Keep them indoor. Sweep the floor with cold water atleast twice a day, specially the place where ur dog sleeps. Spray water droplets on the mat ur dog uses for resting. Fill the cooler with iced water, this cools down the room much faster. If u live at the top floor then pour water on ur rooftop, then switch on the fan along with the cooler. Prevent ur dog from running around or playing a lot to keep him cool. These are some small things which u can do to keep ur dog cool.