Performance of Al₂O₃/TiO₂ nano composite particles in domestic refrigerator

Figures & data

Figure 1. Schematic representation of the experimental setup with instrumentation.

Table 1. Specification of the system.

Gross capacity	175 L
Refrigerant	R134a
Charged mass	120 g
Compressor type	Reciprocating
Lubricant charge	200 mL
Condenser type	Air cooled

Table 2. Specification of the measuring instruments.

Parameters	Measuring Instruments	Measuring space	Accuracy
Temperature	RTD type PT100	−50 to 150 °C	0.2 °C
Pressure	Bourdon type gauge	76 cm Hg vaccum/0/15 kgf/cm^2, 0/35 kgf/cm^2	0.1/0.2 kgf/cm^2
Voltage	Digital voltmeter	0/400 V	1%
Current	Digital ammeter	0/6 A	0.1%
Energy meter	Digital watt hour meter	10 blinkings	±0.01 S

Figure 2. TEM Image of TiO₂ nano particles.

Figure 3. SEM Image of Al₂O₃ nano particles.

Table 3. Physic-chemical data for Al₂O₃ nano particle.

Properties	Average value
Specific Surface Area (BET)	>10 m^2/g
Average primary particle size	ca. 40 nm
Particle size full range	5–200 nm
Moisture, 2 h at 105 °C, wt %	<1.5

Table 4. Physic-chemical data for TiO₂ nano particle.

Properties	Average value
Specific Surface Area (BET)	50 ± 15 m^2/g
Average primary particle size	ca. 21 nm
Particle size full range	5–100 nm
Moisture, 2 h at 105 °C, wt %	<1.5

Figure 4. Preparation of TiO₂ and Al₂O₃ nano particles mixture with POE oil using digital balance and Magnetic stirrer.

Table 5. Composition of samples of nano and nano composite particles in POE oil.

Sample ID	POE oil (mL)	Al2O3 (%)	Al2O3 (g)	TiO2 (%)	TiO2 (g)	POE/Nano mixing Ratio (g L^−1)
S1	200	–	–	–	–	–
S2	200	100	0.02	–	–	0.1
S3	200	–	–	100	0.02	0.1
S4	200	75	0.015	25	0.005	0.1
S5	200	50	0.01	50	0.01	0.1
S6	200	25	0.005	75	0.015	0.1

Figure 5. Samples of TiO₂ and Al₂O₃ nano particles mixture with POE oil in different compositions after 6 months.

Figure 6. Power consumption of the refrigeration system at −18 °C evaporator temperature.

Figure 7. Actual COP of the refrigeration system at −18 °C evaporator temperature.

Figure 8. Compressor work of the refrigeration system at −18 °C evaporator temperature.

Figure 9. Total Irreversibility of the refrigeration system at −18 °C evaporator temperature.

Figure 10. Second law efficiency of the refrigeration system at −18 °C evaporator temperature.