IEA Annex 41 MOIST-ENG Whole Building Heat, Air and Moisture Response Comparison of measured and simulated moisture buffering results

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1 IEA Annex 41 MOIST-ENG Whole Building Heat, Air and Moisture Response Comparison of measured and simulated moisture buffering results VTT Building and Transport Tuomo Ojanen & Mikael Salonvaara

2 VTT EXPERTISE AREAS AND RESEARCH TOOLS WUFI Structures - HAM response TCCC2D LATENITE SIMULATIONS Indoor air & structures interaction IDA -ICE TRNSYS Air flow inside the building FLUENT EXPERIMENTS Material properties Standard tests Performance tests: Materials and building Moisture buffering efficiency components Solar Hot-Box Field tests & monitoring Tailored experiments PASSLINK test cell Drying efficiency Field surveys Test rooms Numerical simulation of small scale performance tests and full scale room tests VTT/ T.Ojanen Zurich 2

3 BACKGROUND: PROJECTS AND RESULTS (1) Wood Focus (Finnish wood industry association) projects A Wooden Building with Comfortable Temperature and Humidity Conditions - Phase I and II' Funded by Wood Focus Ltd., companies and TEKES (Nat. Technology Agency) Phase1 : Extensive numerical analysis humidity interactions between indoor air and structures bedroom in an apartment same indoor loads three different climates effect on T, RH comfort perceived air quality RH (%) time (d.m) Non-hygroscopic Hygroscopic 64 VTT/ T.Ojanen Zurich 3

4 BACKGROUND (2) Field studies in Tapanila Ecological house Test room with similar moisture production (9 g/h) during each night (8 hours) Effect of air change and available moisture capacity of walls No plastic: Gypsum 12 mm +paper + cellulose fiber insulation Plastic: Vapour tight surface Pv (Pa) 35 No Plastic 3 Measured 25 Calculated Q Time (d.m) Plastic Q (ach) No Plastic: The peak humidity was reduced during the night by 15 % RH (at +27 C). This corresponds to 21% RH reduction at 22 C. VTT/ T.Ojanen Zurich 4

5 BACKGROUND (3) Conclusion: Moisture transfer between indoor air and structures exists It can have significant effects on the relative humidity conditions (peak values) of the indoor air Effect during short period (daily) variations of moisture load The effect is positive More stabile humidity conditions Improved thermal comfort and perceived indoor air quality VTT/ T.Ojanen Zurich 5

6 Wood Focus project - Phase 2 Practical applications of moisture buffering structures and building components Test method development Materials Building components Full scale room level experimental testing by Fraunhofer Institut Real climate conditions Well monitored experiments Comparison with reference case VTT/ T.Ojanen Zurich 6

7 Laboratory studies of moisture buffering effect - Experimental test method (1) Need for design and performance characteristics How to define moisture buffering phenomena? How could it be studied in laboratory conditions? How to quantify it? Constant temperature, step changes of humidity: - 8 hours at high RH (occupation period, moisture load, wetting) - 16 hours at low RH (unoccupied period, drying) The change in the mass of moisture is measured by weighing RH % Dynamic tests - Boundary conditions Winter Summer time, h Summer: 75 / 5 % RH Winter: 5 / 23 % RH S1 +23 C 5 % RH room space R H Test sample Scale S2 Shutter doors to control the relative humidity conditions of the air space Salt solution 23 % RH (lower) or 75 % higher Salt solution R H VTT/ T.Ojanen Zurich 7

8 Comparison between tests and numerical simulation mm thick pine, smooth surface without coatings dm", g/m Calculated Measured 5 / 23 % RH +23 C Days Calculation with TCCC2D using material properties of pine Vap.dif.coeff. e-1 kg/(s m Pa) w (kg/kg),3,25,2,15,1, % RH w D v VTT/ T.Ojanen Zurich 8

9 Characteristic moisture buffering effect Moisture buffering effect Average change during 8 h of high and 16 h of low RH dm, g/m 2 Gyp.+2xpaint Wood Gypsum 12 mm Gyp+pap+MW Wood,75/5% G+pap+CFI Ply(perf)+CFI pwfb, 75/5%rh Ply(perf)+pWfb Porousw.fibreb. Wood along gr. Test method development continues in a (applied) NORDTEST project VTT/ T.Ojanen Zurich 9

10 Room tests and simulations Real-size test rooms at Fraunhofer Institut für Bauphysik s building in Holzkirchen Equipped with calibrated heating, ventilation and moisture production systems and fans VTT/ T.Ojanen Zurich 1

11 Moisture load profile Moisture production rate per volume [g/m 3 h] Moisture production rate [kg/h] Hour of the day VTT/ T.Ojanen Zurich 11

12 Wood panels - measured and calculated data Relative Humidity, % Temperature, o C RH Wood RH Wood Sim1 RH Wood Sim2 T Wood T Wood Sim /25/3 12: AM 1/25/3 6: AM 1/25/3 12: PM 1/25/3 6: PM 1/26/3 12: AM 1/26/3 6: AM 1/26/3 12: PM 1/26/3 6: PM 1/27/3 12: AM Day and time VTT/ T.Ojanen Zurich 12

13 Aluminium and plaster sidings Relative Humidity, % Temperature, o C Plaster unpainted Aluminium Plaster sim. Aluminium, sim Analytical decay Plaster Unpainted, T Aluminium, T Plaster, sim T Aluminium, sim T /18/2 12: AM 12/18/2 6: AM 12/18/2 12: PM 12/18/2 6: PM 12/19/2 12: AM Day and time VTT/ T.Ojanen Zurich 13

14 Effect of the area of moisture buffering material surface Relative Humidity, % Temperature, o C RH Wood RH Wood Area = 3 RH Wood Area=5 RH Wood Area=65 T Wood T Wood Sim : AM : AM : PM : PM : AM Day and time VTT/ T.Ojanen Zurich 14

15 Continuation Small scale material tests and full scale room test have been done and simulated numerically good correlation between simulation and measurement config dence about simulations Parameter sensitivity analysis using models surface area ventilation flow rate mass transfer coefficients material properties building component properties etc. VTT/ T.Ojanen Zurich 15