EP224 Beyond Vapor Compression: Smarter DOAS with Liquid Desiccants with Phil Farese (June 2025)

In this in-depth episode of Building HVAC Science, hosts Bill Spohn and Eric Kaiser sit down with Phil Farese, CEO of Mojave HVAC, to explore the cutting edge of desiccant dehumidification technology. Phil, whose career began in physics at Cornell and research at Princeton before moving into consulting at McKinsey and leadership roles at NREL, Enphase, and now Mojave, brings a rare mix of scientific rigor and market savvy to the HVAC space.

 

The conversation traces the evolution of liquid desiccant systems and Mojave's unique approach that combines vapor compression and liquid desiccant in a single DOAS (Dedicated Outdoor Air System) unit. The result? Enhanced dehumidification, reduced energy use, and precision control of sensible and latent loads—at market-competitive prices. Phil outlines how Mojave's patented media bed and regeneration systems avoid many of the pitfalls that plagued earlier desiccant systems, while also maintaining ease of installation, low maintenance, and strong reliability.

 

Listeners also hear about Mojave's service philosophy, tech training programs, and broad rep network, plus a discussion of ideal use cases, efficiency standards like ISMRE (Integrated Seasonal Moisture Removal Efficiency), and how the system outperforms traditional DOAS units. Whether you're an engineer, contractor, or building owner looking to optimize HVAC performance while cutting energy bills, this episode delivers clear, science-backed insight into where dehumidification is headed.

 

Quotes from the episode:

"We're not undoing cooling with reheat—we're using that energy to do something useful: regenerate the desiccant."

 

"Liquid desiccants are like the honey of HVAC—safe, natural, and surprisingly powerful."

 

"It looks like an air conditioner. That's what contractors tell us—and that's the point."

 

 

Phil's LinkedIn: https://www.linkedin.com/in/philip-farese-49a81b1/

 

Mojave Energy Systems: https://mojavehvac.com/

 

Tony Mormino, our friend at HVAC-TV did a recent interview with Mojave: https://creators.spotify.com/pod/show/hvac-tv/episodes/Liquid-Desiccant-Dehumidification-Explained-e33elio/a-abvfahu

 

Eutectic system defined: https://en.wikipedia.org/wiki/Eutectic_system

 

AHRI Standard 920,Performance Rating of Direct Expansion-dedicated Outdoor Air System Units: 

https://www.ahrinet.org/search-standards/ahri-920-i-p-and-921-si-performance-rating-direct-expansion-dedicated-outdoor-air-system-units

 

Papers and reports by Phil:
Tool to Prioritize Energy Efficiency Investments (NREL 2012): 

https://docs.nrel.gov/docs/fy12osti/54799.pdf

 

How to build a low-energy future (2012): https://www.nature.com/articles/488275a

ASHRAE paper on Liquid Desiccants:

https://mojavehvac.com/wp-content/uploads/2025/02/Liquid-Desiccant-Field-Campaign-Final-2.pdf

 

McKinsey paper:Unlocking Energy Efficiency in the US Economy (2009): 

https://www.mckinsey.com/~/media/mckinsey/dotcom/client_service/Sustainability/PDFs/US_energy_efficiency_full_report.pdf

 

 

This episode was recorded in June 2025.