Hello @Grasshope and team,
Good question, as always. You are right that many of these outputs have to be calculated from other E+ otuputs since, even though E+ has hundreds of outputs, it’s missing a few critical ones that are needed to make complete energy balances.
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Your summary is mostly correct. The window conduction is calculated from the Surface Total Window Heat Gain/Loss energy once solar is subtracted out from this total energy (it looks like you already figured this out on this thread).
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The storage term is basically just the remainder after all other energy balance terms have been accounted for. So it’s calculated by computing all of the other gain/loss variables from the E+ outputs and then adding these terms together (since the energy balance terms must sum to 0 in order to obey the first law of thermodynamics). It’s mostly there just to make sure that the energy into the building equals the energy out. For most energy balances, you want this storage term to be relatively small over the long time periods like a month. Otherwise it can be an indication that there’s another important energy balance term that isn’t being accounted for. Along this line of reasoning, the storage term can be useful for accounting for other phenomena that aren’t present in the other terms. For example, if you are looking at the energy balance of a singe zone that is a part of a multi-zone model, the storage term is an indication of the flow to/from your zone to the other zones.
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@SamueldeVries has pretty much answered the question about mechanical ventilation heating/cooling. E+ doesn’t give us the energy needed to heat/cool the outdoor ventilation air on its own. However, we can figure this out because we can get the total amount of heating/cooling done by ideal air system (ventilation + zone cooling) and the amount of heating/cooling that the ideal air system has done to just the zone (without ventilation air).