Kennedy Space Center Pilots Solar Thermal Project at Film Storage Building
March 7, 2007
A solar thermal pilot project was conducted at the film storage building at Kennedy Space Center (KSC), Florida, funded by a grant from the Department of Energy's (DOE) Federal Energy Management Program (FEMP). The project demonstrated that sunlight is a viable source of heat for the regeneration process of a desiccant dehumidification system.
|Solar heating system at Kennedy Space Center's film storage building.|
The desiccant dehumidification system used in this project is part of the film storage building's heating, ventilation, and air conditioning (HVAC) system. This building was constructed to provide cold storage for the Visual Records Control office, which maintains the original engineering drawings for the Space Shuttle Program flight hardware, historical films, photographic records, and other computer media associated with Shuttle and historic Apollo Moon missions. About 80 percent of the building's total electrical load is used by the HVAC system for cooling and dehumidification of conditioned storage space. Due to the unique temperature and relative humidity requirements for records preservation, the building uses more energy than other buildings of similar size.
Climate control is maintained in the cold storage compartment by two redundant seven-ton Direct Expansion (DX) air conditioning units. Each HVAC system includes a desiccant dehumidification package unit. The DX units provide for the cooling, while the desiccant dehumidification units control the relative humidity of the conditioned space. The units are configured to operate in a lead/lag scenario, providing a reliable system.
The desiccant rotates into the air stream to remove moisture and then rotates out for regeneration. Heat is required in the regeneration process to evaporate the moisture from the desiccant. The unit uses a two-stage 19 kilowatt electrical heating element to create 275°F regeneration air that in turn is blown over the moist desiccant, causing the moisture to be evaporated and then exhausted to the outside air. The focus of the project was to offset the electrical consumption of the existing 19 kilowatt heating elements with solar energy. Because of the high temperatures required for the regeneration air, high efficiency evacuated tube solar collectors (Thermomax Mazdon 20) were chosen for this project.
The solar heating system includes 10 evacuated tube collectors mounted on a ground-level stand, a heat exchanger, and a circulation pump. The circulation pump provides heated water to a water-to-air exchanger during daytime operations. To protect against freeze damage, a mixture of 20 percent glycol and 80 percent water was chosen as the operating fluid, with pressure relief valves and an expansion tank included in the system. The entire system is insulated for safety and to ensure maximum efficiency. The installation did not interfere with the existing HVAC equipment and created a redundant heating system for the regeneration equipment during the peak sun hours of a typical day.
KSC documented savings of 26 percent in the building's overall electrical energy consumption over the project timeframe, equating to 196 million Btu saved in FY 2004.
For more information, please contact Harry Plaza, Kennedy Space Center, at Harry.Plaza@nasa.gov or 321-867-8414.