scholarly journals Kinerja Lemari Pendingin Alami yang digunakan Sesuai Kondisi Cuaca di Kota Medan

2018 ◽  
Vol 19 (2) ◽  
Author(s):  
Tulus Buhanuddin Sitorus ◽  
Farida Arianil ◽  
Tekad Sitepu
Keyword(s):  
Solar Radiation ◽  
Cooling System ◽  
Weather Conditions ◽  
Electrical Energy ◽  
Maximum Efficiency ◽  
Temperature Changes ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System ◽  
Teak Wood ◽  
Vegetables And Fruits

One application in a direct evaporative cooling system was a natural cooler. The advantages of this system were not using the electrical energy and so far also environmentally. This research aims to obtain a performance analysis of the natural cooler as a store for vegetables and fruits in Medan city. The materials for natural cooler consists of teak wood and gunny. The experiments were conducted during seven days in the open air, which were exposed to the solar radiation. The parameter measurement on the weather was using HOBO devices and to record the temperature changes for vegetables or even fruits is using its acquisition data. The results showed that the maximum efficiency of the natural cooler could be obtained  for 43.79%  in the average air temperature of 30.51oC, the air humidity average is 85.12%  with  average solar radiation of 183.98 W/m2.  Experimental data were showing that the condition of  freshness on vegetables or even on  fruits was heavily influenced by weather conditions

scholarly journals The Effect of Dry and Wet Bulb Temperature Variation on the Performance of the Indirect Evaporative Cooler

2019 ◽  
Vol 26 (4) ◽  
pp. 8-15
Author(s):  
Maki Zaidan ◽  
Fayadh Abed ◽  
Ali Farhad
Keyword(s):  
Heat Exchanger ◽  
Environmental Changes ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Computer Software ◽  
Volumetric Flow Rate ◽  
Weather Conditions ◽  
Centrifugal Fan ◽  
Pipe Length ◽  
Evaporative Cooling System

The research is about designing and building up an evaporative cooling system, working by two- stages evaporative cooling system using outer air (pure air). The system is founded by designing and making a heat exchanger of orthogonal flow from Aluminum sheets of (30*60*40) cm, which represents the first stage of the system (indirect stage). The second stage (direct stage) of the system is represented by making an equipment of air washing (cylindrical) with (45 height, 60 width, 3 thickness) cm. The cooling system pulls outer air by a Centrifugal fan. The air passes through the heat exchanger pipes to be cooled tangibly (without moistening). Then it goes over the equipment of air washing to be cooled and cools the specified space. Computer software was designed by FORTRAN Language (FORTRAN 90) to predict the evaporative air cooler performance to know the proper environmental and design conditions of the system. Some variables were made to study their effect on the thermal performance of the system. The studied variable is to change the volumetric flow rate of air from (750 cfm) to (2000 cfm) of the dry side, and from (750 cfm) to (2500 cfm) of the wet side. The pipe length was changed from (20 cm) to (45 cm), and its diameter from (0.5 cm) to (3 cm). Those were the design changes. On the environmental changes, we studied the effect of changing the temperature on the dry or wet bulb of the system. The study is taken place in Tikrit University (34. 35N; 43.37 E), to determine the suitability of the weather conditions of the region for the work of the system. It was taken place in the late August for two consecutive days, with readings of 24 hours. The results show that the best quantity of the air supplied, which represent the best performance of the system (750 cfm) and (1000 cfm) for the wet side when the diameter (1-1.5 cm) and length is (45 cm). The results show also the possibility of the work of this system for the region mentioned because it is characterized by its hot and dry climate in the summer, as the efficiency of evaporative evaporator increases the hot and dry environment by 80%.

scholarly journals A MATHEMATICAL MODEL FOR DIRECT EVAPORATIVE COOLING AIR CONDITIONING SYSTEM

2003 ◽  
Vol 2 (2) ◽  
Author(s):  
J. R. Camargo ◽  
C. D. Ebinuma ◽  
S. Cardoso
Keyword(s):  
Mathematical Model ◽  
Air Conditioning ◽  
Cooling System ◽  
Convective Heat Transfer Coefficient ◽  
Evaporative Cooling ◽  
Experimental Tests ◽  
Water Evaporation ◽  
Human Thermal Comfort ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System

Air conditioning systems are responsible for increasing men's work efficiency as well for his comfort, mainly in the warm periods of the year. Currently, the most used system is the mechanical vapor compression system. However, in many cases, evaporative cooling system can be an economical alternative to replace the conventional system, under several conditions, or as a pre-cooler in the conventional systems. It leads to a reduction in the operational cost, comparing with systems using only mechanical refrigeration. Evaporative cooling operates using induced processes of heat and mass transfer, where water and air are the working fluids. It consists in water evaporation, induced by the passage of an air flow, thus decreasing the air temperature. This paper presents the basic principles of the evaporative cooling process for human thermal comfort, the principles of operation for the direct evaporative cooling system and the mathematical development of the equations of thermal exchanges, allowing the determination of the effectiveness of saturation. It also presents some results of experimental tests in a direct evaporative cooler that take place in the Air Conditioning Laboratory at the University of Taubaté Mechanical Engineering Department, and the experimental results are used to determinate the convective heat transfer coefficient and to compare with the mathematical model.

Correlation of Direct Evaporative Cooling Efficiency With Media Porosity

2010 ◽  
Author(s):  
James Walker ◽  
Shenguang Sheng ◽  
A. G. Agwu Nnanna ◽  
Lincang Li
Keyword(s):  
Cooling System ◽  
Evaporative Cooling ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System ◽  
Mass Flow Rates ◽  
The Media ◽  
To Come ◽  
Temperature Constant ◽  
Wetted Surface Area ◽  
Air Conditioning Systems

. Energy consumption of HVAC&R could be reduced by integrating evaporative cooling device into air conditioning systems. Direct Evaporative Cooling (DEC) are suited for climates where the air is hot and humidity is low. In DEC, heat is absorbed whenever water is evaporated and converted to water vapor. By passing through or around a wetted surface, heat is removed from the surrounding air in the vaporization of the water. The process approximates the adiabatic-saturation process and the path lies on a constant wet-bulb temperature which is a constant enthalpy line. The wetted surface area in direct evaporative cooling depends on porosity and absorptivity of the media. This paper evaluates the effect of media porosity on performance of a Direct Evaporative Cooling system. In this experimental work, the porosity is varied by changing the packing density and volume of media. The packing material allows air and water to come in direct contact. Holding all other variables like mass flow rates and inlet dry-bulb temperature constant, the effect Porosity on DEC performance is studied. The performance of DEC system is a function of porosity, dry- and wet-bulb temperatures and relative humidity. Efficiency increases with porosity.

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