoltaic thermal system can be restored from degradation due to light exposure by annealing a photovoltaic thermal cell at an elevated temperature. The elevated temperature at the photovoltaic thermal cell can be provided by redirecting the flow of a heat exchange fluid to bypass a heat exchanger unit. A boiler unit may be employed to provide additional heating of the heat exchange fluid during the anneal. Further, a variable configuration lid can be provided over a front surface of the photovoltaic thermal cell to control ventilation over the front surface. During the anneal, the position of the variable configuration lid can be set so as to trap heat above the front surface and to elevate the anneal temperature further.

1 . A photovoltaic thermal (PVT) system comprising:
 a photovoltaic thermal (PVT) cell configured to generate electricity and to provide a thermal output; and   at least one means for heating a photovoltaic material within said photovoltaic thermal cell to a temperature greater than 130 degrees Celsius for a duration of time.   
     
     
         2 . The PVT system of  claim 1 , wherein said PVT cell includes a variable configuration lid configured to provide at least two different levels of ventilation over a front surface of said PVT cell. 
     
     
         3 . A photovoltaic thermal (PVT) system comprising:
 a photovoltaic thermal (PVT) cell configured to generate electricity and to provide a thermal output; and   a fluid circulation system that is configured to circulate a heat exchange fluid through at least two different circulation paths in different operational modes, wherein said at least two different circulation paths include a first circulation path including a pipe through said PVT cell and a pipe through a heat exchanger unit in which said heat exchange fluid loses heat, and a second circulation path that includes said pipe through said PVT cell and does not include said pipe through said heat exchanger unit.   
     
     
         4 . The PVT system of  claim 3 , wherein said at least one means comprises a first valve that is configured to select one of said at least two different circulation paths. 
     
     
         5 . The PVT system of  claim 4 , wherein said at least one means further comprises a boiler unit configured to heat said heat exchange fluid. 
     
     
         6 . The PVT system of  claim 5 , wherein said first valve is located on a pipe including said heat exchange fluid and located between said boiler unit and said heat exchanger unit. 
     
     
         7 . The PVT system of  claim 5 , further comprising a second valve that is configured to select a circulation path between one of said first and second circulation paths and a third circulation path that bypasses said boiler unit and said heat exchanger unit. 
     
     
         8 . The PVT system of  claim 7 , further comprising a third valve configured to select one of two inlets that are connected to an outlet of said heat exchanger unit and an outlet of said second valve, respectively, and connected to an inlet of said PVT cell. 
     
     
         9 . The PVT system of  claim 8 , wherein said PVT cell includes a variable configuration lid configured to provide at least two different levels of ventilation over a front surface of said PVT cell. 
     
     
         10 . The PVT system of  claim 3 , further comprising a control device configured to control said at least one means to elevate a temperature of a photovoltaic material of said PVT cell above a boiling point of said heat exchange fluid. 
     
     
         11 . The PVT system of  claim 10 , wherein said variable configuration lid is attached to a body of said PVT cell by a hinge around which said variable configuration lid can rotate, wherein a rotation of said variable configuration lid provides different levels of ventilation to said front surface of said PVT cell. 
     
     
         12 . The PVT system of  claim 10 , wherein said variable configuration lid is configured to slide in a plane that is substantially parallel to said front surface of said PVT cell, wherein a sliding of said variable configuration lid in said plane provides different levels of ventilation to said front surface of said PVT cell. 
     
     
         13 . The PVT system of  claim 10 , wherein said variable configuration lid is configured to move in a direction substantially perpendicular to said front surface of said PVT cell, wherein a movement of said variable configuration lid in said direction provides different levels of ventilation to said front surface of said PVT cell. 
     
     
         14 .- 25 . (canceled)