Abstract: In a method of analyzing a lighting environment, the lighting environment is initially divided into a plurality of blocks so that all surfaces defining said lighting environment may be divided into a plurality of surface patches. The surface patch that radiates the most light energy is then searched. If the quantity of light radiated from this surface patch exceeds a given value, the quantity of light radiated from this surface patch which arrives at each of said plurality of surface patches is computed. Thereafter, the surface patch that radiates the next most light energy is searched, and the quantity of light radiated from this surface patch which arrives at each surface patch is computed. In this way, the total quantity of light received by each surface patch is obtained. In this method, mirror reflection is taken into account.

Abstract: A burner has first and second nozzles communicated with a combustion chamber and defined in a wall structure surrounding the combustion chamber. The first and second nozzles are opposed to each other and positioned adjacent an exit opening of a fuel supply passage that is defined in the wall structure. The burner also has first and second secondary air supply ports defined in the wall structure adjacent the exit of the combustion chamber in opposition to each other.

Abstract: A burner includes a number of flame ports each having a fuel supply passage and provided on a pair of opposite walls of a combustion chamber such that each of the walls and the fuel supply passages define a cooling passage. In the burner, a wide stable flame region is achieved at a high excess air ratio, the amount of NOx produced is reduced and backfire is prevented by cooling the fuel supply passages. Furthermore, a flame area per unit area of each flame port is increased such that the burner can effect high-load combustion.