Evaporative cooling of water in a natural draft cooling tower

In this study, effect of desiccant wheel, heat exchanger and cooling coil will be evaluated on decreasing the wet bulb temperature of entering air to cooling tower and decreasing the outlet cold water temperature. For this purpose, change effect of desiccant wheel parameters will be investigated on wet bulb temperature of outlet air from heat exchanger. After that, optimum parameters and minimum wet bulb temperature will be selected. Then, outlet cold water temperature will be achieved for various cooling coil surface temperature with definition of by pass factor and also by using optimum desiccant wheel parameters and entrance air wet bulb temperature to tower related to cooling coil surface temperature. To calculate wet bulb temperature, a mathematical model will be used that shows physical properties of air. After that a nomograph will be used to predict effect of decrease of entrance air wet bulb temperature on reducing the outlet water temperature and it will be done for several cities in Iran. At the end, an equation will be used to calculate required water to air mass flow rate for each outlet cold water temperature. With considering of known circulating water mass flow rate, required air for tower would be calculated and suitable desiccant wheel can be selected.

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“…(8)(9)(10)(11)(12)(13)(14)(15). Outlet T wb from cooling coil for various surface temperatures is shown in Fig.8.…”

Section: Effect Of Cooling Coil Usage On Decreasing the Entrance T Wbmentioning

confidence: 99%

“…The measured data were compared with the predicted results. Fisenko et al [10] developed a mathematical model for predicting the performance of a cooling tower.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Dehumidification Effects on Cooling Capacity of an Evaporative Cooler

Saidi

Aghanajafi²,

Mohammadian

2010

JTST

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“…Searching for the ways to intensify the heat-mass transfer within gas-liquid systems led to the development of fundamentally new apparatuses with vertical grids, drop-film sprinklers, and regular nozzles of increased throughput capacity [2][3][4][5][6]. According to the analysis of the most promising designs of contact devices, developed in recent years, each new design solution gives a slight gain in efficiency.…”

Section: Introductionmentioning

confidence: 99%

Heat-mass transfer efficiency within the cooling towers with jet-film contact devices

2018

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Abstract. Jet-film contact devices with special design elements for intensification of heat-mass transfer processes are proposed. An experimental apparatus has been created in order to study the interaction of water and air flows within these devices. It has been revealed that an increase in the ratio of mass flow rate of liquid and gas phases leads to a decrease in heat efficiency coefficient. Within the area of high values of specific loads, an increase in the local minimum of mass transfer efficiency is observed.

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“…Cooling towers are well known and a lot of studies have been made for increasing their performances. Nevertheless, the disadvantage of this option as a brine cooler is related to the increase in recirculated brine salinity (which means increase in feed salinity) and to the contact of brine with atmospheric air, which generates oxygen (and noncondensable gases) absorption into the recirculated stream, leading, in turn, to the promotion of biological growth in the system, enhancement of corrosion potential of the brine and increase in the non-condensable gases release during the process [6][7][8]. In order to overtake such drawbacks, devices classified as "indirect cooling towers" or "evaporative coolers" can be used.…”

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confidence: 99%

A brine evaporative cooler/concentrator for autonomous thermal desalination units

Cipollina

Micale

Rizzuti

2011

Desalination and Water Treatment

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In recent years growing attention has been paid to the problem of brine disposal due to the raising awareness of significant environmental issues related to the use of desalination processes for fresh water production. This is particularly relevant when desalination units are located in remote sites, characterised by major complexity in the construction and management of intake and outfall structures. In the present work a novel device, named Brine Evaporative Cooler/Concentrator (BECC, patent pending), has been developed for coupling with small-scale thermal desalination plants in order to reduce the problem of brine disposal. Such device fulfils two different functions: i) cooling of the recirculating brine (which is often mixed with cold seawater to feed the unit, acting first as a cooling medium for the condensation of the vapour) and ii) concentration of the brine to de disposed. The BECC device is based on the principle of evaporative cooling, i.e. a primary liquid stream is cooled by means of a secondary liquid stream (by-pass stream), which in turn evaporates in contact with atmospheric air, thus being cooled naturally. The two streams are separated by a heat-conductive surface, through which heat is transferred from the primary stream to the cooling-evaporating by-pass stream. A lab scale BECC pilot unit has been designed, constructed and tested. Geometrical and operating features have been studied in order to allow the operation with concentrated brines, to minimise problems of corrosion, scaling and fouling. The first results have demonstrated the feasibility of the technology and a larger scale prototype unit has been designed for the installation within a 5 m 3 /d Solar Membrane Distillation unit to be constructed in Pantelleria island (Italy).

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Evaporative cooling of water in a natural draft cooling tower

Cited by 93 publications

References 7 publications

Analysis of Dehumidification Effects on Cooling Capacity of an Evaporative Cooler

Analysis of Dehumidification Effects on Cooling Capacity of an Evaporative Cooler

Heat-mass transfer efficiency within the cooling towers with jet-film contact devices

A brine evaporative cooler/concentrator for autonomous thermal desalination units

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