The Pentagon activates solar air conditioning

The solar heating, air-conditioning, power and lighting system installed at the guard station of the Pentagon is one of the most advanced in the US. The system incorporates 12 advanced ways of using solar energy to reduce fossil and electrical energy use, notably in summer. The new solar-desiccant-evaporative air-conditioning system reduces summer humidity levels of outside air and cools the air before supplying it to the guard section. The dry air allows very efficient evaporative cooling to take place even in humid climates; thanks to evaporative cooling, no humidity is added to the air. This is particularly important for buildings such as laboratories or industrial facilities with 100% outside airflow and high energy use and cost in dehumidifying and cooling the air. This system has reduced dew point by as much as 9°C and reduced dry bulb temperatures by 12°C during a mid-day test in July. A 7°C drop is expected when minor adjustments are made to the water flow and air flow between stages. At peak performance, the existing system has demonstrated 3.6 units of cooling/dehumidification output for every 1 unit of electrical input and all of the electrical input from the utility grid is at night, during "off-peak" hours.