Compact Feedwater Heaters

Abstract

With few exceptions, heat exchangers found in existing power plants are conventional shell-and-tube heat exchangers. Compact heat exchanger technologies can offer several advantages over conventional designs, including reduced weight, cost and space. When components occupy less space, reactor buildings can be smaller, resulting in further cost savings. This paper summarizes the results of a sizing and costing study for a condensate heater using conventional shell-and-tube, plate-and-shell and minichannel heat exchanger technologies. A parametric analysis was conducted using a range of principal dimensions and Nusselt-type heat transfer correlations to decide the heat transfer length or number of plates/tubes and reasonable constraints were placed on internal flow velocities and pressure drops. Net Present Costs were estimated using the weight of steel required for the design, assuming manufacturing costs scale with weight. It was found that compact technologies can reduce the weight of the required heat exchanger by a factor of 3, reduce the cost by a factor of 2.4, and reduce the space occupied by a factor of 8. With deployment to remote locations and a higher premium placed on floor space, it is postulated that small reactors serve to benefit most from compact heat exchanger technologies.