Experimental Findings and Analysis of a Split Unit Evaporative Cooler for Efficient and Eco-Friendly Cooling Applications

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Introduction
Evaporative coolers were extensively patented in the twentieth century, with many suggesting the use of excelsior pads for evaporation.The prevailing design consists of a water reservoir, pump to circulate water over the pads, and a fan to draw air into the house.These coolers remain prominent in the American Southwest, where they also serve to increase humidity.However, global energy consumption is rising rapidly, demanding innovative energy conservation methods.Researchers are exploring renewable energy sources and improved energy efficiency.Conventional vapor compression air conditioning systems, powered mostly by fossil fuels, contribute significantly to energy consumption.India, facing an expected doubling of energy demands by 2030, requires efficient energy utilization.The Union Ministry of Power's research indicates substantial electricity wastage (20-25%) in government buildings due to unproductive design, causing an annual energy-related financial loss of about 1.5 billion rupees.To achieve sustainability, drastic energy reduction can be achieved through the adoption of energy-efficient appliances.

Basic Principles
Evaporative cooling is a physical process that involves the evaporation of a liquid, typically into the surrounding air, to cool an object or liquid in contact with it.This cooling effect occurs because the latent heat required for evaporation is drawn from the air.The potential for evaporative cooling can be measured by comparing the wet-bulb temperature, which reflects the cooling potential, to the air's dry-bulb temperature.A greater difference between these two temperatures results in a more significant evaporative cooling effect, while no net evaporation occurs when the temperatures are the same, leading to no cooling effect.An everyday example of natural evaporative cooling is perspiration or sweat, which the body produces to cool itself down.The amount of heat transferred during this process depends on the rate of evaporation, with each kilogram of water vaporized transferring 2257 kJ of energy.The rate of evaporation, in turn, relies on the humidity and temperature of the air.Consequently, on hot and humid days, sweat accumulates as perspiration cannot evaporate as effectively.Evaporative cooling operates on a distinct principle compared to Vapour-compression refrigeration units, despite both processes involving evaporation.However, in Vapourcompression refrigeration, the evaporation takes place within a closed system.In this cycle, the refrigerant evaporates within the evaporator coils, then undergoes compression and cooling to return to a liquid state.On the other hand, evaporative coolers make use of water evaporation singularly.Within space-cooling systems, the evaporated water merges with the cooled air prior to entering the designated area.Conversely, in an evaporative tower, the evaporated water is conveyed away through the airflow.Vital benchmarks for evaluating evaporative cooling consist of saturation effectiveness and unit efficiency.

Applications
Evaporative cooling systems find extensive application in residential, commercial, agricultural, and industrial contexts, especially when higher indoor humidity is acceptable and economical operation is a priority.These systems deliver comfort similar to vapor compression cooling techniques in dry climates.However, during periods of heightened heat and humidity, they could result in indoor conditions that exceed the comfort parameters defined by ASHRAE, as demonstrated in Figure 3. Commonly, single-stage units are mounted on walls, roofs, windows, or ground equipment pads.Adequate indoor air relief is essential for their proper functioning, achieved through barometric dampers installed in the ceiling or walls.Alternatively, open windows or doors are utilized as relief in low-cost wall/window-mounted systems.Manufacturers frequently simplify the process of determining appropriate sizes by indicating airflow rates linked to particular settings or designated wet bulb temperatures.More accurate methodologies involve computing the cooling load for a structure, excluding latent and infiltration loads, and advising a system that can provide an ample air volume.This is determined by the desired indoor air temperature and the design supply air temperature, which is influenced by the system's effectiveness and the design wet bulb temperature.Due to their economical operation and moderate cooling capability, evaporative coolers are commonly regulated using manual switches, timers, and thermostats.Certain models incorporate various fan speeds or entirely adjustable fan speed management, granting users Corrosion Risk: High humidity in the air, especially in the presence of dust, can accelerate equipment corrosion, potentially shortening the lifespan of electronic and other devices.Condensation Issues: Excessive humidity in the air may lead to condensation, posing problems for certain situations such as electrical equipment, computers, paper/books, and old wood.Water Requirements: Constant Water Supply: Evaporative coolers require a continuous water supply to keep the cooling pads wet.Mineral Deposits: Water with high mineral content can leave mineral deposits on the pads and cooler interior.Bleed-off and refill systems may mitigate this issue.Freeze Protection: During off-season winter temperatures, the water supply line and cooler need protection against freeze bursting.Periodic draining, cleaning, and pad replacement are also essential maintenance tasks.
2 Literature review T. Ravi Kiran et al. 1 focused on the increasing energy consumption worldwide and emphasized the urgent need to develop energy-efficient cooling solutions for future generations.They introduced a novel dew point evaporative cooler (DPEC) that effectively cools incoming air close to its dew point temperature.The study investigated the feasibility and energy-saving potential of DPEC for office buildings in various Indian cities, comparing it to conventional vapor compression-based air conditioning systems.J.K. Jain et al. 2 highlighted the popularity of evaporative coolers in arid regions due to their low initial and operational costs compared to refrigerated cooling.They stressed the importance of developing improved and efficient coolers, with several researchers proposing modifications and additions to enhance cooling performance.Notably, the combination of direct and indirect evaporative cooling systems showed energy and cost-saving potential.Chuck Kutscher 3 discussed the decline of conventional evaporative cooling in the United States and identified market barriers such as prototype costs and consumer misconceptions about maintaining comfort conditions.The study investigated novel elements and the integration of systems to tackle these difficulties.It introduced the OASys unit, which combines direct and indirect evaporative cooling stages, as a promising cooling solution for residential use.In the work by Moien Farmahini Farahani et al. 4, a two-stage cooling system was analyzed.This system included a nighttime radiative unit, a cooling coil, and an indirect evaporative cooler.The study demonstrated the improved effectiveness of the indirect evaporative cooler, presenting it as an environmentally friendly and energy-efficient alternative to conventional vapor compression systems.R.H. Turner's 5research concentrated on potential applications of evaporative cooling in small commercial and residential buildings.The paper presented 16 recommendations encompassing issues related to institutions, suitable roles for EC systems, necessary analysis and testing, appropriate applications, and hardware development requirements.The primary goal was to enhance awareness and comprehension of the advantages and potential of EC systems.Rin Yun et al. 6 performed an empirical investigation of a residential air conditioning system utilizing both a fin-and-tube condenser and a microchannel condenser.They determined that the system incorporating a microchannel condenser exhibited reduced refrigerant charge, heightened coefficient of performance, and improved seasonal energy efficiency ratio in comparison to the base system utilizing a fin-and-tube condenser.These reviews of existing literature offer insightful glimpses into the advancements and potential of evaporative cooling systems.They underscore the significance of these systems as sustainable and energy-efficient cooling solutions for various applications.The findings emphasize the need for further research and development to optimize the performance and integration of these systems for practical implementation.

Selection for Evaporative Cooler and Crafting a Split Unit Design
Choosing the appropriate evaporative cooler can prove to be a difficult task for consumers, mainly due to their insufficient familiarity with these cooling mechanisms.The present market is saturated with a multitude of cooler manufacturers, each presenting distinct attributes with notable price discrepancies, which contributes to buyer perplexity.Consequently, a large number of buyers rely solely on the external aesthetics and endorsements from the manufacturer when making their choices.Regrettably, even most manufacturers lack an in-depth comprehension of cooler technology, resulting in the creation of coolers founded on obsolete guidelines and minimal adjustments.To facilitate a more informed purchase, buyers should consider the following key points: Size Selection: Choosing an appropriately sized cooler is crucial, based on the volume of the room to be cooled.The cooling capacity of the cooler should ideally match the room volume, with a recommended airflow rate of one air change per minute.Proper crossventilation is essential, and installing the cooler outside the window is preferable to avoid increased humidity levels inside the room, making it uncomfortable.
Fan and Pump Specifications: Buyers must ensure that the cooler's fan and pump meet the correct specifications.Many substandard fans and pumps are used by some manufacturers to maximize profits, resulting in compromised cooling efficiency.
Internal Fittings: The proper alignment of fan blades within the front panel opening is critical for effective cooling.Ensuring a flush mount with the front panel enhances performance.
Water Spray System: The water droplets from the spray system should uniformly wet the cooling pads.Avoiding the direction of water spray towards the inner surface of the pad is crucial, as the fan may suck and disperse the droplets into the room, potentially causing damage to carpets and the cooling system.
Louver Openings: Optimal air inlet openings should be designed to prevent air obstruction, reducing pressure loss and power consumption.
Cooler Body Size: Properly sizing the cooler body to match the air delivery of the fan is essential.Smaller body sizes can lead to ineffective cooling, as the air may not spend enough time in contact with the water.
Body Material: The cooler body should be constructed from the appropriate gauge of steel to minimize vibration and noise.
Proper Earthling: Ensuring proper earthling of the fan motor and pump motor is essential for safety and to prevent electrical shocks.
By considering these crucial factors, we made more informed decisions when purchasing evaporative coolers, leading to improved cooling performance and energy efficiency.

Development of split cooling unit design
The Split cooling unit is composed of three heat exchangers that are evenly positioned, with chilled water being delivered from the Evaporative cooler through a high-pressure submersible water pump with a power rating of 40W.Positioned between the first and second heat exchanger is an 18W fan, as depicted in the figure .A shared inlet rail is connected to the split unit, ensuring uniform water supply to all three heat exchangers at the same pressure.Additionally, another shared outlet rail is linked to the heat exchangers' outlet, collecting water from the heat exchangers and directing it to the water tank of the Evaporative cooler.
Fan: The modified system employs two fans-one within the split unit and another in the evaporative cooler.The purpose of the fan in the Desert Cooler is to generate air movement and impact that meets the desired requirements for human occupants.Fan Specifications: Exhaust Fan: Diameter -152.4 mm, Speed -1500 rpm, Phase -1 phase, Poles -4 poles Electric Fan: Voltage -220/240V, Frequency -50Hz, Power -18W Submersible Pump: This pump is responsible for circulating water through the Desert Cooler's pads.Tank: The tank's purpose is to store an adequate amount of water for the pump to circulate the required cooling water.It possesses a sufficient capacity, typically ranging from 80 to 120 liters.The water, after each cycle of circulation, returns to the tank to maintain continuous circulation.Due to gradual evaporation, the water content in the tank diminishes over time.Consequently, the tank needs to be refilled after a specific interval, contingent on the hours of cooler usage.Greater usage leads to quicker depletion of the tank's water.While galvanized sheet metal is commonly used for tank construction, other options, such as cement tanks, are also feasible.A drain valve is essential in the tank for cleaning and maintenance purposes.The tank's actual dimensions are 68x60x18 cm³, providing a capacity of approximately 80 liters.Figure 3 illustrates the physical appearance of the tank utilized in the cooler.

Exterior Casing:
The outer casing material can vary, influenced by cost considerations and convenience.
It can be constructed from wood, sheet metal, or, more contemporarily, plastic.Some manufacturers have shifted towards producing coolers with plastic bodies due to their advantages: lightweight, corrosion resistance, and easy maintenance.

Piping:
Piping serves the purpose of conveying circulating water from the pump, uniformly distributing it over all pads to ensure consistent cooling.Contemporary pipes are typically plastic to prevent corrosion and ensure prolonged durability.These pipes are perforated above the pads, allowing water to cascade over them through the openings.Periodic checks are necessary to ensure unimpeded water flow, as dust and dirt can obstruct these openings, requiring proper cleaning.Additionally, other piping is employed to circulate coolant through the split unit.

Front Cover:
The Front Cover situated in front of the fan serves multiple functions.Primarily, it enhances the cooler's aesthetic appearance.Furthermore, it acts as a safety mechanism, preventing human contact with the fan.The integrated louvers in the cover direct the airflow as desired.The novel design, as illustrated in the figure, comprises the following components: • The traditional evaporative cooler.
• A duct with three heat exchangers and a fan for air supply.
• Two submersible pumps.The heat exchangers receive cooled water from the Evaporative cooler via a highpressure submersible pump of 40W using flexible pipes.The outlet water from all heat exchangers converges into a common rail, subsequently collected in the Evaporative cooler's water tank.This water undergoes evaporative cooling within the Evaporative cooler.

Experimental Procedures
The forthcoming procedures will be executed as follows: a) Observation of steady operation of the testing model (air-cooler).b) Placement of three calibrated thermometers at designated setup points to measure temperatures: i. t1 = Wet bulb temperature of moist air.
ii. t2 = Temperature of supply air.
iii. t = Dry bulb temperature of inlet air.c) Parallel measurement of wet bulb temperature, tw2.d) Sequential measurement of readings every hour.e) Repetition of the procedure each hour until 10 pm.f) Duplication of this experiment for three commercially available cooling mediums.
Our purpose is to subject the cooler to testing using coconut coir, adhering to the same investigational method.
Figures 6 and 7 provided below depict the practical arrangement of the evaporative (Desert) cooler employed for experimental evaluation.The components integrated into the cooler assembly have been elaborated upon in the preceding section.These elements have undergone calibration using thermometers and energy meters.

Result
The performance analysis of a split unit evaporative cooler for temperature reduction and humidity control is determined.This technical paper presents a comprehensive analysis of the performance of a Split Unit Evaporative Cooler designed for efficient temperature reduction while controlling humidity levels.the experimental results and analysis of a Split Unit Evaporative Cooler, designed to offer energy-efficient and environmentally friendly cooling solutions.The study assesses the system's performance in terms of temperature reduction, Coefficient of Performance (COP), power consumption, and humidity control.The experimental setup involves the installation of the cooler in a controlled environment, replicating standard room conditions.The cooler integrates evaporative cooling pads and a high-efficiency fan for optimal air circulation.Data is gathered through temperature and humidity sensors, with power consumption measurements obtained using a wattmeter.

Setup for Experiments:
The experimental configuration encompasses the installation of the Split Unit Evaporative Cooler within a controlled setting, mimicking standard room conditions.The cooler is outfitted with evaporative cooling pads and a high-performance fan to facilitate air circulation.Data pertaining to performance is acquired through sensors monitoring temperature and humidity levels, with power consumption quantified through employment of a wattmeter.
Temperature Reduction: The experimental results underscore the Split Unit Evaporative Cooler's effectiveness in reducing the ambient room temperature.Impressively, the cooler achieves a substantial temperature reduction of 17°C.With the ability to maintain room temperatures up to 25°C, the cooling system ensures a comfortable indoor environment, particularly in hot weather scenarios.

Coefficient of Performance (COP):
An integral metric for evaluating energy efficiency in cooling systems is the Coefficient of Performance (COP).Calculated as the ratio of the cooling effect (temperature reduction) to the energy input (power consumption), the COP for the Split Unit Evaporative Cooler stands at an impressive value of 7.This high COP underscores the system's capacity to provide efficient cooling while minimizing energy utilization.
Power Consumption: The energy consumption analysis reveals the Split Unit Evaporative Cooler's commendable energy-efficient performance.The system exhibits a modest total power consumption of 130 watts, accentuating its minimal impact on electricity usage and overall environmental footprint.This energy-saving attribute aligns with the current drive for sustainable cooling solutions.Humidity Control: A distinguishing feature of the Split Unit Evaporative Cooler is its adeptness in maintaining optimal air humidity levels without introducing excess humidity.Capitalizing on the evaporative cooling process, the cooler effectively cools the air while sidestepping the typical pitfall of elevated humidity levels.This characteristic ensures a comfortable and conducive indoor environment, contributing to the overall user experience.The experimental results demonstrate the system's capability to maintain room temperatures up to 25°C while achieving a remarkable reduction in air temperature by 17°C.The Coefficient of Performance (COP) for the cooling system is calculated at an impressive value of 7, indicating a highly energy-efficient operation.Moreover, the total power consumption of the unit is measured at a minimal 130 watts, highlighting its potential for low-energy cooling solutions.Most notably, the Split Unit Evaporative Cooler effectively avoids increasing the humidity of the air, ensuring a comfortable and pleasant indoor environment.These findings underscore the significance of the Split Unit Evaporative Cooler as a viable option for efficient and eco-friendly cooling applications.

Conclusion
The performed experimental inquiry has validated the encouraging capabilities of the split unit as a feasible wetted medium within evaporative cooling setups.This discovery unveils fresh opportunities for the advancement of sustainable engineering solutions, particularly in scenarios where cooling or humidification holds critical importance.With the split unit successfully maintaining a temperature of 25°C and boasting cost-effectiveness in comparison to traditional air conditioners, it stands as a compelling replacement option.Future enhancements can be pursued through the reduction of split unit density, which is expected to yield even better performance outcomes.Additionally, augmenting the pad thickness offers another avenue to achieve improved cooling efficiency.By leveraging these future modifications, the split unit's capabilities can be further optimized, solidifying its position as an efficient and sustainable solution for diverse cooling and humidification requirements.The avoidance of increased humidity further emphasizes the cooler's potential as an eco-friendly and comfortable cooling solution for various indoor environments.The outcomes of this research contribute to the rising figure of knowledge in the field of energyefficient cooling technologies and encourage the adoption of environmentally sustainable cooling solutions.