igbt bridge dimmer
I do not think heat will be a problem, IGBT's can be more efficient than triacs. I work with high voltage motor drives (450volts, 15 Amps) and IGBT's are the device of choice. There are some very good powerful devices available at reasonable cost with high switching speeds. Used as a switch, dissipation is low. Check IR for small metal devices with large heatsink contact area. A reverse phase dimmer can easily be implemented reducing the need for large filter chokes. A better solution is to use PWM control at a frequency of ~20KHz. Comparitivly slow for IGBT devices so low switching losses. A sine wave can be generated by the PWM module if required. One simple topology is to use a bridge rectifier on the AC line with the IGBT across the DC connections. Modern devices also have positive thermal characteristics for simple paralleling. These babies are what control Fork lift Trucks and Welding machines!