Loay saeed

eat Gain through Glass Heat is transmitted through glass due to solar radiation. The heat gain through glass areas constitutes a major portion of the load on the cooling apparatus. This could be direct in the form of sunrays or diffused radiation due to reflection from other objects outside. Heat transmitted through a glass depends on the wavelength of radiation and physical and chemical characteristics of glass. Part of the radiation is absorbed, part is reflected and the rest is transmitted. The heat transfer of glass takes place in the two ways, transmission heat gain and solar heat gain. The following equations are used to calculate heat gain from glass areas. Fig 3.4 heat gain through glass Transmission heat gain through glass: Q =UA(CLTD) corr …………... (3.4) By solar radiation: Q = A´SHGF ´SC´CLF max ………………….(3.5) SHGF max = maximum solar heat gain factor (W/m2) SC = shading coefficient depends on type of shading CLF = cooling load factor   ...

Cooling Loads Computed for worst case scenario: Summer at  max. outdoor design dry bulb temp. ( o.4 % ASHARE or Egyptian environmental agency) Include: n Solar radiation n Heat gain from people, lights, and equipment n Ventilation ( Fresh air) Factors that influence the cooling load SENSIBLE n Glass windows or doors n Sunlight from windows, skylights, or glass doors n Exterior walls, Partitions, Ceilings, Roofs & Floors n Air infiltration through cracks in doors, and windows n People, Equipment and appliances and Lights n Other sensible heat gains such as: Ductwork located in an unconditioned space & Ventilation air introduced into the building LATENT Moisture is introduced into a structure through: n People n Equipment and appliances n Air infiltration through cracks in the building, doors, and windows Room Load –VS- System load n Room Load:    From People, Walls and roof Heat transfer, Solar, Lights & Equipment   n Sy...

Solar Load Fenestration solar heat gain has two components: First is the directly transmitted solar radiation. The quantity of radiation entering the fenestration directly is governed by the solar transmittance of the glazing system. Multiplying the incident irradiance by the glazing area and its solar transmittance yields the solar heat entering the fenestration directly. The second component is the inward-flowing portion of the absorbed solar radiation, radiation that is absorbed in the glazing and framing materials of the window and is subsequently conducted, convicted, and radiated to the interior of the building. The total solar gain (heat flow per unit area) q b   that enters the space due to the incident solar radiation is     q b  = E D (T+NA)  W/m2   = E D ( SHGC) E D is the direct solar irradiance incident upon a single pane of glass, T is its solar transmittance, A is  the solar absorptance, and N be the inward flowing fraction...