FortuneBull777

Nobody use this old school bulb anymore! LCD are much better!

2023-09-23 17:49

i3lurker

For cold countries, as internal lighting, nothing beats incandescent, its the most efficient tool ever invented by man since discovery of wheel.

=> in Winter, incandescent provides both Heat and Light in the most compact form, efficient in use of electricity.

Again like EV, Biden is extremely short sighted.
End up, hard core poor in US will be the ones who suffer by paying more for other heating options during winter.

During a period of Δt=1 h=3600 s
, the light bulb converts electric power of P=60 W
to light and heat. Assuming that none of this energy escapes from the room, the entire power is eventually converted to heat:

Q=P⋅Δt=60 W×3600 s=216 kJ
According to REFPROP (NIST Standard Reference Database 23, Version 9.0), the relevant parameter values of air at the assumed initial temperature of T0=20 ∘C
and pressure p=1 atm=101325 Pa
are a density of ρ0=1.2046 kg/m3
and a specific heat capacity at constant pressure of cp,0=1.0061 kJ/(kg K)
.

The initial volume is given as V0=85 m3
. The corresponding mass is

m=V0⋅ρ0=85 m3×1.2046 kg/m3=102.391 kg
Ignoring the heat capacity of the walls and inventory, the temperature of the air is approximately increased by

ΔT=QC=Qm⋅cp,0=216 kJ102.391 kg×1.0061 kJ/(kg K)=2.1 K
By way of comparison, a better result may be obtained using the enthalpy of air, since the heat capacity of air is not constant. In this case, however, the difference is insignificant because the temperature change is small. The initial specific enthalpy of air is h0=419.40 kJ/kg
. Thus, the enthalpy is

H0=m⋅h0=102.391 kg×419.40 kJ/kg=42943 kJ
At constant pressure, the change in enthalpy corresponds to the heat transferred to the air:

H1=H0+ΔH=H0+Q=42943 kJ+216 kJ=43159 kJ
Thus, the final specific enthalpy is

h1=H1m=43159 kJ102.391 kg=421.51 kJ/kg
At a pressure of p=1 atm=101325 Pa
, this specific enthalpy corresponds to a temperature of T=22.1 ∘C
.

2023-09-23 18:04

FortuneBull777

I3lucker! Wow! Never thought of that!

2023-09-23 18:05

FortuneBull777

But so true! Incandescent bulb do produce alot of heat! I remember when me and wifey were very poor, we rent a room with only one incandescent light but the heat generated was too much to bare!

2023-09-23 18:07