1. By: Reuben Downs Faculty Advisor: Dr. Darin Nutter Graduate Student Advisor: Wei Guo

2.  Refrigerant travels through condenser coils changing from a high pressure vapor to a high pressure liquid  Refrigerant travels through expansion valve changing from high pressure liquid to a mixture of low pressure liquid and vapor http://oee.nrcan.gc.ca/publications/infosource/pub/home/gif/heatpump_fig2b_e.gif  Refrigerant travels through compressor changing from a low pressure vapor to a high pressure vapor  Refrigerant travels through evaporator coils changing from a liquid to a vapor

3.  Stephen U. S. Choi [1] coined the term “nanofluids” in 1995  Metallic and Metallic Oxide Particles used ◦ Enhanced heat transfer of heat transfer fluids  Two Methods of Making Nanofluids ◦ One Step Method – Metallic Nanoparticles ◦ Chemical process ◦ Two Step Method – Metallic Oxide Nanoparticles ◦ Dry powder produced then dispersed in liquid

4. YearInvestigatorRefrigerantNanoparticles Size of Nanoparticles % Volume Concentrations 2007Da-Wei LiuR141bAu3nm0.09%, 0.4%, 1.0% 2007Ki-Jung Park R123, R134a Carbon Nanotubes 20nm × 1µm1.0% 2009Visinee TrisaksriR141bTiO 2 21nm 0.01%, 0.03%, 0.05% 2009Guoliang DingR113CuO40nm0.15% - 1.5% 2009M. A. KedzierskiR134aCuO30nm0.5%, 1.0%, 2.0%

5.  Used a cartridge heater concealed in tube to heat the nanorefrigerant Fig. 1 Da-Wei Liu ’ s apparatus [2]

6.  1.0% concentration performed the best out of the three concentrations Fig. 2 Da-Wei Liu ’ s results for Different Concentrations of Nanoparticles [2] Fig. 3 Da-Wei Liu’s results for test run on five day intervals [2]

7.  Degradations ◦ Tube Surface Roughness due to nanoparticles ◦ Particle Size Change (3nm to 110nm) Fig. 4 Da-Wei Liu’s results for test run on five day intervals with the tube cleaned for the last test [2]

8. Fig. 5 Ki-Jung Park ’ s apparatus [3]

9.  Ki- Jung Park [3] found that heat transfer was enhanced up to 36.6% at low heat flux.  High heat flux – more bubble generation causes less contact for carbon nanotubes Fig. 6 Ki-Jung Park’s results for carbon nanotubes in the R123 refrigerant [3] Fig. 7 Ki-Jung Park’s results for carbon nanotubes in the R134a refrigerant [3]

10. Fig. 8 Visinee Trisaksri ’ s apparatus [4]

11.  Visinee Trisaksri [4] concludes that TiO nanoparticles degrade the nucleate boiling heat transfer in the R141 b refrigerant Fig. 9 Visinee Trisaksri’s results for 0.05 vol% TiO 2 nanoparticles in R141b refrigerant vs. pure R141b refrigerant, both at different pressures [4] Fig. 10 Visinee Trisaksri’s results for 0.01 vol% TiO 2 nanoparticles in R141b refrigerant vs. pure R141b refrigerant, both at different pressures [4]

12.  R113 – Liquid at room temperature Fig. 11 Guoliang Ding ’ s apparatus [5]

13.  Nanoparticles can be released into the gas phase ◦ Guoliang Ding [5] calls it “bubble adhesion away” Fig. 12 Guoliang Ding’s Results: “Migrated mass of nanoparticles vs. original mass of nanoparticles in nanorefrigerant and nanorefrigerant-oil mixture." [5]

14. Fig. 13 M.A. Kedzierski ’ s apparatus [6]

15.  The 1.0% concentration of nanoparticles performed better than the 2.0% concentration Fig. 14 M.A. Kedzierski’s Results for CuO nanoparticles (1.0% concentration) in a refrigerant-oil mixture vs. refrigerant-oil mixture without nanoparticles [6] Fig. 15 M.A. Kedzierski’s Results for CuO nanoparticles (2.0% concentration) in a refrigerant-oil mixture vs. refrigerant-oil mixture without nanoparticles [6]

16.  Developed a new model for determining the thermal conductivity of nanofluids.  Resistance Network Method ◦ Calculates heat flux, thermal conductivity, thermal conductivity between two nanoparticles, thermal conductivity of nanoparticle cluster, thermal conductivity of nanofluid  Difference between his experimental results and the calculated results from his model for nanorefrigerants was within ±5%.

17.  Purpose: To determine if any fouling occurs due to the nanoparticles in the refrigerant.  Procedure: ◦ 1. Test and observe test surface roughness inside of the test pipe ◦ 2. Set up the apparatus by connecting all of the components (copper couplings will be used to connect the test pipe) and charge the nanorefrigerant. ◦ 3. Use the DC variable resistor pump to control the flow rate. ◦ 4. Remove the nanorefrigerant from the unit (vacuum) by the Schrader valve and dismantle the test pipe. ◦ 5. Test and observe test surface roughness. ◦ 6. Record findings of any changes on the surface of the test pipe.  Description: ◦ Ten trials per pipe: Five Short times and Five long times ◦ Three different surface roughnesses ◦ Three different flow rates ◦ Copper Pipe

18. DC Pump Valves Refrigerant Mixture Insert Pressure relief valve Test Pipe Schrader valves

19.  A removable test surface will be inserted into the test pipe Test Pipe

20.  [ 1] Choi, S. U. S., 1995, "Enhancing thermal conductivity of fluids with nanoparticles," Proceedings of the 1995 ASME International Mechanical Engineering Congress and Exposition, November 12, 1995 - November 17, Anonymous ASME, San Francisco, CA, USA, 231, pp. 99-105.  [2] Liu, D., and Yang, C., 2007, "Effect of nano-particles on pool boiling heat transfer of refrigerant 141b," 5th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2007, June 18, 2007 - June 20, Anonymous American Society of Mechanical Engineers, Puebla, Mexico, pp. 789-793.  [3] Park, K., and Jung, D., 2007, "Boiling Heat Transfer Enhancement with Carbon Nanotubes for Refrigerants used in Building Air-Conditioning," Energy and Buildings, 39(9) pp. 1061- 1064.  [4] Trisaksri, V., and Wongwises, S., 2009, "Nucleate Pool Boiling Heat Transfer of TiO2-R141b Nanofluids," International Journal of Heat and Mass Transfer, 52(5-6) pp. 1582-1588.  [5] Ding, G., Peng, H., Jiang, W., 2009, "The Migration Characteristics of Nanoparticles in the Pool Boiling Process of Nanorefrigerant and Nanorefrigerant-Oil Mixture," International Journal of Refrigeration, 32(1) pp. 114-23.  [6] Kedzierski, M. A., 2009, "Effect of CuO Nanoparticle Concentration on R134a/lubricant Pool-Boiling Heat Transfer," Journal of Heat Transfer, 131(4) pp. 043205 (7 pp.).