scholarly journals Energy Performance Comparison between Two Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 522
Author(s):  
Su Liu ◽  
Jae-Weon Jeong
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Dew Point ◽  
Outdoor Air ◽  
Liquid Desiccant ◽  
Energy Saving Potential ◽  
Evaporative Cooler ◽  
Air Conditioning Systems ◽  
Direct Evaporative Cooler

This study investigated the annual energy saving potential and system performance of two different evaporative cooling-based liquid desiccant and evaporative cooling-assisted air conditioning systems. One system used an indirect and direct evaporative cooler with a two-stage package to match the target supply air point. The other was equipped with a single-stage, packaged dew-point evaporative cooler that used a portion of the process air, which had been dehumidified in advance. Systems installed with the two evaporative coolers were compared to determine which one was more energy efficient and which one could provide better thermal comfort for building occupants in a given climate zone, using detailed simulation data. The detailed energy consumption data of these two systems were estimated using an engineering equation solver with each component model. The results showed that the liquid desiccant and dew-point evaporative-cooler-assisted 100% outdoor air system (LDEOAS) resulted in approximately 34% more annual primary energy consumption than that of the liquid desiccant and the indirect and direct evaporative-cooler-assisted 100% outdoor air system (LDIDECOAS). However, the LDEOAS could provide drier and cooler supply air, compared with the LDIDECOAS. In conclusion, LDIDECOAS has a higher energy saving potential than LDEOAS, with an acceptable level of thermal comfort.

scholarly journals Systematic Method for the Energy-Saving Potential Calculation of Air-Conditioning Systems via Data Mining. Part I: Methodology

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Rongjiang Ma ◽  
Shen Yang ◽  
Xianlin Wang ◽  
Xi-Cheng Wang ◽  
Ming Shan ◽  
...  
Keyword(s):  
Data Mining ◽  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Storage System ◽  
Operation Mode ◽  
Systematic Method ◽  
Potential Analysis ◽  
Energy Saving Potential ◽  
Air Conditioning Systems

Air-conditioning systems contribute the most to energy consumption among building equipment. Hence, energy saving for air-conditioning systems would be the essence of reducing building energy consumption. The conventional energy-saving diagnosis method through observation, test, and identification (OTI) has several drawbacks such as time consumption and narrow focus. To overcome these problems, this study proposed a systematic method for energy-saving diagnosis in air-conditioning systems based on data mining. The method mainly includes seven steps: (1) data collection, (2) data preprocessing, (3) recognition of variable-speed equipment, (4) recognition of system operation mode, (5) regression analysis of energy consumption data, (6) constraints analysis of system running, and (7) energy-saving potential analysis. A case study with a complicated air-conditioning system coupled with an ice storage system demonstrated the effectiveness of the proposed method. Compared with the traditional OTI method, the data-mining-based method can provide a more comprehensive analysis of energy-saving potential with less time cost, although it strongly relies on data quality in all steps and lacks flexibility for diagnosing specific equipment for energy-saving potential analysis. The results can deepen the understanding of the operating data characteristics of air-conditioning systems.

scholarly journals Design of a dew point evaporative cooler for buildings in Mediterranean climate

2019 ◽  
Vol 111 ◽  
pp. 02021
Author(s):  
Djallel Abada ◽  
Chadi Maalouf ◽  
Tala MOUSSA ◽  
Amel Ferial Boudjabi ◽  
Guillaume Polidori ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Mediterranean Climate ◽  
Electricity Consumption ◽  
Dew Point ◽  
Outdoor Air ◽  
New Techniques ◽  
Cooling Effectiveness ◽  
Crucial Problem ◽  
Cooling Technology ◽  
Evaporative Cooler

Refreshing air remains a crucial problem in warm climates where electricity consumption for air conditioning has become excessive and irrational for several years, notably in Algeria. Research in this field is increasingly oriented towards new techniques that can reduce costs and environmental impacts. Among these techniques, the evaporative dew point cooling technology is the most promising as it can cool outdoor air to temperatures below its wet bulb temperature. The aim of this work is to model and design a dew point cooler for french and algerian climates. This model is used to study the effect of the cooler parameters such as its length, water temperature and working air ratio on its cooling effectiveness and supply temperature.

scholarly journals Indoor Air Quality Enhancement Performance of Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

2019 ◽  
Vol 11 (4) ◽  
pp. 1036 ◽  
Author(s):  
Beom-Jun Kim ◽  
Junseok Park ◽  
Jae-Weon Jeong
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Reference System ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Quality Enhancement ◽  
Liquid Desiccant ◽  
Air Conditioning Systems ◽  
Indoor Pm2.5

The main objective of this study is to investigate the indoor air quality enhancement performance of two different liquid desiccant and evaporative cooling-assisted air conditioning systems, such as the variable air volume (VAV) system with the desiccant-enhanced evaporative (DEVap) cooler, and the liquid desiccant system with an indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS), compared with the conventional VAV system. The transient simulations of concentration variations of carbon dioxide (CO2), coarse particles, and fine particles (PM10 and PM2.5) in a model office space served by each system were performed using validated system models that were found in the literature. Based on the hourly thermal loads of the model space predicted by the TRNSYS 18 program, each air conditioning system was operated virtually using a commercial equation solver program (EES). The results indicated that the LD-IDECOAS provided the lowest annual indoor CO2 concentration among all the systems considered in this research, while the VAV system with DEVap cooler exceeded the threshold concentration (i.e., 1000 ppm) during the cooling season (i.e., July, August, and September). For the indoor particulate contaminant concentrations, both liquid desiccant and evaporative cooling-assisted air conditioning systems indicated lower indoor PM2.5 and PM10 concentrations compared with the reference system. The LD-IDECOAS and the VAV with a DEVap cooler demonstrated 33.3% and 23.5% lower annual accumulated indoor PM10 concentrations than the reference system, respectively. Similarly, the annual accumulated indoor PM2.5 concentration was reduced by 16% using the LD-IDECOAS and 17.1% using the VAV with DEVap cooler.

Exergy Analysis of Energy Consumption for Central Air Conditioning System

2014 ◽  
Vol 628 ◽  
pp. 332-337
Author(s):  
Xiao Xia Xia ◽  
Nai Jun Zhou ◽  
Zhi Qi Wang
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Dew Point ◽  
Exergy Loss ◽  
Air Conditioning System ◽  
Air Cooler ◽  
Central Air Conditioning ◽  
Air Conditioning Systems

The energy consumption of several central air conditioning systems in summer was researched by the method of exergy analysis. Combined with actual example,the exergy loss of all the equipments and the exergy efficiency of three systems were calculated. The results show that the exergy efficiency of three systems is very low. Relatively speaking, the exergy efficiency of primary return air conditioning system with supplying air in dew point is highest. The equipment of highest exergy loss is air-conditioned room, while the exergy loss of surface air cooler is smallest. Based on this, several improvement measures were proposed to reduce exergy loss and improve exergy efficiency.

Applicability Research on Evaporative Cooling Technology in Hunan Province

2014 ◽  
Vol 1070-1072 ◽  
pp. 1679-1683
Author(s):  
Qin Ouyang ◽  
Guang Xiao Kou ◽  
Min Ouyang
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Waste Heat ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Hunan Province ◽  
Design Parameters ◽  
Climate Conditions ◽  
Energy Saving Potential ◽  
Evaporative Cooling System

According to the climate conditions of Hunan province and the design parameters related to air conditioning, the energy consumption and the related characteristics of the liquid desiccant evaporative cooling system (LDECS) are compared with primary return air conditioning system. The results show that energy consumption of LDECS can be decreased by 11.78% compared to the primary return air system. LDECS has a certain degree of energy saving potential in Hunan province, especially when waste heat is available.

Energy conservation potential of an indirect and direct evaporative cooling assisted 100% outdoor air system

2011 ◽  
Vol 32 (4) ◽  
pp. 345-360 ◽  
Author(s):  
MH Kim ◽  
JH Kim ◽  
OH Kwon ◽  
AS Choi ◽  
JW Jeong
Keyword(s):  
Energy Savings ◽  
Evaporative Cooling ◽  
Outdoor Air ◽  
Variable Air Volume ◽  
Energy Saving Potential ◽  
Air Volume ◽  
Direct Evaporative Cooling ◽  
Air System ◽  
Evaporative Cooler ◽  
Cooling Coil

This study aims to present the fundamentals in which operation of a 100% outdoor air system integrates with indirect and direct evaporative cooling systems and to estimate its energy saving potential. The simulation of the proposed system is performed using a commercial equation solver program, and the annual operation energy saving potential with respect to a conventional variable air volume system is determined. This paper shows that significant operation energy savings (i.e. 21–51% less energy consumption) is possible principally by the pre-conditioning of supply air due to the waste heat recovery using the indirect evaporative cooler and the sensible heat exchanger units. By components, the proposed system shows a 16–25% less annual cooling coil load and an 80–87% reduced annual heating coil load with respect to the conventional variable air volume system, while there is no fan energy savings expected. Practical applications: This paper provides practical insight on how the evaporative cooling based 100% outdoor air system operates and how each essential component, such as the indirect evaporative cooler, cooling coil, direct evaporative cooler, heating coil and sensible heat exchanger should be controlled during the seasons for realising energy conservation benefits. The sequence of operation presented in this paper can be implemented to actual control logic.

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.

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