PHPsychrometric.php

<?php

class PHPsychrometric{
	
	private $T;
	private $UR;
	private $Z;
	private $X;

	function __construct($T=20, $UR=65, $Z=0, $X=null){
		$this->T = $T;
		$this->UR = $UR;
		$this->Z = $Z;
		if(!is_null($X))
			$this->X = $X;
	}

	function Pws($T){
		if ($T <= 0)
			$Pws = exp((((-5.6745359)*10**3)/(273.15+$T))+(((6.3925247)*10**0))+(((-9.677843)*10**(-3))*(273.15+$T))+(((6.2215701)*10**(-7))*(273.15+$T)**2)+(((2.0747825)*10**(-9))*(273.15+$T)**3)+(((-9.484024)*10**(-13))*(273.15+$T)**4)+(((4.1635019)*10**0)*log(273.15+$T)));
		else
			$Pws = exp((((-5.8002206)*10**3)/(273.15+$T))+(((1.3914993)*10**0))+(((-4.8640239)*10**(-2))*(273.15+$T))+(((4.1764768)*10**(-5))*(273.15+$T)**2)+(((-1.4452093)*10**(-8))*(273.15+$T)**3)+(((6.5459673)*10**0)*log(273.15+$T)));
		return $Pws;
	}

	function Pp($UR, $Pws){
		$Pp = ($UR / 100) * $Pws;
		return $Pp;
	}

	function Tbu($T, $UR){
		$Tbu = $T * atan(0.151977*(($UR)+8.313659)**(1/2))+atan($T+($UR))-atan(($UR)-1.676331)+(0.00391838*(($UR)**(3/2))*atan(0.023101*($UR)))-4.686035;
		return $Tbu;
	}

	function Tr($T, $Pp){
		if($T <= 0)
			$Tr = 6.09+(12.608*(log($Pp/1000)))+0.4959*((log($Pp/1000))**2);
		else
			$Tr = 6.54+(14.526*(log($Pp/1000)))+(0.7389*((log($Pp/1000))**2))+(0.09486*((log($Pp/1000))**3))+(0.4569*(($Pp/1000)**0.1984));
		return $Tr;
	}

	function V($T, $X, $Z){
		$V = (0.2871*($T+273.15)*(1+(1.6078*$X/1000)))/((101325*(1-2.25577*10**(-5)*$Z)**5.2559)/1000);
		return $V;
	}

	function H($T, $X){
		$H = 1.006*$T+(($X/1000)*(2501+(1.805*$T)));
		return $H;
	}

	function Tbs($H, $X){
		$Tbs = ((200*((1000*$H)-(2501*$X)))/((361*$X)+201200));
		return $Tbs;
	}

	function X($UR, $Pws, $Z){
		$X = ($UR/100)*(0.622*($Pws/((101325*((1-2.25577*(10**(-5))*$Z)**5.2559))-$Pws)))*1000;
		return $X;
	}

	function UR($Pws, $X, $Z){
		$UR = ($X*100)/(0.622*($Pws/((101325*((1-2.25577*(10**(-5))*$Z)**5.2559))-$Pws)))/1000;
		return $UR;
	}

}

?>