Fundamentals of Heating. Ventilating, and Air-Conditioning

TETD/TA (manual method)

TETD is called the total equivalent temperature differential method. It is similar to CLTD method but not the same. More information can be found in ASHRAE Handbook — Fundamentals (ASHRAE Fundamentals 28.56 — 28.64). Practicum Assignment #1 1. For a winter heating in a PSU classroom, steam enters a radiator at 16 psia and 0.97 […]

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CLTD/SCL/CLF Method (manual method)

ASHRAE Fundamentals 1997 in Chapter 28.39-28.56. • External cooling load Roofs, walls, and conduction through glass: Q = U A (CLTD) Where U = design heat transfer coefficient (Table A24-4, A29-5) A = area of roof, wall, or glass CLTD = cooling load temperature difference (Table A28-32, A28-34) Solar load through glass: Q = A […]

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Radiant Time Series (RTS) Procedure (spreadsheet method)

ASHRAE Fundamentals 2001 in Chapter 29.27-29.37. The RTS method is suitable for peak design load calculations, but it should not be used for annual energy simulations due to its simplified assumptions such as steady-periodic conditions. 50 J W G 3D Л 2 fio S J ID Material R-11 Mвlfil№fl ^rd, Swahnn. R.-11 Sait Irnubdnn, Йяp […]

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Nonresidential building cooling and heating load (manual methods)

In nonresidential buildings, it is important to include (1) the time lag in conductive heat gain through opaque exteriors, and (2) the thermal storage in converting radiant heat gain to cooling load. Calculation of a building cooling loads requires detailed information on: • building characteristics (materials, size, and shape) • configuration (location, orientation and shading) […]

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Residential heating load

Heating loads: • through structural components and windows • through floors and walls below grade • by infiltration Calculation procedure: • Heating load through structural components and windows Q = U A (T0 — T;) • Heating loads through floors and walls below grade Q = U A (Tearth " T;) • Heating load by […]

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Residential building cooling load

Heat gain: The rate at which energy is transferred to or generated within a space Cooling load: The rate at which energy must be removed from a space to maintain the temperature and humidity at the design values Heat gain ^ Cooling load (radiation, thermal mass, thermal lag) Heat extraction: The rate at which energy […]

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High Performance Glazing

• Multiple glazing Venetian blinds are treated as a special type of “glazing”. Multiple transmission, reflection, and absorption are taken into account. • External and internal shading By draperies: Use T Table 6-6 or A Table 29 By external overhangs and side fins: 3HUOI1 ™l) wobniw niEnua iiA ( №Q .nuG bnc noiiM Calculate the […]

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Heat gain through fenestrations

Total heat gain = (Solar heat gain) + (Conduction heat gain) Conduction heat gain = U (T0 — Tj) Define: Solar heat gain factor: SHGF Transmitted solar heat gain factor: TSHGF Absorbed solar heat gain factor: ASHGF SHGF = TSHGF + ASHGF • For double-strength sheet glass (DSA): TSHGF = Gd ‘Ed + Gd xti […]

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Solar optical properties

Any optical material obey the following law under any given wave length: T+a+p=1 T, a, and p are function of А, Total solar heat excluded-16% Total solar heat admitted-84% Figure 6-10 Distribution of solar radiation falling on clear plate glass. Where t = transmittance A = absorptance p = reflectance X = wave length (m) […]

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Solar radiation with a cloudy sky

Total solar radiation on a horizontal surface under a cloudy sky, Gtc GtHc= CCF (GDH + GdH) The CCF is the cloud cover factor detennined from CCF = P + Q CC + R CC2 Where P. Q. R = coefficients CC = cloud cover ( a variable between 0-10)

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