scholarly journals Experimental Study of Optimum Chilled Water Distribution Configuration in Air Conditioning Terminal Unit Using RSM Technique

2018 ◽  
Vol 24 (6) ◽  
pp. 11
Author(s):  
Ahmed Abd Mohammed Saleh ◽  
Ali Reyadh Shabeeb

The distribution of chilled water flow rate in terminal unit is an important factor used to evaluate the performance of central air conditioning unit. A prototype of A/C unit has been made, which contains three terminal units with a complete set of accessories (3-way valve, 2-way valve, and sensors) to study the effect of the main parameters, such as total water flow rate and chilled water supply temperature with variable valve opening. In this work, 40 tests were carried out. These tests were in two groups, 20 test for 3-way valve case and 20 test for 2-way valve case. These tests were performed at three levels of valve opening, total water flow rate and water supply temperature according to the design matrices established by Design of Experiment (DOE) software 'version 7' with Response surface methodology (RSM) technique. The model was conducted for each case of total heat rate, then checked statistically for adequacy by Analysis of variance (ANOVA), and found good with 95% confidence level. The results showed that the water supply temperature has a significant effect on the total heat rate of two cases. It was found that the optimum solution for maximum total heat rate and minimum flow deviation represented by standard deviation was obtained at 10°C water supply temperature, 5.5 l/min total water flow rate and 70% valve opening. The total heat rate and standard deviation were (890.249 Watt), (0.000513), respectively in three-way valve case and (743.155 Watt), (0.00277), respectively in two-way valve case. Finally, the predicted and experimental results of total heat rate and standard deviation were in agreement with a maximum error of 6.6 % in three-way valve case and 1.4% in two-way valve case.  

2019 ◽  
Vol 14 (2) ◽  
pp. 137-146
Author(s):  
Ahmed Abd Mohammed Saleh ◽  
Ali Reyadh Shabeeb

 The distribution of chilled water flow rate in terminal unit is a major factor used to evaluate the performance of central air conditioning unit. In this work, a theoretical chilled water distribution in the terminal units has been studied to predict the optimum heat performance of terminal unit. The central Air-conditioning unit model consists of cooling/ heating coil (three units), chilled water source (chiller), three-way and two-way valve with bypass, piping network, and pump. The term of optimization in terminal unit ingredient has two categories, the first is the uniform of the water flow rate representing in statically permanents standard deviation (minimum value) and the second category is the maximum heat transfer rate from all terminal units. The hydraulic and energy equations governing the performance of unit solved with the aid of FORTRAN code with considering the following parameters: total water flow rate, chilled water supply temperature, and variable valve opening. It was found that the optimum solution of three-way valve case at 8°C water supply temperature, 0.12 kg/s total water flow rate and valve opening order (valve 1: 100%, valve 2: 100% and valve 3: 75%) with total heat rate (987.92 Watt) and standard deviation (1.181E-3). Also, for the two-way valve case the results showed that the optimum condition at 8°C water supply temperature, 0.12 kg/s total water flow rate and valve opening order (valve 1: 75%, valve 2: 75% and valve 3: 50%) with total heat rate and standard deviation (717Watt) and (5.69E-4) respectively.


Author(s):  
Anand. P ◽  
Devipreetha. K ◽  
Haripriya. R

Managing water consumption is important for life preservation. Knowing water consumption at homes can have a great impact on water saving. There is a global water crisis due to increasing population growth, climate change, increasing consumption. Giving a report about the state of the planet’s water, especially in developing countries, the report describes the outlook for future generations as worries. To visually check water taps in the house consumes time and requires a family member to be at the house. To remotely do so, we propose a system that monitors, alerts the user and allows the user to control the water flow through taps whenever there is an unusual reading of the water usage at home. The Water Flow Monitoring and Controlling System is an android- based mobile application. It is equipped with external hardware to sense a tap’s water flow rate and control which means turning on or off the water supply line whenever necessary. Registered users can login and view their house’s current water flowage from the mobile application. The external hardware updates the water flow rate at every specified time to a database through the Internet connection. If the users decide to turn on or off the water supply taps at their homes, it can be done through the on or off button provided in the mobile application. A user’s on or off instruction is set within the database. The hardware receives this instruction and performs the desired action.


2021 ◽  
Vol 16 ◽  
pp. 1-7
Author(s):  
Wojciech Wolak ◽  
Krzysztof Dubaj ◽  
Artur Bartosik

The paper deals with nozzle valve characteristics used in modern portable device, named handy shower, dedicated for personal hygiene. Such device significantly reduces water consumption and can be easily and quickly changed into a shower, sink or bidet. Importance of such device continuously rises as some regions and cities face water shortages. The aim of the paper is to measure and analyse characteristics of nozzle valves in portable handy shower for different hight of hydrostatic pressure, different number of holes in the nozzle and different level of valve opening. Experiments required measurements of volumetric flow rate and pressure drops. The pressure drops on the nozzle valve were measured using differential pressure transducer with accuracy of 1 Pa, while the water flow rate at the outlet of the nozzle was measured using the time-volume method with accuracy for volume and time 1ml and 0.1s, respectively. Experiments confirmed substantial influence of hight of hydrostatic pressure, number of holes in the nozzle, and the level of valve opening on outlet water flow rate from the device. It is demonstrated that for chosen height of hydrostatic pressure and for filled water tank it is possible to calculate duration of the use of handy shower for specific hygiene purpose by choosing appropriate level of valve opening and the right nozzle valve with a certain number of holes. Authors discussed possible reason that some of measured points are scattered at low level of valve opening. Results of experience were presented as graphs and conclusions.


2014 ◽  
Vol 672-674 ◽  
pp. 1670-1675
Author(s):  
Jing Wang ◽  
Shi Bin Geng ◽  
Xu Han ◽  
Hua Zhang

A procedure for deriving a dynamic model of an air condition system was described in this paper. The system consisted of a zone, cooling coils and fan. Room thermal balance model and dynamic model of AC control system components including sensor, cooling coils and ducts, were established. This model accurately predicts the effect of inlet air temperature during closed loop control of output air temperature using chilled water flow rate as a control input. Fuzzy adaptive control (FAC) combined with proportional integral derivative (PID) control algorithms (FAC-PID) were used to control the chilled water flow rate. Computational simulations were carried out in toolbox Simulink of Matlab. The fuzzy parameters were carefully tuned to produce less oscillatory responses. The results show that the system based on FAC-PID control is capable of controlling the disturbance efficiently with less time lag and small error than PID control.


2022 ◽  
Vol 14 (2) ◽  
pp. 684
Author(s):  
Ankit Garg ◽  
Insha Wani ◽  
Vinod Kushvaha

Recently, incentives have been provided in developed countries by the government for commercial production of biochar for soil treatment, and other construction uses with an aim to reduce a significant amount of carbon emissions by 2030. Biochar is an important material for the development of circular economy. This study aims to develop a simple Artificial Neural Network (ANN) based model to predict erosion of biochar amended soils (BAS) under varying conditions (slope length, slope gradient, rainfall rate, degree of compaction (DoC), and percentage of biochar amendments). Accordingly, a model has been developed to estimate the total erosion rate and total water flow rate as a function of the above conditions. The model was developed based on available data from flume experiments. Based on ANN modelling results, it was observed that slope length was the most important factor in determining total erosion rate, followed by slope gradient, DoC, and percentage of biochar amendment. The percentage of biochar amendment was a leading factor in the total water flow rate determination as compared to other factors. It was also found that the reduction in erosion is relatively minimal during an increase in slope length up to 1.55 m, reducing sharply beyond that. At a slope length of 2 m, erosion is found to be reduced by 33% (i.e., 2.6 to 1.75), whereas the total flow rate decreases linearly from 1250 mL/m2/min to 790 mL/m2/min. The ANN model developed shows that soil biochar composite (SBC) with 5% biochar amendment gave the best results in reducing soil erosion. This study can be a helpful tool in providing preliminary guidelines for using biochar in erosion control.


Author(s):  

The article presents the results of analysis of the water flow data for main rivers in the Bolshoy Kinel River basin from the moment of the instrumental observation start in 1993. Analysis of inter/annual runoff of the Bol Kinel River showed that the average flow rate was 37.7 m3/s, the largest – 72.6 m3/s (1991), the smallest – 8.54 m3/s (1935). Starting from the 60s of the last century, the years 1991, 1987, 1990, and the low-water years were 196 7, 1975, and 1984. Due to climatic changes, the annual flow of the river for the period 1933-2010 increased from 34.6 m3/s to 37.5 m3/s. At the same time, the runoff of spring flood increased and the low-water runoff decreased. Analysis of seasonal runoff variability showed that the minimum runoff during the low-water period is a limiting factor for water supply. The smallest minimum monthly flow rate was 3.14 m3/s (January 1939). The lowest daily water flow rate was 0.71 m3/s (September 3.4, 1940). The results obtained prove that the Bol Kinel River during the low-water period of extremely dry years is an unreliable source of water supply. To ensure sustainable water supply in conditions of low water amid global climate warming, it is necessary to develop additional reserve options for supplying water to the urban population.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 682
Author(s):  
Eko Surojo ◽  
Aziz Harya Gumilang ◽  
Triyono Triyono ◽  
Aditya Rio Prabowo ◽  
Eko Prasetya Budiana ◽  
...  

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.


Author(s):  
Afshin Goharzadeh ◽  
Keegan Fernandes

This paper presents an experimental investigation on a modified airlift pump. Experiments were undertaken as a function of air-water flow rate for two submergence ratios (ε=0.58 and 0.74), and two different riser geometries (i) straight pipe with a constant inner diameter of 19 mm and (ii) enlarged pipe with a sudden expanded diameter of 19 to 32 mm. These transparent vertical pipes, of 1 m length, were submerged in a transparent rectangular tank (0.45×0.45×1.1 m3). The compressed air was injected into the vertical pipe to lift the water from the reservoir. The flow map regime is established for both configurations and compared with previous studies. The two phase air-water flow structure at the expansion region is experimentally characterized. Pipeline geometry is found to have a significant influence on the output water flow rate. Using high speed photography and electrical conductivity probes, new flow regimes, such as “slug to churn” and “annular to churn” flow, are observed and their influence on the output water flow rate and efficiency are discussed. These experimental results provide fundamental insights into the physics of modified airlift pump.


Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 112 ◽  
Author(s):  
Yonghong Guo ◽  
Huimin Wei ◽  
Xiaoru Yang ◽  
Weijia Wang ◽  
Xiaoze Du ◽  
...  

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