Experimental Study on a Hybrid Desiccant Dehumidification and Air Conditioning System

2005 ◽  
Vol 128 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Li Yong ◽  
K. Sumathy ◽  
Y. J. Dai ◽  
J. H. Zhong ◽  
R. Z. Wang
Keyword(s):  
Air Conditioning ◽  
Experimental Tests ◽  
Electrical Energy ◽  
Primary Energy ◽  
Coefficient Of Performance ◽  
Air Flow Rate ◽  
Energy Usage ◽  
Humidity Ratio ◽  
Air Conditioning System ◽  
Air Conditioning Systems

This paper presents the experimental tests on hybrid desiccant dehumidification and air conditioning systems. Experimental tests are carried out with LiCl desiccant at typical operative ranges for air conditioning applications, particularly for high humid regions like Hong Kong. Results are reported in terms of coefficient of performance (COP) based on primary energy usage and electrical energy usage, respectively. Experiments have demonstrated consistent reduction in humidity ratio satisfying the sensible as well as latent load through a respective subsystem and thereby resulting in a higher COP based on primary energy usage. Also, results show that the regeneration temperature as well as process air flow rate have a significant role on the system performance. It is found that the hybrid system can achieve a higher part load performance, and hence can assure of its effective operation all year around in hot humid regions.

scholarly journals Improving performance of direct expansion air conditioning systems while reducing electricity consumption through using hybrid energy

2021 ◽  
Vol 289 ◽  
pp. 01014
Author(s):  
Ahmed Al–Okbi ◽  
Yuri Vankov ◽  
Hakim Kadhim
Keyword(s):  
Energy Consumption ◽  
Thermal Energy ◽  
Air Conditioning ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Electricity Production ◽  
Conventional System ◽  
Solar Thermal Energy ◽  
Continuous Power ◽  
Air Conditioning Systems

At the present time, operating hybrid air-conditioning systems that use solar energy to saving electrical energy while improving the performance has become necessary to protect the environment, reduce pollution and emissions caused by using fuels and gases. In Iraq, temperatures reach half the boiling point at summer, therefore the demand for air conditioning systems increases, air conditioning systems consume more than half of average electricity production which affects on reliability and stability of the electrical energy thus leads to a continuous power outage. So, the issue of using renewable energies becomes more attractive. Because of saving energy leads to ensuring the reliability of electricity and reduces the consumption of fuels and gases that pollute on the environment and negatively affect on the ozone layer. In the current research, the atmosphere of Baghdad city was used to collect solar thermal energy and convert it into thermal energy through an evacuated solar collector by water and combine it with a conventional air conditioner in the part that follows the compressor in order to reduce the electrical energy consumption on the compressor and increase coefficient of performance. Several tests were conducted on the proposed system to compare results with the conventional system and evaluate performance. The results showed that the coefficient of performance with the hybrid system became 8.97 more efficient instead of 4.27 compared to the conventional system, and the energy consumption decreased by 52%.

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.

scholarly journals Experimental Thermodynamic Investigation on the Refrigerant Charge in a Transcritical CO2 Electric Bus Air Conditioning System

2021 ◽  
Vol 11 (12) ◽  
pp. 5614
Author(s):  
Haidan Wang ◽  
Shengbo Li ◽  
Yulong Song ◽  
Xiang Yin ◽  
Feng Cao ◽  
...  
Keyword(s):  
System Performance ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Electric Bus ◽  
Maximum Coefficient ◽  
Considerable Impact ◽  
Air Conditioning Systems

Due to its considerable impact on climate, bus air conditioning systems are being pushed to take a new and sustainable path. Electric buses relying on transcritical CO2 air conditioning units are perceived to be eco-friendly and future-proof solutions to achieving such a target. However, in order to have highly efficient air conditioning systems, the CO2 charge needs to be optimized. In this paper the energy and exergy-based analyses were performed to investigate the effect of normalized refrigerant charge on the system performance by using a test rig of a transcritical CO2 air conditioning unit for an 8 m electric bus. Results showed that the normalized refrigerant charge range of 0.248~0.336 was recommended in order to ensure the maximum coefficient of performance (COP). In addition, in sufficient charge conditions, the optimal COP, cooling capacity and exergy efficiency were 1.716, 18.97 kW and 29.79%, respectively, under the standard refrigeration condition of 35 °C/27 °C. As the ambient temperature rose from 35 °C to 40 °C, the COP, cooling capacity and exergy efficiency decreased by 16.03%, 10.90% and 12.22%, respectively. Furthermore, the exergy efficiency was found not to be sensitive to slightly insufficient charge, whereas overcharge was observed to be even beneficial to exergy efficiency under the condition of ensuring the maximum COP. In addition, insufficient refrigerant charging seriously affected the irreversible losses in the indoor and outdoor heat exchangers, whereas slight overcharge had little effect on the component exergy efficiency. Finally, the need to improve the CO2 compressor efficiency to enhance the system performance was revealed.

scholarly journals A Study on the Application Possibility of the Vehicle Air Conditioning System Using Vortex Tube

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5227 ◽  
Author(s):  
Younghyeon Kim ◽  
Seokyeon Im ◽  
Jaeyoung Han
Keyword(s):  
Heat Exchange ◽  
Low Temperature ◽  
Flow Rate ◽  
Air Conditioning ◽  
Vortex Tube ◽  
System Simulation ◽  
Air Flow Rate ◽  
Exchange Method ◽  
Air Conditioning System ◽  
Air Conditioning Systems

Since refrigerants applied to vehicle air conditioning systems exacerbate global warming, many studies have been conducted to supplement them. However, most studies have attempted to maximize the efficiency and minimize the environmental impact of the refrigerant, and thus, an air conditioning system without refrigerant is required. The vortex tube is a temperature separation system capable of separating air at low and high temperatures using compressed air. When applied to an air conditioning system, it is possible to construct an eco-friendly system that does not use a refrigerant. In this paper, various temperature changes and characteristics of a vortex tube were identified and applied to an air conditioning system simulation device. Additionally, an air conditioning system simulation device using indirect heat exchange and direct heat exchange methods was constructed to test the low-temperature air flow rate (yc), according to the temperature and pressure. As a result of the experiment, the temperature of the indirect heat exchange method was found to be higher than the direct heat exchange method, but the direct heat exchange method had low flow resistance. As a result, the direct heat exchange method can easily control the temperature according to the pressure and the low-temperature air flow rate (yc). Therefore, it was judged that the direct heat exchange method is more feasible for use in air conditioning systems than the indirect heat exchange method.

scholarly journals Utilization of Solar Energy for Air Conditioning System

2018 ◽  
Vol 156 ◽  
pp. 03040 ◽  
Author(s):  
Juwari Purwo Sutikno ◽  
Serlya Aldina ◽  
Novita Sari ◽  
Renanto Handogo
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Savings ◽  
Electrical Energy ◽  
Point Of View ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Absorption Refrigeration ◽  
Air Conditioning System ◽  
Single Effect

The purposes of this research are to do a system simulation of air conditioning utilizing solar energy with single effect absorption refrigeration method, analyze the coefficient of performance (COP) for each absorbent-refrigerant variable and compare the effectivity of every absorbent-refrigerant variable used. COP is a constant that denotes the effeciency of a refrigeration system, that is ratio of work or useful output to the amount of work or energy input. The higher the number of COP, the more efficient the system is. Absorbent-refrigerant (working fluids) variables used in this research depend on its chemical and thermodynamics properties. Steps in this research are including data collection and tabulation from literature and do a simulation of air conditioning system both commercial air conditioning system (using electrical energy) and solar energy air conditioning system with Aspen Plus software. Next, run the simulation for each working fluid variables used and calculate the COP for each variable. Subsequently, analyze and compare the effectivity of all variables used from COP value and economical point of view with commercial air conditioning system. From the result of the simulation, can be concluded that solar air conditioning can achieve 98,85 % of energy savings than commercial air conditioning. Furthermore, from the calculation of COP, the highest COP value is achieved by solar conditioning system with LiNO3-NH3 as working fluid where 55% of the composition is the refrigerant and 45% of absorbent.

scholarly journals A hybrid air conditioning system using solar energy to save electrical energy with improving performance

2021 ◽  
Vol 288 ◽  
pp. 01066
Author(s):  
Ahmed Al–Okbi ◽  
Yuri Vankov ◽  
Hasanen Mohammad Hussain
Keyword(s):  
Energy Consumption ◽  
Solar Energy ◽  
Solar Collector ◽  
Air Conditioning ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Electricity Production ◽  
Air Conditioner ◽  
Solar Thermal Energy ◽  
Air Conditioning System

The process of operating an air conditioning system by hybrid energy that uses solar energy for purpose of saving electrical energy with improving the performance from modern and environmentally friendly systems. With high demand for air-conditioning systems in summer in hot regions, especially in Iraq due to high temperatures, the issue of using renewable energies becomes more attractive due to the continuous interruption of electrical energy. Air conditioners in Iraq consume more than half of the average electricity production. Therefore, saving energy leads to ensuring the reliability of electricity and reduces the consumption of fuel and gases that pollute the environment and negatively affect on the ozone layer. In the current research, the atmosphere of the city Baghdad was used to collect the solar thermal energy through a vacuum solar collector and combine it with a conventional air conditioner in order to reduce the electrical energy consumption on the compressor and increase the coefficient of performance. Several tests were conducted on the experimental device for comparing results with the conventional device and evaluating performance. The results showed that the performance with the vacuum solar collector became more efficient 8.97 instead of 4.27 than with the conventional system, and the energy consumption decreased by 52%.

ANALYSIS OF COMPETING VARIANTS OF AIR CONDITIONING SYSTEMS WITHOUT AIR EXTRACTION FROM ENGINES AT THE STAGE OF PASSENGER AIRCRAFT ONBOARD SYSTEMS CONCEPTUAL DESIGN

2019 ◽  
Vol 6 (3) ◽  
pp. 80-85
Author(s):  
Denis Igorevich Smagin ◽  
Konstantin Igorevich Starostin ◽  
Roman Sergeevich Savelyev ◽  
Anatoly Anatolyevich Satin ◽  
Anastasiya Romanovna Neveshkina ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Air Conditioning ◽  
Research University ◽  
Cooling System ◽  
Fuel Efficiency ◽  
Air Cooling ◽  
Moscow Aviation Institute ◽  
Air Conditioning System ◽  
Low Efficiency ◽  
Air Conditioning Systems

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.

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 Absorption and adsorption chillers applied to air conditioning systems

2010 ◽  
Vol 31 (2) ◽  
pp. 77-94 ◽  
Author(s):  
Agnieszka Kuczyńska ◽  
Władysław Szaflik
Keyword(s):  
Heat Source ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Geothermal Heat ◽  
Pump System ◽  
Desorption Process ◽  
Heat Pump System ◽  
Adsorption Chiller ◽  
Air Conditioning Systems

Absorption and adsorption chillers applied to air conditioning systemsThis work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperatureTdes= 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling waterTc= 25 °C and temperature in evaporatorTevap= 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

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