This Small Business Innovation Research Phase I project is aimed at utilizing aerosol technology to solve heat transfer problems in small-scale air conditioning systems, thus enabling the use of water as a refrigerant in small-scale units for domestic and automobile applications. A water-based air conditioning system must operate under vacuum, thus raising concerns of air leaking into the system. Also, the presence of water in a system is associated with the risk of corrosion. Further, the proposed system requires design and development of a special compressor. These issues are addressed in this project and viable solutions are proposed. Advancements in the pertinent technologies are now enabling realization of water-based air conditioning systems. This project underlines the importance of revisiting the conventional technologies with the new tools developed for the advanced technologies. The anticipated outcome of this Phase I project is a fully functional lab prototype of a water-based air conditioning system with a capacity of 0.25 ton. A successful Phase I project will enable development of field prototypes for domestic and automobile applications in the Phase II project.<br/><br/>The broader impact/commercial potential of this project encompasses all air conditioning applications; in particular, the markets of newly built homes and new automobiles. The domestic US market for these two businesses is $5B/year, with potentially 10 times this market on a worldwide basis. Annual revenue expectations exceed $100 million. Besides offering a significant commercial opportunity, the proposed product will have a positive impact on the environment by reducing the use of existing refrigerants that have a high global warming potential, when released into the atmosphere. Production of the existing refrigerants involves multiple steps starting with extraction of chemicals like methane and sodium chloride from the natural environment. Various steps in production of the conventional refrigerants are often energy-intensive and produce hazardous waste. On the other hand, water is abundantly available in the anticipated global marketplace and its purification is a relatively straightforward process. Hence, the proposed approach will enable a new, substantial and sustainable technology.