David Burton, Director, Research & Technology Center
Here’s a brief update on recent activities at our Research & Technology Center (RTC).
Air-cooled Unit (ACU)
HTRI’s newest experimental unit is an air-cooled heat exchanger, capable of operating in multiple configurations.
The ACU consists of two cells, each with an axial fan five feet in diameter, with hot water supplied from the Liquid-Liquid Heat Exchanger Unit (LLHE). The ACU is custom designed to operate in forced-draft or induced-draft configurations, as well as in natural draft with the optional chimneys. Manual louvers control airflow, and variable frequency drives regulate fan speeds.
Airside temperature, pressure, and flow measurements are taken above and below the tube bundle. Rather than using a fixed array of instruments, the ACU is fitted with a motorized transport system that traverses the unit, enabling collection of more data points with fewer instruments.
Initial research with the ACU focuses on forced-draft vs. natural draft correlations at low Reynolds numbers, a specific concern of HTRI members using Xace. We began collecting data with the ACU in January 2018. Early results indicate that we are able to achieve accurate heat balances with our instruments and data acquisition system.
For more details, read an earlier article about the ACU: New air-cooled heat exchanger expands RTC capabilities (October 2017).
HTRI has completed multiyear testing on plate-and-shell and welded plate heat exchangers, incorporating newer plate designs that can improve heat transfer and pressure drop. Results from single-phase liquid testing on the Liquid-Liquid Heat Exchanger Unit (LLHE) and from two-phase testing on the Prototype Test Unit (PTU) will help us improve predictions for exchangers with these designs. The results of this research are documented in reports PHE-15-TR, PHE-16-TR and PHE-17-TR plus two additional reports currently under review.
In addition to focusing on these research areas, HTRI is actively working on several proprietary contracts using other RTC test units. We are also continuing studies of crude oil fouling, vacuum condensation, and vertical thermosiphon reboilers. Our test results benefit members through our research reports, software products, and contract services.