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Filter efficiency (e) can be reasonably estimated as 0.9 pending manufacturer’s information.<br>In a study of three sites in Ontario, STEP found the annual C<sub>vol, A</sub> of the rooftops to be around 0.8 [http://www.sustainabletechnologies.ca/wp/home/urban-runoff-green-infrastructure/low-impact-development/rainwater-harvesting/performance-evaluation-of-rainwater-harvesting-systems-toronto-ontario/]. This figure includes losses to evaporation, snow being blown off the roof, and a number of overflow events.<br> {{textbox|{{plainlist|*Five percent of the average annual demand can be estimated:*<strong>D<sub>0.05</sub> = P<sub>d</sub> × n × 18.25</strong>
Rainwater harvesting: Sizing and modeling (view source)
Revision as of 13:39, 17 August 2017
, 7 years ago→Simple
*''R<sub>a</sub>'' = The average annual rainfall depth (mm)
*''R<sub>a</sub>'' = The average annual rainfall depth (mm)
*''e'' = The efficiency of the pre-storage filter}}
*''e'' = The efficiency of the pre-storage filter}}
Filter efficiency (e) can be reasonably estimated as 0.9 pending manufacturer’s information.<br>
In a study of three sites in Ontario, STEP found the annual ''C<sub>vol, A</sub>'' of the rooftops to be around 0.8 [http://www.sustainabletechnologies.ca/wp/home/urban-runoff-green-infrastructure/low-impact-development/rainwater-harvesting/performance-evaluation-of-rainwater-harvesting-systems-toronto-ontario/]. This figure includes losses to evaporation, snow being blown off the roof, and a number of overflow events.
Five percent of the average annual demand can be estimated:
<math>D_{0.05} = P_{d} \times n\times 18.25</math>
Where:
{{plainlist|
*''D<sub>0.05</sub>'' = Five percent of the average annual demand (L)
*''P<sub>d</sub>'' = The daily demand per person (L)
*D<sub>0.05</sub> = Five percent of the average annual demand (L)
*''n'' = The number of occupants}}
*P<sub>d</sub> = The daily demand per person (L)
*n = The number of occupants}}}}
Then the following calculations are based upon two criteria:
Then the following calculations are based upon two criteria: