EFPLab1 Energy Balance Digital Twin 1

Do you understand how this quiz works?

• yes

• no

• not sure

What assumptions do we make to calculate the power of the cartridge heater?

• channel is frictionless

• channel (surface) has no heat loss

• ideal gas

• neglect kinetic energy

• neglect heat input of fan

What is the power you calculated in Watts [W]?

Round your result reasonably and only type in the number.

The following measurement are taken with a fan voltage of 15 V (see also in the video):

ϑ_air,α = 26.2 °C

ϑ_air,ω = 35.6 °C

c = 2.82 m/s

How much heat does a human body approximately emit while sitting or standing (no activity)?

• 50 W

• 100 W

• 200 W

• 500 W

• 1000 W

what happens if the fan speed is being reduced?

• heat flux increases

• heat flux decreases

• temperature difference increases

• temperature difference decreases

• nothing, only the volume flow changes

What is the power you calculated in Watts [W]?

Round your result reasonably and only type in the number.

The following measurement are taken with a fan voltage of 14 V (see also in the video):

ϑ_air,α = 26.6 °C

ϑ_air,ω = 36.4 °C

c = 2.79 m/s

What would happen if the fluid would be water instead of air?

• nothing

• lower temperature difference

• bigger temperature difference

• less heating power

What is the power you calculated in Watts [W]?

Round your result reasonably and only type in the number.

The following measurement are taken with a fan voltage of 12 V (see also in the video):

ϑ_air,α = 26.5 °C

ϑ_air,ω = 38.1 °C

c = 2.51 m/s

What would happen with the calculated heating power if we consider heat losses in the energy balance equation?

• heating power would increase

• heating power would decrease

• nothing would happen

What is the power you calculated in Watts [W]?

Round your result reasonably and only type in the number.

The following measurement are taken with a fan voltage of 10 V (see also in the video):

ϑ_air,α = 26.9 °C

ϑ_air,ω = 40.7 °C

c = 2.04 m/s