Hardware license CERN-OHL-S Start OSHWA certification

The Waterpod will be collecting rainwater from a few of the impermeable roof areas. The calculations for collection are on this spreadsheet. There are three tabs feeding the results:

• Tab:Collection Calcs - Calculates the monthly availability of the rainwater.
• Tab:Collections Dimensions - Calculates the available rainwater collection area based upon the planned structures.
• Tab:Regional Climate Data - Show monthly rainfall from historical averages. Could be made more current.

## Regional Climate Data

The historical 1971 - 2000 Rainfall Normals for Central Park, New York[1] are:

Jan Feb Mar Apr May Jun
3.42 3.27 4.08 4.2 4.42 3.67
Jul Aug Sep Oct Nov Dec
4.35 4.01 3.89 3.56 4.47 3.91
Annual
47.25

## Basic Calculation

${\displaystyle Collection\ Volume(gal)=Rainfall\ (in)\times {\frac {1ft}{12in}}\times Collection\ Area\ (ft^{2})\times {\frac {7.48gal}{ft^{3}}}\times Roof\ Coefficient\times Efficiency}$

or

${\displaystyle V=R\times A\times k\times e}$

(in some cases the efficiency of the system is assumed to be 100% and therefore equal to 1, having no effect on the rest of the equation.)