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ixed with return air to maintain the mixed air tempgreater than 30F, there is no need for heating the outside because the air is mFor Ventilation calculations, we have used trend data <br /> from Metasys to verify the assumption that when outside temperature is KWTON is the efficiency of the DX unit.Saturated). ENTHALPHY is the difference in enthalpy of Mixed Air (76F <br /> db, 50% RH) and Discharge Air (55F db, HEATCOST is the rate of heating BTU.peak hours -ELECCOST is the rate of electricity during off Measured KW is the Supply Fan energy.he cube of <br /> the CFM ratio. The "Proposed KW" was calculated using both Fan Law #2 and #3, where #3 states the ratio of Break Horse Power (KW) equals t ratio. The "Proposed O.A. CFM" was calculated <br /> using Fan Law #2, where the ratio of Static Pressure is equal to the square of the CFM <br /> <br /> <br /> <br /> <br />EXH D <br />u <br />ct <br />IBI <br /> <br />Seal <br />T <br /> <br />D <br /> <br />i <br />ng <br /> <br /> <br />- <br /> <br /> <br />Li <br />b <br /> <br />ra <br /> <br />r <br />y: <br />Duct Sealing <br /> <br /> <br /> <br />UT <br />Energy Calculations - Variable Frequency Drives Optimization <br />BASELINE PROPOSED SAVINGS <br />HVACHRS <br /> <br />F <br />Proposed Proposed Proposed <br />SUPPLY O.A. Measured Baseline Affected Proposed Baseline Fan Energy Ventilation Cooling Fan Energy Ventilation Cooling Fan Energy Ventilation Cooling <br /> <br />I <br />L <br />S.F. CFM O.A. CFM % Flow <br />AHU # AREA SERVED KWH Therms KWH KWH Therms KWH KWH Therms KWH <br />CFM CFM KW Hrs/Wk Hrs/Wk Hrs/Wk % Flow <br />AC <br />I <br /> <br />T <br />AHU-1 OA 2,055 0 4.66 60.00 60 60 70% 1,719 0 70% 4,990 0 0 4,990 0 0 0 0 0 <br />Y <br /> <br />IL <br />AHU-2 Library 12,905 1635 15.01 60.00 60 60 70% 10,563 1,600 67% 16,067 10,759 4,679 14,088 9,230 4,578 1,978 1,529 101 <br /> <br />SA <br />I <br /> <br />T <br />AHU-3 Community Room 4,270 700 6.15 60.00 60 60 70% 4,177 685 67% 6,586 4,606 2,003 5,775 3,952 1,960 811 655 43 <br />Y <br />V <br /> <br /> <br />O <br />I <br />N <br />27,643 15,366 6,683 24,853 13,182 6,538 2,789 2,184 145 <br />TOTAL <br />P <br /> <br />G <br />ER <br /> <br /> <br />S <br />Assumptions <br />EXH <br /> <br />AT <br />CA <br />I <br />L <br />N <br />I <br />BI <br />C <br />G <br />ULA <br />T <br /> <br />PA <br /> <br /> <br />D <br />VARIABLES CALCULATIONS <br /> <br />PROPOSED O.A. CFM <br />See Table Above ...PRESENT HRS/WK OF SYSTEM OPERATION (HVACHRS) <br />T <br />RA <br />0 ...HRS/WK OF SCHEDULED FOR WARMUP/COOLDOWN (WUCD) Fan Law #2: S.P.n/S.P.o = (CFMn/CFMo)^2 <br />I <br />O <br />therfore: CFMn = CFMo * SQRT(S.P.n/S.P.o) <br />52 ...WKS/YR OF AIR SYSTEM OPERATION (WPY) <br />PROPOSED KW <br />See Table Above …Measured KW / Data Logger KW (FANKW) <br />M <br />N <br />Fan Law #3 BHPn/BHPo = (CFMn/CFMo)^3 (BHP is proportionate to KW); CFMn=CFMo * (S.P.n / S.P.o) <br />...ELECTRICITY UNIT ($) COST/KWHR (ELECCOST) <br />therfore: (CFMn/CFMo)^3 = KWn/Kwo <br />4977 ...HEATING HRS/YR FROM WEATHER DATA (HHPY) <br /> E <br />ME <br />FAN ENERGY (KWH/YR.) <br />See Table Above ...TOTAL SUPPLY FAN CFM (CFM) <br />T <br />Basseline = (WINTER KW * HVACHRS * (HHPY/168)) + (SUMMER KW * HVACHRS * (52-(HHPY/168))) <br />See Table Above …TOTAL OA CFM (OACFM) <br />ER <br />62 ...UNOCCUPIED HRS. SPACE HEATING SETPOINT (HTSPUNOC) Proposed = (PROPOSED WINTER KW * HVACHRS * (HHPY/168)) + (PROPOSED SUMMER KW * HVACHRS * (52-(HHPY/168))) <br />27.9 ...AVERAGE O.A. TEMP. DURING HEATING SEASON (AVEDBT) FAN ENERGY COST ($/YR.) <br />T <br />...$/BTU COST OF HEATING ENERGY (HEATCOST) <br />= FAN ENERGY * ELECCOST <br />HODS <br />0.9 …BOILER EFFICIENCY (BTU) VENTILATION (BTU/YR.) <br /> <br />1.4 …CHILLER EFFICIENCY IN KW/TON (KWTON) Basseline = ((BIN-DELTA T-HRS) * OACFM * 1.08) + (0.4 * (BIN-DELTA T-HRS) * TOTAL-CFM * 1.08) <br />& <br />2462 ...COOLING HRS/YR FROM WEATHER DATA (CHPY) <br />Proposed = ((BIN-DELTA T-HRS) * PROPOSED OACFM * 1.08) + (0.4 * (BIN-DELTA T-HRS) * PROPOSED TOTAL-CFM * 1.08) <br />14.7 ...COOLING WEEKS PER YEAR (CWPY) = (CHPY/168) <br />VENTILATION COST ($/YR.) <br /> <br />= VENTILATION COST * HEATCOST <br />6.2 …COOLING ENTHALPY DELTA (ENTHALPY) <br />S <br />55 …MIXED AIR TEMPERATURE SETPOINT (MAT) COOLING (KWH/YR.) <br /> <br /> <br />Basseline = (HVACHRS * CWPY * OACFM * 4.5 * ENTHALPY / 12,000) * KWTON <br />Proposed = (HVACHRS * CWPY * PROPOSED OACFM * 4.5 * ENTHALPY / 12,000) * KWTON <br />COOLING COST ($/YR.) <br />= COOLING COST * ELECCOST <br /> <br />Pa <br />g <br />e <br /> <br />15 <br /> <br />o <br />f <br /> <br />27 <br /> <br /> <br />