Factory and industrial management . MIDNIGHT FIG, 2. TYPICAL LOAD CURVES OF A HOTEL AND OF AN HOUSE. The use of a storage battery in an isolated plant in connectionwith a central-station auxiliary service, and a charge on basis ofmaximum demand, has been described, notwithstanding its limitedapplication, because it points out clearly and definitely the main func-tion of a battery in all isolated-plant installations. Such a plant doesnot have any expenditure for street mains, feeders, franchises, taxes. 846 THE ENGINEERING MAGAZINE. etc., but the plant installation must be at l
Factory and industrial management . MIDNIGHT FIG, 2. TYPICAL LOAD CURVES OF A HOTEL AND OF AN HOUSE. The use of a storage battery in an isolated plant in connectionwith a central-station auxiliary service, and a charge on basis ofmaximum demand, has been described, notwithstanding its limitedapplication, because it points out clearly and definitely the main func-tion of a battery in all isolated-plant installations. Such a plant doesnot have any expenditure for street mains, feeders, franchises, taxes. 846 THE ENGINEERING MAGAZINE. etc., but the plant installation must be at least equal to the maximumdemand, and usually because of need of a spare unit, from yi io y2more than the maximum. Therefore, for a maximum demand ofone kilowatt, the plant installation will be from one to one-and-one-half kilowatts, costing from $100 to $150, on which the fixed chargeswill be from $10 to $15 per annum. This should be compared withthe $20 allowed the central-service company for maintaining its ser-vice in 300250 200 150 100 50 ? - — 1 1 1/ .| L ?~-~ \\ 1 NON ELEVATOR ._ 1 _ ^ SMALL 1 1 LOAD ,. 1 1 1 1 1 MAHCH 11 5TH no- EL / / _,. - ?t V\ s ... Z^=^ =— 11 ion 12 1 b 6 7HOURS 10 11 12 1 FIG. 3. LOAD CURVE OF A BUILDING WITHOUT ELEVATOR, AND A TYPICAL ELEVATOR LOAD CURVE. From the foregoing, it follows that for every kilowatt of maxi-mum demand in a private plant, the owner of such a plant has tocharge the operation with from $10 to $15, or an average of about$, per year for fixed charges alone, and if he can reduce themaximum demand by some system of energy storage to somethingapproximating the average demand, he can reduce the total oper-ating cost by the difference between the fixed charges on a plant bigenough for the maximum demand, and one big enough for the aver-age demand including the storage system. In the case cited, of the elevator system of two elevators with amaximum demand of 60 kilowatts and an average of 6 kilowatts, thefixed
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Keywords: ., bookcentury1800, bookdecade1890, booksubj, booksubjectengineering
