Table 4 Proposed combinations of FOMs

FOM_R

ΔT/q

K/W

Thermal resistance

FOM_R,m

ΔT m/q

K kg/W

Thermal resistance based on mass

FOM_R,A

ΔT A/q

K cm²/W

Thermal resistance based on surface area

FOM_R,m,A

ΔT m A/q

K kg cm²/W

Thermal resistance based on mass and surface area

FOM_LPW

Φ/P

lm/W

Luminous efficacy

FOM_LPW,m

Φ/P m

lm/W kg

Luminous efficacy based on mass

FOM_LPW,A

Φ/P A

lm/W cm²

Luminous efficacy based on surface area

FOM_LPW,m,A

Φ/P m A

lm/W kg cm²

Luminous efficacy based on mass and surface area

FOM_T,L

ΔT/Φ

K/lm

Opto-thermal resistance

FOM_T,m,L

ΔT m/Φ

K kg/lm

Opto-thermal resistance based on mass

FOM_T,A,L

ΔT A/Φ

K cm²/lm

Opto-thermal resistance based on surface area

FOM_T,m,A,L

ΔT m A/Φ

K kg cm²/lm

Opto-thermal resistance based on mass and surface area