A Study of the Performance of a Hybrid Liquid Desiccant Cooling System Using Lithium Chloride

Author(s):  
Pedro Mago ◽  
D. Yogi Goswami

Abstract A hybrid desiccant system using aqueous lithium chloride was studied by simulation, laboratory test, and field tests. This paper presents field test of a hybrid solar liquid desiccant cooling system conducted at a test house at the University of Florida’s Energy Research and Education Park. These tests consisted of operating the air conditioning system at the test house in two configurations: the conventional vapor compression system and the hybrid desiccant system. For each configuration the system was operated in two modes: recirculation, and 100% ventilation air. Experiments were conduct to study the influence of the air mass flow rate, temperature of the inlet air, temperature of the desiccant, and desiccant mass flow rate on the performance of both system configurations. Based on the field test results it was found that the hybrid desiccant system improves the air conditioning performance in the field test house by decreasing the outlet humidity and temperature of the air. It was also found that the hybrid desiccant cooling system is more cost effective for the case 100% fresh air ventilation than recirculation.

2003 ◽  
Vol 125 (1) ◽  
pp. 129-131 ◽  
Author(s):  
Pedro Mago ◽  
D. Yogi Goswami

This paper presents field test of a hybrid solar liquid desiccant cooling system conducted at a test house at the University of Florida’s Energy Research and Education Park. These tests consisted of operating the air conditioning system at the test house in two configurations: the conventional vapor compression system and the hybrid desiccant system. Experiments were conducted to study the influence of the air mass flow rate, temperature of the inlet air, temperature of the desiccant, and desiccant mass flow rate on the performance of both system configurations. Based on the field test results, it was found that the hybrid desiccant system improves the air conditioning performance in the field test house by decreasing the outlet humidity and temperature of the air.


2014 ◽  
Vol 521 ◽  
pp. 48-51
Author(s):  
Sun Jian

Liquid desiccant air-conditioning system is one kind of thermally driven open-cycle absorption air-conditioning systems which have been widely researched and applied because of its unique advantages in recent years.In this paper, an experimental equipment of liquid desiccant air-conditioning system was set up based on the mechanism of liquid desiccant dehumidification and regeneration. The dehumidifier and regenerator were all counter-flow towers and body of the tower were made of stainless steel to withstand the corrosive effect of the liquid desiccant. In experiments, mixture desiccant of calcium chloride and lithium chloride was applied.The performance of regeneration of the system was studied under different system operating condition. The effects of the inlet parameters on the efficiency of regeneration are discussed. The results show that the mass flow rate,humidity of the air,temperature and mass flow rate of the diluted solution can all affect the performance of regeneration of the system.


Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3503
Author(s):  
Huang ◽  
Chen ◽  
Yang ◽  
Du ◽  
Yang

Adverse wind effects on the thermo-flow performances of air-cooled condensers (ACCs) can be effectively restrained by wind-proof devices, such as air deflectors. Based on a 2 × 300 MW coal-fired power generation unit, two types (plane and arc) of air deflectors were installed beneath the peripheral fans to improve the ACC’s cooling performance. With and without air deflectors, the air velocity, temperature, and pressure fields near the ACCs were simulated and analyzed in various windy conditions. The total air mass flow rate and unit back pressure were calculated and compared. The results show that, with the guidance of deflectors, reverse flows are obviously suppressed in the upwind condenser cells under windy conditions, which is conducive to an increased mass flow rate and heat dissipation and, subsequently, introduces a favorable thermo-flow performance of the cooling system. When the wind speed increases, the leading flow effect of the air deflectors improves, and improvements in the ACC’s performance in the wind directions of 45° and –45° are more satisfactory. However, hot plume recirculation may impede performance when the wind direction is 0°. For all cases, air deflectors in an arc shape are recommended to restrain the disadvantageous wind effects.


2013 ◽  
Vol 49 (11) ◽  
pp. 1587-1593 ◽  
Author(s):  
Abdulrahman Th. Mohammad ◽  
Sohif Bin Mat ◽  
M. Y. Sulaiman ◽  
K. Sopian ◽  
Abduljalil A. Al-abidi

Author(s):  
B. Facchini ◽  
M. Surace ◽  
S. Zecchi

Significant improvements in gas turbine cooling technology are becoming harder as progress goes over and over. Several impingement cooling solutions have been extensively studied in past literature. An accurate and extensive numerical 1D simulation on a new concept of sequential impingement was performed, showing good results. Instead of having a single impingement plate, we used several perforated plates, connecting the inlet of each one with the outlet of the previous one. Main advantages are: absence of the negative interaction between transverse flow and last rows impinging jets (reduced deflection); better distribution of pressure losses and heat transfer coefficients among the different plates, especially when pressure drops are significant and available coolant mass flow rate is low (lean premixed combustion chamber and LP turbine stages). Practical applications can have a positive influence on both cooled nozzles and combustion chambers, in terms of increased cooling efficiency and coolant mass flow rate reduction. Calculated effects are used to analyze main influences of such a cooling system on global performances of power plants.


2011 ◽  
Vol 314-316 ◽  
pp. 686-690
Author(s):  
Cheng Jun Pan ◽  
Yi Da Tang

This study describes the results on the performance of one vehicle air conditioning system. The coefficient of performance, evaporator cooling capacity, compressor power consumption, total mass flow rate, vapor mass flow rate, liquid mass flow rate and oil in circulation, pressures and temperatures of refrigerant at every component (inlets and outlets) are measured and analyzed with the variation of the outside temperatures at the evaporator and condenser, the speed of the compressor, refrigerant charge and oil charge. The systematical experimental results obtained from this real-size test system depict the relations between the above parameters in a vehicle air conditioning system, which constitute a useful source for vehicle air conditioning systems design and analysis. The vapor quality (two-phase flow) measurements realized in this work provide an extremely important tool for diagnosing the system performances.


Author(s):  
Zhiwei Zhou ◽  
Yaoli Zhang ◽  
Yanning Yang

Containment is the ultimate barrier which protects the radioactive substance from spreading to the atmosphere. Sensitivity analysis on AP1000 containment during postulated design basis accidents (DBAs) was studied by a dedicated analysis code PCCSAP-3D. The code was a three-dimensional thermal-hydraulic program developed to analyze the transient response of the containment during DBAs; and it was validated at a certain extent. Peak pressure and temperature were the most important phenomena during DBAs. The parameters being studied for sensitivity analysis were break source mass flow rate, containment free space, surface area and volume of heat structures, heat capacity of the containment shell, film coverage, cooling water tank mass flow rate and initial conditions. The results showed that break mass flow rate as well as containment free space had the most significant impact on the peak pressure and temperature during DBAs.


Author(s):  
Xinran (William) Tao ◽  
John Wagner

Lithium-Ion (Li-ion) batteries are widely used in electric and hybrid electric vehicles for energy storage. However, a Li-ion battery’s lifespan and performance is reduced if it’s overheated during operation. To maintain the battery’s temperature below established thresholds, the heat generated during charge/discharge must be removed and this requires an effective cooling system. This paper introduces a battery thermal management system (BTMS) based on a dynamic thermal-electric model of a cylindrical battery. The heat generation rate estimated by this model helps to actively control the air mass flow rate. A nonlinear back-stepping controller and a linear optimal controller are developed to identify the ideal cooling air temperature which stabilizes the battery core temperature. The simulation of two different operating scenarios and three control strategies has been conducted. Simulation results indicate that the proposed controllers can stabilize the battery core temperature with peak tracking errors smaller than 2.4°C by regulating the cooling air temperature and mass flow rate. Overall the controllers developed for the battery thermal management system show improvements in both temperature tracking and cooling system power conservation, in comparison to the classical controller. The next step in this study is to integrate these elements into a holistic cooling configuration with AC system compressor control to minimize the cooling power consumption.


Author(s):  
Jingya Li ◽  
Xiaoying Zhang

The passive cooling system (PCCS) for reactor containment is a security system that can be used to cool the atmosphere and reduce pressure inside of containment in case of temperature and pressure increase caused by vapor injection, which requires no external power because it works only with natural forces. However, as the driving forces from natural physical phenomena are of low amplitude, uncertainties and instabilities in the physical process can cause failure of the system. This article aims to establish a CFD simulation model for the Passive Containment Cooling System of 1000MW PWR using Code_Saturne and FLUENT software. The comparison of 4 different models based respectively on mixture model, COPAIN test, Uchida correlation and Chilton-Colburn analogy which simulate the condensing effect and the improvement of source code are based on a 3D simulation of PCCS system. To simulate the thermal-hydraulic condition in the containment after LOCA accident caused by a double-ended main pipe rupture, a high temperature vapor with the given mass flow rate are supposed to be the source of energy and mass into containment. Meanwhile the surface of three condensing island applies the wall condensation model. The simulation results show similar transient process obtained with the 4 models, while the difference between the transient simulation and the steady-state analysis of three models is less than 3%. The large mass flow rate of water loss status inside the containment cause a high flow rate of vapor which could be uniformly mixed with air in a short time. For the self-condensing efficiency of 3 groups of PCCS system, the non-centrosymmetric injection position resulting that the condensing efficiency is slightly higher for the two heat exchanger groups nearby. During the first 2400s of simulation time, more than 75.69% of the vapor is condensed, indicating that for the occurrence of condensation at the wall mainly driven by natural convection, the effect of thermodynamic siphon could improve the flow of gas mixture inside the tubes when the velocity of mixture is not large enough, so that the vapor could smoothly enter the tube and reach the internal cooling surface then to be condensed. Besides, PCCS ensure the containment internal pressure maintained below 2 bar and the temperature maintained below 380K during 3600s.


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