DOCSLIB.ORG

Thermal Insulation from Wood for Buildings: Effects of Moisture and Its Control Abstract

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thermal Insulation from Wood for Buildings: Effects of Moisture and Its Control Abstract U.S.D.A. FOREST SERVICE RESEARCH PAPER FPL 86 JULY 1968 U.S. DEPARTMENT OF AGRICULTURE FOREST SERVICE FOREST PRODUCTS LABORATORY MADISON, WIS. THERMAL INSULATION FROM WOOD FOR BUILDINGS: EFFECTS OF MOISTURE AND ITS CONTROL ABSTRACT Thermal insulation is an important component of modern homes and other buildings. It provides for the comfort required for livability and, when properly designed for and installed, pays �or itself in fuel savings during winter heating and power savings during summer cooling. Various kinds of thermal insulation made from wood are described. Consider­ ations required for proper design are discussed. Design values for wood and wood-base materials are presented. Methods are presented for estimating heat flow, fuel savings, and temperatures on surfaces and within typical con­ structions. The effects of moisture as influenced by insulation and cold weather are discussed. Proper vapor barrier practice for good results are presented. This Paper is a revision of U.S. Forest Products Laboratory Report 1740, “Thermal Insulation Made of Wood-Base Materials-- Its Application and Use in Houses, ” originally prepared by L. V. Teesdale in 1949. FOREWORD Wood and wood-base materials are by nature relatively good heat insulators. The natural fiber of wood is in itself a hollow cell which provides a minute air space, hence an insulating unit. Thermal insulations, usually considered to be materials with a unit conductivity of less than are frequently made from wood and wood fiber. The need for factual information on the heat flow factors of materials is more important today because of higher fuel and power costs for winter heat- ing and summer cooling (air conditioning), greater overall comfort demands by the user, and the cost of the equipment needed to maintain this desired comfort. The Forest Products Laboratory, during the course of its engineering investi- gations and allied studies extending over the past 57 years, has obtained much basic information on the thermal insulation of wood and wood-base materials, including their influence on fuel economy, comfort of occupants, attic ventilation, vapor barriers, and cold weather condensation. It is the purpose of this publica- tion to present such information, together with procedures necessary for calculating the thickness of insulation required for a specified installation and the influence of the other components of a building. The fullest efficiency to be derived from the use of insulation, as with any material, is in large part dependent on how it is used. The selection of the wrong materials, the use of improper thicknesses of materials, or faulty installation methods can constitute a severe drain on the owner’s income as well as on the Nation’s resources. This publication is intended to aid in independent judgment regarding insula- tion. To prudent buyers, a knowledge of the fact that they are using insulation is insufficient. Accordingly, this publication aims to assist in a careful estima- tion of where, when, and why insulation is needed; to show how the different wood-base materials meet specific requirements; and to emphasize some of the principles frequently overlooked that should be followed in the proper installa- tion of insulation. CONTENTS Page Introduction . 1 Fundamentals for heating and cooling . 2 Methods of heat transfer . 2 Thermal properties of materials . 3 Method of computing thermal conductivities . 10 Type of window . 14 Inside surface temperatures . 14 Why insulate and where . 16 Influence of insulation on comfort . 16 Relation of climate to insulation . Insulation requirements . 17 Using tables of calculated coefficients of transmission . 20 Where to insulate . 20 Reducing heat loss in existing buildings . 22 Fuel savings from insulation . 23 Influence of insulation on dirt pattern development . 25 Wood and wood-base insulations . 26 Rigid insulation . 26 Flexible insulation . 28 Fill insulation . 28 Reflective insulation . 28 Miscellaneous insulating materials . 29 Cold weather and other condensation as influenced by insulation . 29 Condensation within walls and roofs . 29 Effect of insulation on condensation . 32 Vapor pressure-permeability relationships . 33 Vapor barriers . 35 Ventilation in attics and roofs . 37 Crawl space condensation control . 39 Condensation on interior wall surfaces . 41 Effect of humidity on comfort and health . 41 FPL 86 ii THERMAL INSULATION FROM WOOD FOR BUILDINGS: EFFECTS OF MOISTURE AND ITS CONTROL By WAYNE C. LEWIS, Engineer 1 Forest Products Laboratory Forest Service U.S. Department of Agriculture INTRODUCTION added thermal insulation. These savings will in themselves return the added cost of the insulation in a relatively short time. One of the most important developments in Materials used in construction are selected to modern construction practices is the use of ther- suit the needs of the service they are expected mal insulation in all types of buildings and partic- to perform. For example, in a conventional ularly in the intermediate and low-cost dwellings. frame wall, the exterior may be wood sidingover Comfort is the basic objective establishing the wood or insulating board sheathing fastened to need for insulation, but fuel and power economy the studs, which act as structural supports for may often be the factors justifying the added first the wall. The inner wall surface may be gypsum cost involved in applying insulation. During cold lath and plaster or other suitable wall covering. weather, houses must be heated to maintain com- All these materials offer resistance to the trans- fortable indoor temperatures, and insulation plays mission of heat from one side to the other, and an important part in obtaining the uniformity of the heat transmission is proportional to the dif- temperature that establishes comfortable condi- ferences in temperature on opposite sides of the tions. During hot weather, insulation helps to wall. Stucco or brick or stone veneer may be keep indoor temperatures cooler than they would used in place of wood for exterior wall covering. be in an uninsulated building. Other materials may also be used for walls, Even these advantages would not necessarily such as brick, tile, concrete blocks, or stone, justify the use of insulation were it not for the with the interior surface furred, lathed, and fact that in cold climates there is a material plastered. Such walls, as commonly constructed saving in fuel, smaller heating plants can be used, in the usual thicknesses, will transmit more heat and cleaning and decorating expense may be than will conventional frame walls. Where pre- reduced; where summer conditioning is used, the fabricated construction is used, the wall panels power savings will further offset the cost of may be made of light framing members covered 1 Maintained at Madison, Wis., in cooperation with the University of Wisconsin. on both sides with plywood or other suitable a rate that bears some relation to the tempera- materials. ture differences and to the resistance to heat The heat transfer through any of the wall types flow of intervening materials. To maintain a con- described can be reduced by increasing the thick- stant inside temperature when outside tempera- ness of the basic materials. For example, two tures are constant and below inside temperatures thicknesses of wood sheathing could be used in will require a constant supply of heat, and the place of the one thickness generally used, or the heat supply or inflow in this case equals the heat thickness of a masonry wall could be increased loss or outflow. The amount of heat required at above that required for minimum strength. Gen- any fixed temperature depends upon the rate that erally speaking, however, this means of decreas- the heat will be transmitted through intervening ing heat loss is expensive without being very materials used on the construction of the enclos- effective, and there are better means of accom- ing units. plishing the desired purpose. The transfer of heat may take place by one or The materials used in construction are gener- more of three methods--conduction, convection, ally selected on a basis of initial cost, availabil- and radiation (fig. 1). ity, building code requirements, appearance, fire Heat is transmitted through solid materials by hazard, and similar factors. In some cases, the conduction. In a steam-heated radiator, the steam materials may be selected because they are heats the inner surface of the radiator walls, and more resistive to heat transfer than others. For this heat flows through the walls to the outer sur- example, insulating board products may be used face by conduction. in place of wood sheathing, as wall or ceiling Heat transfer by convection applies to heat surfacing materials, or in some applications as carried by air currents from a warm zone to a sound-deadening material in the wall or floor cold zone. Air in contact with the warm outer system where the thermal resistance is an added surface of a radiator becomes heated above the factor. temperature of the surrounding atmosphere, and Structural and finish materials vary widely in rises, being replaced by colder air. Thus a cir- thermal properties. Wood is much more resistive culation of air over the heated surface carries to heat transmission than is masonry. In this heat from the radiator to raise the temperature respect, 1 inch of Douglas-fir is equal in resist- of the surrounding atmosphere. ance to heat transmission to about 12 inches of Heat may be transmitted from a warm body to concrete or stone, but it would take about 2 inches a cold one by wave motion through space; the of the wood to equal 1 inch of insulating board. process is called radiation, as it represents radiant energy. The waves do not heat the space through which they move, but when they come in contact with a colder surface or object, a part of FUNDAMENTALS FOR the radiant energy is absorbed and converted into HEATING AND COOLING heat and part is reflected.
Load more

Recommended publications
  • Experimental Investigations of Using Silica Aerogel
    EXPERIMENTAL INVESTIGATIONS OF USING SILICA AEROGEL TO HARVEST UNCONCENTRATED SUNLIGHT IN A SOLAR THERMAL RECEIVER By Nisarg Hansaliya Sungwoo Yang Louie Elliott Assistant Professor of Chemical Engineering Assistant Professor of Mechanical (Chair) Engineering (Co-Chair) Prakash Damshala Professor (Committee Member) EXPERIMENTAL INVESTIGATIONS OF USING SILICA AEROGEL TO HARVEST UNCONCENTRATED SUNLIGHT IN A SOLAR THERMAL RECEIVER By Nisarg Hansaliya A Thesis Submitted to the Faculty of the University of Tennessee at Chattanooga in Partial Fulfillment of the Requirements of the Degree of Master of Science: Engineering The University of Tennessee at Chattanooga Chattanooga, Tennessee December 2019 ii ABSTRACT Significant demand exists for solar thermal heat in the mid-temperature ranges (120 oC – 220 oC). Generating heat in this range requires expensive optics or vacuum systems in order to utilize the diluted solar energy flux reaching the earth’s surface. Current flat plate solar collectors have significant heat losses and achieving higher temperatures without using concentrating optics remains a challenge. In this work, we designed a prototype flat plate collector using silica- aerogel. Optically Transparent Thermally Insulating silica aerogel with its high transmittance and low thermal conductivity is used as a volumetric shield. The prototype collector was subjected to ambient testing conditions during the months of winter. The collector reached the temperatures of 220 oC and a future prototype design is proposed to incorporate large aerogel monoliths for scaled up applications. This work opens up possibilities solar energy being harnessed in intermediate temperature range using a non-concentrated flat plate collector. iii DEDICATION This is dedicated to all the mentors, professors and teachers I have had the privilege to learn from.
    [Show full text]
  • 15 – Construction Vocabulary
    CONSTRUCTION VOCABULARY ABC (Aggregate Base Course): used in mixing with concrete and placed below concrete prior to the pouring of sidewalks, driveways, etc. It serves as a compacted solid base. Air return: A series of ducts in air conditioning system to return used air to air handler to be reconditioned. Ameri-mix: Maker of the pre-blended bag mixes we use in masonry work. Anchor Bolts: (also called J-bolts) Bolts embedded in concrete foundation used to hold sills in place. Anchor Straps: Straps embedded in concrete foundation used to hold sills in place, most commonly MASAs in our houses. Apron: A piece of driveway between sidewalk and curb. Back Fill: The replacement of dirt in holes, trenches and around foundations. Backing (aka blocking): a non-structural (usually 2x) framed support (i.e. for drywall). Balloon Framing: A special situationally required type of construction with studs that are longer than the standard length. Bay: The space between two parallel framing members (i.e. trusses). Beam: A horizontal structural member running between posts, columns or walls. Bearing wall (aka partition): A wall which carries a vertical structural load in addition to its own weight. Bevel: To cut an angle other than a right angle, such as on the edge of a board. Bird block (aka frieze board): An attic vent located between truss tails. Bird’s Mouth: A notch cut in the underside of a rafter to fit the top plate. Blocking (aka backing): A non-structural 2x framing support (i.e. for drywall) Board: Lumber less than 2” thick. Board Foot: The equivalent of a board 1’ square and 1” thick.
    [Show full text]
  • Residential I-Joist & LVL Installation Guide
    Engineered Wood Products Wood—the miracle material. Wood is the right choice for a host of construction applications. It is the earth’s natural, energy efficient and renewable building material. Engineered wood is a better use of wood. The miracle in today’s wood products is that they make more efficient use of the wood fiber resource to make stronger plywood, oriented strand board, I-joists, glued laminated timbers and laminated veneer lumber. That’s good for the environment and good for designers seeking strong, efficient and striking building design. A few facts about wood. We’re growing more wood every day. Forests fully cover one-third of the United States’ and one-half of Canada’s land mass. Residential I-Joist & LVL American landowners plant more than two billion trees every year. In addition, millions of trees seed naturally. The forest products industry, which comprises about 15 percent of forestland ownership, is INSTALLATION responsible for 41 percent of replanted forest acreage. That works out to more than one billion trees a year, or about three million trees planted every day. This high rate of replanting accounts for the fact that each year, 27 percent more timber is grown than is harvested. Canada’s replanting record shows a fourfold increase in the number of trees planted between 1975 and 1990. GUIDE Life Cycle Assessment shows wood is the greenest building product. A 2004 CORRIM study gave scientific validation to the strength of wood as a green building product. In examining building products’ life cycles—from extraction of the raw material to demolition of the building at the end of its long lifespan—CORRIM found that wood was better for the environment than steel or concrete in terms of embodied energy, global warming potential, air emissions, water emissions, and solid waste production.
    [Show full text]
  • Deep Energy Retrofits for Buildings a SHARING CITIES PLAYBOOK
    Deep energy retrofits for buildings A SHARING CITIES PLAYBOOK This project has received funding from the European Union’s Horizon 2020 research and innovation 2020 V.1 programme under Grant Agreement No 691895 Click on CONTENTS the buttons to navigate Introduction How to use this through this playbook and introduction What is this playbook? 3 document Who is this guide for? 5 1 Building retrofit: Enhancing energy efficiency 6 The challenge 8 Challenge & Solution Deep energy retrofits - What is it and why is this different to a regular building retrofit? 8 2 How to navigate the challenges of conducting building retrofits- Insights from 16 Sharing Cities Insights 3 What is the value of doing a deep retrofit 19 4 How to implement a deep retrofit 23 Exploring opportunity 24 Audience engagement 29 Benefits Technical design 35 Finance and implementation 38 Monitoring and sharing 42 Implementation Toolkit References 47 Acknowledgements 48 This playbook is produced by Sharing Cities, a major international smart cities project. It addresses some of the most pressing urban challenges cities face today across ten replicable solutions. 2 WHAT IS THIS PLAYBOOK? Introduction How to use this playbook and This guide gives an overview of how Sharing Cities rolled out introduction building retrofit schemes in its three ‘lighthouse cities’ – Lisbon, London and Milan. The aim was to address challenges in each city context and share the experience so other cities can learn from it. Challenge & Solution This playbook will: TOOLS & RESOURCES Help you understand what solutions were tested in the Sharing Cities Insights lighthouse cities and what urban challenges they address.
    [Show full text]
  • Environmental Considerations of Building Insulation National Park Service – Pacific West Region
    Environmental Considerations of Building Insulation National Park Service – Pacific West Region Overview Insulation is a commonly used product in the building industry. The manufacture, use, and disposal of insulation is associated with a number of positive and negative environmental impacts. What follows is a brief overview of “green” insulation, vendors, and an in-depth article from Environmental Building News on the environmental comparisons of insulation materials. • The most significant environmental issue associated with insulation manufacture in recent years has been the use of chlorofluorocarbons (CFCs) as foaming agents. By 1993 virtually all CFCs had been eliminated from insulation manufacture; hydrochlorofluorocarbons (HCFCs) have been substituted in most products. These are significantly better than CFCs, but they still result in some ozone depletion, and they contribute to global warming, and are, therefore, also scheduled for phaseout over the next decade. • All insulation materials reduce pollutant and greenhouse gas emissions by reducing heating and air-conditioning requirements of a building. This benefit almost always outweighs environmental problems associated with certain materials. • Do not substitute a “green” insulation material for a non-green material if doing so will result in lower overall energy performance. Even though the environmental impacts of the insulation material might be lower for the green product, the overall environmental impact of the building would likely be greater by lower insulating values. • Fiber insulation materials (cellulose, fiberglass, mineral wool, cotton) generally have lower environmental impacts associated with their manufacture than foam plastic insulation materials, although they usually do not offer as high per- inch R-values. When insulation thickness is not unduly restricted, specify fiber insulation.
    [Show full text]
  • Section 2: Insulation Materials and Properties
    SECTION 2 INSULATION MATERIALS AND PROPERTIES SECTION 2: INSULATION MATERIALS AND PROPERTIES 2.1 DEFINITION OF INSULATION 1 2.2 GENERIC TYPES AND FORMS OF INSULATION 1 2.3 PROPERTIES OF INSULATION 2 2.4 MAJOR INSULATION MATERIALS 4 2.5 PROTECTIVE COVERINGS AND FINISHES 5 2.6 PROPERTIES OF PROTECTIVE COVERINGS 6 2.7 ACCESSORIES 7 2.8 SUMMARY - INSULATION MATERIALS AND APPLICATION WITHIN THE GENERAL TEMPERATURE RANGES 8 2.9 INSULATION AND JACKET MATERIAL TABLES 10 MP-0 SECTION 2 INSULATION MATERIALS AND PROPERTIES SECTION 2 INSULATION MATERIALS AND PROPERTIES 2.1 DEFINITION OF INSULATION Insulations are defined as those materials or combinations of materials which retard the flow of heat energy by performing one or more of the following functions: 1. Conserve energy by reducing heat loss or gain. 2. Control surface temperatures for personnel protection and comfort. 3. Facilitate temperature control of process. 4. Prevent vapour flow and water condensation on cold surfaces. 5. Increase operating efficiency of heating/ventilating/cooling, plumbing, steam, process and power systems found in commercial and industrial installations. 6. Prevent or reduce damage to equipment from exposure to fire or corrosive atmospheres. 7. Assist mechanical systems in meeting criteria in food and cosmetic plants. 8. Reduce emissions of pollutants to the atmosphere. The temperature range within which the term "thermal insulation" will apply, is from -75°C to 815°C. All applications below -75°C are termed "cryogenic", and those above 815°C are termed "refractory". Thermal insulation is further divided into three general application temperature ranges as follows: A. LOW TEMPERATURE THERMAL INSULATION 1.
    [Show full text]
  • Technical Performance Overview of Bio-Based Insulation Materials Compared to Expanded Polystyrene
    buildings Article Technical Performance Overview of Bio-Based Insulation Materials Compared to Expanded Polystyrene Cassandra Lafond and Pierre Blanchet * Department of Wood and Forest Sciences, Laval University, Québec, QC G1V0A6, Canada; [email protected] * Correspondence: [email protected] Received: 5 February 2020; Accepted: 22 April 2020; Published: 26 April 2020 Abstract: The energy efficiency of buildings is well documented. However, to improve standards of energy efficiency, the embodied energy of materials included in the envelope is also increasing. Natural fibers like wood and hemp are used to make low environmental impact insulation products. Technical characterizations of five bio-based materials are described and compared to a common, traditional, synthetic-based insulation material, i.e., expanded polystyrene. The study tests the thermal conductivity and the vapor transmission performance, as well as the combustibility of the material. Achieving densities below 60 kg/m3, wood and hemp batt insulation products show thermal conductivity in the same range as expanded polystyrene (0.036 kW/mK). The vapor permeability depends on the geometry of the internal structure of the material. With long fibers are intertwined with interstices, vapor can diffuse and flow through the natural insulation up to three times more than with cellular synthetic (polymer) -based insulation. Having a short ignition times, natural insulation materials are highly combustible. On the other hand, they release a significantly lower amount of smoke and heat during combustion, making them safer than the expanded polystyrene. The behavior of a bio-based building envelopes needs to be assessed to understand the hygrothermal characteristics of these nontraditional materials which are currently being used in building systems.
    [Show full text]
  • Study of Thermal Properties of Lightweight Insulation Made of Flax Straw
    Slovak Journal of Civil Engineering Vol. 26, 2018, No. 2, 9 – 14 DOI: 10.2478/sjce-2018-0008 STUDY OF THERMAL PROPERTIES OF LIGHTWEIGHT INSULATION MADE OF FLAX STRAW Maryna BABENKO1*, Adriana ESTOKOVA2, Mykola SAVYTSKYI1, Stanislav UNČÍK3 Abstract Address The article presents the results of a study of the properties of flax 1 “Prydniprovska State Academy of Civil Engineering and straw as a raw material and as a lightweight, environmental- Architecture” State Higher Education Establishment, Ukraine, ly-friendly insulation made of a two-component mixture of flax Department of Reinforced Concrete and Stone Constructions straw and liquid glass. The flax is considered to be renewable 2 Technical University of Kosice, Slovak Republic and Department and is a 100% natural waste product of the agriculture industry, of Material Engineering/Institute of Environmental Engineering, which may be widely used as sustainable building insulation af- Faculty of Civil Engineering ter light modifications. The ratio mixes of the two-component 3 Slovak University of Technology in Bratislava, Bratislava, Slovak eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have Republic, Department of Material Engineering, Faculty of Civil been developed in terms of sustainability principles such as en- Engineering vironmental friendliness and energy efficiency. We used thermal * Corresponding author: [email protected] analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decompo- sition of the composite and shorter peaks, which supports the Key words concept of the transformation of flax straw with liquid glass to in- ● Flax, straw, crease its fire resistance properties.
    [Show full text]
  • Identifying Design Opportunities for Deep Energy Retrofits
    RetroFit Depot Identifying Design Opportunities for Deep Energy Retrofits Available for download at www.RetroFitDepot.org Introducing the Retrofit Depot: Deep Energy Retrofit Guides Several commercial building energy retrofit guides already exist, but none address deep energy retrofits. Rocky Mountain Institute wants the owners, occupants, service providers, and retrofit practitioners1 of our nation’s commercial buildings to be aware of the opportunity in deep energy retrofits. We want them to know the value. We want them to have a solid understanding of the process. We also want to arm them with design recommendations that will help make their deep energy retrofits most effective. Provides comprehensive guidance on BuIlDInG framing and quantifying the value of thE CasE Such is the aim of the RetroFit Depot website. It is an unbiased source of 1 deep energy retrofits. information about deep energy retrofits for commercial buildings. On the website people are able to gain a high level understanding of the value of deep retrofits and the required process to achieve them. For those who would like to learn more, we have created a set of three guides. Lists the key components of the manaGInG deep energy retrofit process that Since you are now reading the Guide to Managing Deep Energy Retrofits, DEEp EnERGy limit or eliminate cost premiums, you are likely motivated to realize the value of deep energy retrofits as 2 REtROfIts enable risk management, and create described on the RetroFit Depot website and the Building the Case guide. maximum value. This guide will help you understand the key action items for a deep energy retrofit.
    [Show full text]
  • Energy Efficiency: Building Insulation Volume I – Theory & Materials
    PDHonline Course E446 (3 PDH) Energy Efficiency: Building Insulation Volume I – Theory & Materials Instructor: Lee Layton, P.E 2018 PDH Online | PDH Center 5272 Meadow Estates Drive Fairfax, VA 22030-6658 Phone & Fax: 703-988-0088 www.PDHonline.org www.PDHcenter.com An Approved Continuing Education Provider www.PDHcenter.com PDHonline Course E446 www.PDHonline.org Energy Efficiency: Building Insulation Volume I – Theory & Materials Lee Layton, P.E Table of Contents Section Page Introduction ……………………………………….. 3 Chapter 1, How Insulation Works .………….…..... 5 Chapter 2, Types of Insulation …………………..... 9 Chapter 3, Moisture Migration …………………… 27 Chapter 4, Environmental & Regulatory Issues ….. 30 Summary …………………………………………. 33 © Lee Layton. Page 2 of 33 www.PDHcenter.com PDHonline Course E446 www.PDHonline.org Introduction The efficiency of a building envelope, which includes anything that encloses a building such as walls, ceilings, windows, foundations, is a key to improving the energy efficiency of structures. Basically, the envelope is anything that separates the inside of a building from the outside environment. A good energy efficiency program begins with having a building envelope that efficiently minimizes heat loss. Heating and cooling accounts for 50 to 70% of the energy used in an average home. Inadequate insulation and air leakage are leading causes of energy waste in most residential homes. The benefits of a good building envelope include: • Saves money, • Makes the home more comfortable by helping to maintain a uniform temperature throughout the house, and • Makes walls, ceilings, and floors warmer in the winter and cooler in the summer. The amount of energy efficiency improvements depend on several factors: local climate; the size, shape, and construction of the house; the living habits; the type and efficiency of the heating and cooling systems; and the fuel used.
    [Show full text]
  • Glass Wool] by Applying Coating on It
    International Journal of Engineering Research and Technology. ISSN 0974-3154 Volume 10, Number 1 (2017) © International Research Publication House http://www.irphouse.com Evaluating The Performance of Insulation Material [Glass wool] By Applying Coating on It. Utkarsh Patil. Assistance Professor, Department Of Mechanical Engineering D.Y.Patil College of Engineering and Technology, Kolhapur, Maharashtra. India. Viraj Pasare. Assistance Professor, Department Of Mechanical Engineering D.Y.Patil College of Engineering and Technology, Kolhapur, Maharashtra. India. Abstract: Keyword: A refrigerator is a popular household appliance that Domestic refrigeration system, Glass Wool, consists of a thermally insulated compartment and Polymethyl methacrylate (PMMA). a heat pump that transfers heat from the inside of the fridge to its external environment so that the inside of Introduction the fridge is cooled to a temperature below the ambient temperature of the room. Refrigeration is an Vapor-Compression Refrigeration or vapor- essential food storage technique. Insulating material compression refrigeration system (VCRS) in which is the one of the main sub systems. The primary the refrigerant undergoes phase changes, is one of the function of thermal insulating material used in many refrigeration cycles. It is also used in domestic domestic refrigerator is to reduce the transfer of heat. and commercial refrigerators, frozen storage of foods Hence the efficiency of the system is depends upon and meats, Refrigeration may be defined as lowering the temperature of an enclosed space by removing the on the insulating material use in the refrigerator. heat from that space and transferring it elsewhere.[3] [1]The insulating capability of a material is measured Insulating material is the one of the main sub with thermal conductivity (k).
    [Show full text]
  • Facts About Moisture and Fiber Glass Metal Building Insulation
    INSULATION FACTS Facts About # Moisture and Fiber Glass 26 Metal Building Insulation Information from NAIMA nlike many other insula- What effect does mois- tion products, fiber glass Q ture have on insulation metal building insulation performance? is often visible to the Uoccupants of the building. Making Moisture from rain, ground sure that roofs and walls do not A water,humidity or other leak, that the product is clean and forms of condensation creates the dry prior to installation, and that potential for several problems in condensation is controlled after metal buildings. First, the pres- installation is critical to the insula- ence of water (or ice) in the insu- tion performance and to the lation seriously degrades the building’s interior aesthetics. thermal performance and can Because of performance require- degrade the effective service life ments, fiber glass metal building of the insulation system. Second, insulations are most frequently water in contact with metals can installed with a facing material contribute to corrosion and laminated to the surfaces that may degrade the service life of the be visible.This facing serves building.Third, collection of several purposes: water can lead to dripping, stain- ing, and other undesirable effects I Provides vapor retarder such as mold, mildew and odors, protection to retard passage of which degrade the building’s water vapor through the insu- intended service. lation to cold surfaces where condensation can occur I Protects the insulation from damage Should wet insulation I Provides light reflectivity Q be replaced? I Provides an aesthetic appearance Yes. When fiber glass metal Fiber glass metal building insu- A building insulation is lation will provide long service exposed to storm waters or flood life and optimum performance damage, the wet insulation should when a few simple precautions be removed and replaced since are followed.
    [Show full text]