Anti-freezing water flow rates of various sectors for natural draft dry cooling system under wind conditions. (November 2016)

• Record Type: Journal Article
• Authors: Wang, Weijia; Yang, Lijun; Du, Xiaoze; Yang, Yongping
• Is Part Of: International journal of heat and mass transfer. Volume 102(2016:Nov.)
• Page Start: 186
• Page End: 200
• Publication Date: 2016-11
• Subjects: Natural draft dry cooling system -- Air-cooled heat exchanger -- Anti-freezing -- Water flow rate -- Residual anti-freezing coefficient -- Thermo-flow performances; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2016.06.031
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Anti-freezing water flow rate of air-cooled heat exchanger is investigated. Heat exchanger model is applied based on the heat load balance between water and air. Residual anti-freezing coefficient is introduced to describe the affluent capacities. Anti-freezing water flow rate of the frontal sector is higher than other sectors. Middle and middle-rear sectors have small anti-freezing water flow rates. Abstract: Freezing risk of air-cooled heat exchangers for natural draft dry cooling system is a key concern in power plants during cold days, so it is beneficial to the safe and economic operation of natural draft dry cooling system to propose the anti-freezing measures at various ambient conditions. As a main issue, the anti-freezing water flow rate of air-cooled heat exchanger is investigated by using the macro heat exchanger model based on the heat load balance between the circulating water and ambient air. The detailed thermo-flow characteristics of the cooling deltas and the anti-freezing water flow rate for each sector at various wind speeds are obtained with reference to the water freezing temperature, and the residual anti-freezing coefficient is introduced to describe the affluent anti-freezing capacities of each sector and cooling delta at the anti-freezing water flow rate. The results show that the anti-freezing water flow rate is highest and the residual anti-freezing coefficient is lowest for the frontal sector compared with those for other sectors. For the middle and middle-rear sectors, even with small anti-freezing water flow rates, the residual anti-freezing coefficients can be high because of the reduced heat rejection to the deteriorated air flows.