TYPE OF THERMAL INSULATION FOR ROOF

Transcription

1 GBI PROFESSIONAL SERIES 2018 Seminar on MS 2680, Advance OTTV & Roof U-Value for Radiant Barrier 30 th January 2018, Pullman Hotel, Bangsar. TYPE OF THERMAL INSULATION FOR ROOF By Ar. Dr. Lim Chin Haw Senior Research Fellow

2 Thermal Insulation HEAT GAIN = COOLING ENERGY USED COOLING ENERGY USED = EXPENSE $$$ SOLUTION is to CONTROL HEAT GAIN

3 Solar Irradiation: Source of Heat

4 Sun Path determine the exposure of the building components to solar radiation: Equatorial Region = Roof Sun Path for Countries in Northern Region Sun Path for Countries in Equatorial Region

5 Five Key Strategies for Low Energy Buildings Orientate Shade Insulate Ventilate Daylit

6 Green Technology Master Plan Malaysia

7 RSI 2.5 m 2.K/W) RSI 1.67 m 2.K/W)

8 Heat Transfer through Roof Typically in tropical countries, the high solar radiation intensity is being absorbed by the roof component which causes high amount of solar heat gain emitted inside the building which ultimately will increase the energy consumption for air conditioning system in order to maintain thermal comfort for its occupants. Heat is transferred in 3 ways: 1. Radiation heat transfer 2. Convection heat transfer 3. Conduction heat transfer

9 Radiant heat transfer into building through roof in hot climate accounts for approx. 93% compared to conduction & convection 100% Solar Radiation ROOF Up to 7% Conduction & Convection Up to 93% Radiation

10 Fundamental of R-Value & U-Value RSI, which stands for R-value Systeme International. RSI Value R-Value (imperial unit): ft 2. F.hr/BTU whereas RSI (metric unit): m 2 K/W R-Value (Imperial) = RSI x RSI = R-Value / 5.678

11 Fundamental of K-Values

12 Key parameters of a thermal insulation material Lowest thermal conductivity as possible (W/m.K) Lowest Thermal conductivity High thermal resistance (m 2 K/W) = R-Value High R-Value Lowest thermal transmittance U-value (W/m 2 K) Lowest U-Value

13 Building Insulation 1. Building insulation material should have high thermal resistance 2. Commonly installed on roof, façade, walls and floor components 3. For low rise and medium rise buildings in equatorial region, with high intensity of infra-red solar radiation, the most effective position of insulation installation is on the roof. Potential reduction of thermal heat gain up to 50%. 4. Four main types of insulation technologies: a) Bulk/Mass b) Reflective insulation / radiant barrier c) Nano technology d) Vacuum technology

14 Types of Insulation Technologies Thermal Insulation Technologies Bulk / Mass Technology Reflective Technology Nano Technology Vacuum Technology Mineral Wool Mineral Wool Radiant Barrier Aerogel Vacuum Insulation Panels (VIPs) GFP (Kyrpton/Xenon) Fiberglass Reflective Insulation EPS Expanded Polystyrene (EPS) Interior Radiation Control Coating (IRCC) Extruded Polystyrene (XPS) Gas Filled Panel (GFP) Vacuum Insulation Panels Reflective Insulation Aerogel

15 Bulk / Mass Technology Mainly to prevent heat transfer through conduction and convection using pockets of trapped air within its structure Types of bulk insulation: mineral wool, fibreglass wool, Expanded polystyrene (EPS), Extruded polystyrene (XPS), polyurethane foam or panel and cellulose. Effective in reducing conduction and convection heat transfer Physical properties: Weight and density varies and depend on applications/requirements; some are rigid/panel form and some are roll form Physical issues: shrinkage due to air moisture / high humidity, compression of thickness during installation for low density materials, Health issues: irritation of skin, eyes and throat during handling of fibreglass wool insulation, produces particles in the air when expose which can cause respiratory issues, hazardous to food processing factory. RSI *Thermal resistance based on 50mm thickness

16 Concrete Flat Roof UBBL Section 38A: Heavy Weight Roof = 0.6 W/m 2 K Results were based on simulation Source: Building Energy Efficiency Technical Guideline for Passive Design, 2013

17 Pitch Roof: Metal deck UBBL Section 38A: Light Weight Roof = 0.4 W/m 2 K Results were based on simulation Source: Building Energy Efficiency Technical Guideline for Passive Design, 2013

18 Reflective Technology Reflective insulation and radiant barrier do not have an inherent RSI or R-Value because it relies on still air to be effective. Definition by Reflective Insulation Manufacturers Association (RIMA) International: Reflective insulation: thermal insulation consisting of one or more low-ɛ surfaces, bounding one or more enclosed air spaces Radiant barrier: the Low-Ɛ material facing an open air space Types of Reflective insulation & Radiant Barrier: Bubble foil, Woven foil, foam foil & multi layered-foil. Characteristics: light weight, effective in reducing radiant heat transfer especially downwards heat flow Thermal resistance: Must of Low-Ɛ surface that face the air gap & depends air gap and heat flow directions Issues: Low Ɛ surface decreases due to dust accumulation over time or from dusty environment Reflective insulation

19 Key parameters that influence the performance of reflective insulation and radiant barrier The thickness of the air space facing the reflective material. Low-E surface: ability of the a material s surface to emit radiant energy. The lower the E-value the better Surface temperature difference between the spaces on both side of the reflective materials. The greater the temperature difference, the greater the performance The direction of heat flow. Heat flow upwards tends to give lower RSI as compared to heat flow downwards

20 R VALUE A Comparison On R-Value For Mass Insulation vs Reflective Insulation Materials (ASTM C518) 1.02 The temperature boundary conditions is based on MS Mass Insulation Reflective insulation without air gap TYPES OF INSULATION Rockwool Mineral wool (60kg/m3) 3 ) Foam Foil (10mm) Foam Foil (5mm) Bubble Foil (ø 30mm) Bubble Foil (ø 10mm) TESTS CONDUCTED USING HEAT FLOW METER

21 R VALUE 3.00 B Comparison On R-Value For Mass Insulation vs Reflective Insulation Material with 50mm Air Gap Top & Bottom (ASTM C518) Reflective insulation with 50mm air gap Mass Insulation TYPES OF INSULATION Rockwool Mineral wool (60kg/m3) 3 ) Foam Foil (10mm) Foam Foil (5mm) Bubble Foil (ø 30mm) Bubble Foil (ø 10mm) Woven Foil (140μ) TESTS CONDUCTED USING HEAT FLOW METER

22 Cost RM / m2 Nano Technology: Aerogels Invented in 1930s by NASA application in astronaut suit. Considered as super insulation material. Aerogel is a ultralight weight material mostly derived from silica gel with high porosity(<100nm) and very low density ( g/cm 3 ). Only 15 times heavier than weight of air. Very low thermal conductivity (0.017 W/m.K) as compared to mineral wool (0.035 to W/m.K) Still very expensive insulation material compared to conventional insulation (RM200/m 2 ) Insulation materials Mineral wool (40 kg/m3) Bubble foil EPS XPS VIP (25mm) Aerogel blanket

23 Vacuum Technology: Vacuum Insulation Panels (VIPs) The vacuum is sandwiched in core micro-porous material like fumed silica or glass fiber. Aluminium foils are used to seal the vacuum. Very Low Thermal conductivity between to W/mK compared to mineral wool W/mK Very high thermal resistance with 20mm thick, RSI=5 m 2 K/W or U-Value= 0.2 W/m 2 K Very rigid due to standard factory sizes of VIPs. Limited applications. Very fragile, Cannot be cut onsite due to vacuum conditions / state; Vacuum can leak/puncture overtime, hence thermal performance will also drop. Limited service life and may requires replacement Still costly as compared to conventional insulation Components of VIPs technology Comparison of thermal conductivity between insulation materials (left); the same required RSI value comparison between glass wool and a VIPs thickness (10 times thinner)

24 Criteria for choosing the right thermal insulation for building application Thermal resistance: high RSI (R-Value) insulation material to fulfil Standards and By- Laws requirements Material thickness and density: e.g additional weight on roof Ease of installation: speed and workmanship, flexibility to install Cost and budget: constraint Impact on safety & health issues: odour, skin/eye irritation due to particles in the air Durability: R-Value change over time due to air moisture effects(high RH), mould and fungal growths and shrinkage due to thermal expansion & contraction and dust accumulation. Acoustics issue: sound absorption & insulation Fire resistance: According to fire standards & requirements

25 Optimum insulation thickness and cost Insulation Cost Cost Optimum level Energy Cost Insulation Thickness Can achieve a trade-off between the insulation cost and energy cost

26 Insulation Materials R-Value UBBL Section 38A: Light weight roof RSI 2.4 and above Woven foil with 50mm air gap top & bottom Small bubble foil with 50mm air gap top & bottom Vacuum Insulation Panel (VIPs) 50mm thick Big bubble foil with 50mm air gap top & bottom Lower RSI Higher RSI Fiberglass wool (50mm thick) Aerogel 50mm thick Gas Filled Panels (GFP): Krypton 50mm thick Mineral wool (50mm thick) Expanded Polystyrene (EPS) 50mm thick Extruded Polystyrene (XPS) 50mm thick Foam Foil (10mm thk) with 50mm air gap top & bottom Mineral wool + Foam Foil with bottom 50mm air gap Mineral wool + Big Bubble Foil with bottom 50mm air gap Mineral wool + Woven Foil with bottom 50mm air gap

27 Test Standards and Methods

28 International Standards for Testing Insulation Materials

29 Air gap Top 40mm (hot side) and bottom 60mm (cold side)

30 TEST METHODS TO DETERMINE U-Value and RSI HEAT FLOW METER GUARDED HOT BOX Laboratory FIELD MEASUREMENT USING TEST CELLS

31 HEAT FLOW METER : MODEL FOX 600 International Test Method: ISO 8301, ASTM C-518 Max 180mm Heat flow meter provide steady state measurement of thermal conductivity and thickness of specimen R value = 1 λ L m2 K/W λ = Thermal conductivity (W/mK) L = Thickness (m)

32 Heat Flow Meter (ASTM C518) Pros Provide measurement of material properties according to ASTM C 518 and ISO 8301; thermal conductivity, thermal resistance (R-value) and U- value. Most widely used equipment by renown labs & Internationally accepted method of measurement Measurement can be repeated due to control boundary conditions (steady-state) Fast and easy measurement Cons Only measure the thermal properties of the material itself and unable to measure the entire/total R- value of the roof system as required by UBBL Specimen size and thickness limitation according to equipment model

33 Heat Flow Meter at SERI UKM: Model FOX600 Laser Comp-Test Method ASTM C-518 Heat Flow Meter funded by GBI and UKM

34 Temperature Settings according to MS 2095 Diagram of the heat flow meter top and bottom plate temperature settings, air gaps and heat flow downwards direction Timber frames are used to create air gaps for bubble foil for heat flow meter measurement

35 Guarded Hot Box (ASTM C177) Pros Test method under ISO 8302 Test operate under control boundary conditions Test can be repeated Test results can be compared Can test big/actual specimen Cons Too expensive to operate (consume large amount of energy) Normally for wall (vertical) test only and not for roof Take longer time to reach steadystate condition Not so popular now in UK

36 Field Measurement: Test cells Pros Able to test full scale actual roof system or assembly Actual climate conditions Provide actual onsite performance and trend Cons Need to build full scale actual roof system Higher cost to operate due to installation of roof assemblies Test cannot be repeated due to local climatic conditions (ever changing and dynamic conditions: fluctuation of solar radiation) Different test locations give different results (micro climate, surroundings landscape) Test results cannot be compared if tested in different time/days/months/year. Life span of test cells due to outdoor conditions Difficult to test under steady-state

37 Research Findings using Heat Flow Meter Method Research conducted by Solar Energy Research Institute (SERI) UKM

38 R-Value BIG BUBBLE FOIL G202A - big bubble foil Bottom Top Air Gap Air Gap 25mm 50mm 75mm Comparison of R-Value (Big bubble foil) Top Air Gap 25mm Top Air Gap 50mm 1.2 Top Air Gap 75mm Bottom Air Gap (mm) Optimum configuration for Big Bubble foil for R-value 2.38: Top air gap 50mm and bottom air gap 75mm

39 R-Value WOVEN FOIL WF202A - woven foil Bottom Top Air Gap Air Gap 25mm 50mm 75mm Comparison of R-Value (Woven foil) Top Air Gap 25mm 1.6 Top Air Gap 50mm 1.4 Top Air Gap 75mm Bottom Air Gap (mm) Optimum configuration for Woven foil for R-value 2.16: Top air gap 50mm and bottom air gap 50mm

40 R-Value SMALL BUBBLE FOIL S202A - small bubble foil Air Gap Top Air Gap 25mm 50mm 75mm Comparison of R-Value (Small bubble foil) Top Air Gap 25mm Top Air Gap 50mm 1.2 Top Air Gap 75mm Bottom Air Gap (mm) Optimum configuration for Small Bubble foil for R-value 2.32: Top air gap 50mm and bottom air gap 50mm

41 R-Value METALIZED FOIL Comparison of R-Value (MP2) MP2 - metalized foil Air Gap Top Air Gap 25mm 50mm 75mm Top Air Gap 25mm Top Air Gap 50mm Top Air Gap 75mm Bottom Air Gap (mm) Optimum configuration for Metalized foil for R-value 0.63: Top air gap 75mm and bottom air gap 75mm

42 R-Value COMPARISON OF R-VALUE AMONG DIFFERENT FOILS Comparison of R-Value among different foils Top air gap 50mm (Big Bubble foil) Top air gap 50mm (Woven foil) Top air gap 50mm (Small bubble foil) Top air gap 75mm (Metalized foil) Bottom Air Gap (mm) Big Bubble foil with top air gap 50mm & bottom air gap 75mm has the highest R-value of 2.38 compared to small bubble foil, woven foil and metalized foil.

43 TECHNO-ECONOMIC : Internal Rate of Return (IRR) STUDY COMPARISON OF IRR of AN AIR-CON WAREHOUSE BUILDING WITH VARIOUS CONFIGURATIONS OF REFLECTIVE INSULATION Air condition space/size: 15, m 2 Input parameters: Daily 10am-10pm operational hrs and weather data from Subang Airport was used for simulation, Air-Con temp 23 Deg. C, only varies the types of roof insulation materials and configurations. Price $$$ & Performance plays vital role 3D model building in IES-VE Energy Modelling Software Internal Rate of Return (IRR) of various combination types of reflective insulation and bulk insulation

44 What is the most cost-efficient reflective insulation? Ranking of roof insulation systems according to cost per m 2 per R-value Source: Sau W.L. et al

45 Future Research Project: Empirical Test based on Parameters that influence the total U-value and RSI (R-value) of the Entire Roofing System Inclination of roof slopes Types of roofing materials and insulation Arrangement / configurations of roofing system Boundary conditions: Different intensity of solar radiation, surface temperature of materials and air velocities inside the roof system.

46 THANK YOU = Insulation equals to money save