Selective Membrane Dehumidification for Buildings HVAC
We develop thermodynamic models, as well as system-level prototypes, for systems which rely on vapor-selective membranes to separate water vapor out from air flows. These membrane-driven separations can provide substantial energy savings by (1) mitigating the need for over-cooling and reheating of air in buildings and (2) by largely avoiding, or at least minimizing, the energy penalty associated with condensation of water vapor. The technology also provides independent control of temperature and humidity in buildings which can provide even more energy savings over conventional refrigeration technologies. This class of technologies is still very young, and thus we are at the fore front of research and development for this technology.
Current Projects (as of 8/3/2026): Currently, we are developing thermodynamic models for closed-cycle membrane dehumidification systems as well as conducting a holistic analysis on water vapor compression technologies. At this point, the membrane are quite advanced, but designing effective water vapor compression technologies remains a significant challenge in this field that has limited commercial adoption.
Figure 1. (Left) Schematic representation of the dual-module humidity pump (DMHP), which is one of the most efficient proposed selective membrane dehumidification systems in the literature. We provided a first-ever experimental demonstration of the technology in 2024 and are continuing development. (Right) Dehumidification (latent) coefficient of performance (COP) as a function of membrane selectivity, providing guidance as to the selectivity required to provide competitive dehumidification efficiency.
Vapor Selective Membrane Fabrication and Characterization
In order to support our analysis of novel, membrane-based air conditioning systems, membranes must be made in lab, as they are not commercially available. Our efforts in this field have focused on the application of high-performance polymer coatings onto new support substrates. Furthermore, of notable interest was our analysis of the temperature dependence of many polymeric vapor separation membranes, adding to the benefits of non-isothermal vacuum membrane dehumidification
Current Projects (updated 8/3/2026): We are extending our work on Pebax-based membranes and also working with scientists at Kraton in Houston, TX on new membrane materials. We are also collaborating with Prof. Manish Kumar on the development and implementation of carbon molecular seive membranes for dehumidification applications as well as atmospheric water generation systems (funded by the UT Energy Institute. Lastly, we are evaluating the efficacy and accuracy of different water vapor permeance characterization procedures and developing guidance on best-practices for characterizing materials with exceptionally high water vapor permeance.
Figure 2. Scanning electron microscopy (SEM) image of the side-view of a Pebax and Graphene Oxide coated onto a PVDF substrate, clearly showing the different between the dense coating layer and the porous PVDF support structure.
Atmospheric Water Harvesting (AWH)
As water scarcity grows, we will need to rely on a range of different technologies for producing drinking water. Atmospheric water harvesting has the advantage of providing a de-centralized source of clean water. Our research in this area focuses on the thermodynamic system design and modeling/simulation of various technologies including, water vapor selective membrane separations, metal organic framework (MOF) sorbent systems, and dew systems. Additionally, we have developed a theoretical “least work” framework to provide the first robust comparison method across different technology categories. We are employing super computing resources to calculate global spatial-temporal trends in AWH energy requirements.
Current Projects (updated 8/4/2026): We are collaborating with H2O Now on lab and field testing of DC-powered, refrigeration-based atmospheric water harvesting systems for agricultural applications. Additionally, we have a project funded through the Energy Institute at the University of Texas, in collaboration with Professor Manish Kumar, on developing carbon molecular seive (CMS) membranes and systems for atmospheric water capture to reduce water stress in Texas. We are working on demonstrating small-scale emergency AWH prototype systems designed and developed in our lab. Lastly, we have students working on evaluating the potential for air conditioner condensate recovery as a means of AWH as by product of cooling our buildings.
Figure 3. Global geospatially-resolved thermodynamic minimum energy requirement to harvest water vapor from the atmosphere. This is the theoretical limit for energy consumption against which any AWH technology should be compared against to quantify second-law thermodynamic efficiency.
Prototype Development
Across all of our research areas, we generally invent new systems and equipment. Thus, our experimental efforts are rarely limited to observation based research and the observational research we do conduct usually relies on custom in-house facilities. Generally, we aim to build working prototypes of the novel systems we invent or build custom test facilities to evaluate materials and components that cannot be easily evaluated in commercial test equipment. While this is not necesarily an "area" of our research, novel system prototype development is important aspect of most of our projects.
Current Projects (updated 8/4/2026): We currently developing experimental test facilities to demonstrate the long-term degradation of selective membrane performance under realistic operating conditions. We are also rennovating a walk-in environmental chamber to provide temperature and humidity control. Finally, we are building a prototype of a novel, small-scale emergency atmospheric water harvesting device.
Figure 4. Sample of experimental prototypes developed by our group including an experimental prototype of the dual-module humidity pump (left), a small-scale humidity management test facility for electronics moisture control (top right), a membrane module with integrated cooling tubes in the dehumidification air channel (bottom center), and a test facility for a heat pump wood dryer (bottom right).