Psychrometry: Best In Chicago Mold Removal!

Psychrometry

Psychrometry is the system used to measure the temperature and humidity of air. It allows for careful analysis of these properties and their effects on the surrounding environment. Psychrometrics or psychrometry or hygrometry are terms used to describe the field of engineering concerned with the determination of physical and thermodynamic properties of gas-vapor mixtures.

Psychrometry deals with thermodynamic properties of moist air and uses these properties to analyze conditions and processes involving moist air. In other words, Psychrometry is the measurement system associated with evaluating the properties of moist air, namely temperature and humidity. Psychrometry allows the restorer to analyze these properties and better understand their effects on evaporation in the environment.

Rate of Evaporation

Three factors influence the rate of evaporation: humidity, airflow and temperature. Each factor can be measured and evaluated in a number of ways. Each has a direct influence on the rate of evaporation (or condensation that will occur when moisture and materials interact. Evaporation will increase when:

• Wet materials are made warmer.
• When drier air is used.
• When air is moved more rapidly across a wet surface.

Humidity, Airflow, Temperature

After excess water has been removed by extraction, the time required to dry wet materials is determined by the rate of evaporation. As the water is evaporated, the water vapor is removed by dehumidification or ventilation.

Humidity, airflow and temperature directly affect the state in which water exists – solid, liquid or gas and the rate at which the change of state occurs. It is critical to have control of these factors and an understanding of how the properties relate when drying a structure.

The Influence of Temperature

Drying structural materials rapidly requires a technician to increase the rate of evaporation from wet materials. The primary factor that determines what state water will take is the amount of energy it contains. As water molecules gain or lose enough energy to create or break bonds with one another, changes in state occurs. For example, when changing from liquid to gas, energy must be added.

The amount of energy available in a wet material can be assessed by measuring the material temperature (usually measured at the surface). Where the material temperature is higher, more energy is present to support evaporation.

Evaporation: Liquid changing to a vapor. Occurs as energy is increased. As moisture evaporates from a wet material, the surface of the material becomes cooler because energy is released from the material.
Condensation: Vapor changing to a liquid. Occurs as energy is removed. Surfaces below dew point temperature will condense water of the air.
Sublimation: Solid changing to a vapor (without going through a liquid phase). Occurs when solid water is exposed to a vacuum in a freeze drying chamber. Commonly known as “freeze drying,” this process can be used to restore valuable saturated books and documents. Books and documents saturated with clean water may be restorable if frozen or dried as quickly as possible.
Deposition: Vapor changing to a solid (without entering the liquid phase).
Melting: Solid changing to liquid. Occurs as energy is increased.
Freezing: Liquid changing to solid. Occurs as energy is removed.