In this study, the air-side pressure drop and heat transfer performance of plate-fin and microchannel coils were tested under clean and fouled conditions. The heat exchangers were tested with two different types of dust, ASHRAE Standard Dust and Arizona Road Test Dust. The ASHRAE dust was found to have a very significant impact on the pressure drop of the microchannel heat exchanger, increasing...

Equations developed for packed columns may be used to predict the overall heat transfer coefficient and friction loss in massecuite reheaters. The results seem to indicate that exchangers with the tubes staggered give higher heat transfer rates than those with the tubes in line.

An experimental database is compiled in order to fingerprint the scales formed over the hot surfaces of heat exchangers, in cooling water systems or other systems with similar chemistry. To collect these data, a dynamic simulating pilot plant was designed with considerable application flexibility among which simultaneous flow of water with different velocity and heat fluxes to three simulat...

Heat exchangers are of key importance in overall performance and commercialization of thermoacoustic devices. The main goal in designing efficient thermoacoustic heat exchangers (TAHXs) is the achievement of the required heat transfer rate in conjunction with low acoustic energy dissipation. A numerical investigation is performed to examine the effects of geometry on both the viscous and therma...

This paper describes a simplified system model for rapidly evaluating disturbance propagation through a heat exchanger network. The model depicts cause-effect relationships between a set of stream output variables (target temperature fluctuations) and a set of input variables (disturbances of source temperatures and heat capacity flowrates). The model, which consists of a set of linear equation...

Simple-to-fabricate woven mesh structures, consisting of bonded laminates of two-dimensional plain-weave conductive screens, or three-dimensional orthogonal weaves are described. Geometric equations show that these porous matrices can be fabricated to have a wide range of porosity and a highly anisotropic thermal conductivity vector. A mathematical model of the thermal performance of such a mes...

The paper attempts to show that using the robust model-based predictive control (RMPC) strategy for control of thermal processes can lead to energy savings in comparison with classical control approaches. RMPC is applied for control of a tubular heat exchanger that is used for pre-heating petroleum by hot water. The heat exchanger is a nonlinear system with time delay and uncertainty. The contr...

The analytical solutions for the temperature variation of two streams in parallel flow, counter flow and cross-flow heat exchangers and related entropy generation due to heat exchange between the streams are presented. The analysis of limiting cases for the relative entropy generation is performed, and corresponding analytical expressions are given. The obtained results may be included in a mor...

1 his paper provides a U-J;P,G work for selecting heat exchangers materials especially those used in nuclear power plants. Typical examples of materials selection for heat exchanger tubing of nuclear power plants and condensers are presented. The paper brings out also, the importance of continued intensive R & D in materials in order to enhance the reliability and reduce cost by improving upon ...