scholarly journals Effects of pressure loss coefficients of heat exchanger on thermal performance of the dry cooling tower

2017 ◽  
Vol 136 ◽  
pp. 169-175
Author(s):  
Huan Ma ◽  
Fengqi Si ◽  
Xuebo Li ◽  
Junshan Wang
Author(s):  
A. Montakhab

Because of its relatively high coolant temperature, the closed cycle gas turbine HTGR is well adapted to dry cooling and its waste heat can be rejected with relatively low cost. The preliminary design of natural-draft dry cooling towers for a 1200 MW(e) GT-HTGR is presented. The effects of air approach velocity, capacity rates of air and water mediums, and number of heat exchanger cross flow passes on salient tower and heat exchanger dimensions are studied. Optimum tower designs are achieved with three cross flow passes for the heat exchanger, resulting in a simultaneous minimization of tower height, heat exchanger surface area and circulating water pumping power. Four alternative tower designs are considered and their relative merits are compared. It is concluded that the 1200 MW(e) plant can be cooled by a single tower design which is well within the present state of the natural-draft dry cooling tower technology. In comparison, the fossil-fired or HTGR steam plants of the same output is shown to need three such towers.


1981 ◽  
Vol 103 (4) ◽  
pp. 715-719 ◽  
Author(s):  
J. A. Valenzuela ◽  
L. R. Glicksman

A novel design of a rotary heat exchanger to be used as a dry cooling tower is described. The heat exchanger consists of a matrix of thin steel disks which rotate between a hot water bath and a forced draft air stream. On top of the water floats a 2 cm thick layer of oil which coats the rotating disks and thus eliminates evaporation. An analytical model of the heat exchanger was developed and validated with experimental measurements taken on a 1.5 m dia test section. The model was then used to determine the net effect of the oil on the heat transfer performance. Although the oil film that coats the disks presents an additional resistance to the transfer of heat, it also contributes to the heat capacity of the disks. It was found that the reduction in the overall heat transfer rate due to the presence of the oil is small, of the order of 5 to 10 percent.


Author(s):  
Masoud Darbandi ◽  
Ali Behrouzifar ◽  
Ahmad Mirhashemi ◽  
Hossein Salemkar ◽  
Gerry E. Schneider

Thermal powerplants report a reduction in their dry cooling tower performances due to surrounding wind drafts. Therefore, it is very important to consider the influence of wind velocity in cooling tower design; especially in geographical points with high wind conditions. In this regard, we use the computational fluid dynamics (CFD) tool and simulate a dry cooling tower in different wind velocities of 0, 5 and 10 m/s. To extend our calculations; we also consider the temperature variation of circulating water through the tower heat exchanger or deltas one-by-one. We show that some heat exchangers around the tower cannot reduce the circulating water temperature sufficiently. This causes an increase in the mean temperature of those heat exchangers. The worst performances can be attributed to heat exchanger located on side wind places. We will discuss the detail performance of each delta and their assembly in draft wind conditions. This study suggests some effective ways to overcome thermal-performance of cooling tower in wind conditions.


1980 ◽  
Vol 102 (4) ◽  
pp. 807-812 ◽  
Author(s):  
Ali Montakhab

An analysis of heat exchanger surface geometries for the purpose of reducing dry cooling tower cost is presented. Two sets of results are derived. The first set can be used to evaluate heat transfer surface geometries in an attempt to select those most suitable for dry cooling tower applications. The second set of results can be used to direct research and development efforts toward developing better geometries for dry cooling tower applications. The first set of results is general and is applicable to all heat exchanger surface geometries. The second set is valid only for helical round or continuous fins having smooth, serrated, or cut fins and for staggered and in-line tube arrangements. The methods developed in this paper are not restricted to dry cooling towers per se, but are valid for other applications of fin tube heat exchangers as well.


2021 ◽  
Vol 188 ◽  
pp. 116628 ◽  
Author(s):  
Yuchen Dai ◽  
Yuanshen Lu ◽  
Alexander Y. Klimenko ◽  
Ying Wang ◽  
Kamel Hooman

Author(s):  
Shuo Li ◽  
M. R. Flynn

AbstractVisible plumes above wet cooling towers are of great concern due to the associated aesthetic and environmental impacts. The parallel path wet/dry cooling tower is one of the most commonly used approaches for plume abatement, however, the associated capital cost is usually high due to the addition of the dry coils. Recently, passive technologies, which make use of free solar energy or the latent heat of the hot, moist air rising through the cooling tower fill, have been proposed to minimize or abate the visible plume and/or conserve water. In this review, we contrast established versus novel technologies and give a perspective on the relative merits and demerits of each. Of course, no assessment of the severity of a visible plume can be made without first understanding its atmospheric trajectory. To this end, numerous attempts, being either theoretical or numerical or experimental, have been proposed to predict plume behavior in atmospheres that are either uniform versus density-stratified or still versus windy (whether highly-turbulent or not). Problems of particular interests are plume rise/deflection, condensation and drift deposition, the latter consideration being a concern of public health due to the possible transport and spread of Legionella bacteria.


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