Investigation of Evaporation Rate for Covered and Uncovered (using recycled materials) Conditions in UiTM Shah Alam

The evaporation rate varies according to temperature, humidity, and wind. The evaporation rate tends to be higher in the hot, dry months and lower in the wetter ones. This may affect the nation’s energy use, indoor air quality, and water availability. This study conducted experiments under three conditions—uncovered, partially, and fully covered to ascertain the evaporation rate at UiTM Shah Alam, Malaysia. Recycled materials such as bottle caps were used in the experiment. The study examined the evaporation rate at UiTM Shah Alam in Selangor. The study discovered that the uncovered surface area evaporated at the highest rates in the morning, noon, and afternoon due to direct solar exposure. As some or all of the surface was shielded from the sun’s rays, partially covered and fully covered surface areas had lower evaporation rates. It shows the evaporation rate for fully covered condition reduced 22 – 50 percent from uncovered condition. Meanwhile, evaporation rate for partially covered condition decreased by 10 – 17 percent compared to uncovered condition. The study offers important information about the variables influencing evaporation rate, which can be used to enhance understanding of evaporation processes and optimize evaporation in various applications. The findings may shed important light on the evaporation process and the variables that influence it, such as temperature, humidity, and cover material. The research results can be used to enhance building design and construction methods, increase building energy efficiency, and guide water management and conservation policies.


Introduction
Evaporation is a crucial part of the Earth's water cycle, as it is the process of a liquid transforming into a gas.It is the primary source of moisture in the atmosphere, accounting for 90% of the moisture, with plant transpiration accounting for the remaining 10%.The evaporation rate is influenced by the capacity to transport the vapor away from the evaporative surface, energy availability to generate the latent heat of vaporization, and factors such as temperature, humidity, and airflow over the liquid surface.A study by [1] monitored various factors affecting the evaporation rate of water in order to understand the impact of water temperature, air temperature, and humidity on the evaporation process.They monitored the temperature of the water at various depths using a temperature sensor that floated under the surface to avoid air exposure.In Malaysia, the evaporation rate varies depending on the location and weather conditions.As a tropical country with high humidity levels, the evaporation rate would be relatively lower than in areas with lower humidity and higher temperatures.The actual evaporation rate can also be affected by wind speed, solar radiation, atmospheric pressure, the type of liquid, and the surface area of the liquid exposed to the air.The increased evaporation rate in an educational building can negatively impact indoor air quality, student health, energy consumption and costs, and pest infestations.
Reservoirs increase the availability and temporal stability of water supplies, yet evaporation losses may dramatically diminish their operating efficiency.The efficacy of many chemical or physical evaporation barriers has been assessed in studies, frequently on a qualitative basis [2].[3] also stated that another physical technique for preventing water from reservoirs from evaporating is the use of floating coverings.A study by [4] showed that floating and suspended coverings could minimize evaporation from water storage in Southeast Queensland, where large water reservoirs serve as the main source of drinking water.The amount of water lost to evaporation each year is significant, making research into new methods for reducing evaporation necessary as the population expands.Floating covers are physical barriers that float on the water's surface and prevent the movement of water vapor both vertically and horizontally.A recent application of floating covers was the city of Los Angeles' use of 96 million black polyethylene spheres to cover drinking water reservoirs, which showed that floating covers are a scalable solution to evaporation suppression.A recent numerical study by [5] showed that self-assembling floating covers have a high potential for evaporation suppression effectiveness and can provide up to 80% suppression with centimetre-sized gaps between the floating elements.Table 1 shows some of the proposed evaporation mitigation plans by previous study to reduce the evaporation rate in open water.

Author & Year
Evaporation Mitigation Technique Reduction Rate [6] 68% of recycled plastic modular coverage Around 43% reduction in evaporation.
[7] Shade balls Reduce up to 43-45% evaporation rate relative to the uncovered conditions in reservoirs.
Reducing of the evaporation rate helps in maintaining a healthy and productive learning environment, reduces energy consumption, lowers energy bills, decreases the building's carbon footprint, and prevents pest infestations.Recycled materials are used in this study to know the impact on the evaporation rate and are beneficial to waste management systems.The experiment's results can be used to improve the understanding of the factors that affect evaporation rates, including the relationship between evaporation, temperature, and humidity.Moreover, the study could be used as a reference for other researchers looking to conduct similar experiments, as it provides detailed information on the methodology used and the results obtained.Finally, the results of this study could be used to improve existing models of evaporation or to develop new models that more accurately predict the evaporation rate under different conditions.Hence, this study aims to determine the evaporation rate at UiTM Shah Alam and the effect of fully covered and partially covered conditions on the evaporation rate.

Sampling Locations
The experiment was conducted at two buildings chosen around UiTM Shah Alam.The first experiment location in UiTM Shah Alam was conducted at the Schoolof Civil Engineering of UiTM Shah Alam building.The School of Civil Engineering is located in the Engineering Complex of the UiTM Shah Alam campus, and it is easily identifiable by the big signboard and the location of the building.The faculty has a good infrastructure and is well-equipped with state-of-the-art labs and facilities, including a geotechnical lab, materials lab, hydraulic lab, and computer laboratory.The experiment was carried out on the 11th balcony area of the building.The second selected experiment location in UiTM Shah Alam was conducted at Kolej Melati.It is one of the five colleges that provide residential facilities for UiTM students.Kolej Melati is a women's college accommodating female students studying at UiTM Shah Alam.The college provides a comfortable and safe student environment with single and doubleroom accommodation, a dining hall, a computer lab, a library, sports and recreation facilities, and a mosque.This experiment was carried out on the level 8 rooftop near the water tank of this building.

Data Collection
Three models have been arranged in an open area near the School of Civil Engineering and Kolej Melati buildings.Subsequently, a circular plastic container with dimensions 237mm in diameter and 102mm in height was employed as a substitute for an evaporation pan in the simulation.Recycling bottle caps, measuring 3.3cm in diameter and 1cm in height, were utilized to cover the water surface of the simulated evaporation pan.To completely cover the simulated evaporation pan's surface, 30 bottle caps were required, while 15 caps were needed for partial coverage.Evaporation measurements were taken using a ruler as a measuring tool, recording the water level every 3 hours from 9 am to 3 pm daily.Figure 2 shows the model setup of three different conditions which are fully covered, partially covered, and uncovered.

Rate of evaporation at both locations
The evaporation rate was calculated by subtracting the volume at each interval and dividing it by the time span between measurements.In the case of evaporation pans, the evaporation depth is computed as the reduction in water surface level over a specific period, accounting for intentionally introduced water or rainfall.The evaporation rate is defined as the quantity of liquid evaporating per unit of time.Figure 3 and Figure 4 show the rate of evaporation for both locations, which are at the School of Civil Engineering and Kolej Melati UiTM, for 31 days.The experiment was conducted daily for uncovered conditions at 9 am, 12 pm, and 3 pm.The evaporation rate at Kolej Melati, UiTM Shah Alam, relatively close to data at the School of Civil Engineering, UiTM Shah Alam, is nearly identical, with only a slight variation.The evaporation rate can vary between places based on factors such as temperature, humidity, wind speed, and solar radiation.
The distance between the School of Civil Engineering and the building and the Kolej Melati building of UiTM Shah Alam is only about 500m.For both locations, it was observed that the evaporation rate was low in the morning and increased at noon.However, the evaporation decreases to about 50% from 12 noon to 3 pm.The average evaporation rate at 9 am was recorded as 0.081 cm/h, while 0.39cm/h at noon.0.24 cm/h was measured as the evaporation rate for both locations at 3 pm.

The difference in surface coverage conditions
The rate of evaporation due to different conditions of surface coverage were determined in this study.Figure 5, Figure 6, and Figure 7 show the rate of evaporation for uncovered, partially covered, and fully covered conditions at three different times, which are 9 am, 12 pm, and 3 pm, for 31 days at the School of Civil Engineering, UiTM Shah Alam.It shows that uncovered condition leads to the highest evaporation rate every time measured.Overall, evaporation rate is higher at 12pm, follow by 3pm and the lowest is 9am.Percentage difference in evaporation rate for uncovered and fully covered condition is approximately 50% at 9 am, 22% at 12 pm, and 25% at 3 pm.The evaporation rate is affected by several factors, including wind, sun, temperature, and humidity.An uncovered surface area was exposed to the full force of the wind, which can increase the evaporation rate.The wind can help to increase the movement of air around the surface of the water, which can help to carry away the water vapor as it is created, then increasing the evaporation rate.Additionally, an uncovered surface is exposed to the sun's rays; this increases the temperature of the water and the surrounding air, which in turn increases the amount of heat energy available to transfer into the water and causes evaporation.A fully covered surface area would have the lowest evaporation rate.It is because the cover completely blocks the wind and sun from reaching the surface of the water, which significantly reduces the amount of heat energy available for evaporation and ultimately limits the amount of air circulation around the water's surface.With a full cover, the evaporation rate would be significantly limited as the wind and sun cannot reach the water's surface, and the heat transfer rate is greatly reduced.

Conclusion
In conclusion, the research aimed to determine the rate of evaporation at the School of Civil Engineering and Kolej Melati of UiTM Shah Alam, Selangor, and to evaluate the impact of different percentage covers on the evaporation process was successfully done.For both locations, it was observed that the evaporation rate was low in the morning and increased at noon.The evaporation decreases to about 50% from 12 noon to 3 pm.The study found that the evaporation rate varies greatly depending on various weather conditions such as temperature, humidity, wind, and sunlight.The study found that the uncovered surface area would have the highest evaporation rate because it would be directly exposed to the sun's rays.However, a fully covered surface area would have the lowest evaporation rate as the entire surface is blocked from the sun's rays.It shows the evaporation rate for fully covered condition reduced 22 -50 percent from uncovered condition.Meanwhile, evaporation rate for partially covered condition decreased by 10 -17 percent compared to uncovered condition.The partially covered surface area would have a lower evaporation rate due to some of the surface being blocked by the sun's rays.This research provides valuable insights into the factors that affect the evaporation rate at different times of day and in different covered and uncovered conditions.These findings can improve our understanding of evaporation processes and design strategies that optimize evaporation in various applications.

Figure 1 (Figure 1 .
Figure 1.Location of the study area at School of Civil Engineering (a) and Kolej Melati (b)

Figure 2 .
Figure 2. The model setup of three different conditions which are fully covered, partially covered and uncovered.

Figure 3 . 5 Figure 4 .
Figure 3.The rate of evaporation at School of Civil Engineering of UiTM Shah Alam

Figure 5 . 6 Figure 6 .Figure 7 .
Figure 5.The rate of evaporation for uncovered, partially covered and fully covered condition at 9am