STBE Special Edition Highlights Recent Advances On Heat And Mass Transfer

From eSociety, October 2017

Science and Technology for the Built Environment

ASHRAE members have free online access to Science and Technology for the Built Environment using their existing ASHRAE.org login credentials.

From energy security to reliability, interest in heat transfer equipment is growing, according to Lorenzo Cremaschi, Student Branch Adviser Member ASHRAE. The August edition—a special issue—of Science and Technology for the Built Environment (STBE) included ten articles that focused on recent advances in heat and mass transfer in refrigeration and air-conditioning systems. Cremaschi, an associate editor for STBE, discusses why STBE focused on the topic.

1. Explain the focus of the special edition.

My special edition of Science and Technology for the Built Environment covers selected articles that recently investigated advances in heat and mass transfer processes and advanced heat transfer equipment for air-conditioning and refrigeration systems.

The topics included: boiling, evaporation and condensation of natural refrigerants and of low global warming potential (GWP) refrigerants; refrigerant and nanoparticles and lubricants mixtures; pulsating two-phase flow boiling; modeling, analysis and optimization of novel and compact refrigerant-to-air heat exchangers; and feasibility studies of membrane-based heat exchangers for building air-conditioning applications.

2. Why did you choose this topic?

With the increasing concern about energy efficiency and energy security, there is a growing interest in heat transfer equipment when it operates under field type conditions. Challenges arise from trade-offs between energy efficiency and reliability when new equipment and R&D technologies run under actual field type operating conditions, and the efforts required for the implementation of these new technologies in HVAC&R systems. This special issue of STBE presents articles that covered these aspects.

3. What is the significance of the research?

This special issue covers recent studies on efficient and innovative ways to exchange thermal energy between the air-conditioning and refrigeration equipment and the building environment. Five articles focused on natural- and low-GWP refrigerants and refrigerant and lubricant mixtures boiling, evaporation and condensation processes in the presence of enhanced heat transfer surfaces. One article suggested using nanoparticles directly dispersed in the mixture to augment the heat transfer during refrigerant and lubricant mixture flow boiling. Two articles focused on design, analysis, modeling, and optimization of refrigerant-to-air heat exchangers. Two articles focused on heat and mass transfer processes in membrane heat exchangers and in surfaces with different wettability for frost and defrost control.

4. What lessons, facts, and/or guidance can an engineer working in the field take away from this research?

The selected articles of the STBE Special Issue covered a wide range of topics related to recent advances on heat and mass transfer processes and on heat transfer equipment of air-conditioning and refrigeration systems. A lot of research and development is ongoing in laboratory environments and for prototype systems. Simulation and modeling tools are also being developed and continuously upgraded in order to achieve a level of confidence in the simulation predictions that is comfortable and fits well the actual engineering applications. But there is still a lot more research and work that has to be done. Researchers are addressing how to transfer new technologies for enhanced heat and mass transfer to actual equipment and systems operating in the field. Engineers should follow these developments to see if they are suitable and could possibly be adopted in their application environments.

5. Were there any surprises or unforeseen challenges for you when preparing this issue?

The special issue covered papers that were presented at the 16th International Refrigeration and Air Conditioning Conference held at Purdue University, West Lafayette, Ind., July 11 to 14, 2016. All articles were required to include additional technical content with respect to the conference paper version. Each article presents challenges, issues, and case studies of a particular technology. However, it also addresses some of the concerns and proposes new solutions that could augment energy efficiency in the heat transfer equipment of air-conditioning and refrigeration systems.

While the August edition was a special issue, October is a general issue that includes ceiling radiant panels and passive wall design among other topics.

Table of Contents

Volume 23, Issue 7, October 2017

Editorial

Building energy research and the “duck curve”

General Issue

· Correct design of vertical borehole heat exchanger systems through the improvement of the ASHRAE method

· The effects of mixing air distribution and heat load arrangement on the performance of ceiling radiant panels under cooling mode of operation

· Sensitivity of personalized ventilation air terminal device geometry with regard to a human thermal sensation

· Thermal comfort investigation of an outdoor air-conditioned area in a hot and arid environment

· Experimental determination and computational ﬂuid dynamics predictions of pressure loss in close-coupled elbows (RP-1682)

· A passive wall design to minimize building temperature swings for Algerian Saharan climate

· Updated generalized natural gas reciprocating engine part-load performance curves for cogeneration applications

· Literature review on ﬁeld study of ventilation and indoor air quality performance veriﬁcation in high-performance commercial buildings in North America

· An acoustic performance analysis of AC-motor bathroom ventilation fans for a decade-long period, 2005–2015

· Experimental feasibility study of a new load-based method of testing for light commercial unitary heating, ventilation, and air conditioning (ASHRAE RP-1608)