Component loads -- internal gains vs surfaces #2097
Description
Consider adopting the approach taken in the ComStock measure to better attribute heat gains:
Lighting, equipment, and people generate heat that is released as instantaneous convective heat gain to the zone air and as radiant heat that is absorbed by zone surfaces. If the surfaces are warmer than the zone air, this radiant heat will later be released by the surfaces as convective heat gain. If the surfaces are colder than the zone air, the radiant heat will warm them, reducing convective heat loss from the zone air to the surfaces. Reporting of load components from the heat balance calculations performed by EnergyPlus will attribute the delayed load to the surfaces, not the equipment. Correctly attributing the impact of internal gains on system load requires calculating the delayed effect.
To calculate the delayed component, we use terms from another load calculation method – the radiant time series method (ASHRAE American Society of Heating Refrigerating and Air-Conditioning Engineers 2017). The instantaneous radiant component of internal gains is diffused over 24 hours using a set of radiant decay coefficients. Most of the delayed radiant components are realized in the first 12 hours, though we use 24 hours to capture any prolonged interactions with thermal mass. These delayed radiant components are subtracted from surfaces within the zone proportional to surface area and added back to the internal gain components that originally generated them.
Should check how significant the impact is before taking the effort to implement it.