The Effect of Outdoor Environment Modification Towards Building Energy Efficiency. Mohd Fairuz Shahidan, PhD Universiti Putra Malaysia

Transcription

1 The Effect of Outdoor Environment Modification Towards Building Energy Efficiency Mohd Fairuz Shahidan, PhD Universiti Putra Malaysia

2 CONTENTS The Influence of Outdoor Environment on Building Energy Efficiency Outdoor Environment Modification Tree and Cool Material Material & Methods Environment Modification Results The Indirect Effect of Outdoor Modification vs. Indoor & Improvement on Building Energy Efficiency Conclusion

3 THE INFLUENCE OF OUTDOOR ENVIRONMENT ON BUILDING ENERGY EFFICIENCY Increased Pollution (Heat) Tropics Higher Energy Bills Squares, Courts, Open Spaces Health Problems Range of Different Street Modify Local Climate into Urban Microclimate Changes of Street Surface Materials (Gartland, 28) Increased Contribute Urbanization Urban Heat Island Abrupt Changes of Outdoor Environment Temperature Rises (Wong et al., 27) URBAN ISSUE Crowded Out Vegetation and Trees (Scudo, 22) (Santamouris et al, 21) Causes Reduction of Green Areas Human Discomfort Concrete Buildings (replacement) Variety of Urban Grid

4 THE INFLUENCE OF OUTDOOR ENVIRONMENT ON BUILDING ENERGY EFFICIENCY Increased Pollution (Heat) Inadequate Shading Unable to intercept and balance the heat from direct solar gains Higher Energy Bills Inadequate Green Spaces leading Air Temperature Increases Influence Building Energy Consumption Human Thermal Comfort Surface Temperature Increases leading Use of Dark Materials in Building Collects and traps more of the sun s energy Use of Dark Materials in Pavements

5 OUTDOOR ENVIRONMENT MODIFICATION TREE AND COOL MATERIAL However, the effects vary from tree species to tree species Types and features of plants around building can affect cooling (Givoni, 1989) Shading MITIGATE THE IMPACT Building Energy Consumption Tree shading reduce the radiative exchange process ground and wall surfaces Two Main Strategies at Street Level Study both Building physical More Energy Consumption properties Vegetation UHI Mitigation Improvement Human Higher of Building thermal Albedo Material Comfort Energy Performance Human Thermal Comfort (Shashua-Bar & Hoffman, 2; Akbari et al, 21; Solecki et al, 25) Can Offset or Reverse the UHI through Cooling Effect (Shashua-Bar & Hoffman, 2) Prominent in Tropics Urban Tree Cooling Effect More latent heat will be released causing evaporative cooling of the air + effective effective + To support cooling effects from tree- High albedo materials (Brown and Gillespie, 1995; Dimoudi and Nikolopolou, 23) Evapotranspiration Can reduce absorption of solar radiation through urban ground surface and building envelopes and keep cooler

6 = OUTDOOR ENVIRONMENT MODIFICATION TREE AND COOL MATERIAL Thermal Shade + + Performance Effectiveness Tree Canopy Density Solar Radiation Interception Ability Leaf Area Index (LAI) Terrestrial Radiation Interception Ability Determine the density of tree canopy (Shahidan et al, 21; Fahmy et al, 21; Jonckheere et al, 24) Evapotranspiration Foliage and Branch Characteristic Tree s Mature Shape (Scudo, 22; Shahidan et al, 21) GREATER DENSITY COOLING BENEFITS ACHIVED High Quality High Quality of Incoming Shade Creation Radiation Interception TOTAL RADIATION absorbed at site can be manipulated by shading & changing albedo of objects OPTIMUM COOLING EFFECT Both modification Study both will 1. Decreases pysical intercepted solar properties radiation Tree s 2. Physical Reducing UHI Mitigation the absorption Cool Material of Properties excessive radiation Properties 3. Increasing Improvement evapotranspiration of Building process 4. Lowering Energy surrounding air Performance. temperature = Lowering Surface and Air Temperature Albedo Emmisivity Absorbing less incident solar radiation Absorbing less incident solar radiation Reflecting power of Surfaces The relative ability of its surface to emit energy by radiation OPTIMUM COOLING BENEFITS ACHIVED Amount of Tree GREATER IMPROVEMENT The COOLING EFFECT MUCH GREATER INCOMING RADIATION Controlled by Material Underneath Canopy

7 MATERIAL AND METHODS

8 MATERIAL AND METHODS Conditions A CURRENT B 2.4/1. Maleleuca leucadendro n/ Mean Albedo Values Tree Quantities 1. Wawasan Park 2. Mahkamah 3. Perbadanan 4. Putra Square 5. P3P Road 6. Rakyat Square 7. Open space 8. P2N Road 9. Perdana Boulevard 1. Wisma Tani Entrance 11. Wisma Tani s Pedestrian Area 12. Tunku Abdul Rahman Road 13. Other Areas TOTAL D LAI 9.73 LAI 9.73, Albedo > / > / >1.5 LAI.93.93/<.5 Average LAI/LAD C Asphalt and concrete pavement Ficus benjamina Asphalt and concrete pavement Ficus benjamina.8 White/gray granite & polished white granite Current Add Tree Increase (%) % 1% 35% 98% 56% 1% 75% 94% 5, 1 5, 36 99%

9 ENVIRONMENT MODIFICATION RESULTS Air temperatures at four different conditions; current condition (A) and modified environments (B) to (D) were compared at 15: in three metres height

10 ENVIRONMENT MODIFICATION RESULTS Air Temperature ( C) Air Temperature ( C) Wawasan Park 2 Mahkamah 3 Perbadanan 4 Putra Square 5 P3P Road 6 Rakyat Square (A) Current (C) Add and change trees to LAI 9.7 and ground materials of.3 albedos Observation measurement Ta ave Wawasan Park 2 3 Mahkamah Perbadanan 4 Putra Square 5 P3P Road 6 Rakyat Square 7 Open Space 8 P2N Road 9 Perdana Boulevard 1 Wisma 11 Pedestrian Tani Entrance Area Infront Wisma Tani Building Location Points (B)Add and change trees to LAI.9 and ground materials of.3 albedos (D)Add and change trees to LAI 9.7 and ground materials of.8 albedos 7 Open Space 8 P2N Road 9 Perdana Boulevard 1 Wisma Tani Entrance 11 Pedestrian Area Infront Wisma Tani Building 12 Tunku Abdul Rahman Road 12 Tunku Abdul Rahman Road Location Points (A) Current (B)Add and change trees to LAI.9 and ground materials of.3 albedos (C) Add and change trees to LAI 9.7 and ground materials of.3 albedos (D)Add and change trees to LAI 9.7 and ground materials of.8 albedos The variation of average temperature differences with a magnitude of.9 C, condition (B) 1.4 C condition (C), 1.5 C condition (D). Almost 6% of average temperature differences were achieved through the increased in tree canopy densities,. Noted that the differences in changing to cool materials was less than 1% (condition C to D). Within 24 h periods, the highest reduction of air temperature were originally obtained from high canopy density and large tree quantities while, a lesser effect was found from the changes of ground surface material properties. Thus, modification of the trees physical aspect offers larger cooling potential than is available through ground material modifications.

11 ENVIRONMENT MODIFICATION RESULTS Air Temperature Reduction ( C) LAI 6.1, Alb.4, 9nos LAI.9, Alb.4, 9nos LAI 9.7, Alb.4, 9nos LAI 9.7, Alb.8, 9nos LAI 3.9, Alb.4, 28nos LAI.9, Alb.4, 28nos LAI 9.7, Alb.4, 28nos LAI 9.7, Alb.8, 28nos LAI 3.3, Alb.3, 36nos LAI.9, Alb.3, 36nos LAI 9.7, Alb.3, 36nos LAI 9.7, Alb.8, 36nos LAI., Alb.3, nos LAI.9, Alb.3, 124nos LAI 9.7, Alb.3, 124nos LAI 9.7, Alb.8, 124nos Wawasan Park Mahkamah Perbadanan P3P Road LAI, Albedo and Nos of Trees Air temperature reduction influence by variation of tree canopy density, quantity and types of ground material (albedo)

12 THE INDIRECT EFFECT OF OUTDOOR MODIFICATION VS. INDOOR Outdoor Air Temperature ( C) Wawasan Park Perbadanan Rakyat Square P3P Road Wisma Tani Pedestrian Perdana Boulevard Location CONDITION A Ave CONDITION A Max CONDITION B Ave CONDITION B Max CONDITION C Ave CONDITION C Max CONDITION D Ave CONDITION D Max Ave. Observation Max. Observation CONDITION D Ave Pecentage Reduction (%) CONDITION D Max Pecentage Reduction (%) Percentage Reduction (%) The highest outdoor temp. reduction - condition (D) in the P3P Road location, 124 high canopy density trees had been placed. Average and maximum reductions of 2. C (7.7%) and 2.1 C (6.4%) over the baseline condition (A). Influenced further reduction in indoor air temperature with average and maximum of 1.7 C (6%) and 1.9 C (6%). Indoor Air Temperature ( C) Percentage Reduction (%) Meanwhile, location point with the lowest tree quantity, Perdana Boulevard with four trees, shows the lowest average and maximum reduction of.7 C (2.4%) and 1.2 C (3.7%), respectively Wawasan Park Perbadanan Rakyat Square P3P Road Wisma Tani Pedestrian Location CONDITION A Ave CONDITION A Max CONDITION B Ave CONDITION B Max CONDITION C Ave CONDITION C Max CONDITION D Ave CONDITION D Max CONDITION D Ave Pecentage Reduction (%) CONDITION D Max Pecentage Reduction (%)

13 THE INDIRECT EFFECT OF OUTDOOR MODIFICATION VS. INDOOR Maximu Air Temperature Reduction ( c) y =.6x R² =.9164 y =.64x R² =.9234 y =.63x R² =.8827 y =.69x R² =.8769 y =.84x R² =.9483 y =.61x R² = Tree Quantities (No.) Indoor Condition (D) Outdoor Condition (D) Indoor Condition (B) Outdoor Condition (B) Indoor Condition (C) Outdoor Condition (C) Linear (Indoor Condition (D)) Linear (Outdoor Condition (D)) Linear (Indoor Condition (B)) Linear (Outdoor Condition (B)) Linear (Indoor Condition (C)) Linear (Outdoor Condition (C)) The calculated and plotted maximum outdoor and indoor air temperature reduction against high canopy density tree quantities The slope value is corresponding to a.1 C maximum outdoor and indoor air temperature reduction per single high canopy density trees added to the site, starting from 1.4 C to 1.1 C reduction in 4 trees in condition (D), respectively. Meanwhile, condition (C) and (B) reduced by.1 C; starting from.9 C to.4 C of outdoor and.7 C and.3 C of indoor Ta reduction in 4 trees, respectively. This effect of outdoor modification provides a significant reduction in indoor air temperature during the hottest period of the day. Thus, by having high canopy density and tree quantities, combined with cool materials, can improve the outdoor and indoor air temperature in an urban area.

14 IMPROVEMENT ON BUILDING ENERGY EFFICIENCY Total Cooling Load (KWh) Percentage Reduction (%) Wawasan Park Perbadanan Rakyat Square P3P Road Wisma Tani Pedestrian Perdana Boulevard Location CONDITION A CONDITION B CONDITION C CONDITION D Reduction (%) Summary on the comparison of total cooling load based on each modification in six selected location points in Persiaran Perdana It can be observed that condition (A) shows the highest total cooling load in all six locations between 154 and 17 kwh for one single typical day in Malaysia. Present - assumed that most buildings have similar cooling load result of increased demand for urban electricity consumption. Condition B 5 to 22% reduction due to added vegetation to the site although with loose density. Condition C 8 to 29 % reduction due to higher canopy density, added vegetation Condition D 1 to 29% reduction due to higher canopy density, added vegetation and cool material

15 IMPROVEMENT ON BUILDING ENERGY EFFICIENCY 35 Total Cooling Load Reduction (%) y =.1239x R² =.8476 y =.1312x R² =.8982 y =.153x R² = Tree Quantity (No.) Condition D - Cooling Load (%) Condition B - Cooling Load (%) Condition C - Cooling Load (%) Linear (Condition D - Cooling Load (%)) Linear (Condition B - Cooling Load (%)) Linear (Condition C - Cooling Load (%)) Correlation between total cooling load percentage reduction and tree quantities in six selected location points The findings from this study also found that the reduction in total building cooling load is well correlated to high canopy density tree quantities. The building cooling load reduces with the increase of tree quantities. In fact, the highest building load reduction can be found in condition (D) where application of high canopy density trees and cool material was proven effective in improving building cooling load.

16 CONCLUSION 1. In the context of outdoor and indoor modification, it can be observed that almost all were improved within the average range from 2.7% to 7.7% outdoor and 2.4% to 4.1% indoor respectively with modification to high canopy density trees and cool materials. 2. In fact, both outdoor and indoor air temperature reduction was found to be correlated significantly with tree quantities. 3. The higher the quantity of trees planted and density of tree canopies, together with cool materials with high albedo, the higher the reduction can be found in both outdoor, indoor air temperature and thus improved building energy savings. 4. It is recommended that these three major factors need to be considered in combination in order to optimize the cooling effect in urban environment at street level, High tree canopy density (LAI 9.7), Larger tree quantity (9% increased) and Cool materials (a;.8). 5. Thus,these modifications optimally modify outdoor and indoor air temperature and ultimately offer better improvement towards building energy performance especially in hot urban tropical climate condition.

17 Thank You