scholarly journals Heat and mass transfer performance and exergy performance evaluation of seawater cooling tower considering different inlet parameters

2021 ◽  
pp. 312-312
Author(s):  
Yang Yu ◽  
Xiaoni Qi ◽  
Xiaochen Hou ◽  
Xiaohang Qu ◽  
Qianjian Guo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Thermal Efficiency ◽  
Cooling Tower ◽  
Exergy Efficiency ◽  
Optimum Operating ◽  
Transfer Performance ◽  
Cooling Towers ◽  
Air Speed ◽  
Exergy Performance

Cooling towers are important components within recirculating cooling water systems. Due to a shortage of freshwater resources, seawater cooling towers are widely used both in manufacturing and everyday life. This paper researches the mechanical draft counterflow wet seawater cooling tower (MDCWSCT), and establishes and verifies a detailed thermal performance calculation model. Referring to the second law of thermodynamics, the heat and mass transfer performance and exergy performance of the seawater cooling tower were studied. The effects of salinity, inlet air speed, and air wet-bulb temperature on the cooling efficiency, thermal efficiency, and exergy efficiency were analyzed. The results show that compared to the air wet-bulb temperature, changes in air speed have more influence on cooling and thermal efficiency under the study conditions. Moreover, the air wet-bulb temperature is the significant parameter affecting exergy efficiency. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.40-8.25 %, 1.06-3.09 %, and 2.47-7.73 % lower than that of freshwater, respectively, within an air speed of 3.1-3.6 m/s. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.28-8.47 %, 1.03-3.37 %, and 2.44-7.99 % lower than that of freshwater, respectively, within an air wet-bulb temperature of 25-27 ?. Through the exergy analysis of the seawater cooling tower, it is obvious that the heat and mass transfer performance and exergy performance can be improved by selecting the optimum operating conditions and appropriate packing specifications.

Experimental Study of Hydraulic and Heat and Mass Transfer Parameters of Inclined-corrugated Contact Elements of Cooling Tower Sprinkler

2020 ◽  
Vol 24 (1) ◽  
pp. 4-8 ◽  
Author(s):  
A.V. Dmitriev ◽  
I.N. Madyshev ◽  
O.S. Dmitrieva
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Heat And Mass Transfer ◽  
Hydraulic Resistance ◽  
Thermal Efficiency ◽  
Cooling Tower ◽  
Air Velocity ◽  
Contact Devices ◽  
Cooling Technology ◽  
Transfer Parameters

The scheme of cooling tower operation with non-contact evaporative cooling technology is presented. A new design of the cooling tower sprinkler unit consisting of inclined-corrugated contact devices has been developed. The structure contains a system of pipes through which the flow of water moves without contacting the air. Studies have been carried out to determine the hydraulic resistance of inclined-corrugated contact elements with changes in air velocity and irrigation density. Thermal efficiency in a cooling tower with inclined-corrugated contact elements can reach 33 %.

scholarly journals Energy efficiency indicators of cooling towers

2018 ◽  
Vol 11 (3) ◽  
pp. 217-221
Author(s):  
E. A. Lapteva ◽  
A. G. Laptev ◽  
M. L. Farakhov
Keyword(s):  
Mass Transfer ◽  
Energy Efficiency ◽  
Transfer Coefficient ◽  
Thermal Efficiency ◽  
Cooling Tower ◽  
Polymer Materials ◽  
Cooling Towers ◽  
Efficiency Criterion ◽  
Industrial Enterprises ◽  
Film Type

For selecting optimal regimes and design characteristics, an energy efficiency criterion of a mass transfer apparatus is considered, and on its basis, some particular cases of energy efficiency criteria for cooling towers, including the cases with a structured counter-current film-type packing, are obtained. The criteria include heat transfer efficiency in the gas and liquid phases, as well as kinetic characteristics of the process of cooling the water in blocks of film-type packings. Expressions are given for determination of thermal efficiencies in the gas (air) and liquid (water) phases of the cooling tower. Three notations for the energy efficiency criterion of cooling towers are obtained. In the first notation, the efficiency criterion is written down using the thermal efficiency of cooling the water; in the second notation, it is written down using the thermal efficiency of heating the air; in the third notation, it is written down via the transfer coefficient (mass transfer) and mean driving force in the form of an enthalpy difference. A notation of writing down the energy efficiency criterion for a film-type packing in the cooling tower with a volumetric mass transfer coefficient is presented. Irrigator blocks filled with structured film-type contact devices of various designs having an irrigation density of 12 m3/m2h and an air speed of 1.5 m/s are considered. Results of calculations of five types of structured packings are presented: tubular packing made of polyethylene net; metal packings VACU-PAK, PIRAPAK G, “Inzhekhim” IRG and segmentary-structured packing “Inzhekhim”. Values are obtained of the criterion of energy efficiency of these packings for cooling the water as well as the required height of irrigator blocks for a given temperature regime and hydraulic load. Values of the power expended for supplying the air to the irrigator blocks are determined and a histogram is plotted. It is concluded that modern domestic and foreign metal packings have high thermal and hydraulic efficiency and are recommended for use in mini-cooling towers (except for tubular packings made of polyethylene net). For reducing the cost of irrigator blocks, these can be made of polymer materials. Then such blocks of irrigators are recommended for creating a contact between the phases in large-scale cooling towers, which will significantly improve the efficiency of cooling the water at thermal power plants and industrial enterprises.

Review of Technology Used to Improve Heat and Mass Transfer Characteristics of Adsorption Refrigeration System

2016 ◽  
Vol 24 (02) ◽  
pp. 1630003 ◽  
Author(s):  
Anirban Sur ◽  
Randip K. Das
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Waste Heat ◽  
Transfer Characteristic ◽  
Low Grade ◽  
Transfer Performance ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
System A ◽  
Absorption Refrigeration System

Researchers proved that, heat powered adsorption refrigeration technology is very effective methods for reutilization of low-grade thermal energy such as industrial waste heat, solar energy, and exhaust gases from engines. But to make it commercially competitive with the well-known vapor compression and absorption refrigeration system, the processes require high rates of heat and mass transfer characteristic between adsorbate and adsorbent as well as externally supplied heat exchanging fluid. This paper reviews various techniques that have been developed and applied to enhance the heat transfer and mass transfer in adsorber beds, and also discuss their effects of the performance on adsorption system. A comprehensive literature review has been conducted and it was concluded that this technology, although attractive, has limitations regarding its heat and mass transfer performance that seem difficult to overcome. Therefore, more researches are required to improve heat and mass transfer performance and sustainability of basic adsorption cycles.

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