Solar energy is a widely available energy resource that is clean, inexhaustible, and economical if costeffective solar collector systems are available. Recent research indicates that freon phase-change solar heating systems have significant advantages (i.e., high efficiency, corrosion-free, freeze-proof, reliable, and economical) and will cause a significant improvement in the state-of-the-art solar equipment, but further research and development are needed to obtain the most reliable, cost-effective, and optimized systems. Research will be conducted to investigate the feasibility of developing a passive pumping module (PPM) that can control and circulate freon in phase-change solar systems. The PPM should be packaged in a single unit and should be economical, efficient, reliable, and simple to install. The research also will investigate the feasibility of aluminum top-fed heat pipe solar collectors that are highly cost-effective and are ideal for use with the PPM in freon phase-change solar systems. Also, the feasibility of developing a simple analytical computer model of the PPM phase-change solar systems will be investigated.Anticipated Results/Potential Commercial Applications as described by the awardee:It is anticipated that this project could lead to the development of a practical PPM that can be adopted by the solar industry for use in highly efficient passive freon phase-change solar systems. The PPM will be a single unit that will replace a pump, motor, and controls, and be cost-effective and simple to install. Aluminum top-fed heat pipe solar collectors that are highly cost-effective and ideal for use with freon phase-change solar systems also will be developed along with a computer model to predict system performance. This research could - lead to improved residential and commercial solar hot-water and spaceheating systems that are 30% to 60% more costefficient, reliable, and longer-lived than current systems.
