This paper presents a mixed-integer nonlinear programming (MINLP) model for the optimal design of mechanical counter-flow cooling towers, subjected to standard design constraints. The objective function consists of the minimization of the total annual cost, which includes the capital cost of the cooling tower (that depends on the filling material and the air flowrate) and the operating cost (th...

OBJECTIVES To determine the presence of legionellae and species composition of the genus Legionella in Sri Lankan hotel cooling towers, and to determine the previous exposure of hotel workers to Legionella pneumophila. DESIGN Collection of water samples from 16 cooling towers of air conditioning plants from 7 representative hotels, and blood samples from hotel workers. SETTING Department of...

Years of service in industrial plant operating environments can cause varying types and degrees concrete deterioration on reinforced hyperbolic shell natural draft cooling towers. Exposure to water potentially result material erosion corrosion embedded reinforcing steel associated delamination spalling over time. Such affect the integrity structure degree that repair programs are required relia...

CONTEXT The incidence of legionellosis has sharply increased in the United States as a result of contaminated water systems. Jurisdictions across the country are considering whether to develop and implement regulations to protect individuals against Legionnaires' disease with its associated high morbidity and mortality. OBJECTIVE This article sheds light on the implementation and effectivenes...

Re-circulating cooling water systems are generally used to remove waste heat from hot process streams in conditions above the ambient temperature in many types of industries such as chemical and petrochemical, electric power generating stations, refrigeration and air conditioning plants, pulp and paper mills, and steel mills. Typical re-circulating cooling water systems are constituted by a mec...

Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances...

mydia sequanensis, a new intracellular Chlamydiales isolated from Seine river water using amoebal co-culture.lence of different Chlamydia-like organisms in an asymptomatic population. Clin Microbiol Infect. In press 2008. To the Editor: The importance of nontuberculous mycobacteria (NTM) in various clinical situations recently has increased. Members of the My-cobacterium avium complex (MAC) cau...

This paper presents a universal engineering model, which can be used to formulate both counterflow and crossflow cooling towers. By using fundamental laws of mass and energy balance, the effectiveness of heat exchange is approximated by a second order polynomial equation. Gauss-Newton and Levenberg-Marquardt methods are then used to determine the coefficients from manufactures data. Compared wi...