To ?roll your own? savings for pool covers:

1. First calculate heating loads sans pool cover measures.

a. I do not do pools every day, but have also adapted the 2004 Shah method in lieu of ASHRAE Applications approach a few times now (discussed in the link shared previously by Elizabeth). Note both models are intended for indoor pool applications, so ?correctly? adapted/applied to exterior conditions you might get odd results ? keep a sharp eye out!

b. An outdoor heated pool would be a slightly trickier problem to accurately calculate, as you are now dealing with variables from your weather file to include air velocity (hourly windspeed ? you mentioned rooftop so this might require further processing considering elevation) and a broader range of air conditions (DB temperature + RH), from which you could derive hourly dewpoint ? saturation pressure for those air conditions , and then also the saturation pressure at the pool surface . You may also want to consider conductive losses to the environment/ground below the pool depending on the circumstances. I haven?t done it, but it seems like there may be a workable path here (looking at the 2015 ASHRAE Applications equation #1, specifically).

c. I recommend at minimum reading up on some of the already cited literature, but here?s an open-source/public tool building upon the Shah approach to if you need to get a fast approximation ? be mindful again this is without further edits intended for indoor applications: http://www.energyideas.org/documents/spreadsheets/IndoorPoolCalc.xls

2. Take a moment to look hard at the pool cover system(s) under consideration. Decide for yourself by what factor that cover system, when deployed, will reduce evaporation/convection losses (a lot, typically), and radiation losses as well if an insulated variety (I?d estimate this leveraging the hourly weather data + pool temperature profile + cover R-value ? UAdT).

3. Determine a likely profile for cover system deployment ? consider whether the system is automated or human-deployed when evaluating your results? if you are ultimately into ?guessing at human behavior? territory here, recognize you shouldn?t spend too much time worrying about the finer nuances for this estimation and should consider presenting your savings as more of a ?range.?

4. With that information at-hand, calculate hourly heating reductions from your ?sans cover? calculations.

5. To spoon feed back into eQuest:

a. Take your before/after hourly heating loads columns,

b. Normalize each to a maximum hourly load (loop process load input for eQuest),

c. Punch them into EMIT to generate annual normalized load profile INP files you can import,

d. Assign those schedules & maximum hourly load to the appropriate eQuest heating loop

Note if this is already a large model, be mindful EMIT?s 8760 hour fractional schedules can be quite heavy to deal with in multiples ? use that tool judiciously and simplify to averaged daily/weekly/monthly load profiles if it doesn?t make a huge difference ;).

~Nick

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Nick Caton, P.E.

Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric

D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com
F 913.564.6380

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Lenexa, KS 66219
United States