Saturday, February 4, 2012

Selection criteria

Thermodynamic properties. The appearance change actual should possess:3

Melting temperature in the adapted operating temperature range

Top abeyant calefaction of admixture per assemblage volume

Top specific heat, top body and top thermal conductivity

Baby aggregate changes on appearance transformation and baby breath burden at operating temperatures to abate the ascendancy problem

Congruent melting

Kinetic properties

Top nucleation amount to abstain supercooling of the aqueous phase

Top amount of clear growth, so that the arrangement can accommodated demands of calefaction accretion from the accumulator system

Chemical properties

Chemical stability

Complete capricious freeze/melt cycle

No abasement afterwards a ample amount of freeze/melt cycle

Non-corrosiveness, non-toxic, non-flammable and non-explosive materials

Economic properties

Low cost

Availability

edit Thermophysical backdrop of called PCMs

Material

Organic

PCM

Melting

point

oC

Heat of

fusion

kJ·kg−1

Heat of

fusion

MJ·m−3

cp

solid

kJ·kg−1·K−1

cp

liquid

kJ·kg−1·K−1

ρ

solid

kg·m−3

ρ

liquid

kg·m−3

k

solid

W·m−1·K−1

VHC

solid

kJ·m−3·K−1

VHC

liquid

kJ·m−3·K−1

e

solid

J·m−2·K−1·s−1/2

Cost

USD·kg−1

Water No 0 333.6 319.8 2.05 4.186 917 1,000 1.64-2.225 1,880 4,186 1,890 0.0031256

Lauric acerbic Yes78 44.29 211.6 197.7 1.76 2.27 1,007 862 ? 1,772 1,957 ? 1.6 1011

TME(63%w/w)+H2O(37%w/w) Yes78 29.8 218.0 240.9 2.75 3.58 1,120 1,090 ? 3,080 3,902 ? ?

Mn(NO3)2·6H2O+MnCl2·4H2O(4%w/w) No1213 15–25 125.9 221.8 2.34 2.78 1,795 1,728 ? 4,200 4,804 ? ?

Na2SiO3·5H2O No1213 48 267.0 364.5 3.83 4.57 1,450 1,280 0.103−0.12814 5,554 5,850 801 8.0415

Aluminium No 660.32 396.9 1,007.2 0.8969 ? 2,700 2,375 2371617 2,422 ? 23,960 2.0462618

Copper No 1,084.62 208.7 1,769.5 0.3846 ? 8,940 8,020 40119 3,438 ? 37,130 6.8125620

Gold No 1,064.18 63.72 1,166.3 0.129 ? 19,300 17,310 31821 2,491 ? 28,140 34,297.820

Iron No 1,538 247.3 1,836.6 0.4495 ? 7,874 6,980 80.422 3,539 ? 16,870 0.324823

Lead No 327.46 23.02 253.2 0.1286 ? 11,340 10,660 35.324 1,459 ? 7,180 2.115120

Lithium No 180.54 432.2 226.0 3.5816 ? 534 512 84.825 1,913 ? 12,740 62.216426

Silver No 961.78 104.6 1,035.8 0.235 ? 10,490 9,320 42927 2,465 ? 32,520 492.52420

Titanium No 1,668 295.6 1,273.5 0.5235 ? 4,506 4,110 21.928 2,359 ? 7,190 8.046929

Zinc No 419.53 112.0 767.5 0.3896 ? 7,140 6,570 11630 2,782 ? 17,960 2.1573520

Volumetric calefaction accommodation (VHC) J·m−3·K−1

VHC = \rho\cdot c_p

Thermal Inertia (I) = Thermal effusivity (e) J·m−2·K−1·s−1/2

I = \sqrt{k\cdot\rho\cdot c_p} = e = {(k\cdot\rho\cdot c_p)}^{1/2}

No comments:

Post a Comment