CHAPTER FOUR: RESULTS

Experimental Approach

The site-specific data were obtained through field experiments. The process started by site studying where satellite images were used to concentrate the form vegetation level of sub-municipality to neighborhood and district level. Then the climber plants were examined and compared to each other from growth speed, lifespan, resilience towards the direct sun and heat. Then the search for a site began with preexisting green facades after nominating six various plants.

Concentration of vegetation in Jeddah from Sub-Municipality to Neighborhood/ District

Research started with a look at the governance of the city to divide it into small segments that are workable for study.  The municipality of Jeddah provided information of 14 sub-municipalities. A thorough investigation using visuals was conducted, and zoning maps were employed to understand the areas that were mainly home to the apartment building, an area reserved for villas and an average number of floors of each building (Pulselli, et.al, 2014). Finally, an evaluation of land values correlation demonstrated that plants are predominant in a wealthy neighborhood. Zoning maps examination for all 202 districts of Jeddah found three sub-municipalities having the highest number of detached and attached houses. Thus, the district of Jeddah Al Jeddah was selected for this study. A thorough walk-through and driving was carried out in five districts which form Jeddah Aljadedah to familiarize with the chosen sub-municipality. The satellite images were reviewed to understand the number of private space that the public eye can view.

Regarding Selected Vines/Climbers in Jeddah, non-native and native plants in the city of Jeddah were studied in Saudi Arabia’s Illustrated Guide to the Flowers. Careful consideration was given to the different ability of plants to thrive and survive in an arid region, grow vertically to create a green façade and sustain exposure for long hours to direct sun.

In field experiment, 20 sites were situated in Jeddah across the various districts. Four locations were selected for the experiment after filtering out the unnecessary site for this experiment. Data from existing green facades was recorded that exhibited diverse vegetation, orientation, arrangement and installations. The measured parameters included leaf dimension, area index, appearance, color, relative humidity, ambient air temperature and carbon dioxide (Stav, & Lawson, 2012). Seven tools were then chosen to measure the research parameter with special consideration given to price, error margin and require output. The field experiment covered 1m by 1m study areas in the center of each green wall situated 1m above the level of the ground and other non green facade area for comparison purposes. Heat reduction was computed in part by subtracting front ambient heat from behind ambient temperature of the green façade.

The instrument used included HP Officejet 4500, RIDGID micro IR-100 Non-Contact Infrared Thermometer and The HOBO MX1102 CO2 data logger. HP Officejet 4500 was employed to scan the samples of leaf from all sites to enable digitization. RIDGID micro IR-100 Non-Contact Infrared Thermometer was used to provide accurate surface readings of temperature with a squeeze trigger and single point that activates Class laser at the surface which is measured and render the LCD temperature measurement. The HOBO MX1102 CO2 data logger was employed to record temperature, carbon dioxide and the data of RH in the indoor environment by using non-dispersive infrared, integrated temperature, self-calibrating sensor technology of CO2 and RH sensor.

The experiment lasted for one month. The highest mean temperature is experienced on June 19 in Jeddah, and the lowest is experienced on Jan 12. Thus, the requirement of annual energy for the specific structure was estimated using the number of HDD/CDD at the location. The cooling and heating degree days were calculated over a baseline of 18 ℃. The hottest days measured in Jeddah was used to find green facades’ useful during hours of the day in minimizing sun radiation. The field experiment research was carried out on Sep 2015 at four altered times during the day as the scholarship approval for travel was offered in the 2015 fall semester. This was opposed to doing it in June which is the hottest month.

The data logger’s tools were calibrated, and their functionality was tested and assured.  The radiation shield was structured to deter the direct radiation from interfering with the readings. Simple planters of black plastics were painted to enable radiation reflection. The string was used to hang the logger to provide an accurate reading. Then the logger was protected by a light plastic piece in case of rain.

The first site to be selected was Site A: Al-Kayal Restaurant plants. It was the first experiment and data collected from loggers included relative humidity, temperature and carbon dioxide and was exported to jpeg, hoboware file format and Excel for analysis and comparison. Site B was conducted in an Ali Reda house which was the second experiment (Perini, et.al, 2011). Also, the collected data from loggers included relative humidity, temperature and carbon dioxide and was exported to jpeg, hobo ware file format, and Excel for analysis and comparison. Site C was conducted in Major Kadi which was the third experiment and finally site D was carried out in the Abo Maram House which was the fourth experiment. Similarly, collected from loggers included relative humidity, temperature and carbon dioxide and was exported to jpeg, hobo ware file format, and Excel for analysis and comparison. The field experiment was in two parts where each part contained two sites and level of relative humidity, ambient temperature, and carbon dioxide were measured.

The first part was site A&B which started at 18.00 on 09/15/2015 and ended at 03.00 on 09/19/2015. A total of 973 data points of each parameter was logged in at an interval of five minutes covering a total of 81 hours. The second part was site C&D and commenced on 09/20/2015 at 12.00am and ended at 6.00 on 09/23/2015.A total of 973 data points of each parameter were logged in at an interval of five minutes covering a total of 78 hours.

Energy Saving through Energy Simulation

The energy simulation in this study was embraced from the attempt to simulate the impact of green façade with the plant through Energy Plus thermally. Also, the research proves this by using the Jeddah’s arid climate.

Energy plus 8.4 was utilized to perform one-year simulation on a sample building to examine the two baselines. The first simulation was a usual Saudi wall designed before the institution of the current law. The second was a wall designed after current implementation of insulation law were announced in 2014 and started working in 2015. Also, the sensitivity test was carried on a variable like leaf area index, orientation, leaf color, the thickness of green façade to gain an understanding of what will lead to energy saving (Olivieri, Olivieri & Neila, 2014).

Finally, the evaluation of the required energy to cool down space to attain comfort zone was carried out and measured in kilowatts per hour. This was to determine the possible savings that can be obtained for the sample building made over and before implementation of the insulation law of Saudi Arabia and the level of effectiveness the green façade installation has in backing to saving on both post and pre-implementation construction. The climate was used to identify the appropriate location for investigation. The site was determined by weather data review. Free weather files for Jeddah city were not available from the US Department of Energy except for Riyadh that has a climate that is different from Jeddah (Green, 2004). Thus, an EPW file was bought from Meteonorm at 100 Swiss francs. The data offer averages from 2000-2009 and greater than 30 parameters involving air temperatures, relative humidity, wind speed, wind direction, sunshine duration and precipitation. The EPW weather data were used to stimulate evaluation of various pertinent weather conditions.

The energy plus version 8.4 software was employed to compute the necessary cooling and heating loads for sustaining the optimal set point of thermal control, the original plant equipment’s energy consumption and other necessary factors to enable simulation to occur in the way that replicated the actual building environment (Dinsdale, Pearen & Wilson, 2006). There was no model that was provided by the software except for three material that serves as a substitution for a green roof. The material includes LowLAI, BaseEco, and ThickSoil. Two methods were chosen to simulate green facades that employed shading element to serve as a substitution for vegetation. The first modeling was done by a building shading object that considered green wall as a shading device of the building with foliage layer transmittance. Second modeling was done by window shading device object. The glass layer absorption and system transmittance for long-wave radiation and short wave radiation are affected by the shading device.

Concerning simulation, construction and geometry of the sample home were reduced to the one-story building to get the comparative study of green facades impacts in minimizing the solar radiation on the envelopes of the building by comparing loads that were cooling. The sample home did not have lighting, occupants or equipment. The first procedure for simulation was to find the simulation parameters that were fixed by clicking transition version in the EP – launch file. Second, the location and the climate of Jeddah were done manually using DDY file. Third, the type limit was scheduled by a template that was already made which made it easier to figure out the input. Fourth, the surface construction materials to recreate the envelope of the building like exterior walls, exterior ceiling, windows, floor, and door were completed. Fifth, detailed construction was assigned for each roof, wall, and floor (Sheweka & Mohamed, 2012). Then, HVAC Template was selected from energy plus file to represent simple ideal systems of loads. Finally, control of zone HVAC and the thermostat was done.

Finally, manipulation of individual parameters was done to achieve maximum results. For instance, green façade orientation, spacing the green façade and wall in centimeters and varying the solar reflectance according the plant used. The rate of growth was also tested in this sensitivity test.

Purpose & Meaning of Plants to locals

The relationship between the residents and how they are utilizing plants are investigated in two ways. The first way is survey and photo analysis that was conducted by thought interviews and digital means. Photo review was like in social science, video; visual methods encompass photography and graphical representation (Tan, et.al, 2014). Regarding visual, it was noted that all the interpretations that depend on the photography ontologically needed more definition. However, questioning the homeowners in the photo added beyond the interpretation of the author in the discussion.

The second way embraced survey and enhanced its means to get direct insight from the targeted neighborhood resident of Jeddah. This aimed at capturing the resident’s firsthand experience concerning plants in that climate. The participants were chosen with the benefit of having plants on the external of their residential building that is low-rise. The unstructured Survey was used and constructed with multiple choices; open-ended questions and five scale questions. The questions were presented in both Arabic and English using print form and monkey form. The process was to text, email or offer the link of survey to qualified participants. However, a survey in some places was conducted in the form of interviews and responses were submitted manually in the monkey survey tool.

Significance of the results

Observations

Regarding field experiments, it was observed that at site A, the temperature peaked at 36.91℃ on the vegetated wall and 43.65℃ on a bare wall. It was noted that the temperature was affected by sun radiation on plant blocking from 07:00 to 17:55. The relative humidity reduced as the temperature was increased by sun radiation. Lastly, carbon dioxide was observed to increase throughout the entire period. On Site B, it was found that temperature peaked with35. 64°C on the vegetated wall and 40.43°C on the bare wall at 11:35. It was noted that the temperature was affected by sun radiation on plant blocking from 07:30 to 13:50. Relative humidity reduced with an increase in temperature due to sun radiation and it reached its lowest level with 66.41% of the vegetated wall and 11.1% on a bare wall. RH was increased by 11.1%. Finally, vegetation decreased CO2 by 286 from 02:50 to 8:45. At site C, the temperature peaked at 09:40 with 40.26°C on the vegetated wall and 45.19°C on a bare wall, and it was noted that the temperature was affected by plants blocking sun radiation for 11 hours. Also, the relative humidity decreased with increase in temperature, reaching the lowest level at 10.15 to 56.19% of the vegetated wall and 46.36% on bare walls. RH was increased by 9.83%. Lastly, vegetation decreased carbon dioxide from 10:30 to 08:30. In site D, the temperature was maximum at 11:40 with 37.56°C on the vegetated wall and 41.36 on bare walls. It was noted that temperature affected solar radiation for about 8 hours. Also, the relative humidity reduced with an increase in temperature, reaching the lowest level of 57.55% on the vegetated wall and 49.21% of the bare wall at 09:40. RH was increased by 8.34%. Finally, vegetation decreased CO2 from 00:00 to 09:00 attaining its maximum at 14:40.

Concerning Energy Saving through Energy Simulation, it was observed that adding exterior wall on the wall of east facing led to the following: Energy saving of 47.19% in baseline A. This was due to the absence of wall insulation allowing the space to get solar radiation, hence, requiring additional energy to cool the indoor space to the required temperature. Baseline A represents 70% of the Jeddah construction. For baseline B, there was energy saving of 23.71% due to the presence of insulation that reduced the effect of solar on the space and hence reducing the required amount of energy for cooling the space of indoor In this baseline presence of green façade assist to save energy of 30% of the Jeddah construction.

Regarding Purpose and Meaning of plants to locals, it was noted that people have an emotional attachment to plants. Also, it was observed that people like shrubs and lean towards the aesthetical appeal of plants and their psychological benefit (Susorova, et.al, 2013). Some of the people were noted to be satisfied with planting climber plants. Moreover, it was observed that people liked least about plant maintenance and insect but liked more the color of plants. Thus, the majority of the people feel happy because of the nature of plants.

Challenges of the study.

The study has some challenges which included; not able to start life-size test cells as they required additional time and funding to install, monitor and grow green facades. Hence, an existing example was chosen for study and comparison. Also, the time given for the survey was September whereas Saudi experiences the strongest hot period in the month of June. This led to a decision of carrying out the experiment research on the month of September instead of June. Moreover, the financial challenge prevented the use of useful tools that would have supported accurate information for comparison.

Recommendations

The people of Saudi should build envelope with Green Facades to lower the indoor heat gain that allows reduction instead of air conditioning. Hence the people should avoid wall insulation and embrace Green Facades.

The vertical vegetation should have a balance of a suitable selection of plants, efficient irrigation and right Façade depending on the exposure to direct sunlight and orientation. Thus, vertical vegetation should save energy. The cost of vertical vegetation should also be affordable to make it remain practical.

Moreover, the Green Façade should be created by the use of plants that have the ability to thrive and survive in the arid region, ability to form vertical vegetation and sustain sun exposure for long hours (Stav & Lawson, 2012). Hence, efficient irrigation, right plant selection, and orientation should be employed during the creation of Green Facade. Besides, the people of Saudi should have positive attitudes towards trees so as to conserve and take good care of them.

Future studies

The future study of the research involves the following;

• The study of the influence of greening on the microclimate of the urban to save energy by reduction of the effect of heat islands.
• Comprehensive experiments where the variable walls are investigated to undergo similar environmental factors, situated in close vicinity to facilitate comparison and a spanning period of more than one year to obtain long-term and accurate seasonal changes.
• A study on measurement of plant emissivity and comparison for better examination of their ability to absorb and reflect solar radiations.
• A study on the opportunity of water recycling and utilize it in irrigating vegetation and green Façade.

Conclusion.

The Green Façade are significant in creating envelope building that will lead to energy-efficiency solution in Jeddah. Direct experience with the computer simulation and field experiment are necessary for designing the Green Facade that will assist in minimizing the effect of solar radiation on the Building Jeddah (Rosenlund, 2014). The study wanted to know if the implementation of Green Façade is socially acceptable and economically practical to replace existing building in Jeddah. Also, the study wanted to know the evidence of energy saving from using a green façade on a building without insulation instead of insulated buildings in the city of Jeddah. Lastly, the study wanted to know the best practices, plant type and design recommendation for Green Façade in the arid climate of Jeddah.  From the research that was conducted, the study found out that Green façade are socially acceptable and economically practical to replace the existing building in Jeddah. It also shows that green façade without insulation contributed to energy saving of 30% as compared to building with insulation that contributed to energy saving of 47.19%. Finally, the study found out that in plants that have the ability to thrive and survive in an arid region, ability to form vertical vegetation and sustain sun exposure for long hours are suitable to create green façade.

Bibliography

Dinsdale, S., Pearen, B., & Wilson, C. 2006. Feasibility study for green roof application on Queen’s University campus. Documento interno. Queens University. Kingston, Ontario.

Green, B. 2004. A guide to using plants on roofs, walls and pavements. Jacklyn Johnston and John Newton, London Ecology Unit.

Olivieri, F., Olivieri, L., & Neila, J. 2014. Experimental study of the thermal-energy performance of an insulated vegetal façade under summer conditions in a continental mediterranean climate. Building and Environment, 77, 61-76.

Perini, K., Ottelé, M., Haas, E., & Raiteri, R. 2011. Greening the building envelope, façade greening and living wall systems. Open Journal of Ecology, 1, 1.

Pulselli, R., Pulselli, F., Mazzali, U., Peron, F., & Bastianoni, S. 2014. Emergy based evaluation of environmental performances of Living Wall and Grass Wall systems. Energy and Buildings, 73, 200-211.

Rosenlund, H. 2014. Vertical Green as a Modern Building Material and Its Consequences for Building Performance and Street Canyon Climate. Retrieved from Olofstrom, Sweden:

Sheweka, S. M., & Mohamed, N. 2012. Green facades as a new sustainable approach towards climate change. Energy Procedia, 18, 507-520.

Stav, Y., & Lawson, G. M. 2012. Vertical vegetation design decisions and their impact on energy consumption in subtropical cities. The Sustainable City VII: Urban Regeneration and Sustainability, 155, 489-500.

Susorova, I., Angulo, M., Bahrami, P., & Stephens, B. 2013.  A model of vegetated exterior facades for evaluation of wall thermal performance. Building and Environment, 67, 1-13.

Tan, C. L., Wong, N. H., Jusuf, S. K., & Chia, P. Y. 2014. Effects Of Vertical Greenery On Mean Radiant Temperature In The Tropical Urban Environment. Globe, 21, 001