Table 1 Comparison of WD-ER cooling unit with passive cooling methods

WD-ER

13X/H₂O/NH₄NO₃

2876

Operating range: 20–70 °C

Cooling power: 403 W/m²

Temperature drop: 15.1 °C

Phase change materials

RT55

170

Melting: 51–57 °C

⁴⁰

RT28HC

220

Melting: 28 °C

⁴¹

C-PCM

199

Melting: 21.8 °C

⁴²

OM47

196

Melting: 48 °C

⁴³

MF-PW30

139.8

Melting: 56.8 °C, crystallization: 45.1 °C

⁴⁴

PCMB

141.7

Steady range: 40.4–84.9 °C

⁴⁵

GO-HS/PAAAM

200.3

Melting: 23 °C

⁴⁶

Eicosane

237.4

Melting: 36.5 °C

⁴⁷

Tricosane

269.2

Melting: 42–48 °C

⁴⁸

MIL-101(Cr)

1950

Operating range: 20–70 °C

³¹

PAN-CNT-CaCl₂

–

Operating range: 20–70 °C

Cooling power: 295 W/m²

Temperature drop: 10.0 °C

¹⁸

Radiative cooling

Cooling assembly system

–

Operating range: 74 °C

Cooling power: 310 W/m²

Temperature drop: 36.6 °C

⁴⁹

Silica pyramid

–

Operating range: 20–70 °C

Temperature drop: 18.3 °C

⁵⁰

Multilayer photonic film (Al₂O₃/SiN/TiO₂/SiO₂)

–

Operating range: 40–70 °C

Cooling power: 149 W/m²

Temperature drop: 5.7 °C

¹⁹

Multilayer stack (SiO₂/TiO₂/MgF₂)

–

Operating range: 10–30 °C

Cooling power: 29.5 W/m²

⁵¹