Thermodynamics HW Solutions 206

# Thermodynamics HW Solutions 206 - R_total=R_conv_i R_ins...

This preview shows page 1. Sign up to view the full content.

Chapter 15 Steady Heat Conduction 3-72 "GIVEN" L=2 "[m]" D_i=0.40 "[m]" D_o=0.46 "[m]" r_1=D_i/2 r_2=D_o/2 "T_w=55 [C], parameter to be varied" T_infinity_2=27 "[C]" h_i=50 "[W/m^2-C]" h_o=12 "[W/m^2-C]" k_ins=0.03 "[W/m-C]" Price_electric=0.08 "[\$/kWh]" Cost_heating=280 "[\$/year]" "ANALYSIS" A_i=pi*D_i*L A_o=pi*D_o*L R_conv_i=1/(h_i*A_i) R_ins=ln(r_2/r_1)/(2*pi*k_ins*L) R_conv_o=1/(h_o*A_o)
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: R_total=R_conv_i+R_ins+R_conv_o Q_dot=(T_w-T_infinity_2)/R_total Q=(Q_dot*Convert(W, kW))*time time=365*24 "[h/year]" Cost_HeatLoss=Q*Price_electric f_HeatLoss=Cost_HeatLoss/Cost_heating*Convert(, %) T w [C] f HeatLoss [%] 40 7.984 45 11.06 50 14.13 55 17.2 60 20.27 65 23.34 70 26.41 75 29.48 80 32.55 85 35.62 90 38.69 3-49...
View Full Document

## This note was uploaded on 01/14/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

Ask a homework question - tutors are online