The Effect of Water Volume Variation on Evaporation Time

Study Case The Effect of Water Volume Variation on Evaporation Time and Temperature in a Simple Diffuser Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract This study discusses the various functions of diffusers commonly used in everyday life. Diffusers play a role in purifying the air of viruses, dust, and pollution, and are often combined with essential oils to produce a refreshing aroma in the room. The purpose of this study is to analyze the physical concepts that apply to diffusers, specifically the relationship between water volume and evaporation time, as well as the relationship between time and temperature in mode 1 and mode 2. The research was conducted using an experimental method with continuous stages of changes in the volume of water evaporated, so that quantitative data on diffuser performance could be obtained. Based on the graph results, the relationship between volume and evaporation time in mode 1 shows that 15 ml of water requires 35 minutes, 25 ml requires 90 minutes, 35 ml requires 120 minutes, and 45 ml requires 240 minutes, with a correlation coefficient of R^2=0.9072, indicating a relationship level of 90% (high accuracy). In mode 2, a similar relationship shows evaporation times of 10 minutes for 5 ml, 25 minutes for 15 ml, 70 minutes for 25 ml, 90 minutes for 35 ml, and 120 minutes for 45 ml, with R^2=0.981, indicating a relationship level of 98% (very high accuracy). Additionally, the relationship between time and temperature in mode 1 shows an increase in temperature from 29.6°C at minute 15 to 37.9°C at minute 420, with R^2=0.9094, while in mode 2, the temperature increased from 27.8°C at minute 10 to 31.4°C at minute 120 with R^2=0.9067. These results indicate a strong correlation between time and temperature in both operating modes. Keywords: Diffuser; Time; Temperature MICHAEL KURNIAWAN 1 Study Case INTRODUCTION Air quality is a crucial factor for human life and other living creatures. However, in the modern era with rapid technological, industrial, and urbanization developments, air quality has significantly declined due to pollution caused by aerosol particles and harmful gases in the atmosphere [1]. During the COVID-19 pandemic, several regions in the United States recorded improvements in air quality due to mobility restrictions and reduced transportation activities [2]. These social restriction policies were regulated by the Centers for Disease Control and Prevention (CDC) and the Department of Health and Human Services (HHS). Diffusers are devices widely used to improve indoor air quality. They work by dispersing water particles or essential oils into the air, thereby helping to reduce micropollution and viruses, as well as providing a relaxing effect [3]. In practice, diffusers are often combined with essential oils such as lavender oil, which contains linalool—a compound known to have calming and anti-anxiety effects [4]. Research on diffuser efficiency was conducted to understand the relationship between water volume and evaporation duration, as well as temperature changes during the process. Testing was carried out using repeated experimental methods to ensure data consistency. In the context of thermodynamics, temperature is a physical quantity that indicates the level of heat energy in a system. Temperature changes are influenced by the heat capacity of the substance receiving the energy [5]. Heat is defined as energy that is transferred due to temperature differences, and its unit in the International System is joules [6]. Heat transfer occurs from a hightemperature system to a low-temperature system until thermal equilibrium is achieved. This phenomenon forms the basis of the first law of thermodynamics, which states that energy cannot be created or destroyed, but can be changed in form [7]. The equation for the first law of thermodynamics is written as: ΔU=Q+W where ΔU is the change in energy in the system, Q is the heat absorbed, and W is the work done by the environment on the system. In the context of diffusers, the principles of thermodynamics are applied to open systems, where mass and energy can freely enter and exit through the system boundaries, but the volume remains constant [8]. In this system, energy can be transferred in the form of heat or work through the control surface. Analysis of this type MICHAEL KURNIAWAN 2 Study Case of system is used to understand the efficiency of energy transfer in the water evaporation process that occurs in the diffuser [9]. In addition to being an air humidifier, diffusers are unique in their ability to disperse essential oils into the air, producing aromatherapy vapors that can enhance comfort and relaxation. Several studies also show that essential oil components, such as linalool, play an important role in providing therapeutic effects [10]. The main objective of this study is to review the physics concept in diffusers by analyzing the relationship between water volume (5 ml, 15 ml, 25 ml, 35 ml, and 45 ml) and evaporation time and temperature changes in two different operating modes. The experimental data are presented in graphical form to visualize the influence of these variables on the efficiency of the diffuser. METHOD This study was conducted on the campus of the University of Cincinnati from December 22 to 31, 2022. The type of research used was experimental research, which aimed to test, compare, and confirm the results based on the variables observed [1]. Experimental research was chosen because this method allows researchers to control and manipulate one or more independent variables to observe their effect on the dependent variable. The data obtained from the experiment was analyzed and visualized in graph form to examine the relationship between the volume of water (ml) used in the diffuser and the evaporation time (t), as well as the relationship between time (t) and the temperature produced by the diffuser. Through these graphs, the relationship between variables can be clearly observed to determine the differences in diffuser performance under various conditions. The research stages follow the flowchart shown in Figure 1, which illustrates the process of making and testing aromatherapy diffusers. In general, the research stages consist of four main steps, namely: 1. Preparation Stage This includes gathering the necessary tools and materials, such as essential oils, a circuit board (PCB board), USB cable, cutter knife, double-sided adhesive tape, scissors, plywood board, hot glue gun, and measuring cup. 2. Tool Assembly Stage MICHAEL KURNIAWAN 3 Study Case At this stage, all components are assembled into a simple diffuser unit that can convert electrical energy into water vapor mixed with essential oils. 3. Data Collection Stage The diffuser is tested with various volumes of water (5 ml, 15 ml, 25 ml, 35 ml, and 45 ml) using two different operating modes. The evaporation time and temperature changes are measured using a digital thermometer and a stopwatch. 4. Analysis and Conclusion Stage The collected data is then analyzed to determine the relationship between water volume and evaporation time, as well as the relationship between time and temperature, using the linear regression method to obtain the R^2 correlation value. Figure 1. Flow chart of the aromatherapy diffuser manufacturing process. Figure 2. Simple diffuser device assembly. MICHAEL KURNIAWAN 4 Study Case RESULTS AND DISCUSSION Diffusers are clocelly related to the basic principles of thermodynamics, particularly in terms of temperature and heat energy. Temperature is a quantitative measure of the degree of heat or cold of an object or system, while heat is the thermal energy that transfers from one object to another due to temperature differences [1]. When a certain amount of heat energy is applied to an object, the temperature of the object will increase. The relationship between the heat absorbed (Q), the mass of the substance (m), the specific heat capacity (c), and the change in temperature (ΔT) is expressed by the equation: Q=m×c×ΔT In addition, for the process of changing a liquid into water vapor, the energy required is known as the latent heat of vaporization, and can be calculated using: Q=m×U where U is the latent heat of vaporization of water. This relationship is used to determine the heat energy required by the diffuser to produce steam. Relationship between Water Volume and Time The diffuser was tested using 2 W of power, 0.4 A of current, and 5 V of voltage. The test was conducted in two operating modes with five variations in water volume: 5 ml, 15 ml, 25 ml, 35 ml, and 45 ml. The evaporation time was recorded and analyzed using a linear regression approach to determine the relationship between water volume and evaporation time. Figure 1. Graph of the relationship between water volume and evaporation time in mode 1. MICHAEL KURNIAWAN 5 Study Case In mode 1, the experimental results show that the evaporation time increases with increasing water volume: 5 ml takes 15 minutes, 15 ml takes 35 minutes, 25 ml takes 90 minutes, 35 ml takes 120 minutes, and 45 ml takes 240 minutes. The coefficient of determination value R^2=0.9072, indicating a correlation level of 90%, which means that the relationship between volume and evaporation time is quite strong and accurate. Figure 2. Graph showing the relationship between water volume and evaporation time in mode 2. In mode 2, the results show that 5 ml of water evaporates in 10 minutes, 15 ml in 25 minutes, 25 ml in 70 minutes, 35 ml in 90 minutes, and 45 ml in 120 minutes. The R^2 value is 0.981, indicating a relationship level of 98%, which is classified as highly accurate. In general, these results show that the greater the volume of water used, the longer the time required for complete evaporation, in accordance with the theory of heat transfer in open systems. Relationship between Time and Temperature Figure 3. Graph showing the relationship between time and temperature in mode 1. MICHAEL KURNIAWAN 6 Study Case In mode 1, the temperature increases gradually as the diffuser operating time increases. At the 15th minute, the temperature was recorded at 29.6°C; at the 35th minute, it was 29.4°C; at the 90th minute, it was 30.2°C; at the 120th minute, it was 32.9°C; and at the 420th minute, it reached 37.9°C. The R^2 value of 0.9094 indicates a strong correlation of 90% between operating time and temperature increase. Figure 4. Graph of the relationship between time and temperature in mode 2. In mode 2, the temperature increase pattern shows a similar trend. The temperature increases from 27.8°C at the 10th minute to 31.4°C at the 120th minute. The R^2 value of 0.9067 indicates a correlation of approximately 90%, indicating high accuracy in the relationship between time and temperature in this mode. Both modes show that the longer the diffuser operates, the higher the temperature of the space around the device due to the increase in heat energy generated by the internal heating element. This phenomenon is consistent with the First Law of Thermodynamics, which states that the energy in a system increases as it absorbs heat energy from outside [2]. Thermodynamic Analysis Based on the research results, the process of water evaporation in the diffuser is a direct application of the concept of energy conservation. Electrical energy is converted into heat energy through the heating element, which is then used to convert water into water vapor that is dispersed into the air. Systemically, the diffuser behaves as an open system, where mass (water and vapor) and energy (heat) can cross the system boundary. Evaporation efficiency depends on the amount of electrical power, the surface area of the water, and the ambient temperature. The linear relationship between these variables indicates that the diffuser's working mechanism is in line with the basic principles of heat energy transfer and the law of energy conservation. MICHAEL KURNIAWAN 7 Study Case CONCLUSION Based on the results of the thermodynamic study and analysis, it can be concluded that the volume of water has a direct effect on the evaporation time. The greater the volume of water used, the longer the time required for the diffuser to evaporate all the liquid. This relationship has a high correlation with an R^2 value above 0.90 in both operating modes. Meanwhile, the relationship between time and temperature shows that the temperature increases with the duration of diffuser operation. With 2 W of electrical power, 0.4 A of current, and 5 V of voltage, the diffuser is capable of evaporating up to ±300 ml of water in approximately 24 hours of continuous operation. Overall, this study proves that the First Law of Thermodynamics applies to the diffuser system, where electrical energy is converted into heat energy which is then used for the process of evaporating water and dispersing aromatherapy vapors into the air. REFERENCE MICHAEL KURNIAWAN 8 Study Case MICHAEL KURNIAWAN 9