Solving Room Temperature Issues - Help!

  • Thread starter Thread starter a13x
  • Start date Start date
Click For Summary

Homework Help Overview

The problem involves determining the indoor air temperature of a room when a fan is turned on, given specific parameters such as outdoor temperature, power consumption of the fan, and heat transfer characteristics. The subject area relates to thermodynamics and heat transfer principles.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the implications of the fan's power consumption and how it contributes to the indoor temperature. There are questions about the conversion of energy and the assumptions regarding heat transfer.

Discussion Status

Some participants have offered hints and guidance regarding the assumptions that need to be made about the energy output of the fan. There is an ongoing exploration of how to relate the energy consumed by the fan to the indoor temperature, with multiple interpretations being considered.

Contextual Notes

Participants are navigating assumptions about energy conversion and heat transfer, including the idea that all the energy from the fan contributes to heating the room. There is also an emphasis on the need to clarify the relationship between energy and temperature in the context of the problem.

a13x
Messages
9
Reaction score
0
room temperatures, please help!

Homework Statement


A room is initially at the outdoor temperature of 25C. Now a large fan that consumes 200W of electricity when running is turned on. The heat transfer rate between the room and the outdoor air is given as Q = UA(Ti - To) where U = 6 W/m^2^.oC is the overall heat transfer coefficient, A = 30 m^2 is the exposed surface area of the room, and Ti and To are the indoor and outdoor temperatures, respectively. Determine the indoor air temperature when steady operating conditions are established.


Homework Equations


Q = UA(Ti - To)


The Attempt at a Solution



Not really sure where to start with this problem.
 
Physics news on Phys.org
Hint: What happens to the 200 W of power "consumed" by the fan?
 
I take it that only a percentage of the energy consumed is given off as heat the rest is transferred into other energy forms obeying the energy cannot be creasted or destroyed rule just transformed from one source to another.
 
I know some of the energy used will be converted to heat and noise but can't seem to find an equation to work it out.

I think the indoor temperature will be the initial 25^oC plus however much heat is given off by the fan. Not sure if I am correct in this assumption or not.
 
You have to assume that all the 200W is put out as heat.
You probably also have to assume that this heat all goes into the room, otherwise there would be no point in telling you the value!
 
Got it now. Energy in and out have to be equal. With the energy in being 200J, the same has to be said or energy out. Ti = To = 200.

Just have to convert the equation so Ti is the unknown.

Thanks for the help guys
 
Yes, but be careful, Ti/To are the temperatures not the energy.
 

Similar threads

Energy Efficient AC unit by returning air to the building
  • · Replies 1 ·
Replies
1
Views
1K
High School Cooling effect of evaporation occurs even if the surroundings are colder?
  • · Replies 10 ·
Replies
10
Views
3K
Problem set with air conditioners and thermodynamics
  • · Replies 5 ·
Replies
5
Views
3K
Heat Transfer - finding rate of heat transfer
  • · Replies 6 ·
Replies
6
Views
2K
Does Turning on a Fan Affect Room Temperature?
  • · Replies 9 ·
Replies
9
Views
4K
Thermodynamics relating to temperature and phase changes
  • · Replies 1 ·
Replies
1
Views
2K
Heat Transfer Problem for Titanium Capsule
  • · Replies 5 ·
Replies
5
Views
2K
Radial Heat Conduction through a Cylindrical Pipe
  • · Replies 3 ·
Replies
3
Views
2K
Thermal Energy in 1 cubic meter of air at room temperature
  • · Replies 8 ·
Replies
8
Views
10K
Solving Heat Transfer Problem with Melting Ice Cube
  • · Replies 4 ·
Replies
4
Views
4K