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

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.

2020 ◽  
Vol 10 (10) ◽  
pp. 3622 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple

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.


Author(s):  
Noor Asyikin Sulaiman ◽  
Md Pauzi Abdullah ◽  
Hayati Abdullah ◽  
Muhammad Noorazlan Shah Zainudin ◽  
Azdiana Md Yusop

Air conditioning system is a complex system and consumes the most energy in a building. Any fault in the system operation such as cooling tower fan faulty, compressor failure, damper stuck, etc. could lead to energy wastage and reduction in the system’s coefficient of performance (COP). Due to the complexity of the air conditioning system, detecting those faults is hard as it requires exhaustive inspections. This paper consists of two parts; i) to investigate the impact of different faults related to the air conditioning system on COP and ii) to analyse the performances of machine learning algorithms to classify those faults. Three supervised learning classifier models were developed, which were deep learning, support vector machine (SVM) and multi-layer perceptron (MLP). The performances of each classifier were investigated in terms of six different classes of faults. Results showed that different faults give different negative impacts on the COP. Also, the three supervised learning classifier models able to classify all faults for more than 94%, and MLP produced the highest accuracy and precision among all.


2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.


2011 ◽  
Vol 19 (01) ◽  
pp. 57-68 ◽  
Author(s):  
MIGUEL PADILLA

Commercial multiple evaporators variable refrigerant flow (VRF) HVAC systems present many advantages such as being energy saving and the capability of adjusting refrigerant mass flow rate according to the change of high rises occurrence. This paper deals with an experimental control volume exergy analysis in a VRF air conditioning system. The experimental results show that the brunt of the total exergy destroyed in the whole system occurs in the outdoor unit, where the exergy destroyed in the condenser is more important. The values of coefficient of performance (COP) obtained for the tests increase as the system reaches operational conditions imposed in every indoor unit zone. The VRF system analyzed is highly sensitive to the action of the constant speed compressor. The use of an inverter compressor improves the system performance by adjusting the power consumption according to the cooling load in the evaporators.


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.


2016 ◽  
Vol 24 (02) ◽  
pp. 1650012 ◽  
Author(s):  
T. O. Ahmadu ◽  
C. O. Folayan ◽  
F. O. Anafi

In this study, a solar absorption air conditioning system has been modeled simulated and optimized for an office block covering a total floor area of 90[Formula: see text]m2using the TRNSYS 16 software. Meteorological data over a period of a typical year for Zaria in Nigeria where the office block is located was used in the simulation and optimization. The hourly cooling energy demand of the office block for the whole year was simulated using the TRNSYS sub program TRNbuild. The peak cooling energy demand was used to size the components of the solar absorption air conditioning system. Based on the initial sizes, a TRNSYS model of the air conditioning system was developed. The simulation and optimization process was done by employing a monthly average data approach in which the TRNSYS software was combined with Microsoft excel. The simulation was done on an hourly time step, optimization was done by studying effect of varying system component sizes on performance indices: coefficient of performance (COP), solar coefficient of performance (SCOP) and solar fraction (SF). Results indicate that the system is capable of attaining an average annual SF of 0.79 in the given location.


Author(s):  
Ajay Landage

A simulation approach to heat pump systems is proposed in this paper. The evaluation of working fluids is conducted. Moreover, the selected refrigerants are used in the simulation. Subsequently, the system is analyzed in terms of the coefficient of performance (COP) and energy efficiency. Some alternative refrigerants, instead of R22 used R290 refrigerent. It is described the selection of refrigerants adapted to each utilization, based on the thermodynamic and -physical properties, the technological behaviour, costs and use constraints as principal aspects of the environmental protection. Also, it is performed a comparative analysis in function of the total equivalent warming impact (TEWI) for some possible substitutes of refrigerant R22 used in various refrigeration and heat pump systems.


Author(s):  
Sachin Sunil Mothiravally ◽  
Sachidananda Hassan Krishanmurthy

Air conditioning plays a significant role to maintain a cool atmosphere in warm conditions, However, the power consumed by the machine is higher. The commercial prevailing cooling systems are required to operate ventilation and cooling systems in buildings and in turn consumes more power. These systems apart from consuming electricity it also adds to the CO2 emissions to our environment. These energy consumption and CO2 emissions can be decreased by the assistance of energy effective frameworks to the prevailing air conditioning system. The study was conducted on a package unit of 414.2 kW by measuring the relative humidity, dry bulb, and wet bulb temperature to investigate the effect of indirect evaporative cooling on the systems COP. Also, the modelling of the package unit was done using Creo software and the analysis was carried out using ANSYS considering the flow and thermal analysis for different components of the package units. From this analysis it can be observed that by implementing the adiabatic cooling in package unit it is possible to save energy consumption. From the results it can be concluded that energy efficiency was more and the return on investment is high. Also, coefficient of performance of this machine is high and consumes less electricity and the expected energy savings is 20%.


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