AC Units


HumidAIR is packaged unit designed to maintain humidity at acceptable levels in extreme environments such as swimming pools, aquatic centers, or industrial drying applications. This article takes a closer look at how the system works.

Starting with unoccupied mode, hot humid return air is brought into the unit and enters the evaporator coil. This evaporator cools the air below its dew point to remove moisture achieving both sensible and latent cooling. The refrigeration system rejects the heat from this evaporator into the condenser where the heat is re-added as sensible heat. The result is air that is warmer, but also dryer. This is similar to other conventional dehumidification systems.


In occupied mode, the exhaust fan starts and controls air to either a constant air flow rate, or based on room pressure. The fresh air damper is opened and fresh ventilation air is brought into the system. This air mixes before entering the evaporator. Again, the evaporator cools the air to achieve dehumidification and the condenser re-heats the air. If there is system demand and the fresh air has less humidity than the return air, the unit can automatically bring in an excess amount of fresh air to reduce the amount of mechanical dehumidification.



HumidAIR is available with an optional heat recovery feature. This helps to reduce energy costs by extracting heat from the exhaust air when further heating is needed. This heat is applied through a secondary water-cooled condenser and can be used to heat domestic hot water or swimming pool water. What makes this feature unique is that it remains as a completely separate and independent refrigeration circuit. That means it can control to the exact amount of heating demand while the dehumidifier controls to the humidity demand. Keeping these two systems separate improves system control, efficiency and reliability.

With the heat recovery (HR) feature enabled, the HR evaporator removes heat from the return air stream, cooling it somewhat. When in occupied mode, some of this air is then exhausted and the remainder is mixed with fresh air. The air then moves through the evaporator where it is dehumidified as usual. In this mode of operation, the HR evaporator helps remove heat and moisture before the air is introduced into the dehumidifier. This helps saves energy in summer months when less heat is required in the supply air.



In winter months, additional heat energy may be required in the system. In this mode, the return air is separated and only the exhaust portion of this air moves through the HR evaporator. This way, the air entering the dehumidifier is warmer and more humid. This provides more load on the dehumidifier which allows it to develop more heat energy, increasing the supply air temperature. This feature is great for colder climates and helps eliminate the need for auxiliary space heating.


All of these sequences are pre-programmed and operate automatically based on the room humidity and temperature set point. For more product information on HumidAIR, click here.