1. North vs. South. A heat pump is designed for southern climates extracts heat from the outside air, and delivers air at 20C to the inside of the houses. What is the average coefficent of performance of the heat pump: (Consider this to be a Carnot device)(adsbygoogle = window.adsbygoogle || []).push({});

a) In the south where the average outside temperature is 5C?

b) In the north where the average outside temperature is -10C?

c)Two Identical houses, one in the north and one in the south, are heated by this pimp, and maintain indoor temperatures of 20C.Considering heat loss through the walls, windows, and roof,what is the ratio of the electrical powers required to heat the houses and to maintain the interiors at 20C. Express your result as P_n_/P_s_

a) K = T_h_/(T_c_-T_h_)

T_c_ = 5C + 273.15 = 278.15K

T_h_ = 20C + 273.15 = 293.15K

K = 293.15/(278.15-293.15)

= 19.54

b) K = T_h_/(T_c_-T_h_)

T_c_ = -10C + 273.15 = 263.15K

T_h_ = 20C + 273.15 = 293.15K

K = 293.15/(263.15K-293.15)

= 9.77

c) solving for P_n_

(9.77kWh)(3.6x10^6J)= 3.51x10^7 J/s

solving for P_s_

(19.54kWh)(3.6x10^6J)=7.03x10^7 J/s

P_n_/P_s_ = (3.51x10^7 W)/(7.03x10^7 W)

= .5

I would really appreciate it if someone reviewed my answeres. What confuses me is the line "Considering heat loss through the walls, windows, and roof". Did I miss plugging in a number somehwere, how do I calculate it? Or is it just theoretical?

Thanks alot in advance!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Heat Pump performance

**Physics Forums | Science Articles, Homework Help, Discussion**