HVAC System Design- Formulae

I have been approached by lot of people to teach them system design for the HVAC&R product development and I thought it fit for them to start from basics as without  solid foundation there can be no building.So I thought of compiling the basic formulae first and then go for the system design aspects.It has taken me considerable time to compile these formulae.
I would like to thank Ms. Ashima Saxena for helping me in editing the list of the compilation.

Thermodynamic Design Formulae
Sr. No.	EQUATION	FORMULAE
1	F = m a	Newton's law of motion
2	P = F / A	Pressure
3	ρ = m / V	Density
4	W = F d	Work
5	PE = m g H	Potential energy
6	KE = ½ m V2	Kinetic energy
7	Q = m Cp( t2 - t1 )	Sensible heat
8	Q = m ( h2 - h1 )	Total heat
9	W - Q = dE	1st law of thermodynamics
10	Cpa = 1.005 kJ/kgK	Heat capacity of dry air
11	Cpw = 4.193 kJ/kgK	Heat capacity of water
12	Cpv = 1.884 kJ/kgK	Heat capacity of water vapor
Heat Transfer Formulae
13	Q = - k A dt/dx	Conduction
14	Q = hc A ( ts - tf )	Convection
15	Q=σ A Fε FA (t1⁴-t2⁴)	Radiation
16	Re = ρ V Dh / µ	Reynolds number
17	Pr = µ Cp / k	Prandtl number
18	Nu = hc D / k	Nusselt number
19	Nu = 0.023 Re0.8 Pr0.4	Dittus-Boelter
Moist Air Phase Formulae
20	P = Pa + Pv	Dalton's Law of partial pressure
21	Pv = R T	Perfect gas law
22	Ra = 0.287 kJ/kgK	Gas constant of dry air
23	Rv = 0.4615 kJ/kgK	Gas constant of water vapor
24	W = 0.622 Pv / (P - Pv)	Humidity
25	Pv = P / [1+0.622/W]	Vapor pressure from humidity
26	r = (1+W) / v	True density of moist air
27	Ps = 0.6105 exp [ 17.27 t / (237.3+t) ]	Magnus saturation pressure
28	t = 237.3 / [17.27 / Ψ - 1] where Ψ = ln (Ps / 0.6105)	Dew point temperature using the Magnus equation
29	f = Pv / Ps	Relative humidity
30	Pv = Psw - 1.8( P- Psw )( db - wb )/( 2800 - 1.3 wb )	Carrier vapor pressure
31	H = 1.005 db + W [ 2500.6 + 1.85 db - 0.023 wb]	Enthalpy
32	hfg = 2501.9 - 2.4189 t	Latent heat of water vapor
Air Psychometric Formulae
33	ma = ρ Qa	Mass flow of dry air
34	Qs = ma Cpm ( t2 - t1 )	Sensible duty
35	Cpm = 1.023 kJ/kgK	at typical air-conditioning conditions
36	Qt = ma (h2 - h1 )	Total duty
37	SHR = Qs / Qt	Sensible heat ratio
38	b = ( db0 - adp ) / ( dbi - adp )	Bypass factor
39	Qs = h A (db - wb)	Sensible heat at wet wick
40	Ql = hd A (Ws,w - W) hfg,w	Latent heat at wet wick
41	hd = hc / Cpm	Mass transfer coefficient
Room Heat Formulae
42	Q = Uo Ao ( to - ti )	Heat conduction through a wall
43	r = ro + Σ t/K + ri	Wall resistance
44	Qsg = SHGF SC  A  CLF	Solar heat gain
45	Q = U A CLTD	Cooling load temperature difference method
Cold Room Formulae
46	Qpulldown = m C dT	Pull down load
47	Qlatent = m ∆W λ	Latent load
48	Qrespiration = m R	Heat of respiration
Solar Angle Formulae
49	d = 23.45 sin ( 360 (284+n) / 365)	Solar Declination
50	LST = CT + (Lstd - Lloc)/15 + E + DT	Local Solar Time
51	E = 0.165 sin 2B - 0.126 c os B - 0.025 sin B	Equation of Time
52	B = 360 (n- 81) / 364	Parameter in E
53	h = 15 (LST - 12)	Hour angle
54	sin β = cos l  c osh  cos d + sin l  sin d	Altitude angle
55	cos φ = (cos d  sin l  cos h - sin d  cos l) / cos β	Solar Azimuth
56	cos θ = cos β  cos λ  sin Σ + sin β  cos Σ	Angle to surface normal
Solar Radiation Formulae
57	IDN = A e -B / sin β	Direct Normal Solar Flux
58	IdH = C IDN	Diffuse Horizontal Solar Flux
59	ID = IDN cos θ	Direct Solar Flux on Surface
Coil Calculation Formulae
60	dQ = hd dA ( ha - hi )	Heat flow on the c oil air side
61	dQ = hr dAi ( ti - tr )	Heat flow on the c oil fluid side
62	dQs = hc dA ( ta - ti )	Air sensible heat
63	Q = U A lmtd	Duty from UA LMTD method
64	Lmtd = (dti - dto) / Ln( dti / dto )	Log mean temperature difference
65	Q = e Qmax	Effectiveness method
66	e = (1 - exp(- Ntu (1- Cr)) / (1 - Cr exp(- Ntu (1-Cr))	Counter-flow effectiveness
67	Cr = Cmin / Cmax	Capacity ratio
68	Ntu = U A / Cmin	Number of transfer units
Steam Formulae
69	λ = 2164 kJ/kgK	Latent heat of vaporization at 2 bar gauge pressure
70	λ = 333.6 kJ/kg	Latent heat of freezing
Fluid Flow in Pipes Formulae
71	dPfriction = ½ ρ ƒ L V2 / Dh	D'Arcy Weisbach friction equation
72	1/√ƒ = -2 Log [ ε / (3.7 Dh) + 2.51 / (Re √ƒ) ]	Colebrook friction factor
73	Dh = 4 A / P	Hydraulic diameter
Duct Design Calculation Formulae
74	P + ½ ρ V2 + ρ g H = constant	Bernoulli equation
75	P1 + ½ ρ V2 + r g H1 = P1 + ½ ρ V2 + ρ g H1 + Ploss	Modified Bernoulli
76	dP = ½ ρ Vd2 [ 0.4 ( 1 - Vd/Vu)2 ]	Branch straight through dp
77	Def = 1.3 (ab)0.625 / (a+b)0.25	Effective diameter of rectangular duct
78	dP = ½ ρ V2 [ (A1/A2)2 - 1 ]	dP for ideal flow through a nozzle
79	dP = ½ ρ V2 [ 1 - (A1/A2) ]2	dP for sudden enlargement
81	Re ≈ 67 V Dh	standard air with V (m/s) and Dh (mm)

Fan Laws
82	Law 1	ρ = const	Q ~ ω	SP  ~  ω2	Pw ~  ω3
83	Law 2	ω = c onst	Q = const	SP  ~  ρ	Pw ~   ρ
84	Law 3	ω  ~  1/√ρ	Q  ~  1/√ρ	SP = const	Pw ~  1/√ρ