Impact of ambient air temperature and heat load variation on the performance of air-cooled heat exchangers in propane cycles in LNG plants – Analytical approach

Fahmy, M.F.M.; Nabih, H. I.

doi:10.1016/j.enconman.2016.05.013

Cited by 26 publications

(5 citation statements)

References 52 publications

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“…He et al [7] investigated the performance of the NDDCT at different ambient conditions and proposed the wetted-medium pre-cooling technology to cool the air when the ambient air is hot and dry. Fahmy and Nabih [10] investigated the impact of ambient air temperature and the heat load variation on the performance of air-cooled heat exchangers in a LNG plant. Li et al [11,12] tested the performance of a 20-m tall NDDCT under different ambient conditions and then validated with the numerical model.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Gurgenci

Guan

et al. 2018

Applied Thermal Engineering

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Section: Introductionmentioning

confidence: 99%

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Gurgenci

Guan

et al. 2018

Applied Thermal Engineering

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“…The research above studied the design and selection of air coolers. Other scholars studied the environmental effects on air cooler performance, including the impact of ambient air temperature and heat load variation [3], the freezing of air coolers [4], and fouling effects [5].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Cascade Cooling System Based on Lithium Bromide Refrigeration in the Polysilicon Industry

Yang

Wang

2021

Processes

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Cascade cooling systems containing different cooling methods (e.g., air cooling, water cooling, refrigerating) are used to satisfy the cooling process of hot streams with large temperature spans. An effective cooling system can significantly save energy and costs. In a cascade cooling system, the heat load distribution between different cooling methods has great impacts on the capital cost and operation cost of the system, but the relative optimization method is not well established. In this work, a cascade cooling system containing waste heat recovery, air cooling, water cooling, absorption refrigeration, and compression refrigeration is proposed. The objective is to find the optimal heat load distribution between different cooling methods with the minimum total annual cost. Aspen Plus and MATLAB were combined to solve the established mathematical optimization model, and the genetic algorithm (GA) in MATLAB was adopted to solve the model. A case study in a polysilicon enterprise was used to illustrate the feasibility and economy of the cascade cooling system. Compared to the base case, which only includes air cooling, water cooling, and compression refrigeration, the cascade cooling system can reduce the total annual cost by USD 931,025·y−1 and save 7,800,820 kWh of electricity per year. It also can recover 3139 kW of low-grade waste heat, and generate and replace a cooling capacity of 2404 kW.

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“…), installation of draw stack with significant height for increasing the velocity of air propagation. The rate of heat removal by PEHRS, as well as heat removal in dry cooling towers influence the NPP operational performance, it can vary under the effects of different ambient factors, such as ambient air temperature, sun radiation, side wind, rain and snow (Yang et al 2013;Fahmy and Nabih 2016;Li et al 2018). The location of the NPPs plays an important role in the efficiency of the equipment.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer intensification in emergency cooling heat exchanger and dry cooling towers on nuclear power plant using air-water mist flow

Abed¹,

Щеклеин²,

Pakhaluev³

2019

NUCET

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Advanced nuclear power plants are equipped with passive emergency heat removal systems (PEHRS) for removing the decay heat from reactor equipment in accidents accompanied by primary circuit leakage to the final heat absorber (ambient air). Herein, the intensity of heat dissipation to air from the outer surface of the heat exchanger achieved by buoyancy induced natural convection is extremely low, which need to a large heat exchanger surface area, apply different types of heat transfer intensification including (grooves, ribs and extended surfaces, positioning at higher altitudes, etc.). The intensity of heat removal is also strongly dependent on the ambient air temperature (disposable temperature head). Construction of nuclear power plants in countries with high ambient temperatures (Iran, Bangladesh, Egypt, Saudi Arabia, and others) which are characterized by a high level of ambient temperature imposes additional requirements on the increase of the heat exchange surfaces. The experimental investigation results of heat transfer intensification by a low energy ultrasonic which supply a fine liquid droplet (size ~3 µm) in the cooling air are presented in the present paper. In such case, the heat transfer between the surface and cooling flow involves the following three physical effects: convection, conductive heat transfer, and evaporation of water droplets. The last two effects weakly depend on the ambient air temperature and provide an active heat removal in any situation. The investigation was performed using a high-precision calorimeter with a controlled rate of heat supply (between 7800 and 12831 W/m2) imitating heated surface within the range of Reynolds numbers from 2500 to 55000 and liquid (water) flow rates from 23.39 to 111.68 kg·m-2·h-1. The studies demonstrated that the presence of finely dispersed water results in a significant increase in heat transfer compared with the case of using purely air-cooling. With a fixed heat flux, the energy efficiency increases with increasing water concentration, reaching the values over 600 W·m-2·C-1 at 111.68 kg·m-2·h-1, which is 2.8 times higher than for air cooling. With further development of research in order to clarify the optimal areas of intensification, it is possible to use this technology to intensify heat transfer to the air in dry cooling towers of nuclear power plants and thermal power plants used in hot and extreme continental climates.

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Impact of ambient air temperature and heat load variation on the performance of air-cooled heat exchangers in propane cycles in LNG plants – Analytical approach

Cited by 26 publications

References 52 publications

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Optimization of Cascade Cooling System Based on Lithium Bromide Refrigeration in the Polysilicon Industry

Heat transfer intensification in emergency cooling heat exchanger and dry cooling towers on nuclear power plant using air-water mist flow

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