Vacuum Insulated Panel(VIP)

Vacuum insulated panel(VIP) is a thermal insulation choice used in building construction. Although it’s not suitable in our situation due to its high cost, but it’s worthwhile to know something about it.

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VIPs consist of  membrane walls to prevent the air from entering the panel, a panel of a rigid, highly-porous material, such as aerogel, fumed silica or glass fiber to surport the membrane wall against atmosphere pressure and chemicals to collect gas leaked through the membrane.

The principle of VIPs is reduction of convection and conduction with a better perfomance than conventional insulation due to less gas molecules.

The advantage of VIPs is its low thermal conductivity of 0.004 W/(m*K) at panel center, compared to standard mineral wool 0.044 W/(m*K) rigid polyurethane foam 0.024 W/(m*K). It’s indicated in the figure below.                                                 .

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The disadvantage of VIPs is much lower thermal resistance per unit price than conventional materials. Aerogels are more difficult to manufacuture and high quality of membrane and sealing joins are reaquired to maintain vacuum in a long time. Besides, VIP can not be cut to fit and non-standard sizes must be ordered to make, which also increases the cost.

Here is the reference link: http://www.microthermgroup.com/low/EXEN/site/vip-intro.aspx

Commonly Used Thermal Insulation Materials

Recently I have read an article where 5 most commonly used thermal insulation materials are introduced, they are suitable for different situations because of different up and downs.

Since we are finding thermal insultation materials for indurialisation, commonly uesd thermal insulation materials should be the first thing to look at, because they must have a reason to be extensively used, such as cheap and realiable.

1. Fiberglas is made by effectively weaving fine strands of glass into an insulation material. It is cheap but danderous to handle and low insulation ability. So it’s not a good option for us because of the safety.

pink fiberglass insulation

2. Mineral wool is mainly produced from the slag from steel mills. It’s cheap but low insulation ability. It’s not a good option for us because it’s suitable for insulation large areas instead of filiing in little holes.

mineral wool

3. Cellulose is  plant fiber used in wall and roof cavities to insulate, draught proof and reduce noise. It is cheap and ecofriendly but skilled individuals are needed to install it. Maybe it doesn’t need that much skill to fill in little holes but hard to industrilise.

cellulose

4. Polyurethane foam has high insulation ability but expensive.

polyurethane insulation spray application

5. Polystyrene(EPS) is cheap and easy to handle in our situation.

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So sphere EPS foam in the picture above is the most hopeful candidate among the common thermal insulation materials for our project.

Here is the reference link:  http://www.thermaxxjackets.com/5-most-common-thermal-insulation-materials/,

Introduction of Thermal Insulation

There are three ways of heat transfer: conduction, convection and radiation.

Conduction is the transfer of energy by physical contact. Convection is the transfer of energy between an object and its environment due to fluid motion. Radiation is the transfer of energy to or from a body by means of the emission or absorption of electromagnetic radiation.

Accordingly, thermal insulation is decreasing heat transfer from conduction, convection and convection.

Thermal insulation materials that reduce conduction, convection or both are called thermal insulator. The effectiveness of an insulator is indicated by its R-value. The R-value of a material is the inverse of the conduction coefficient (k) multiplied by the thickness (d) of the insulator.

Thermal insulation materials that reduce radiation is called radiant barrier. The effectiveness of a radiant barrier is indicated by its reflectivity, which is the fraction of radiation reflected. A material with a high reflectivity has a low emissivity (at the same wavelength). At any specific wavelength, reflectivity = 1 – emissivity. An ideal radiant barrier would have a reflectivity of 1, and would therefore reflect 100 percent of incoming radiation.

Industrially, there are two ways of thermal insulation according to thermal insulator and radiant barrier.

In the case of my thesis, one way for thermal insulation is to fill the honeycomb cells with thermal insulator such as spherical EPS foam or put anther layer of thermal insulator sheet on top of the panel.

The other way is to put a radiant barrier on top of the panel such as aluminum foil.

Here is the reference link: http://en.wikipedia.org/wiki/Thermal_insulation

Thesis Introduction

Do you remember the hot feeling when you get into the car which is exposed to the big sun in summer?

Have you thought of building temporary warm houses for homeless people after a earthquake?

Do you want to own a suitcase that can keep the inside temperature from going too high in summer?

Yes, my thesis is about thermal insulation for the sandwich material produced by Econcore company which is the leader of this field.

The picture below is the representative product of Econcore company. They are applied in various markets like packaging, automotive, building and construction, furniture, etc.

econcore

As you can see, between the two skins are honeycomb structured core which is composed of empty cells.

My task is to find the suitable material to fill in the honeycomb cells to improve thermal insulation performance.

Also preparation of background for industrialization and commercialization of the concept.

The tour has just started!

Here is the website of Econcore company: http://www.econcore.com/en