Specifications

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whether the sensor is weather proof or resistant, cost - effectiveness, size, and
maintainability.
Relative humidity is an important concept especially in the state of Florida
because in the summer season it is extremely hot and humid above what the
actual temperature outside is supposed to be. Sometimes when the actual
temperature is 96 degrees F, the relative humidity (for example; 100% humidity)
causes the temperature to feel like it is 102 degrees F outside. Basically high
humidity will enable people to feel extremely hot because it makes the body
sweat more and thus will succumb to a lot of perspiration from the skin.
Some essential concepts that come across when calculating relative humidity are
dew point temperature, saturation vapor pressure of the air (Es), and the vapor
pressure of the air (E). Dew point temperature, relative humidity, and absolute
humidity are terms used in the everyday lives for meteorological forecasters in
order to predict the weather for a certain areas or regions around the world. Dew
point temperature is also a factor in the development of HVAC system controls.
The dew point temperature is defined as the temperature for liquid water to
evaporate at the same rate at which it condenses at a constant barometric
pressure. Dew point temperature is very significant because of the various
contributions in heat transfer, fossil fuels, printed goods, and plastics. It also has
considerable roles in efficient use of energy in chemical manufacturing
processes. When temperature is decreased, dew will appear as fog or change
from a gas to liquid on a cooler surface more quickly than it does changing from
a liquid to a vapor.
The most accurate dew point sensor is the chilled mirror hygrometer. In
determining the accuracy of the chilled mirror dew point sensor one must account
for measurement error from the calculation of relative humidity percentage due to
dry bulb temperature and dew point temperature. A really good hygrometer out
on the market that a customer can purchase now is the General Eastern M4 - RH
system. This system can display and calculate dew point temperature and
relative humidity. The hygrometer detects moisture buildup on a polished mirror
that contains a chilled cooling system. The cooling system is a small
thermoelectric heat pump. Light is reflected from a mirror to a photo cell which
functions as feedback so it can check the dew point temperature of the mirror. In
order to find and calculate the mirror temperature of this sensor, a platinum
resistance temperature detector is utilized. The disadvantage of the chilled mirror
dew point sensor is that it is relatively expensive.
Relative humidity is stated as the amount of water vapor which exists in a
combined air and water vapor mixture. The following formula can compute the
relative humidity: RH is equaled to E / Es * (100%).
The saturated vapor pressure of air is calculated according to the following
formula: