Performance analysis of a liquid desiccant system with an adjustable reflux ratio of regeneration solution

2016 ◽  
Vol 38 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Xiaofeng Niu ◽  
Yue Zhang ◽  
Xing Li ◽  
Yan Tong ◽  
Guangli Zhang
Keyword(s):  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Reflux Ratio ◽  
Thermal Coefficient ◽  
System Configuration ◽  
Liquid Desiccant ◽  
Average Growth Rate ◽  
Air Conditioning System ◽  
Average Growth ◽  
Water Condensation

In the liquid desiccant system, the amount of the diluted solution sent to the regenerator has a great influence on the system performance. The liquid desiccant system with an adjustable reflux ratio of regeneration solution was proposed in the paper, and the effect of the solution regeneration reflux ratio on the system performance was analysed by simulation. The energy consumption, the electric coefficient of performance and the thermal coefficient of performance under different water condensation rates and varied solution regeneration reflux ratio were obtained. The results show that, the overall performance of the liquid desiccant system can be improved by reducing the solution regeneration reflux ratio; a 1% decrease in the reflux ratio leads to a 0.56–1.02% average growth rate of electric coefficient of performance and a 0.51–0.95% average growth rate of thermal coefficient of performance. Moreover, when the regeneration temperature is high and the water condensation rate of the process air is low, the improvement from decreasing the solution regeneration reflux ratio is more significant. However, the reflux ratio cannot be reduced to an unlimited extent. There is a rational optimum range of the reflux ratio to achieve high thermal coefficient of performance, the optimum range under low dehumidifying load is different from that under high load. Practical application: The performance of a liquid desiccant system can be improved by the proposed system configuration with an adjustable reflux ratio of regeneration solution, such novel system configuration could be applied for the design of air conditioning system, which is beneficial for the energy saving in building. Moreover, the rational optimum ranges of the reflux ratio to achieve high coefficient of performance under different dehumidifying loads are obtained, which could provide guidelines for the design and operation management of the liquid desiccant based building air conditioning system.

A Novel Experimental Apparatus of a Liquid Desiccant Air-Conditioning System

2012 ◽  
Vol 516-517 ◽  
pp. 1121-1127
Author(s):  
Qing Zhang ◽  
Jian Hua Liu ◽  
Wen Zhong Gao ◽  
Liang Zhang
Keyword(s):  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Thermal Coefficient ◽  
Liquid Desiccant ◽  
Total Load ◽  
Air Conditioning System ◽  
Refrigeration Equipment ◽  
Experimental Apparatus ◽  
Lithium Chloride Solution ◽  
Definition Of

A novel experimental apparatus of a liquid desiccant air-conditioning system was introduced. The system differed from similar researches in that it could handle the total load of the conditioned space without any refrigeration equipment and it worked in ventilation mode, which could greatly improve the indoor air quality. The schematic diagram of the system was presented and circulating processes of air, water and lithium chloride solution in the system were introduced. The definition of thermal coefficient of performance (TCOP) for the system was introduced and main operating parameters that could affect TCOP were analyzed. The tested TCOP of the system was 0.72～0.98 in summer and 0.30～0.51 in autumn, which showed that liquid discussant air conditioning system was especially suitable for hot and humid conditions.

Evaluation of Cooling Water Storage for Liquid-Desiccant Air Conditioning System

2014 ◽  
Author(s):  
Danial Salimizad ◽  
Chris McNevin ◽  
Stephen Harrison
Keyword(s):  
Air Conditioning ◽  
Electrical Power ◽  
Water Storage ◽  
Cooling Water ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Liquid Desiccant ◽  
Air Conditioning System ◽  
Electrical Power Consumption ◽  
Evaporative Cooling Tower

Liquid-desiccant (LD) dehumidification technology has been used to extract moisture from humid air while attempting to consume less electricity than traditional air-conditioning methods. An evaporative cooling tower (ECT) was used as a cooling device to reject the latent heat gained by the system to regenerate the desiccant solution. The performance of an ECT was evaluated both experimentally and through TRNSYS simulations to investigate optimal operating conditions. The ECT often operated in humid conditions which resulted in reduced heat rejection rates and ineffective operation. To improve performance, cooling water storage (CWS) was investigated as a way to reduce ECT usage during periods of higher ambient humidity. To undertake this study, the complete LD system, incorporating CWS, was modelled in TRNSYS for a range of typical operating conditions. The results indicated that operation of the CWS system reduced the electrical power consumption and increased the electrical coefficient of performance (COPE) of the liquid desiccant air conditioning unit system by up to 16%. The total cooling rate improved by up to 6%. Smaller gains in COPT and solar fraction were also found in the simulation results.

Comparison study of air mixing modes in liquid desiccant based all-air air conditioning systems

2011 ◽  
Vol 33 (4) ◽  
pp. 423-435 ◽  
Author(s):  
Fu Xiao ◽  
XiaoFeng Niu
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Liquid Desiccant ◽  
Total Energy Consumption ◽  
Air Conditioning System ◽  
Operation Conditions ◽  
Air System ◽  
Air Mixing ◽  
Air Conditioning Systems

Liquid desiccant is an energy-saving, environmentally friendly and healthy means of air dehumidification. A liquid desiccant-based all-air air conditioning system is studied by simulation. Two different modes of air mixing between the return air and the fresh air are compared, that is mixing before and mixing after the liquid desiccant dehumidifier, respectively. System performance and total energy consumption of the two modes under different operation conditions are obtained. The results show that mixing air after dehumidification consumes less energy than mixing air before dehumidification. Coefficient of performance (COP) of the all-air system with air mixing after dehumidification is higher. The differences of COP and energy consumption between the two air mixing modes increase when the outdoor air temperature and relative humidity increase. Practical application: Liquid desiccant based all-air system is quite suitable for museums, libraries and computer centres where water is not allowed to enter the space for property safety and strict thermal-hygrometric control is necessary. The results of this paper provide guidelines on the selection of air mixing modes in liquid desiccant-based all-air systems, considering energy consumption and system COP.

Performance Test on a Solar Powered Two-Stage Solid Wheel Desiccant Air Conditioning System

2013 ◽  
Vol 732-733 ◽  
pp. 609-614
Author(s):  
Tong Hua Zou ◽  
Gu Jia ◽  
Fa Li Cao ◽  
Rong Yu
Keyword(s):  
Relative Humidity ◽  
Air Conditioning ◽  
Performance Test ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Outlet Temperature ◽  
Thermal Coefficient ◽  
Two Stage ◽  
Air Conditioning System ◽  
Solar Powered

In the paper, changes of both outlet temperature and relative humidity of solar powered two-stage wheel desiccant air conditioning system are tested with time under the typical Tianjin summer condition. It is found that supply air temperature of the solar driven desiccant cooling system could steady below 21 degrees Celsius, and the relative humidity of it is more than sixty percent in most of time of the actual operation. When operating, the thermal coefficient of performance of the whole air conditioning unit is about 0.5, and the reliability of two-stage wheel desiccant air conditioning system is verified.

scholarly journals Research on Double-Stage and Multi-Stage Capacitive Deionization Absorption Air-Conditioning System

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 395
Author(s):  
Feng Cheng ◽  
Boqing Ding ◽  
Xiuwei Li
Keyword(s):  
Air Conditioning ◽  
Pure Water ◽  
Good Choice ◽  
Coefficient Of Performance ◽  
Capacitive Deionization ◽  
Joint Work ◽  
Thermal Regeneration ◽  
Air Conditioning System ◽  
Multi Stage ◽  
Stage System

An absorption air-conditioning system is a good choice for green buildings. It has the superiority in the utilization of renewable energy and the refrigerant is environment-friendly. However, the performance of the traditional absorption system has been restricted by the energy waste in the thermal regeneration process. Capacitive deionization (CDI) regeneration is proposed as a potential method to improve system efficiency. In the new method-based air-conditioning system, strong absorbent solutions and pure water are acquired with the joint work of two CDI units. Nevertheless, the practical CDI device is composed of a lot of CDI units, which is quite different from the theoretical model. To reveal the performance of multiple CDI units, the model of the double/multi-stage CDI system has been developed. Analysis has been made to expose the influence of some key parameters. The results show the double-stage system has better performance than the single-stage system under certain conditions. The coefficient of performance (COP) could exceed 4.5, which is higher than the traditional thermal energy-driven system, or even as competitive as the vapor compression system. More stages with proper voltage distribution better the performance. It also provides the optimization method for the multi-stage CDI system.

scholarly journals Performance analysis of a novel liquid desiccant-vapor compression hybrid air-conditioning system

Energy ◽  
2016 ◽  
Vol 109 ◽  
pp. 180-189 ◽  
Author(s):  
Li Yinglin ◽  
Zhang Xiaosong ◽  
Tan Laizai ◽  
Zhang Zhongbin ◽  
Wu Wei ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Air Conditioning ◽  
Vapor Compression ◽  
Liquid Desiccant ◽  
Air Conditioning System

scholarly journals A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq

2020 ◽  
Vol 10 (10) ◽  
pp. 3622 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Thermal Performance ◽  
Air Conditioning ◽  
Cooling System ◽  
Electrical Power ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Solar Fraction ◽  
Design Variables

The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.

Sign in / Sign up

Export Citation Format

Share Document