... the burkert 2822 is that the lowest watt ? i guess the lower the watts the less heat it gives out as i heard... also is there one in a 12vdc or a 24vdc doesnt matter or play into any heat problems?
Why are you so enamored with the idea of heat and Burkert solenoids? They don't get hot to melt plastic or catch paper on fire. They will melt the wax on a candle though. Does that sound dangerous to you?
If you are worried about heat, check out ballasts and light bulbs. These pose a slight danger.