| The U.S. Department of Energy, working through the National Renewable Energy Laboratory, has initiated a research directive of reducing the levelized cost of saved energy (COSE) for residential solar water heating systems by 50 percent. A number of cost reduction strategies are analyzed using thermal performance simulations and detailed cost models to determine the cost effectiveness of different system configurations across all 215 TMY sites. Three systems types are analyzed: glycol, drainback and thermosiphon; with a number of system variations including: balance of system components (BOS), and collector types. BOS variations considered include: eliminating one pump in the glycol systems, using un-pressurized polymer solar storage tanks, using polymer heat exchangers, and using integrated polymer piping. The collector variations include the use of selective and non-selective metal-glass and polymer collectors, and unglazed polymer collectors. The detailed cost modeling includes costs for hardware, labor, overhead and profit, and O & M.; This analysis has shown that a reduction in COSE of 50 percent is achievable, but with technology that is not available in the market today. (Abstract shortened by UMI.)... |
