The way of opening the top window includes one-side top window drove by rack and pinion, two-sides top window drove by rack and pinion, staggered top window drove by rack and pinion, electric roll top window, side window drove by rack and pinion, electrical roll side window, sliding window and etc. The rack and pinion system has a number of rack and pinion racks. Under the action of the drive shaft, the greenhouse windows open. Due to conform to the direction of hot air flow, it can conducive to