general, for the entire system the pump capital costs will be assumed to be of the

following form

˙

(2-14)

where *A*1 =

empirical constant ($/pump)

empirical constant ($/W)

number of pumps

∆*P*d =

total pressure drop (supply and return) at design flow rate (N/m2).

The total pressure drop at maximum flow conditions is given by

∆*P*d = *a *εb (4/π)2+*c *A6 md 2+*c *L d(5+*b+c*)

˙

(2-15)

where *A*6 = [(ρ1 *c*)d,s+ (ρ1 *c*)d,r]/2 (m3+*c *sc/kg1+*c*).

So, our pump cost becomes

(2-16)

where *A*5 = *A*2a εb(4/π)2+*c *A7,d md 3+*c *L ($ m5+*b+c*)

˙

For the capital cost of the supply and return piping, including installation, we

assume the following form

(2-17)

where *A*3 = empirical constant ($/m)

The cost of maintenance and repair is assumed to be of the following form

(2-18)

where *A*m&r = annual maintenance and repair rate as a fraction of initial capital cost

(dimensionless)

less).

With each of the component costs defined, our expression for the objective

function, the total cost *C*t, becomes

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