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17 Cards in this Set
- Front
- Back
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For a 4.7 kW PV array at a location with an average of 5sun-hour and an operating efficiency of 77% we what is kWhrs daily output?
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4.7kW x 5 x77%=18.09kW
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Net energy question? PV Array: 6kWAverage annual daily sun-hours: 5Estimated PV system PCE%: 80%
Daily? Monthly? Yearly? Annual MWh? |
Daily kWh= 6*5*80%=24kWh Monthly kWh=24kWh*30.4=729kWh monthly Yearly kWh=24kWh(365)=8760Annual MWh=8760/1000=8.760 MWhShow annual kWh using 85% PCE=6*5*.85*365=9307kWh
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How to cover 50% of energy usage of a 2000 kWh per monthelectricity bill when the average sun hours per day is 5 and PCE=80%.
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2000 kWh x 50%=1000 kWh 50%offset 1000/30.4=32.9kWh daily requirement 30.4days per month32.9kWh/5=6.58kW PV system AC output 5sun hours 6.58/.80(PCE)=8.33kW PV array DC rating 80%PCE
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If a PV array loses 9% of voltage due to heat, 2% toreflection, 2% to voltage drop and is connected to a 96% efficient inverter,what is the apparent PCE%?
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.91 * .98* .98 * .96=.839
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For 50% coverage of a load demand of 1000 kWh per monthaverage daily sun hours of 4.5 pv system operating efficiency of 80%.
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1000*50%=500 watts 500/30.4=16.4516.45/4.5=3.663.66/.80=4.575=kWh system needed to install 4.575(.80)*4.5=16.45kWh produced per day
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a 5000 watt PV array using modules rated at 16% efficientrequires how much space?
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16% efficient * 92.9= 14.86 w/ft^2
5000/14.86=336.48 ft squared |
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A site at latitude 34N has 500 ft available roof facingsouth with a 8/12 pitch. Thecustomer average monthly utility usage is 2500 Kwhs. The system operating efficiency is 80% and the moduleefficiency is 15%. Average sunhours are 5. What % of the customers utility bill will be offset by thePV system?
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500(92.9)(.15)=6967 watt array6.967kW x 5 x .8 x 30.4=847kWh monthly 847/2500 kWh = .3388%
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If a PV system operates as utility interactive and as astand alone system, what is it called?
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Bimodal or Multimodal
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A 5kW PV array is losing 10% of voltage due to heat, soilingand reflection account for 5% loss, the inverter efficiency is 95% and voltagedrop from the PV array to the inverter is 1%. What is the approximate PV system output?
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.90*.95*.95*.99=.803*5=4.0kW
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If a PV array is rated at 5kW the average daily insolationis 4.5 hours and the system conversion efficiency is 82% what is the expectedannual kWh produced?
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5kW x 4.5 sun hours x.82 x 365=6734.25kWhs
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A customer has a monthly electrical energy usage of 2000 kWhand wants to offset 50% of the electrical energy with a PV system. What size PV array (STC rated) would berequired to achieve this if the average annual sun hours are 5 and the PVsystem conversion efficiency is 80%?
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1000 / 30.4 / 5 / .8= 8.22kW
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If a customer pays the utility company three different ratesdepending on the time of day, what type of rate plan is in place?
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Time of use rate
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If a customer has a 750 ft squared south facing roof areawith a 8/12 pitch and 500ft squared useable for a PV array what size PV arraycan be installed if the module efficiency is 15.1?
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500 x 92.9=7013.9 w 46.5 x 1000w/msq x .151=7021
7kw |
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A PV system produces 200,000 kWhs over a 20 yearperiod. The net cost of the PVsystem is 20,000. What is thelevilized cost of Energy of the PV system or this period of time?
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20,000/200,000=.10 cents a kWh
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If the above PV system produces 11,000 kWhs of electricalenergy in the first year and the utility rate is 11 cents kWh how much of thecost of electrical energy is offset for that period?
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11,000 x .11=1210
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If a customer wants an 8kW PV array mounted on their roof,approximately how many square feet or square meters will it occupy if themodule efficiency is 15%?
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8000/92.9/.15=574ft squared8000/ 1000 / .15= 53 m squared
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If a PV module is STC tested to be 19% efficient what is theapproximate AC energy density in watts per square foot if the PV systemconversion efficiency is 80%?
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.19 x 92.9= 17.65w/ftDC x .80= 14.12 w/ftAC
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