HVAC-unit humidity control
Temperature and humidity control, such as modulating hot-gas reheat and return-air bypass, is available on AAON packaged rooftop, split, and self-contained systems. Modulating hot-gas reheat uses a reheat coil downstream of the evaporator coil. During the dehumidification mode of operation, free condenser heat is used to reheat dehumidified air, which has been cooled to dew point by the evaporator to maximize dehumidification. Return-air bypass uses a modulating damper, which bypasses return air around the evaporator coil. Free return air then is used to reheat dehumidified air.
EcoDry industrial dehumidifiers feature BrySmart microprocessor-based control technology to optimize system performance. BrySmart uses dynamic control of dehumidifier operating parameters to improve part-load energy efficiency. Only the amount of energy needed in the drying process at any particular time is used, reducing energy usage and operating costs. The controls can be retrofitted to existing installations.
Dedicated outdoor-air systems
TotalAire dedicated outdoor-air systems (DOAS) have several new options, including an enthalpy wheel with a return-air bypass damper as well as additional carbon-dioxide (CO2) monitoring. Combining all three options increases energy efficiency, enhances nighttime setback capabilities during unoccupied periods, and addresses elevated CO2 levels. The DOAS provide conditioned 100-percent outdoor air with dew points as low as 50˚F, while delivering air within ±2˚F of set-point temperatures.
For indoor pools of all sizes, PoolPak products include refrigerant-based dehumidification in a variety of sizes and fan configurations, as well as units that utilize outside air for moisture removal. For total environmental control, S-Series units manage humidity and temperature while providing ventilation, heating, and cooling for complex indoor-pool applications.
A new desiccant-wheel option on Innovent Latent and Sensible Energy Reduction (LASER) packaged air-conditioning units provides additional dehumidification capacity. Primarily for dedicated outdoor-air applications, the units include single or dual air-to-air heat exchangers for dehumidifying and reheating outside air prior to delivery to occupants. The units can reduce peak cooling loads by up to 80 percent.
—Unison Comfort Technologies
A modulating-hot-gas-reheat option is now available on RoofPak applied and Maverick II commercial rooftop systems, allowing users to optimize dehumidification to control and maintain a desirable air temperature without using additional energy to reheat cooled air. The modulating-hot-gas-reheat option features MicroTech III controls with integrated compressor and reheat control to automatically energize reheat when dehumidification is needed.
Desiccant dehumidification systems
Secure Environmental Systems exchange temperature and humidity between air and a desiccant transfer solution. The air is cleaned by the desiccant solution as it passes through high-efficiency packing in each section. Outside and exhaust air are handled with independent units connected only by piping. Incorporating separate units and utilizing a liquid desiccant with decontamination properties ensures no microbiological cross contamination/leakage can occur.
—Kathabar Dehumidification Systems Inc.
DryCool HCU dehumidification units feature a center-hung desiccant wheel, a microchannel condenser coil, and a smaller box size. The 15-ton units handle up to 5,000 cfm of return air and are suitable for retrofit applications. The units require only 6 lb of R-410a refrigerant per circuit, and condenser waste heat is utilized for desiccant reactivation.
The G3MA passive desiccant dehumidification wheel regenerates desiccant with 50-percent-relative-humidity room return air, allowing moisture to be removed through the dehumidification of fresh air being supplied to the room. Fully water-washable and 100-percent non-flammable, the wheel removes moisture from a saturated air stream without heat or thermal regeneration.
—Desiccant Rotors International Inc.
A brochure from Dectron outlines several of the company’s dehumidification products, such as dehumidifiers for commercial and industrial indoor pools/whirlpools, ice/curling rinks, water-treatment plants, and pumping stations. The brochure lists benefits and specifications and includes product photos.