×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

thermal conductivity comparison glass and concrete2

thermal conductivity comparison glass and concrete

(OP)
Dear All,

I am trying to compare the thermal conductivity of
10 mm tempered glass and 6" concrete wall.

Any inputs or best practices for evaluation please ...

RE: thermal conductivity comparison glass and concrete

You look up the thermal conductivity by Google search, then you calculate the R-factor for each case.

RE: thermal conductivity comparison glass and concrete

(OP)
This comparison requirement is for selecting either glass wall or brick wall for living rooms.

Should i check for convection also ? But convection involves liquids and gases ...

RE: thermal conductivity comparison glass and concrete

(OP)
Dear sir,
I could not understand your comment "vacuum environment "

RE: thermal conductivity comparison glass and concrete

Your wall, glass or otherwise, is surrounded by what?

Moreover,
> units in row 7 are incorrect, should be W/mm^2-K
> row 12 is nonsensical, because you used mm^2 as the area unit. The temperature for conduction is the delta temperature, not the absolute. Absolute temperature only shows up in radiated heat and heat transfer coefficient calculations.
> mm^2 for area is a nonsensical
> row 16 is nonsensical, since that's per mm^2 of area.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: thermal conductivity comparison glass and concrete

Your living room and outside environment is filled with air, which is a gas. Therefore, you should consider convection.

You have an HVAC problem here. There are a lot of HVAC knowledge in books, for example ASHRAE Handbook, that can aid you in solving your problems.

RE: thermal conductivity comparison glass and concrete

If you want a glass wall then choose glass.

If you want a concrete wall then choose concrete.

Design the HVAC accordingly.

RE: thermal conductivity comparison glass and concrete

@vij36: text book suff - heat transfer has 3 elements, conduction, convection and radiation. Each element has constant for specific maerials that are easy to find. If you are really considering building a room, then for HVAC design you will be able to find table/graphs that will tell you the amount of heat influx based on temperature difference. The tables etc ha solved the problem for you in a standard way that will be valid for most cases.

Best regards, Morten

RE: thermal conductivity comparison glass and concrete

Here is a third option. Instead of concrete or glass panes, consider glass blocks, then contact the manufacturer for the K or R value. For regular glass panes, concrete blocks or plain concrete walls CE or ME handbooks will have those values.

RE: thermal conductivity comparison glass and concrete

(OP)

Quote (MortenA)

text book suff - heat transfer has 3 elements, conduction, convection and radiation. ...

my doubt is whether it is glass or brick wall the surrounding media such as air remains the same. Or if I am wrong will the surrounding area's medium such as air will have separate effects on glass and brick ?

RE: thermal conductivity comparison glass and concrete

(OP)

Quote (IRStuff)

You need to explain the problem, in MORE DETAIL, rather than just tossing out random disjoint questions.

Apologize for the inconvenience.

Am relatively new to hvac material selection.

Basically the task in my hand is to choose between 10 mm glass or porotherm brick.

Glass U value is ranging from 1.67 to 5.88. W/ m k

Porotherm thermobrick U value is 0.6 W/ m k

So for less heat gain inside should we need to choose less U vale material ?

Spare me if I am awfully wrong .

RE: thermal conductivity comparison glass and concrete

(OP)

Quote (IRStuff)

Aren't glass blocks a bit 1960s?

Are the double glazing units are better than glass blocks ? Will the spacer can improve the hvac performance ?

RE: thermal conductivity comparison glass and concrete

Glass blocks are thick, so should be less conductive than double pane, but double pane is more modern and you can see through it. This is all pretty common knowledge.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: thermal conductivity comparison glass and concrete

Double pane windows with warm edge spacer a) basically eliminate thermal bridging from the inside to the outside (i.e. there is NO CONDUCTION to speak of) and also minimize convection by reducing the space between the glass sheets to the optimum (the spacing that results in the lowest heat transfer from one glass sheet to the other) and, generally, filling that space between the glass sheets with another gas (argon) to further reduce convection. They usually also add a low emissivity coating to reduce radiant heat transfer.

In typical building construction for a cold climate, glazing (windows and doors) represent a greatly higher rate of heat loss than properly constructed walls. But we're not talking about bare concrete extending from the outside to the inside of the structure in that case- there's an insulating material designed into the wall somewhere.

RE: thermal conductivity comparison glass and concrete

(OP)
Dear All,

This website says awnings are effective to block only 50% of solar radiation (location specific) south facing. Any calculations exists.

RE: thermal conductivity comparison glass and concrete

Per IRstuff "Aren't glass blocks a bit 1960s?" nothing is wrong with the 1960's appearance but one thing that glass bocks offer is better security than glass panes and I have seen several structures over the years with glass block walls and even now.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!