The procedure for calculating the heat flow necessary for preparing hot water

a)Basic scheme-summer

Φ_acb  = G_ac x C_2b x (  t_ac – t _{21 b} ) / 3600

G_ac = 0.8 x  3600 / 0.9832 = 2929 kg/h

Φ_acb  = 2929 x 4198.6 x (  60 - 10 ) / 3600

Φ_acb  = 170800 w

b) Mode  peak - winter

Φ_acv  = G_ac x C_2v x (  t_ac – t _21v ) / 3600

Φ_acv  = 2929 x 4198.6 x (  60 - 7  ) / 3600 = 181048

Φ_acv  = 181048

Primary heat flow

Primary water heating

a)Basic scheme-summer

Φ: heat flux [w]

acb : hot water [the regime basic, top]

G: flow of fluid [kg / h]

C: specific heat of fluid [J / kg x degrees]

2b: the primary circuit in the scheme - final value

t: temperature [° C]

Action: hot water in the basic regime

2.1b: secondary circuit in the scheme - initial value

Ψac: specific weight [kg/m3]

                        

VALUES OF STATE FOR WATER TABLE

Tm		Ψac	Cp
° K                 ° C		kg/m3	j/kg x °K
303	30	995.6	4198.6
313	40	992.2	4198.6
323	50	988	4198.6
333	60	983.2	4202.7
343	70	977.7	4211.1
353	89	971.8	4215.3
363	90	965.3	4223.7
373	100	958.3	4227.9
383	110	951.7	4238.3
393	120	943.1	4248.8

                                     

t _ac    = 60° C

t _{21 b}= 10° C

C_2b = 4198.6 j/kg °K for  35 ° C

C_1b = 4200    j/kg °K for 55 ° C

C_1v = 4220    j/kg °K for  85 ° C

Flow Calculation

STORAGE VOLUME CALCULATION

Q_A = 3600 x Φ_acb x 0.8 = 3600 x 170800 x 0.8 = 491.904.000

Volume of water consumption be accumulated

V = Q_A x 45 / ( t_ac - 10  ) x C_2b x Ψac x 60

V = 491.904.000 x 45/( 60 -10  ) x 4198.6 x 983.2 x 60

_{V = 1.49 mc}

_{Vertical Boiler}

_{QA = 3600 170800 x 0.57 = 350481600}

_{V =} 350481.600 x 45/( 60 -10  ) x 4198.6 x 983.2 x 60 =

_{V =1.2mc}

_{Choose a vertical boiler with a capacity of 1600 liters}