In a warm and humid climate, supply air can be drawn into a system and then exposed to cooling coils that drop the air temperature to 55☏.

The Uniform Mechanical Code (Uniform Mechanical Code, 2003) calls for OR relative humidities of 50%-60%. Control of humidity is not required by most codes in all areas, but is for some in most geographic areas. This template allows a designer or operator to “work backwards” from a desired room relative humidity to the desired condition of the air as it enters the supply duct. The psychrometric chart ( Figure 108-2) is a tool for understanding the relationships between the various parameters of supply air and the relative humidity. This can be done with steam or other methods steam can be provided by steam boilers or electric steam generators that boil water. In climates of low humidity, it is necessary to inject water vapor into the supply air to increase the humidity to the target level. Then, if the air is heated to 70☏ without the addition of water the humidity will change to about 60%, according to the chart. According to the psychrometric chart, if the relative humidity of the outside air is 80% and the outside air temperature is 85☏, when the air is cooled to 55☏, vapor will condense out of the air and the relative humidity will be 100%. In a warm and humid climate, the supply air can be drawn into a system and then exposed to cooling coils that drop the air temperature to 55☏. The Uniform Mechanical Code ( IAPMO, 2018) calls for OR relative humidities of 50%–60%. Control of humidity is not required by most codes in all areas but is for some in most geographic areas.

2) is a tool for understanding the relationships between the various parameters of supply air and the relative humidity.

Ashrae psychrometric enthalpy