How to calculate the wattage needed

Click For Summary

Discussion Overview

The discussion revolves around calculating the wattage needed to heat an enclosed glass deck floor to prevent freezing. Participants explore the heating method, material specifications, and environmental conditions affecting the heating requirements.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes a project involving heating a glass deck floor to prevent freezing, specifying the glass construction and dimensions.
  • Another participant questions how the glass will be heated, noting that glass is generally a thermal insulator.
  • A participant suggests using ITO (Indium Tin Oxide) as a heating method, which is commonly used in electrically heated windows.
  • There is a query about the ambient temperature conditions above and below the deck, and whether the sides of the deck are open to ambient conditions.
  • Updated information reveals that the glass floor will now be enclosed above and below, prompting a request for a calculation to determine how warm the glass will get.
  • Another participant expresses confusion about the necessity of glass if the floor is enclosed and suggests considering air exchange and insulation for the room.
  • The original context of the floor being part of an outdoor balcony is clarified, indicating it is now an indoor room with controlled temperatures.
  • Specific parameters are provided, including the glass construction, sheet resistance, size, weight, and ambient air temperature, to facilitate the calculation of heating requirements.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the best approach to calculate the wattage needed, and multiple viewpoints regarding the heating method and environmental conditions remain present.

Contextual Notes

Limitations include the need for further clarification on the air exchange dynamics and insulation properties of the surrounding structure, as well as the specific heating requirements based on the provided parameters.

Scott Sperbeck
Messages
4
Reaction score
0
I have a project in which a client is wanting an outside glass deck floor to be heated to keep from freezing. Below the floor is ambient temperatures. The glass is 1.25 ( 3 layers of 3/8" with a /060 inter-layer between each lite of glass) thick each panel is 30" x 60". I don't want to overpower the units as if we can get away without a control unit it would be much easier as there is over 30 panels. Also we want to watch the total amperage draw.
 
Engineering news on Phys.org
Scott Sperbeck said:
I have a project in which a client is wanting an outside glass deck floor to be heated to keep from freezing. Below the floor is ambient temperatures. The glass is 1.25 ( 3 layers of 3/8" with a /060 inter-layer between each lite of glass) thick each panel is 30" x 60". I don't want to overpower the units as if we can get away without a control unit it would be much easier as there is over 30 panels. Also we want to watch the total amperage draw.
Welcome to the PF. :smile:

Glass is generally a thermal insulator. How do you propose to heat it?
 
The same we make electrically heated windows, ITO.
 
Scott Sperbeck said:
The same we make electrically heated windows, ITO.
Yes, looking at your website I see it's commonly done. You'll put the ITO between each of the 3 glass layers in this project? You said the air below the deck is ambient temperature, but the deck is also outdoors? What will the ambient temperature be in the space above the deck? Whatever it is heated to by the floor panels? Are the sides of the deck open to ambient too, or is there some sort of siding?
 
"Ambient?" Where?
 
Just received updated information. The glass floor will now be enclosed both above and below the floor. They are looking just to keep the glass warm in the winter months. Is there a calculation that can be used?
 
Scott Sperbeck said:
Just received updated information. The glass floor will now be enclosed both above and below the floor. They are looking just to keep the glass warm in the winter months. Is there a calculation that can be used?
If the floor is now enclosed, why is it glass? Sorry, I'm not tracking what you're saying very well.

If it's just a heated floor, you would look at air exchange for the room and insulation for the walls and floor...
 
Originally, the floor was part of an outdoor balcony. It is now an indoor room with an indoor room below, thus the meaning "enclosed". I'm looking for the calculation to know how warm the glass will get. The known parameters are: Glass: 3 layers of laminated 3/8" with .060" interlayers for a thickness of 1.25". The glass is coated with ITO and has a sheet resistance of 15 ohms. Glass size is 30" x 60" total weight is 190 lbs. The ambient air temperature on both sides of the glass will be approximately 70 degrees f.
 

Similar threads

  • · Replies 27 ·
Replies
27
Views
6K
Replies
7
Views
27K
  • · Replies 30 ·
2
Replies
30
Views
4K
  • · Replies 21 ·
Replies
21
Views
3K
  • · Replies 8 ·
Replies
8
Views
8K
Replies
3
Views
2K
Replies
2
Views
8K
  • · Replies 23 ·
Replies
23
Views
6K
  • · Replies 2 ·
Replies
2
Views
8K
  • · Replies 7 ·
Replies
7
Views
5K