Preparation and characterisation of nano enhanced phase change material by adding carbon nano tubes to butyl stearate

Figures & data

Table 1. Specification of the carbon nanotubes.

	MWCNT	Modified-MWCNT	SWCNT
Outer diameter	30–50 nm	30–50 nm	1–4 nm
Inside diameter	5–10 nm	5–10 nm	0.8–1.6 nm
Ash	<1.5%	<1.5%	<3%
Purity	>95%	>95%	>60%
Length	10–20 μm	0.5–2 μm	5–30 μm
Specific surface area	60 m^2/g	60 m^2/g	407 m^2/g
Electrical conductivity	>100 S/cm	>100 S/cm	>100 S/cm
Bulk density	0.28 g/cm^3	0.22 g/cm^3	0.14 g/cm^3
True density	∼2.1 g/cm^3	∼2.1 g/cm^3	∼2.1 g/cm^3

Figure 1. SEM micrographs of a: MWCNT, b: modified-MWCNT, c: SWCNT.

Figure 2. Thermal conductivity of different nanofluids.

Figure 3. Variation of thermal conductivity with temperature.

Figure 4. DSC curves of different NEPCMs.

Table 2. Thermal specifications of NEPCMs obtained from DSC analysis.

CNT (wt., %)	Tm (°C)	Tc (°C)	ΔHm (j/gr)	ΔHc (j/gr)
PCM (Butyl stearate)
0	23	14.66	64.74	70.75
NEPCM (SWCNT/PCM)
1	22	18.12	124	84
2	23.98	12.71	81	108
3	24.14	12.55	74	143
4	26	14	110	143
5	30	12	130	146
NEPCM (MWCNT/PCM)
1	22	12.76	80	88
2	21.3	12.78	84.6	92.7
3	20.78	12.68	77	89
4	21.56	12.82	81	90
5	22.9	12.89	95	114
NEPCM(Modified-MWCNT/PCM)
1	23.6	10.4	65	162
2	23.8	10.2	255	140
3	24.7	10.4	207	133
4	26.8	9.8	195	88
5	22.9	11	134	83

Figure 5. Variation of latent heat of fusion with weight fraction of CNTs.

Figure 6. Variation of latent heat of freezing with weight fraction of CNTs.

Figure 7. Effect of CNTs on the melting point of butyl stearate.

Figure 8. Effect of CNTs on supercooling.