by: reuben downs faculty advisor: dr. darin nutter graduate student advisor: wei guo

By: Reuben DownsFaculty Advisor: Dr. Darin Nutter

Graduate Student Advisor: Wei Guo

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

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

Year Investigator Refrigerant NanoparticlesSize of

Nanoparticles% Volume

Concentrations

2007 Da-Wei Liu R141b Au 3nm 0.09%, 0.4%, 1.0%

2007 Ki-Jung ParkR123, R134a

Carbon Nanotubes

20nm × 1µm 1.0%

2009 Visinee Trisaksri R141b TiO2 21nm0.01%, 0.03%,

0.05%

2009 Guoliang Ding R113 CuO 40nm 0.15% - 1.5%

2009 M. A. Kedzierski R134a CuO 30nm 0.5%, 1.0%, 2.0%

Used a cartridge heater concealed in tube to heat the nanorefrigerant

Fig. 1 Da-Wei Liu’s apparatus [2]

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]

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]

Fig. 5 Ki-Jung Park’s apparatus [3]

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]

Fig. 8 Visinee Trisaksri’s apparatus [4]

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% TiO2 nanoparticles in R141b refrigerant vs. pure R141b refrigerant, both at different pressures [4]

Fig. 10 Visinee Trisaksri’s results for 0.01 vol% TiO2 nanoparticles in R141b refrigerant vs. pure R141b refrigerant, both at different pressures [4]

R113 – Liquid at room temperature

Fig. 11 Guoliang Ding’s apparatus [5]

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]

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

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]

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%.

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

DC PumpValves

Refrigerant Mixture Insert

Pressure relief valve

Test Pipe

Schrader valves

A removable test surface will be inserted into the test pipe

Test Pipe