Dynamic distributed tower receiver system for collecting, aiming and receiving solar radiation

Abstract

The invention involves a time dependent method for reducing cosine loss from heliostat fields in receiver system solar power plants with not one but multiple towers and multiple receivers. In this method heliostats change which tower mounted receiver they aim reflected Sun rays through day times to reduce cosine loss. In preferred embodiments a field of heliostats of several tens of acres has many towers and receivers. These systems are called dynamic distributed tower receiver systems (DDTRS).

1 . An apparatus and method, called a dynamic distributed tower receiver system, for collecting, aiming and receiving concentrated solar radiation, comprising:
 a field of heliostats;   two or more towers located within or adjacent to the field of heliostats;   two or more receivers mounted on top of two or more towers in or adjacent to the field of heliostats and to which the field of heliostats can reflect and aim Sun rays;   one or more calibration tables holding all heliostat to receiver direction vectors;   means for obtaining the Sun's apparent direction repeatedly in day times;   making decisions, repeatedly in day times, of which receiver heliostats should aim reflected Sun rays at, not usually the same receiver for all heliostats;   neighbor circuit or wired or wireless transmission of the receiver aim decisions to the field of heliostats' aim actuator units; and   implementation of the receiver aim decisions by the field of heliostat's aim actuator units.   
     
     
         2 . The apparatus and method of  claim 1  additionally comprising:
 one or more memory devices that can store calibration tables of heliostat to receiver direction vectors and allow electronic access to such calibration tables to integrated circuit devices that can implement logical and analytical programs; and 
 one or more integrated circuit devices, for example field-programmable gate arrays (FPGA), application-specific integrated circuits (ASIC), CPUs of general purpose computers, to implement logical and analytical programs that make aim decisions about which receiver heliostats should aim reflected Sun rays at and initiate transmission of such aim decisions. 
 
     
     
         3 . The apparatus and method of  claim 2  wherein means for obtaining the Sun's apparent direction repeatedly in day times is implemented in a logical and analytical program, based on Newton's laws, some solar system facts, the longitude and latitude coordinates of the DDTRS site and the current time, and run on the integrated circuit devices running logical and analytical programs that make aim decisions. 
     
     
         4 . The apparatus and method of  claim 2  wherein means for obtaining the Sun's apparent direction repeatedly in day times is a prior art Sun tracking device that can electronically signal one or more of the integrated circuit devices running logical and analytical programs that make aim decisions. 
     
     
         5 . The apparatus and method of  claim 2  wherein, for heliostats moved individually by an aim actuator unit, the heliostat to receiver aim decisions are made such that the cosine loss of each heliostat is minimized over the choice of receivers to aim at. 
     
     
         6 . The apparatus and method of  claim 2  wherein, for groups of heliostats that are moved collectively by a group aim actuator unit, the heliostat group to receiver aim decisions are made such that the cosine loss of the heliostat closest to the group's plan middle is minimized over the choice of receivers to aim at. 
     
     
         7 . The apparatus and method of  claim 1  wherein the receiver aim decisions are repeated in day time intervals not exceeding 5 minutes. 
     
     
         8 . The apparatus and method of  claim 1  wherein the calibration table is revised with remeasured calibration direction vectors between the heliostats and receivers after known ground moving and structure moving events such as earthquakes, high winds, flooding, mudslides, explosions, fires, above and below ground local structure collapse, vehicle accidents, heavy vehicle traffic, stampeding herds of animals, pile-driving, digging, earth grading and earth or rock moving for construction or mining. 
     
     
         9 . The apparatus and method of  claim 1  wherein the calibration table is revised with remeasured calibration direction vectors between the heliostats and receivers at least every five years. 
     
     
         10 . The apparatus and method of  claim 1  wherein the number per heliostat field area density of towers, with receivers mounted on top, is in excess of 1 tower for every 4 acres (1.6 hectares) of heliostat field. 
     
     
         11 . The apparatus and method of  claim 10  wherein the towers, including top mounted receivers, are less than 90 feet (27.4 m) tall, excluding tower parts intentionally buried below ground. 
     
     
         12 . The apparatus and method of  claim 11  wherein the number per heliostat field area density of towers, with receivers mounted on top, is in excess of 1 tower for every 1.5 acres (0.6 hectares) of heliostat field. 
     
     
         13 . The apparatus and method of  claim 12  wherein the towers, including top mounted receivers, are less than 50 feet (15.2 m) tall, excluding tower parts intentionally buried below ground. 
     
     
         14 . The apparatus and method of  claim 13  wherein the heliostats are not more than seven feet (2.13 m) tall with any heliostat mirror orientation, excluding heliostat parts intentionally buried below ground. 
     
     
         15 . The apparatus and method of  claim 10  wherein the towers, on top of which receivers are mounted, are aligned roughly or exactly in rows and roughly or exactly in an east-west direction. 
     
     
         16 . The apparatus and method of  claim 15  wherein towers aligned along a single row are roughly equally spaced along that row. 
     
     
         17 . The apparatus and method of  claim 16  wherein the rows the towers are aligned on are roughly equally separated on the north-south direction.