Questions tagged [thermal-insulation]

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Heat Loss from Domestic Oven Door

Our kitchen electric oven has a large glass door approx 530 x 440mm, overall thickness 35mm. There is a front and back glass pane, no insulation and the air cavity is open at the bottom. I'm wondering ...
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What is the thermal conducivity of Air between two plates?

What is a rough cut figure I could use to determine what the thermal conductivity of 10mil and/or 20mil of air sandwiched between two plates (perfectly conducting)? I understand that convection dies ...
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How much a 0.1 mm air gap between 2 materials will affect heat transfer rate?

I have a disc with drilled holes with a 0.1 mm tolerance. The plate is 6061 T6 Aluminum and I want to insert a polyethylene tube with water in it that is frozen. Assuming some tubes are in full ...
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Can a lunchbox made from neoprene be as effective as one made from foam and aluminum foil at keeping its contents hot or cold over time?

Aluminum foil reflects radiant heat while neoprene doesn't. On the other hand, aluminum is highly conductive while neoprene is an insulator. So there must be differences in the way these two materials ...
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Figuring out power requirements of pool heater elements powered directly by solar panels (panel efficiency & sun,evaporation, insulation, ), etc.)

EDIT 1: firstly, thank you for the comments and the input In this calculations the panels are already involved from the start as being the source (due to other connections to other systems when not ...
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2 answers
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Thermally insulate roof windows

I have two 3 by 4 foot roof windows facing south and want to keep the heat out in summer. What I did on the hottest days was I opened them a bit and strapped cardboard on top. That way a bit (hot) ...
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Heating an uninsulated campground building with high ceiling and radiant floor in New England

We have a beautiful dining hall designed for summer camp use, which we want to keep warm enough for group activities in the winter. The chosen heat is radiant floor, hoping to keep temperatures ...
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4 votes
2 answers
185 views

More efficient to use LED lighting than to open blinds for light and thereby lose heat when very cold outside?

Currently here it is 9 degrees Farenheit. My home is heated by electric resistance heating (not a heat pump, just plain heating coils). Am I correct in believing that it's more energy efficient to ...
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What is the ideal gap between two panes of glass for insulation

I have two panes of glass, about a 3/8" thick (.95 cm). Space efficiency and aesthetics ignored, how far apart should they be spaced to maximize heat insulation, assuming the gap contains regular ...
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What is the white fiber in the copper wire of headphones?

I got a pair of in-ear headphones, broke the left earphone, bought another set, broke the right earphone, and joined the leftovers of both. I found white, grey, or beige fibers near the copper of the ...
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3 votes
1 answer
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Trapping sun heat the most - greenhouse

Greenhouse have recently caught my attention lately, which yesterday I posted in Why greenhouse's inside temperature never been infinitely hot? From what I understand recently, greenhouse gases traps ...
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Cheap material and construction to insulate balcony during the winter?

It's a long shot, but I was wondering whether there is any material I can wrap around my balcony to be able to use it like a sun room during the winter. A plastic-like material that I could span ...
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What material might by used to 'staple' coils down in this stovetop element?

I have the stovetop element shown in the image below. If you look at the coils, they're fixed down by what look like little staples. I'm wondering what material those staples might be. The surface ...
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Increase in internal energy and temperature

A banquet hall (150 m3) is to be used for a formal dinner for 20 persons. Each person occupies 0.075 m3 of space and has an average heat transfer rate of 500 kJ/hr. If the AC system fails, determine ...
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Heat loss calculation and Energy Balance

The image shows the CAD model of the annealing zone in a galvanization simulator. The zone is electrically heated with a AC current of 5597A at 2.09V. This whole zone is surrounded by insulating ...
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1 answer
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How are the electronics and chips inside the microwave protected from the microwave radiation/energy?

Let's say I put in an endoscope like camera with the lens at the inside edge of the box and the wire behind metal sheet. Here's a mockup: Could use microwave reflecting or absorbing wrap to wrap the ...
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2 votes
1 answer
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Simulation of temperature in insulated box

I have a box outside that I want to insulate such that the temperature inside the box doesn't drop below 10°C given outside temperatures of (in the most extreme case - at night) -10°C. Inside the box ...
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3 answers
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How to calculate the volume of air required to keep electrical box cool?

I have a steel electrical box that is 15 cm x 15 cm x 10 cm. The weight of the box is 1kg. Inside the box is a relay that loses 30 Watts of heat while in operation (it's attached to a heat sink that ...
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Time to change temperature inside the box

I have an interesting problem here. I have a box of certain dimensions. Inside of the box is some insulation and another box, from the same material as the outer box. I know everything possible about ...
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In a warmer/sunnier climate, window (or roller shutters) superior to curtains?

When -on a hot day- the sun is incident on a window covered from the outside by a closed window shutter, the resulting heat is absorbed by the layers of air surrounding the shutter, subsequently ...
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3 answers
187 views

Freezing water in bent copper pipe

I would like to make an ice cream machine for home use. That is a mixing bowl which can be stored in the freezer over night and then keeps cold long enough to freeze the ingredients while mixing them. ...
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How does concrete perform in an Insulated Concrete Form (ICF) house?

From: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033560/ I can see that concrete can really go bad after a few hundred freeze and unfreeze cycles: If an ICF house has insulation from the inside ...
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1 vote
1 answer
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Protecting heat-sensitive media from fire: fire-safe + Thermos?

Protecting paper documents from fire is quite straightforward with, for example, a Sentry fire chest. This product has been tested hold the inside temperature under 177°C (350F) for 1 hour. This is ...
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Flow of hot gasses around the pipe

I have the following problem: there is a copper pipe getting through a wooden wall. On one side of the wall (hot side), I have elevated temperature which is defined by radiation and convection. On the ...
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3 answers
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DIY thermally insulating construction material

I need to thermally insulate two metal (say aluminum) parts, the first of which is at 200-400 °C (473-673 K), and the second one is at room temperature. It should be possible to screw the parts ...
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How cold for lack of heat?

I know that on the moon, while the daytime surface temperature can be above 270° F, in the shade but a few feet above the surface temperature can get quite low. Wondering whether a similar phenomenon ...
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5 votes
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What colour of tarp will let in the least amount of heat?

Source: Low Tunnel Construction: How to Build a Mini Hoop House I have a small greenhouse that I want to keep as cold as possible in the spring. I plan to cover the greenhouse with a polyethylene ...
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What is the gray-body emissivity value of air

Wonder if anyone would know what is the average thermal emissivity value of air relative to blackbody at near room temperatures? I am looking for that magical number between 0 and 1. Looked everywhere ...
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2 votes
1 answer
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Insulator thermal resistance

I have a machine that has power output of 2750 watt, which is blasted to a insulator foam with thermal resistance of 2.1 m2 kelvin/watt where the insulator is 5 cm thick and it drives the heat into ...
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2 answers
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Calculating R-value from temperature differential

A home windows installation rep gave me a quote today and conducted the following temperature differential demonstration. Alice pointed a heat gun (with a surface temperature of 165F) at the interior ...
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When does window insulation have more impact than attic?

Is there any way to determine either empirically or by convention a rule-of-thumb when one should spend money on insulating windows rather than insulating the attic of a house or building to keep it ...
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Does attic insulation help cool a building?

Given that hot air rises, it's easy to understand how attic insulation can help keep a building warm; say, in the winter, for example. But when winter changes to summer, does the attic insulation help ...
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2 votes
1 answer
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How thick do I need to make the insulation in my homemade furnace?

(This is probably a simple question, but I've been staring at it so long I'm not sure I know how to do it any more. I have an Excel spreadsheet with like 3 different ways to calculate this, and they ...
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3 votes
2 answers
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Heat Loss in Typical House

I recently looked up the recommended insulation value for my area (7) and was surprised how much lower the wall insulation value was shown to be. As you can see it is almost a third of the recommended ...
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transient heat losses approximation, closed chamber

I want to build a small 1x1x1 m insulated (wooden) box, with the purpose of testing an internal coating (the idea is to buy 5 square meters of it instead of 60 for a full scale room). My idea was to ...
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Best insulation material for pipes @ 500℃

What will be the best thermal insulation material for insulation of pipe lines having temperature of 500℃. Mineral wool and Calcium Silicate can be used but here we have a constraint of both weight ...
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4 votes
2 answers
490 views

Suggestions on how to keep electronics cool in high ambient temperature location?

What are the best materials and methods to keep the internal temperature of a device lower then the ambient temperature outside of the device? Based on the following information: Starting temp of ...
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2 votes
1 answer
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Why Heat Exchangers are preferred to work in Constant Pressure Process than Constant Volume Process?

Why Heat Exchangers are preferred to work in Constant Pressure Process than Constant Volume Process? Mostly, all problems are solved in Constant Pressure Process
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1 answer
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What is a transparent material that insulates well? [closed]

I need to create a transparent box that can stay warm inside while in cold temperatures, below 0 degrees, for as long as possible. Glass and plastic are transparent but afaik they don't insulate that ...
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2 votes
1 answer
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What paint/spray on material should I use to insulate a metal pole?

I am not entirely sure if this is the correct forum to ask this question so please refer me on if there is a better arena. I am creating a small weather station and I wish to measure soil ...
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1 answer
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Determination of thermal expansion of a hollow cylinder

I have a heater rod inside a brass rod, which is wrapped by PTFE insulation. The dimensions of the assembly are: Heater diameter = 9.5 mm Brass rod diameter = 25 mm Insulation diameter = 100 mm ...
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309 views

How to choose an insulating material for a heated metal rod

I have a rod heater mounted in a brass rod and I need to coat the rod with a solid thermal insulator. I have the following options: PTFE Teflon Polyurethane foam However, I doubt that the foam would ...
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1 vote
1 answer
2k views

thermal resistance and thermal time constant with ambient temperature

If water at the same temperature is heated with the same heat power source in two different ambient temperatures (one ambient is low and the other ambient is high) then which water sample will reach ...
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3 votes
2 answers
341 views

Effective R-value of radiant barriers

I know that radiant barriers (i.e., reflective films applied over or under insulated spaces) don't technically have R-values (because they primarily reflect heat, instead of primarily slowing ...
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4 votes
1 answer
277 views

How to connect butted or overlapping fiberglass insulation

We are working on a project requiring a temperature-controlled oven for melting lead, tin and other low-temperature metals. The inner cylinder is aluminum. The heat comes from Kanthal wire, for ...
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