I have seen many comments in this forum stating that plug loads should be metered seperately from lighting loads. I'm not sure if seperating these loads is actually necessary. We have a high rise building seeking C&S certification. The owner is installing all the lighting and outlets for tenant spaces. A number of busways run vertically through all the tenant occupied spaces. One Busway feeds lighting and pug loads on each of the floors. This busway is equiped with one electrical meter at the base of the building to measure the lighting and plug loads together. Our energy model seperates plug load energy use from lighting energy use. The ASHRAE baseline plug load use is identical to the proposed in our energy model. Therefore we have no ECMs associated with plug loads.
Question: Is there any problem with this metering setup for an M&V plan? Should we be asking Project teams to seprate plug load circuitry from lighting circuitry? Why?
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5922 thumbs up
October 25, 2013 - 9:22 am
You cannot properly calibrate the energy model without some mechanism to verify the accurate modeling of energy use by each end use. You do not necessarily have to submeter each one to do so. You can use spot measurements/short term trending to estimate one or the other of these uses and derive a separation through calculations based on data without having to separately submeter. The Plan should outline how you are going to separate these loads.
The fact that there are no ECMs associated with the plug loads does not matter. You still must claibrate the proposed energy model against the actual utility bills and verify that you modeling assumptions related to the plug loads and the lighting were correct or not. If not you change the model to reflect the data collected. This is a fundamental difference between the IPMVP applied to ECM project where there is before and after data versus new construction where there is no before data.
There is no problem with your metering set up (metering is not required at all by the IPMVP) as long as your Plan describes how these loads will be separately measured without submetering. However, in a large high rise it is often far cheaper to submeter as opposed to gathering the necessary data by hand post-occupancy.