Vol. 2 No. 4 (2023): IJRVOCAS – Special Issues – INCOSTIG – PP. 160~167 Print ISSN 2777-0168| Online ISSN 2777-0141| DOI prefix: 10.53893 https://journal.gpp.or.id/index.php/ijrvocas/index
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Study of heat Energy Disposal in Hollow Roof Cooling Water Tank
Sudirman Lubis, Farel H Napitupulu*, Ilmi Abdullah & Tulus Burhanuddin Sitorus Mechanical Engineering Doctoral Study Program, Faculty of Engineeringy, Universitas Sumatera Utara, Indonesia
ABSTRACT
Cooling tank is defined as a heat exchanger whose working fluid material is water, and air which functions to cool water by direct contact with air which causes a small portion of the water to evaporate. This water will flow in the hollow roof which is expected to absorb heat as it passes through the cavity.
This study aims to obtain the value of the effectiveness of the heat transfer rate on the hollow roof, as well as to determine the amount of energy in the cooling water tank of the hollow roof that can be discharged every hour and to determine the water flow required to supply the hollow roof. During the study, the results obtained varied with the volume of water entering about 0.00064 m³ in each cavity, with a pump capacity of 5.5 LPM. From the test data obtained, if the intensity of sunlight is low, the heat will be absorbed by the environment and vice versa if the intensity of sunlight is high, the heat will be absorbed by the water. That is why the intensity of sunlight greatly affects the data collection process. From the results obtained in the field at the time of the study for 7 days, the average water temperature was 28.4ºC. This result can be categorized as safe because the water temperature does not exceed or is not far from the temperature in the water tank with an average temperature of 40.5ºC.
Keywords:
Cooling Tank Effectiveness Value Conduction Convection
Corresponding Author:
Farel H Napitupulu,
Mechanical Engineering Doctoral Study Program, Faculty of Engineeringy, Universitas Sumatera Utara, Indonesia,
Jl. Dr. T. Mansur No.9, Padang Bulan, Medan, North Sumatera, Indonesia.
Email: farelnapitulufn@gmail.com
1. INTRODUCTION
Indonesia has a tropical climate with high humidity (it can reach 80%) and relatively high air temperature up to 35°C [1,2]. High thermal conditions make humans feel uncomfortable in carrying out daily activities. Humans need thermal comfort ranging from 22.5°C-29°C with air humidity ranging from 20% - 50% [3]. With these climatic conditions, it is necessary to create comfortable thermal conditions in the room for activities. Thermal comfort involves comfortable room temperature conditions and can help the human body maintain its ideal body temperature of 37°C. This ideal body temperature is needed so that the organs of the body can work properly [4]. Based on the results of previous research conducted on "Online optimization methods of air conditioning systems based on heat transfer models for cooling towers" it is still possible to develop variations of heat transfer for cooling water tanks [5,6,7]. Therefore, the authors are interested in continuing the research by using a hollow roof which is specially designed for fluid (air) to pass along the roof cavity so that heat is absorbed more maximally. hollow roof as a heat exchanger that is specially made and will conduct trials, as well as perform calculations and testing tests on the heat exchanger that will be made on the value of effectiveness [8].
The heat exchange that will be made is a hollow roof in this study, to get the effectiveness of heat transfer, it is carried out with series and parallel fluid flows. The fluid used in this experiment is in the form of water sourced from PDAM. The variation is done by knowing the flow rate of the fluid (water) with the
incoming cold temperature and the temperature of the hot (warm) fluid (water) coming out of the hollow roof every hour [9,10,11].
The cooling water tank is identified as an air container for heat exchange whose working material is air, and air that works in direct contact with air which causes a small part of the air to evaporate. In most cases, cooling water tanks are used in centrifugal pump systems to move air vertically across the tower (El Vice. 1992). The function of the cooling water tank is used to lower the temperature of the fluid (water) flow, by extracting heat from the fluid and emitting it to the atmosphere [12].
The cooling system is an air conditioning system in which the system circulates air in the room, in the system there is a condenser that releases heat energy from the circulation of the cooling system which can be used as a water heater, in order to save energy. (A.P. Dermawan, F. Ariskyawan, G.L. Rahino, 2020).
According to (EL.Wakil, 2015) a cooling tank is defined as a heat exchanger whose working fluid material is water, and air which functions to cool water by direct contact with air which causes a small portion of the water to evaporate. Most cooling towers used in air cooling systems use a centrifugal pump system to move water vertically across the tower. Cooling tower performance is usually expressed in terms of range and approach.
Figure 1. Range and approach temperature in the cooling tank
Cooling tanks are also used in an effort to increase productivity and efficiency in the machine production process in industry. Because in some cases in the industry required the appropriate level of efficiency and temperature in order to work optimally. To be able to produce the desired temperature, the equipment to be used must meet the capacity in accordance with the cooling load owned by the machine used [13].
1.1 Cooling Tank Working Principle
The fluid that comes out of the cooling process in the plastic injection machine has a hot or large temperature. So that cooling is needed so that the fluid from the engine process can be reused with a stable temperature. The fluid here is water which in the medium and large capacity refrigeration system is water as the condenser cooling medium. This is because water has a better heat transfer ability. Water-cooled condensers based on their working methods have two classifications. The function of the cooling tank is to lower the temperature of the fluid flow, be it water or oil, by extracting heat from the fluid and emitting it into the atmosphere.
After going through the condenser, the water temperature will rise because it absorbs some heat from the refrigerant in the condenser, the water temperature will rise because it absorbs some heat from the refrigerant in the condenser.This hot water then enters through the hot water inlet port on the cooling tank and then rises to the top of the cooling tank. The water then exits through the holes in the sprinkler. The sprinkler will rotate while releasing the water and distributing it evenly over the top of the cooling tank. The water that comes out of this sprinkler then enters the water column and comes into contact with the air flow in the opposite direction (hot water goes down to the bottom of the cooling tank, while air enters from the bottom and then comes out from the top). At the contact between water and air, some heat will be released by water at a higher temperature to air at a lower temperature [14].
2. RESEARCH METHOD
In my research, I will use an experimental method, namely by testing the cooling tower with 3 different test times in the morning, afternoon, and evening
.
Testing that has been carried out for a period of 7 days with a vulnerable time of retrieval starting at 08:00 – 17:00 WIB with a hollow roof media that will flow water, where this water is expected to absorb heat given direct sunlight on the hollow roof. With the hope that the flowing water can reduce the temperature in the room to keep it cool and comfortable. The way it works is by flowing water from the tank into the roof through the
cavity with the help of a pump whose water flow is 5.5 LPM. On each roof there are 10 cavities each with an incoming water volume of about 0.0064 m3 [11,14,15]
3. Result and Discussion
Table 1. First Day Data
Figure 3. Data Chart for the First Day
From the graph above, it can be seen that the ambient temperature on Thursday at 08:00 is the highest and has the lowest wind speed, while the incoming temperature on Thursday is the highest at 30.7 C at 12:00 WIB and the highest exit temperature is 43.8 C at 4:00 p.m. And the lowest entry temperature on Thursday at 10:00 am and the lowest temperature out of 37.6 C at 10:00 pm. To get the desired results or success in research will be discussed further in 3 and 4 continuing from explanation 2.
Table 2. Second Day Data
Figure 4. Graph of data for the second day
On the second day of the graph above, it can be seen that the environmental temperature condition on Thursday at 08:00 is the highest and has the lowest wind speed, while the incoming temperature on Thursday is the highest at 30.7 C at 12:00 WIB and the highest exit temperature is 43. ,8 C at 16:00 pm. And the lowest entry temperature on Thursday was 22.8 C at 10:00 am and the lowest temperature was 37.6 C at 10:00 am.
And has an average wind speed of 4.52 km / h and affects the humidity and temperature of the surrounding environment.
Table 3. Third Day Data
Figure 5. Third Daily Chart
Entering the third day of the study, the research graph shows that the environmental temperature is quite high at 08:00 wib with 33 C and slowly drops back to 22ºC until 17:00 wib with the influence given by wind speed, the lowest inlet water temperature occurs at 10:00 am with 22.8 C and the highest at 16:00 pm with 43.82ºC.
Table 4. Fourth Day Data
Figure 5. Fourth Day Chart
On the fourth day, a test graph was obtained which was not much different from the results from the first day to the third day with the results obtained that the exit temperature was greater than the inlet temperature which made the room maintain its comfortable temperature for the human body.
Table 5. Data for the Fifth Day
Figure 6. Fifth Day Graph
Next on the fifth day, the highest environmental temperature results were obtained at 08:00 WIB because the weather on Wednesday was brighter than the previous day which made the environmental temperature rise and fall again at 09:00 WIB and remained stable until 17:00 WIB.
Table 6. Sixth Day Data
Figure 7. Sixth Day Graph
On Thursday, entering six days of research, the results obtained in tables and graphs are not very significant and are still in a safe condition to continue the research until the next seventh day.
Table 7. Seventh Day Data
Figure 8. Seventh Day Chart
On the last day of the study on the seventh day, the results obtained were quite satisfactory and it can be concluded from the data obtained that the temperature of the water entering and leaving the back into the holding tank is still in a safe condition and does not exceed the temperature coming out of the roof.
4. CONCLUSION
From the research that has been carried out for 7 days of data collection in the field, it is obtained as follows:
1. From testing the data obtained, if the intensity of sunlight is low, the heat will be absorbed by the environment and vice versa if the intensity of sunlight is high, the heat will be absorbed by the air. That's why sunlight greatly affects the data collection process.
2. From the results obtained in the field at the time of the study for 7 days, the average air temperature was 28.4ºC. This result can be categorized as safe because the air temperature does not exceed or is not far from the temperature in the water tank with an average temperature of 40.5ºC
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How to Cite
Lubis, S., Napitupulu, F. H., Abdullah, I. ., & Sitorus, T. B. (2023). Study of heat Energy Disposal in Hollow Roof Cooling Water Tank. International Journal of Research in Vocational Studies (IJRVOCAS), 2(4), 160–167.
https://doi.org/10.53893/ijrvocas.v2i4.189
