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Humidity Utopia w/ Nikki & Bryan

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This podcast episode is Nikki Krueger (Santa Fe Dehumidifiers) and Bryan’s 2023 HVACR Training Symposium session about how we can optimize dehumidification and efficiency to create an HVAC design and humidity utopia.

While we attempt to achieve comfort and high indoor air quality in humid climates, we may find challenges integrating these with the HVAC system and getting customers to understand the need for proper dehumidification. Older homes that are built “leaky” allow for uncontrolled infiltration and exfiltration, but newer constructions are a lot tighter and rely on mechanical ventilation to control where the outdoor air comes from and make sure it is properly filtered and distributed.

We deal with both sensible and latent BTUs in a home, and we can’t treat them as though they’re all equal. Many high-efficiency systems have high sensible heat ratios (SHRs) and are designed to remove sensible BTUs very efficiently, but they’re not adequate at removing latent BTUs. Ideally, we would rely on an A/C system or heat pump to dehumidify the air in cooling mode before adding a dehumidifier. However, some of the systems that are best equipped to handle high latent loads will be less efficient.

If you wish to install supplemental humidification, the ideal design will have a dedicated return and tie into the main HVAC supply duct.

Nikki and Bryan also discuss:

Willis Carrier’s real invention
Strategies for reducing conductive, convective, and radiant gains
Understanding relative humidity and dew point
Design loads
Electrification and energy efficiency incentives
Adiabatic heating and cooling
Single-stage vs. multi-stage equipment
Dehumidification for ductless mini-splits
Supplemental dehumidifier designs

Learn more about Santa Fe Dehumidifiers at https://www.santa-fe-products.com/.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://www.hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Topics Covered

What a glycol secondary loop system is, and how it differs from direct expansion
Why retrofits are happening: refrigerant charge reduction, safety, EPA regulation, and zero-emissions goals
Efficiency penalties at small scale, and why efficiency isn’t the driver
How glycol behaves in the coil: no latent exchange, a temperature gradient, and frost patterns
Reliability trade-offs: simple case controls versus centralized, mission-critical valves
Staging a retrofit so the store stays open, including pre-piping, pre-testing, and pipe cleaning
Brazing versus soft solder, and whether nitrogen flow matters with glycol
Skid components: heat exchanger, VFD pumps, air separator, feeder tank, expansion tank, strainers, and suction guide
Controller inputs, EEV drivers, and emergency mobile chiller connections
Balance valves (automatic versus manual) and defrost methods, including off-time and electric
Fluid distribution: pitching pipe for air and drainage, plus vents and drains
Propylene versus ethylene glycol, the 35% mix, freeze point, and why more glycol hurts heat transfer
CO2 as a secondary fluid for low-temperature applications
Commissioning steps: electrical checks, pressure testing, filling, purging, and testing valve operation
Proving performance: flow, glycol concentration, temperature, and superheat on the rack side
Troubleshooting air in the system and pressure changes as glycol chills
Store humidity, dew point targets, and case performance
Heat reclaim using glycol loops
Tools: PT ports, manometers, female-to-female hoses, refractometer, and transfer pumps
Service tips: distilled water, matching glycol brands, and glycol safety