To add passive cooling to the house you can utilize what are sometimes called “Geo-coupled thermal tubes”, simple pipes or passages below ground where hot air is cooled before entering the shelter....SO AWESOME!
Passive Cooling: Rock Wall. A Natural Thermostat: "Large rocks squeezed into together by 'wood shelves' insulate the South face of the house. The rocks absorb the heat during the day lowering the solar gain. At night the rocks give heat back into into the air as the temperature outside drops. The rock wall and the desert climate work in concert to passively cool the house."