scholarly journals Performance of Desiccant Enhanced Evaporative Cooling System Based on High-Low Control

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1377
Author(s):  
Yi Chen ◽  
Huaxia Yan ◽  
Yimo Luo
Keyword(s):  
High Speed ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Research Work ◽  
Ambient Air ◽  
High Dependency ◽  
Humid Region ◽  
Evaporative Cooling System ◽  
Evaporative Cooler ◽  
Secondary Air

Desiccant enhanced evaporative cooling system is a sustainable air-conditioning (A/C) system which deals the latent load and sensible load separately by a dehumidifier and an evaporative cooler. A LDD-RIEC system consists of a liquid desiccant dehumidifier (LDD) and a regenerative indirect evaporative cooler (RIEC) were investigated. The LDD-RIEC system is characterized by low energy consumption compared with conventional mechanical cooling system, but the main shortcoming is the high dependency on ambient air conditions. To maintain stable indoor temperature, a control scheme is essential. However, very limited research work regarding control strategy can be found in open literatures. In this paper, a novel controller named high-low (H-L) control is proposed. Multi-speed technology is utilized for primary air fan and secondary air fan operating either at high speed or at low speed. The annual performance of a LDD-RIEC system is simulated in Hong Kong, a typical hot and humid region. The results indicate that H-L control is effective in maintaining stable indoor thermal comfort with temperature fluctuation from 24 °C to 27 °C for 99% of time.

scholarly journals Disain dan Uji Kinerja Pendingin Evaporatif Tipe Aliran Searah Menggunakan CFD (Computational Fluid Dynamics)

2021 ◽  
Vol 10 (3) ◽  
pp. 338
Author(s):  
Hikmah Yuliasari ◽  
Kavadya Syska ◽  
Ropiudin Ropiudin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Cold Chain ◽  
Cfd Analysis ◽  
Direct Flow ◽  
Flow Type ◽  
Evaporative Cooling System ◽  
Evaporative Cooler

 After harvesting, fruits will change due to physiological, physical, chemical, and microbiological influences, and they are living materials. Therefore, it is necessary to know how to harvest and handle fresh fruits and their storage conditions to handle the fruits after harvesting so that the quality of the products can be maintained. One of the first treatments in the fruit cold chain is evaporative cooling. In order to get an evaporative cooling system that has an even temperature distribution, it is necessary to make a spatial model when designing an evaporative cooling system using CFD (Computational Fluid Dynamics). The objectives of this research are: (1) design of direct flow type evaporative cooling systems and (2) test the performance of direct flow type evaporative coolers. This research method uses design methods, experiments, and computer simulations. The results showed the performance of the evaporative cooler system in the scenario with the roof on, the highest effectiveness value was 1.198, the highest approximation value was 2.832, and the highest range value was 4.589. In the scenario without a roof on the evaporative cooler system, the highest effectiveness value was 1.767, the highest approach value was 2.139, and the highest range value was 4.835. The CFD analysis in the scenario with a roof had the highest temperature value of 25.9 ° C and the lowest temperature of 21.9 ° C, while the CFD analysis in the scenario without roof had the highest temperature of 23.7 ° C and the lowest temperature of 20.4 ° C. Keywords: CFD, direct flow type,  evaporative cooler, quality, fruit

scholarly journals Numerical investigations of solar-assisted hybrid desiccant evaporative cooling system for hot and humid climate

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093499
Author(s):  
Shafqat Hussain ◽  
Abdulrahim Kalendar ◽  
Muhammad Zeeshan Rafique ◽  
Patrick Oosthuizen
Keyword(s):  
Relative Humidity ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Vapor Compression ◽  
Humid Climate ◽  
Numerical Investigations ◽  
Evaporative Cooling System

This article presents numerical investigations of the solar-assisted hybrid desiccant evaporative cooling system integrated with standard air collectors for applications under the hot and humid climatic conditions of Kuwait city. The objective is to introduce the energy-efficient and carbon-free solar-assisted hybrid desiccant evaporative cooling system to alleviate the principal problems of electricity consumption and carbon emissions resulting from the use of the conventional vapor-compression cooling systems. In the normal building, during cooling load operation, the solar-assisted hybrid desiccant evaporative cooling system can cope with the cooling load particularly sensible by evaporative cooling and latent through desiccant dehumidification. The outcomes of this work indicate that solar-assisted hybrid desiccant evaporative cooling device integrated with air collectors is capable of providing average coefficient of performance of 0.85 and has the potential to provide cooling with energy saving when compared with conventional vapor-compression refrigeration systems. It was concluded that under the intense outdoor environmental conditions (ambient air at greater than 45°C and 60% relative humidity), the delivered supply air from the evaporative cooling was nearly at 27°C and 65% relative humidity. To solve this problem, the system was assisted with conventional cooling coil (evaporator of heat pump) to supply air at comfortable conditions in the conditioned space.

scholarly journals Numerical Investigation of a Novel Plate-Fin Indirect Evaporative Cooling System Considering Condensation

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 332
Author(s):  
Yuanyuan Zhou ◽  
Zhen Yan ◽  
Ming Gao ◽  
Qiumin Dai ◽  
Yanshun Yu
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Operating Conditions ◽  
Dew Point ◽  
Inlet Temperature ◽  
Thermoelectric Cooling ◽  
Evaporative Cooling System ◽  
Evaporative Cooler ◽  
Indirect Evaporative Cooling

An indirect evaporative cooling system combining with thermoelectric cooling technology (i.e., TIEC system) is proposed, in which a counter-flow plate-fin indirect evaporative cooler is inserted with thermoelectric cooling (i.e., TEC) modules. In hot and humid climate, condensation may occur on the dry channel surface of the cooler. For the TIEC system, with the aid of TEC technology, the surface temperature of the dry channel can be much lower than that of a traditional indirect evaporative cooler, thus, the condensation from the primary air is more likely to take place. A numerical model of this novel TIEC system is developed with specifically taking condensation from primary air into account. Detailed performance analysis of the TIEC system is carried out. Analytical results found that the condensation from primary air reduces the dew point effectiveness by up to 45.0% by weakening the sensible heat transfer but increases the coefficient of performance by up to 62.2% by increasing the latent heat transfer, under given conditions. The effects of main operating conditions, such as the electrical current I and number n of TEC modules, inlet temperature Tp,i, humidity ratio RHp and velocity Vp of the primary air, and the mass flow rate ratio x of secondary to primary air, are investigated under non-condensation and condensation states. It is shown that condensate is more easily produced under higher I, n, Tp,i, RHp, x and lower Vp.

scholarly journals Alternative Air-Conditioning Options for Developing Countries

2017 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
Muhammad Kashif ◽  
Muhammad Sultan ◽  
Zahid Mahmood Khan
Keyword(s):  
Developing Countries ◽  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Climatic Conditions ◽  
Individual Characteristics ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Evaporative Cooling System

This study assesses the potential selection of efficient air-conditioning (AC) and cooling systems in order to avoid excess power consumption, mitigation of harmful refrigerants generated by the existing AC systems. Several varieties of active and passive air-conditioning systems i.e. heating ventilating air-conditioning (HVAC), vapor compression air-conditioning (VCAC) conventional direct evaporative cooling (DEC) and indirect evaporative cooling (IEC)  and desiccant air-conditioning (DAC) systems are under practice for the cooling and dehumidification. The storage of agricultural products mainly based on product individual characteristics i.e. respiration rate, transpiration rate and moisture content of that product. Variant ambient air conditions and the type of application are the main parameters for the choice of air-conditioning system to get optimum performance. The DAC system subsidize the coefficient of performance (COP) in humid regions, coastal ranges of developing countries e.g. Karachi and Gawadar (Pakistan) with hot humid climatic conditions. In similar way, hottest regions of the country such as Sibbi, Jacobabad and Multan perform better results when incorporates with M-cycle evaporative cooling system. Variation in ambient air conditions directly affect the cooling load and the choice of sustainable air-conditioning system

scholarly journals Development of an evaporative cooler system applied to the air conditioning of urban buses

2020 ◽  
Vol 8 (1) ◽  
pp. 46-56
Author(s):  
César Ramos Broliato ◽  
Carlos Roberto Altafini ◽  
Carlos Alberto Costa
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Airflow Rate ◽  
Total Energy Consumption ◽  
A Value ◽  
Evaporative Cooling System ◽  
Evaporative Cooler

Air conditioning for buses is an important incentive tool for the public transport, since it offers comfort to passengers and stimulates the use of this kind of transport which is fundamental to improve urban mobility. Currently, air conditioning equipment for buses is the mechanical vapor compression (MVC) type. However, this kind of system has two main disadvantages: the high financial cost and power consumption by the vehicle engine. The purpose of this study is to develop an evaporative cooler for buses, which is a simple, environmental friendly, low-cost solution that does not use engine power for its operation. The first step was the design and construction of the prototype. The following step was to evaluate the built prototype through performing experimental tests. The prototype presented a saturation efficiency of approximately 70%, airflow rate of 421.5 m³/h and energy consumption of 98.4 W. After determining the prototype technical characteristics, the evaporative cooling system was developed for an urban bus, seeking to meet the air renewal required by ANSI/ASHRAE standard 62.1 and to promote the passenger’s thermal comfort as specified by ISO 7730 and ANSI/ASHRAE Standard 55. The thermal comfort provided by the new cooling system was evaluated through the PMV-PPD indexes. A value of 0.35 was obtained for the PMV index and the PPD index obtained a value of 7, indicating that approximately 93% of the passengers will be satisfied regarding their thermal comfort for the established environmental conditions. The evaporative cooling system had a total energy consumption of approximately 0.4 kW, which represents only 5% of the energy that would be consumed by a MVC system. Therefore, the evaporative cooling performance depends on the climatic conditions of the environment, especially humidity. However, when applied in favorable conditions (low humidity), the evaporative cooling system proved to be a viable solution to replace the MVC systems in buses air-conditioning application, where its main advantage is its positive cost-benefit and energy savings.

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