Also with this concept some clarifications must be made. Relative humidity is defined as the relationship between the mole fraction of water vapor in air and the mole fraction of water vapor in saturated air at the same temperature[4]​.

Admitting the behavior of air as an ideal gas:

and then:.

That is, practically, relative humidity is defined as the percentage of vapor pressure that the air has with respect to the maximum it can have at that temperature.

There is another concept called degree of saturation, which is defined as the relationship between the amount of water vapor contained in the air and the maximum amount it could contain if it were saturated at that temperature[5]​.

Combining this equation with relative humidity, we obtain:.

Taking into account that in the temperature range with which air conditioning is normally worked, the corresponding vapor pressures range between 500 Pa and 4000 Pa, which, in relation to the total air pressure of 101,325 Pa, makes the second factor of the equation negligible. So, it can be estimated that:

Consequently, it can be considered, without much error, that relative humidity is the percentage of water vapor that the air has in relation to the maximum it could have if it were saturated at that temperature.

Contenido

El grado o la cantidad de humedad de aire se mide con el higrómetro. Cuando el higrómetro marca el 100 % se dice que el aire está saturado, es decir, contiene el máximo de humedad que puede tener a la temperatura actual.

Unit of measurement

In physics, and especially in meteorology, it is established that, for a given pressure and temperature, air has a maximum capacity to contain water vapor (saturation humidity). The relative humidity of the air is defined as the ratio between the humidity contained in the air and the saturation humidity, expressed as a percentage [%].

It varies between 0% (completely dry air) and 100% (completely saturated air).[6]​.

Relative humidity is related to personal comfort.[7]​ Evapotranspiration is a phenomenon necessary to dissipate the heat produced in the human body. Curiously, what influences the feeling of well-being is not the amount of water vapor contained in the air, but the relationship between the amount it contains and the maximum it could contain if it were saturated at that temperature, that is, its relative humidity. In cold environments, the relative humidity increases, since the air admits less water vapor, while in warm environments the relative humidity decreases or, in other words, the availability of the air to admit water vapor increases, which produces a feeling of dryness. In winter, in heated environments, humidification is necessary, even more so the warmer the air is.

Air moistened by evapotranspiration tends to stay close to the skin, making the cooling process difficult. An air current can replace this saturated air with another with lower moisture content, which favors evaporation. Hence, the air moved by a fan or by an air current causes a sensation of freshness, even when its temperature has not changed: what cools the body is the evaporation of sweat on the surface of the skin, since for the phase change (from liquid to vapor) it needs to absorb its latent heat and takes it from the closest thing, which is the skin, which cools the body.

When the relative humidity is high, body sweat does not evaporate easily and cannot lower its temperature properly; When it is low, evaporation is excessive, causing dryness of the skin and mucous membranes.[8]​.

Humidity is one of the fundamental abiotic factors that define any habitat (tundra, wetlands, and desert are some examples), and is a determining factor in which animals and plants can thrive in a given environment.[9]​.

The human body dissipates heat through perspiration and evaporation. Convection of heat to the surrounding air and thermal radiation are the main modes of heat transport from the body. In high humidity conditions, the rate of sweat evaporation from the skin decreases. Furthermore, if the atmosphere is as hot or hotter than the skin at times of high humidity, blood reaching the body surface cannot dissipate heat by conduction to the air. As so much blood goes to the outer surface of the body, less goes to working muscles, the brain, and other internal organs. Physical strength decreases and fatigue sets in sooner than it would otherwise. Alertness and mental capacity may also be affected, causing heat stroke or hyperthermia.

Typical construction methods often produce building envelopes with a poor thermal limit that require an insulation system and air barrier designed to preserve indoor environmental conditions while resisting outdoor environmental conditions.[10]​ The tightly sealed, energy-efficient architecture introduced in the century also sealed off the movement of moisture and this has led to a secondary problem of condensation forming in and around walls, which encourages the development of mold and mildew. Additionally, buildings with foundations not properly sealed allow water to flow through the walls due to capillary action from pores found in masonry products. Solutions for energy efficient buildings that avoid condensation are a current topic in architecture.

For climate control in buildings that use heating, ventilation and air conditioning systems. The key is to keep the relative humidity in a comfortable range, low enough to be comfortable but high enough to avoid the problems associated with very dry air.

When the temperature is high and the relative humidity low, water evaporation is rapid: the soil dries out, wet clothes hanging on a clothesline or coat rack dry quickly, and perspiration evaporates easily from the skin. Wooden furniture can shrink, causing the paint that covers these surfaces to fracture.

When the temperature is low and the relative humidity high, water evaporation is slow. When relative humidity approaches 100%, condensation can occur on surfaces, causing problems with mold, corrosion, rot, and other moisture-related deterioration. Condensation can pose a safety risk as it can encourage mold and wood rot, as well as freezing emergency exits.

Certain technical and production processes and treatments in factories, laboratories, hospitals and other facilities require the maintenance of specific levels of relative humidity using humidifiers, dehumidifiers and associated control systems.

The basic principles applicable to buildings also apply to vehicles. Additionally, there may be security considerations. For example, high humidity inside a vehicle can cause condensation problems, such as fogging up of windows and short circuits in electrical components. In vehicles and pressure vessels, such as pressurized aircraft, submersibles, and spacecraft, these considerations can be critical to safety, and complex environmental control systems that include pressure-maintaining equipment are needed.

https://www.humidifiersinfo.com/how-to-fill-pure-enrichment-humidifier/.

Also with this concept some clarifications must be made. Relative humidity is defined as the relationship between the mole fraction of water vapor in air and the mole fraction of water vapor in saturated air at the same temperature[4]​.

Admitting the behavior of air as an ideal gas:

and then:.

That is, practically, relative humidity is defined as the percentage of vapor pressure that the air has with respect to the maximum it can have at that temperature.

There is another concept called degree of saturation, which is defined as the relationship between the amount of water vapor contained in the air and the maximum amount it could contain if it were saturated at that temperature[5]​.

Combining this equation with relative humidity, we obtain:.

Taking into account that in the temperature range with which air conditioning is normally worked, the corresponding vapor pressures range between 500 Pa and 4000 Pa, which, in relation to the total air pressure of 101,325 Pa, makes the second factor of the equation negligible. So, it can be estimated that:

Consequently, it can be considered, without much error, that relative humidity is the percentage of water vapor that the air has in relation to the maximum it could have if it were saturated at that temperature.

Contenido

El grado o la cantidad de humedad de aire se mide con el higrómetro. Cuando el higrómetro marca el 100 % se dice que el aire está saturado, es decir, contiene el máximo de humedad que puede tener a la temperatura actual.

Unit of measurement

In physics, and especially in meteorology, it is established that, for a given pressure and temperature, air has a maximum capacity to contain water vapor (saturation humidity). The relative humidity of the air is defined as the ratio between the humidity contained in the air and the saturation humidity, expressed as a percentage [%].

It varies between 0% (completely dry air) and 100% (completely saturated air).[6]​.

Relative humidity is related to personal comfort.[7]​ Evapotranspiration is a phenomenon necessary to dissipate the heat produced in the human body. Curiously, what influences the feeling of well-being is not the amount of water vapor contained in the air, but the relationship between the amount it contains and the maximum it could contain if it were saturated at that temperature, that is, its relative humidity. In cold environments, the relative humidity increases, since the air admits less water vapor, while in warm environments the relative humidity decreases or, in other words, the availability of the air to admit water vapor increases, which produces a feeling of dryness. In winter, in heated environments, humidification is necessary, even more so the warmer the air is.

Air moistened by evapotranspiration tends to stay close to the skin, making the cooling process difficult. An air current can replace this saturated air with another with lower moisture content, which favors evaporation. Hence, the air moved by a fan or by an air current causes a sensation of freshness, even when its temperature has not changed: what cools the body is the evaporation of sweat on the surface of the skin, since for the phase change (from liquid to vapor) it needs to absorb its latent heat and takes it from the closest thing, which is the skin, which cools the body.

When the relative humidity is high, body sweat does not evaporate easily and cannot lower its temperature properly; When it is low, evaporation is excessive, causing dryness of the skin and mucous membranes.[8]​.

Humidity is one of the fundamental abiotic factors that define any habitat (tundra, wetlands, and desert are some examples), and is a determining factor in which animals and plants can thrive in a given environment.[9]​.

The human body dissipates heat through perspiration and evaporation. Convection of heat to the surrounding air and thermal radiation are the main modes of heat transport from the body. In high humidity conditions, the rate of sweat evaporation from the skin decreases. Furthermore, if the atmosphere is as hot or hotter than the skin at times of high humidity, blood reaching the body surface cannot dissipate heat by conduction to the air. As so much blood goes to the outer surface of the body, less goes to working muscles, the brain, and other internal organs. Physical strength decreases and fatigue sets in sooner than it would otherwise. Alertness and mental capacity may also be affected, causing heat stroke or hyperthermia.

Typical construction methods often produce building envelopes with a poor thermal limit that require an insulation system and air barrier designed to preserve indoor environmental conditions while resisting outdoor environmental conditions.[10]​ The tightly sealed, energy-efficient architecture introduced in the century also sealed off the movement of moisture and this has led to a secondary problem of condensation forming in and around walls, which encourages the development of mold and mildew. Additionally, buildings with foundations not properly sealed allow water to flow through the walls due to capillary action from pores found in masonry products. Solutions for energy efficient buildings that avoid condensation are a current topic in architecture.

For climate control in buildings that use heating, ventilation and air conditioning systems. The key is to keep the relative humidity in a comfortable range, low enough to be comfortable but high enough to avoid the problems associated with very dry air.

When the temperature is high and the relative humidity low, water evaporation is rapid: the soil dries out, wet clothes hanging on a clothesline or coat rack dry quickly, and perspiration evaporates easily from the skin. Wooden furniture can shrink, causing the paint that covers these surfaces to fracture.

When the temperature is low and the relative humidity high, water evaporation is slow. When relative humidity approaches 100%, condensation can occur on surfaces, causing problems with mold, corrosion, rot, and other moisture-related deterioration. Condensation can pose a safety risk as it can encourage mold and wood rot, as well as freezing emergency exits.

Certain technical and production processes and treatments in factories, laboratories, hospitals and other facilities require the maintenance of specific levels of relative humidity using humidifiers, dehumidifiers and associated control systems.

The basic principles applicable to buildings also apply to vehicles. Additionally, there may be security considerations. For example, high humidity inside a vehicle can cause condensation problems, such as fogging up of windows and short circuits in electrical components. In vehicles and pressure vessels, such as pressurized aircraft, submersibles, and spacecraft, these considerations can be critical to safety, and complex environmental control systems that include pressure-maintaining equipment are needed.

https://www.humidifiersinfo.com/how-to-fill-pure-enrichment-humidifier/.