Ecosystem model - Revision history

en>Comtebenoit: tidy up mention of archaeology

2014-12-07T07:22:42Z

tidy up mention of archaeology

← Older revision		Revision as of 09:22, 7 December 2014
Line 1:		Line 1:
	~~'''Sol-air temperature''' (''T''<sub>sol-air</sub>) is a variable used to calculate cooling load of a building and determine the total heat gain through exterior surfaces~~. It is ~~an improvement over~~:		Hi there, I extended car warranty am Yoshiko Villareal but I never truly liked that title. Delaware is our beginning [http://www.Consumerreports.org/cro/magazine/2014/04/extended-warranties-for-cars-are-an-expensive-game/ location]. [http://www.5starwarranty.com/ Bookkeeping] is how he supports his family members and his salary has been truly fulfilling. [http://www.adt-clan.at/index.php?mod=users&action=view&id=7667 extended auto warranty] Her friends say [http://Www.Allstate.com/tools-and-resources/car-insurance/whats-in-a-new-car-warranty.aspx extended] car warranty it's not great for her but what she loves doing is flower arranging and she is attempting to make it a car warranty occupation.<br><br>Also visit my blog - extended [http://brunswickjets.com/UserProfile/tabid/1126/userId/227159/Default.aspx car warranty] ([http://www.vegan-Victory.de/index/users/view/id/5378 click through the up coming website])

	~~:<math>\frac{q}{A} = h_o(T_o - T_s)<~~/~~math>~~

	~~Where:~~

	* <math>q</~~math> = rate of heat transfer [W]~~
	* <math>A</~~math> = heat transfer surface area [m²]~~
	* <math>h_o</~~math> = heat transfer coefficient for radiation (long wave) and convection [W~~/~~m²K]~~
	* <math>T_o</~~math> = outdoor surroundings' temperature [°C]~~
	* <math>T_s</~~math> = outside surface temperature [°C]~~

	The above equation only takes into account the temperature differences and ignores two important parameters, being 1) solar radiative flux; and 2) infrared exchanges from the sky. The concept of ''T''<sub>sol-~~air</sub> was thus introduced to enable these parameters to be included within~~ an ~~improved calculation. The lower formula results:~~

	~~<math>T_\mathrm{sol~~-~~air} = T_o + \frac{ (a \cdot I~~ - ~~\Delta Q_{ir})}{h_o}<~~/~~math>~~

	~~Where~~:

	* <math>a</~~math> = solar radiation absortivity (surface solar absorptance or the inverse of the solar reflectance of a material) [-]~~
	* <math>I</~~math> = global solar irradiance (i~~.e. ~~total solar radiation incident on the surface) [W~~/m²]
	* <math>\Delta Q_{ir}</math> = extra infrared radiation due to difference between the external air temperature and ~~the apparent sky temperature~~. ~~This can be written as <math>\Delta Q_{ir} = F_r * h_r * \Delta T_{o-sky}<~~/~~math> [W~~/~~m²]~~

	~~The product <math> T_\mathrm{sol~~-~~air} <~~/~~math> just found can now be used to calculate the amount of heat transfer per unit area, as below:~~

	~~<math>\frac{q}{A}~~ = ~~h_o(T_\mathrm{sol-air} - T_s)</math>~~

	~~An equivalent, and more useful equation for the net heat loss across the whole construction is:~~

	~~<math>\frac{q}{A}~~ = ~~U_c(T_i - T_\mathrm{sol-air})</math>~~

	~~Where~~:
	* <math>U_c</~~math> = construction U-value, according to ISO 6946 [W~~/~~m²K]~~.
	* <math>T_i</~~math> = indoor temperature [°C]~~
	* <math>\Delta T_{o-~~sky}<~~/~~math> = difference between outside dry~~-~~bulb air temperature and sky mean radiant temperature [°C]~~

	~~By expanding the above equation through substituting <math>T_\mathrm{sol-air}<~~/~~math> the following heat loss equation is derived:~~

	~~<math>\frac{q}{A} = U_c(T_i~~ - ~~T_o)~~ - ~~\frac{U_c}{h_o} {[~~a ~~\cdot I~~ - ~~F_r \cdot h_r \cdot \Delta T_{o~~-~~sky}~~]~~}</math>~~

	~~The above equation is used for opaque facades in,<ref>ISO 13790, '~~'~~Energy performance of buildings — Calculation of energy use~~ for ~~space heating~~ and ~~cooling''~~<~~/ref~~> ~~and renders intermediate calculation of~~ <~~math~~>~~T_\mathrm{sol~~-~~air}<~~/~~math> unnecessary~~. The main advantage of this latter approach is that it avoids the need for a different outdoor temperature node for each facade. Thus, the solution scheme is kept simple, and the solar and sky radiation terms from all facades can be aggregated and distributed to internal temperature nodes as gains/~~losses~~.

	~~Note to Editor~~: ~~Items <math> F_r <~~/~~math> and <math> h_r <~~/~~math> require further definition to complete this article~~.

	~~== References ==~~
	~~<references~~/>
	~~#Fundamentals volume of~~ the ~~''ASHRAE Handbook'', ASHRAE, Inc., Atlanta, GA, USA, 2005~~
	~~#''Heating and Cooling of Buildings'', 2nd ed., Kreider, Curtiss, Rabl, McGraw-Hill, New York, USA, 2002~~

	~~==See also==~~
	*[[HVAC]]
	*[[ASHRAE]]
	*[[Active solar]]
	*[[Passive solar]]

	~~[[Category:Heating, ventilating, and air conditioning]]~~
	~~[[Category:Building engineering]~~]

en>BD2412: /* Example: The Lotka–Volterra equations */Fixing links to disambiguation pages, replaced: human overpopulation → human overpopulation using AWB

2013-12-30T23:43:19Z

Example: The Lotka–Volterra equations: Fixing links to disambiguation pages, replaced: human overpopulation → human overpopulation using AWB

← Older revision		Revision as of 01:43, 31 December 2013
Line 1:		Line 1:
	~~Claude~~ is ~~her title~~ and ~~she completely digs that title~~. ~~Years ago we moved to Kansas~~. ~~What he truly enjoys doing is~~ to ~~perform handball but he is having difficulties~~ to ~~discover time for it. Managing individuals is how she makes money and she will not alter it whenever soon~~.<br><br>~~My weblog car warranty~~ ([~~http:~~//~~Postarticle~~.~~net~~/~~30665~~/~~automotive~~-~~basics~~-the-~~way~~-to-~~employ~~-a-~~professional~~-~~mechanic~~/ ~~click~~ this ~~over here now~~])		'''Sol-air temperature''' (''T''<sub>sol-air</sub>) is a variable used to calculate cooling load of a building and determine the total heat gain through exterior surfaces. It is an improvement over:

			:<math>\frac{q}{A} = h_o(T_o - T_s)</math>

			Where:

			* <math>q</math> = rate of heat transfer [W]
			* <math>A</math> = heat transfer surface area [m²]
			* <math>h_o</math> = heat transfer coefficient for radiation (long wave) and convection [W/m²K]
			* <math>T_o</math> = outdoor surroundings' temperature [°C]
			* <math>T_s</math> = outside surface temperature [°C]

			The above equation only takes into account the temperature differences and ignores two important parameters, being 1) solar radiative flux; and 2) infrared exchanges from the sky. The concept of ''T''<sub>sol-air</sub> was thus introduced to enable these parameters to be included within an improved calculation. The lower formula results:

			<math>T_\mathrm{sol-air} = T_o + \frac{ (a \cdot I - \Delta Q_{ir})}{h_o}</math>

			Where:

			* <math>a</math> = solar radiation absortivity (surface solar absorptance or the inverse of the solar reflectance of a material) [-]
			* <math>I</math> = global solar irradiance (i.e. total solar radiation incident on the surface) [W/m²]
			* <math>\Delta Q_{ir}</math> = extra infrared radiation due to difference between the external air temperature and the apparent sky temperature. This can be written as <math>\Delta Q_{ir} = F_r * h_r * \Delta T_{o-sky}</math> [W/m²]

			The product <math> T_\mathrm{sol-air} </math> just found can now be used to calculate the amount of heat transfer per unit area, as below:

			<math>\frac{q}{A} = h_o(T_\mathrm{sol-air} - T_s)</math>

			An equivalent, and more useful equation for the net heat loss across the whole construction is:

			<math>\frac{q}{A} = U_c(T_i - T_\mathrm{sol-air})</math>

			Where:
			* <math>U_c</math> = construction U-value, according to ISO 6946 [W/m²K].
			* <math>T_i</math> = indoor temperature [°C]
			* <math>\Delta T_{o-sky}</math> = difference between outside dry-bulb air temperature and sky mean radiant temperature [°C]

			By expanding the above equation through substituting <math>T_\mathrm{sol-air}</math> the following heat loss equation is derived:

			<math>\frac{q}{A} = U_c(T_i - T_o) - \frac{U_c}{h_o} {[a \cdot I - F_r \cdot h_r \cdot \Delta T_{o-sky}]}</math>

			The above equation is used for opaque facades in,<ref>ISO 13790, ''Energy performance of buildings — Calculation of energy use for space heating and cooling''</ref> and renders intermediate calculation of <math>T_\mathrm{sol-air}</math> unnecessary. The main advantage of this latter approach is that it avoids the need for a different outdoor temperature node for each facade. Thus, the solution scheme is kept simple, and the solar and sky radiation terms from all facades can be aggregated and distributed to internal temperature nodes as gains/losses.

			Note to Editor: Items <math> F_r </math> and <math> h_r </math> require further definition to complete this article.

			== References ==
			<references/>
			#Fundamentals volume of the ''ASHRAE Handbook'', ASHRAE, Inc., Atlanta, GA, USA, 2005
			#''Heating and Cooling of Buildings'', 2nd ed., Kreider, Curtiss, Rabl, McGraw-Hill, New York, USA, 2002

			==See also==
			*[[HVAC]]
			*[[ASHRAE]]
			*[[Active solar]]
			*[[Passive solar]]

			[[Category:Heating, ventilating, and air conditioning]]
			[[Category:Building engineering]]

92.76.241.252 at 09:48, 28 July 2012

2012-07-28T09:48:47Z

New page

Claude is her title and she completely digs that title. Years ago we moved to Kansas. What he truly enjoys doing is to perform handball but he is having difficulties to discover time for it. Managing individuals is how she makes money and she will not alter it whenever soon.<br><br>My weblog car warranty ([http://Postarticle.net/30665/automotive-basics-the-way-to-employ-a-professional-mechanic/ click this over here now])