Ertan Buyruk

Exergoeconomic analysis of condenser type heat exchangers

In this study, an exergoeconomic analysis of condenser type parallel flow heat exchangers is presented. Exergy losses of the heat exchanger and investment and operation expenses related to this are determined with functions of steam mass flow rate and water exit temperature at constant values of thermal power of the heat exchanger at 75240 W, cold water mass flow rate and temperature. The inlet temperature of water is 18 °C and exit temperatures of water are varied from 25 °C to 36 °C. The values of temperature and pressure of saturated steam in the condenser are given to be Tcon=47 ° C and Pcon=10.53 kPa. Constant environment conditions are assumed. Annual operation hour and unit price of electrical energy are taken into account for determination of the annual operation expenses. Investment expenses are obtained according to the variation of heat capacity rate and logarithmic mean temperature difference and also heat exchanger dimension determined for each situation. The present analysis is hoped to be useful in determining the effective parameters for the most appropriate exergy losses together with operating conditions and in finding the optimum working points for the condenser type heat exchangers.

Experimental Studies on Influence of Process Variables to the Exergy Losses at the Double Tube Heat Exchanger

Heat Exchangers are widely used at different applications related with heat science and techniques. Today at the investigation of heat exchanger projection, First Low of Thermodynamics is not anymore sufficient. The reason of this more effective use of heating sources and systems, not the quantity of energy but quality of energy must be taken into consideration. Energy transformation in the heat exchangers, in the scope of Second Law of Thermodynamics can be listed in two groups depending on chosen variables for analysis. These are a) entropy based work b) exergy based work. In this study, it is aimed to analysed theoretically and investigate experimentally effect of inlet and outlet temperatures of temperatures differences and flow directions for same path parallel flow and counter path parallel flow by using double tube heat exchanger. According to the obtained results, it is aimed to detennine necessary information for projection and to bring down to the most economical value of the heat exchanger cost and of energy consumption.

Enhancement of Heat Transfer for Plate Fin Heat Exchangers Considering the Effects of Fin Arrangements

ABSTRACT In the present study, the potential of rectangular fins with different fin types of inner zigzag-flat-outer zigzag (B-type) and outer zigzag-flat-outer zigzag (C-type) and with different fin angles of 30° and 90° for 2 mm fin height and 10 mm offset from the horizontal direction for heat transfer enhancement with the use of a conjugated heat transfer approach and for pressure drop in a plate fin heat exchanger is numerically evaluated. The rectangular fins are located on a flat plate channel (A-type). The numerical computations are performed by solving a steady, three-dimensional Navier–Stokes equation and an energy equation by using FLUENT software program. Air is taken as working fluid. The study is carried out at Reynolds number of 400 and inlet temperatures, velocities of cold and hot air are fixed as 300 K, 600 K and 1.338 m.s−1, 0.69 m.s−1, respectively. This study presents new fin geometries which have not been researched in the literature for plate fin heat exchangers. The results show that while the heat transfer is increased by about 10% at the exit of a channel with the fin type of C, it is increased up to 8% for the fin angle of 90° when compared to a channel with A-type under the counter flow. The heat transfer enhancements for different values of Reynolds number and for varying fin heights, fin intervals and also temperature distributions of fluids are investigated for parallel and counter flow.