![ashrae psychrometric chart 2 ashrae psychrometric chart 2](https://engineerspointofviewcom.files.wordpress.com/2020/06/annotation-2020-06-10-161317-e.jpg)
All points falling on a given vertical line will have the same dry-bulb temperature.įigure 3. The vertical lines along the chart represent "dry-bulb" temperatures, which are the temperatures measured by an ordinary thermometer. Refer to the psychrometric chart shown in Figure 1. Other charts often deal with additional values including absolute humidity, specific volume and enthalpy. The frost protection psychrometric chart deals with the relationships among dry-bulb temperature, wet-bulb temperature, dew point temperature and relative humidity. This publication primarily focuses on a chart specifically developed as a reference for managing the use of frost protection methods. There is no set format for psychrometric charts and charts from different sources vary in format and in the parameters plotted on the charts. A psychrometric chart is a graphical representation of the thermal and physical properties of moist air. Dry air has a defined composition of the following gases listed in Table 1.Ī moist air mixture is defined as a mixture of dry air and water vapor. The amount of water vapor in the air in Florida varies from around 1% by volume under cold dry conditions to above 5% during hot, humid summer months.
![ashrae psychrometric chart 2 ashrae psychrometric chart 2](https://0.academia-photos.com/attachment_thumbnails/40312983/mini_magick20190221-4396-tcex4o.png)
The composition of atmospheric air is variable, particularly with regards to the amount of water vapor. For example, it is used for sizing air conditioning equipment (Sherif 2002). The psychrometric chart is used in many other calculations related to heating or cooling of the air (Kodama et al.
![ashrae psychrometric chart 2 ashrae psychrometric chart 2](https://i.ytimg.com/vi/rR_w73nttDo/maxresdefault.jpg)
These properties are needed when you need to calculate 1) the time to turn your irrigation system on, 2) the time to turn your irrigation system off, and 3) the danger of frost damage (Parsons and Boman 2003).
ASHRAE PSYCHROMETRIC CHART 2 HOW TO
In this introduction to psychrometrics, you will learn the relationships between dry bulb temperature, relative humidity, wet bulb temperature and dew point temperature and how to use the chart and any two of these properties to determine the other two properties. Learning how to read a psychrometric chart will help to understand how relative humidity and air temperature can be used to predict freezing and frost conditions and how it can be used as a tool to time the use of frost protection methods. Relative Humidity (RH)-The ratio of actual water vapor pressure to the vapor pressure of saturated air at the same dry bulb temperature. This quantity may also be called Absolute Humidity. Humidity Ratio-Weight of water vapor in pounds per pound of dry air or grains of water vapor per pound of dry air or kilograms of water vapor per kilogram of dry air expressed as a decimal. Wet Bulb Temperature-The lowest possible temperature to which an air mixture can be cooled solely by the addition of water.ĭew Point Temperature-The temperature at which moisture starts to condense from air cooled at constant pressure and humidity ratio. Moist Air-A mixture of dry air and water vapor.Īir Mixture-A mixture of dry air and water vapor.ĭry Bulb Temperature-The temperature measured by an ordinary. A psychrometric chart is commonly used to establish variations in the environment based on changes in the air heat-moisture. Psychrometrics is the study of the physical and thermodynamic properties of air-water mixtures (Gatley 2004 Knox et al. Haman, Haimanote K Bayabil, and Sandra M Guzman