To make carbon dioxide (CO2) heat exchangers in refrigeration systems more efficient and
compact, passive methods for heat transfer enhancement produced by tubes in various …

Parabolic trough collectors are the most mature technology for utilizing the solar energy in
high temperature applications. The objective of this study is the thermal efficiency …

Generally, there are two main methods to increase the thermal performance of the heat
exchanger, which include active and passive methods. Passive mode, unlike active mode …

Most important challenge in evacuated tube solar collector is lower performance in off-pick
hours of sunlight which leads to utilizing thermal energy storage. In present study, thermal …

In this study, the use of internal fins in parabolic trough collectors operating with gas working
fluids is examined. Air, helium and carbon dioxide are the investigated working fluids, while …

The hydrothermal behavior in a helical double-tube heat exchanger is numerically
estimated. A new type of swirl generator with two sections, including; outer curved blades …

In the present work, a parabolic trough solar (PTC) collector with inner helical axial fins as
swirl generator or turbulator is considered and analyzed numerically. The three-dimensional …

In this paper, for improvement of the performance of shell and tube heat exchanger, the
effect of adding circular grooves on the shell of heat exchanger is considered numerically …

In this numerical investigation, the flow behavior, pressure drop, and heat transfer
enhancement for the fluid in a corrugated pipe with varying geometrical configurations …

In this study, the use of corrugated surfaces as one of the passive heat transfer improvement
methods on straight tubes is numerically investigated related to the determination of Nusselt …