scholarly journals Selection of parameters to predict dew point temperature in arid lands using Grey theory: a case study of Iran

2019 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Mojtaba Qolipour ◽  
Ali Mostafaeipour ◽  
Mostafa Rezaei ◽  
Elham Behnam ◽  
Hossein Goudarzi ◽  
...  
Keyword(s):  
Water Vapor ◽  
Air Temperature ◽  
Sunshine Duration ◽  
Water Vapor Pressure ◽  
Arid Lands ◽  
Dew Point ◽  
Grey Theory ◽  
Effective Parameters ◽  
Point Temperature ◽  
Dew Point Temperature

Dew point is the temperature at which water vapor in the air condenses into liquid with the same rate it evaporates. Dew point study is important in arid lands with low rainfall, also in other regions with various hydrological and climatological conditions. In this study, the Grey theory is applied for the first time to propose a framework approach to identify the important parameters affecting the prediction of dew point temperature. The ability of Grey theory to estimate and rank the parameters of a problem with missing data and uncertain conditions means that it has a good potential for mentioned application. For this research, 8 parameters are selected using literature review including: global solar radiation on a horizontal surface (H), water vapor pressure (VP), atmospheric pressure (P), sunshine duration (n), minimum air temperature (Tmin), maximum air temperature (Tmax), average air temperature (Tavg), and Relative Humidity (RH). The study is conducted for the city of Abadeh in Iran by using the data pertaining to a 10 year period between 2005 and 2015. The findings show that RH, Tavg, P, Tmax, Tmin, H, n and Vp with the grey possibility degrees of, respectively, 0.534, 0.551, 0.608, 0.622, 0.635, 0.695, 0.697 and 0.712, are the most important and effective parameters in prediction of dew point temperature. The proposed method also prioritizes the studied parameters in the order of their effectiveness on predicted dew point temperature.

Automatic dew-point temperature sensor

1982 ◽  
Vol 52 (6) ◽  
pp. 1658-1660 ◽  
Author(s):  
H. Graichen ◽  
R. Rascati ◽  
R. R. Gonzalez
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Skin Surface ◽  
Dew Point ◽  
Pressure Gradients ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Peltier Module ◽  
Local Water

A device is described for measuring dew-point temperature and water vapor pressure in small confined areas. The method is based on the deposition of water on a cooled surface when at dew-point temperature. A small Peltier module lowers the temperature of two electrically conductive plates. At dew point the insulating gap separating the plates becomes conductive as water vapor condenses. Sensors based on this principle can be made small and rugged and can be used for measuring directly the local water vapor pressure. They may be installed within a conventional ventilated sweat capsule used for measuring water vapor loss from the skin surface. A novel application is the measurement of the water vapor pressure gradients across layers of clothing worn by an exercising subject.

Heat and Mass Transfer in Double-Filmwise Heat Exchanger for Industrial Food Processing Applications

2011 ◽  
Author(s):  
Helen Skop ◽  
James Pezzuto ◽  
Valeriy G. Oleynikov-White ◽  
John F. Cavallo ◽  
Robert Fesjian
Keyword(s):  
Water Vapor ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Cost Effective ◽  
Dew Point ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Gas Cooling ◽  
Stack Gas

The baking industry is considered as one of the major energy consuming food industries in North America. More than 40% of bakery fuel consumption is used to evaporate water in the processes [1]. In addition to the baking process’ vapor the oven stack gas contains water vapor from combustion products. Overall the content of water vapor in the typical oven stack gas is about 20% by volume. Most bakeries waste this vapor and its latent heat. Bakeries’ ovens have wide diversity in power and design. Off-the-shelve heat exchangers are not considered as cost effective equipment for stack gas cooling below gas’ dew point temperature. At typical oven stack gas composition water vapor condensation begins to condense at about 72° C. Not using the latent heat of stack water vapor and the heat from gas cooling from dew point temperature to ambient temperature results in low effectiveness of waste heat recovery. Mainly the effect from the recovery of stack gas cooling prior to condensation is considered as non cost effective and waste heat recovery is neglected.

Chart of Air-Vapor Mixture Properties at Different Pressures

1941 ◽  
Vol 8 (1) ◽  
pp. A14-A16
Author(s):  
R. C. Binder
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Total Pressure ◽  
Limited Range ◽  
Dew Point ◽  
Specific Humidity ◽  
Vapor Mixture ◽  
Close Approximation ◽  
Point Temperature ◽  
Dew Point Temperature

Abstract A discussion is given of the use of a total pressure-temperature diagram provided with reversible adiabatic and specific-humidity lines for mixtures of air and water vapor. The graphical relation between dew-point temperature, dry-bulb temperature, and specific humidity is given directly for any total pressure on this chart. From this relation the vapor pressure and relative humidity can be easily calculated. Certain chart lines give a close approximation to the wet-bulb temperature for a limited range. This pressure-temperature chart should be convenient and useful for a wide variety of problems which involve these fundamental thermodynamic properties.

Sign in / Sign up

Export Citation Format

Share Document