1. Jomal Whiteside Najeeb Reyes Javier Garcia Dr. Yiding Cao (Advisor)

2. Problem Statement Coolants used in commercial AC systems such as R-12 and R-134a have adverse impacts on the environment European countries are outlawing harmful refrigerants such as R-134a for AC systems by 2011. Other countries such as U.S. are considering similar measures There are no efficient AC systems which use natural coolants available for commercialization

3. Project Objectives Design a workable A/C system which uses a natural and environmentally friendly refrigerant that serves as an alternate for halogenated refrigerants: Without the hazards of toxicity and flammability With comparable performance measured by Refrigeration Efficiency (RE), Coefficient of Performance (COP), and Refrigerating Capacity (RC) Without high-costs of manufacturing or maintenance

4. Project Metrics AC system with cooling capacity 5000 – 7500 Btu/hr Use of natural coolant with zero GWP and zero ODP compared to Achieve a COP comparable to R-134a of 3 – 4

5. Conceptual Design Includes two major areas Refrigerants Air CO2 Prototype Cooling Chamber Valve System

6. Alternate Refrigerant: Air Advantages Natural Working Gas GWP: 0 Abundant Single Phase Gas Disadvantages No relevant studies High compression required, which causes a significant loss of energy

7. Alternate Refrigerant: CO2 Advantages GWP: 1 Prior research has been conducted CO 2 can improve efficiency by recovering the energy lost due to high operating pressures Disadvantages High operating pressures Low critical Temperatures

8. Wankel Rotary Engine Operating pressure 15-20 Atm (220-300 psi) Operating RPM range 750 -1200 Powered by 1 – 5 kW electric motor

9. Cooling Camber Single chamber volume 280-380cc (1.5: - 2:1) Material considerations Metals or plastics with low thermal conductivity

10. Valve system

11. Prototype: Cooling Camber Circular Configuration Provides tangential velocity, allowing for effective cooling capabilities. Pressure Ratio less than 3:1 Improves overall coefficient of performance(COP). Four identical chambers will be implemented Ensures the constant flow and cooling of refrigerant

12. Prototype: Cooling Chamber Conceptual Design The size of the cooling chamber is the focus of its design. The size of the cooling chamber must be determined through the specified pressure of the system

13. Prototype: Valve System Rotary Valve System Easy modification to specific application Simplistic design Can be used in conjunction with the rotation of rotary shaft. Two identical shafts will be used to implement the idea and a rotary valve.

14. Prototype: Rotary Valve Configuration Concepts Butterfly Configuration Valve Assembly

15. Prototype: Cooling Chamber with Rotary Valve Assembly

16. Schematic of Prototype Wankel Rotary engine Combines compressor and expander Cooling Camber Allows proper cooling of refrigerant Valve System Allows sufficient flow into and out of cooling chambers

18. Conclusion Integrate a cooling chamber into rotary engine block. Implement a valve system that ensures a consistent and efficient flow of working fluid in and out of the cooling chamber. Implement the use of a natural gas such as air, as the working fluid for the designed air conditioning system. Increase system efficiency by using a Wankel engine which integrates the use of a compressor and expander in one machine.