Document aB40J7drgOr31pYw8XEp12YnY

,v; - 'jt-y'*? ?> American Society of Heating and Ventilating Engineers Guide jgj*! 5 per cent; October, 6 per cent; November, 8 per cent- 16 per cent. ' To determine the amount of exhaust steam available, it is nci first to develop electric current or power load curves and from tlf^ estimate the amounts of steam used during various periods. Fje the ideal water rate for engines or turbines working under different' - -i pressure and back pressure or vacuum conditions, with correctin'01^ superheat in the initial steam. Table 1 gives the factors by whichV' water rates may be multiplied to obtain average expected water ^ KW MAXIMUM LOADS DAY EVEN. Total LIGHT 130 130 shop Power. si SI S7 fan elevator* so SO SO 55 55 ss 242 372 372 ASSEMBLYON- 4th floor, lighting on i Total average _ LOAD AT switchboard! weatimg. -ftgAT/. Fan Power.) (lighting], X Elevators^ uiL--iu--jj Fig. 4. High School Load Curves 10 for engines and turbines of various capacities when operating under fuUl load conditions. Table 2 gives the factors by which the actual water rate] under full load operating conditions should be multiplied to obtain exj pected water rates under various load conditions. From the load curves; and these tables it is a simple matter to develop curves showing the steam] required by the electric generating or power units. The next step is to determine the amount of heat available in this steal?] for heating, etc., after it has passed through the generating units. This] can be done by deducting the heat transferred into work, plus that lost by radiation from the heat in the steam entering the generating units.; 286 Chapter 18--Special Sources of Heat Approximate Full Load Efficiencies for Non-Condensing Engine and r Multi-Stage Impulse Turbo-Generators--Geared Type i i j --p BrHdB18 orCEmitooTM Mechanical Efficiencies of Turbine Units Brarb Potential Efficiency Ratio of Tubbdihs Factors tor Cokvhbt* UfQ EDBAX WATBB BATES TO ACTUAL WATRB BATHS (fob turbines onlt) GbNH&AYOH Efficiencies poo 1200 feoo. >400 1500 KOO *75 ?iooo '#1250 "isoo , 2000 500 J r 600 rgy-'750 * 1000 1250 javisoo * 2000 0.900 0.905 0.910 0.915 0.920 0.925 0.930 0.935 0.940 0.945 0.950 0.930 0.935 0.940 0.942 0.945 0.947 0.950 0.952 0.955 0.957 0.960 0.45 0.50 0.54 0.58 0.61 0.64 0.65 0.67 0.67 0.67 0.68 2.22 2.00 1.85 1.74 1.64 1.56 |. 1.54 1.49 1.49 1.49 1.45 FrvNTTR.NSING TURBINES 0.950 0.952 0.954 0.956 0.958 0.960 0.960 0.932 0.934 0.936 0.938 0.940 0:942 0.944 0.945 0.947 0.950 0.954 0.940 0.942 0.944 0.945 0.947 0.950 0.954 (For Non-Condrnsijio Emmas Onlt) Single valve automatic engine units up to 400 kw... . Four valve automatic engine units up to 400 kw.I Unaflow engine units up to 400 kw._------------------------ 1 1.64 1.42 1.20 ' CThesefactors-arefor indicated engine or bra-ke turbine loads and1 do not take into account the mechanical . efficiency of engine units or generator efficiencies for either engine or turbine units; but do include the T^gfechaoical efficiency of turbines. fxTmg 2. Factors by Which to Multiply Actual Water Rates at Full Load 58610Obtain Estimated Water Rates at Fractional Loads on Non-Condensing BPS*. . Engine and Turbine-Driven Electric Generating Units11 & Bizi am Kim of Umr Loan KM Full phr.--- - 1 --- ; B'* Single valve engines up to 400 kw.-- g -Four valve engines up to 400 kw._. i'ljjtaaflo'w engines up to 400 lew........ Geared turbines up to 600 kw........ ^Geared turbines 600 to 2000 kw.__ 1.32 1.30 1.10 1.57 1.50 lT09 1.08 1.02 1.25 1.20 1.03 1.03 0.980 1105 1.04 1.00 1.00 1.00 1.00 1.00 fe*these values are for indicated or brake loads and do not take into accountvanatioiia .efficiencies under various load conditions. Generator efficiencies vary from 85 per cent at one quarwr to 95 per cent at full load. 287