I am using EE4 to model an office building with natural gas RTU's but electric reheats at the zone level. The reference building is only using natural gas for heating, rather than gas + electricity as in the proposed design. I'm getting very nice energy savings overall, but since my electricity use for the proposed case is actually higher than that of the reference, the cost has not gone down much at all (electricity is a lot more expensive here than natural gas.)
Is there any way to get EE4 to model the electric zone reheat capacity in its reference case?
I have the RTU's defined with electric zone reheat coils.
Thanks!
Alex Blue, EIT
P.S. I'm new to the list, so hi! Nice to meet you all.
Hi Alex,
Define your system as a 2 pipes fan coil (or 4 pipe if you also do zone
cooling ). The heating at the zone level will be handled by the hot water
coming from your plant boiler. Define your plant boiler energy source as
electric. The energy consumption for your zone heating coil should then be
electric for the proposed and reference building.
You can also look in the EE4 modelling guide for 2 or 4 pipes systems
operation.
Don?t hesitate if you have more questions.
Regards,
Marc-Antoine Paquin, eng.
De : bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] De la part de Alex Blue
Envoy? : 30 mai 2011 11:17
? : bldg-sim at lists.onebuilding.org
Objet : [Bldg-sim] EE4 heating source
I am using EE4 to model an office building with natural gas RTU?s but
electric reheats at the zone level. The reference building is only using
natural gas for heating, rather than gas + electricity as in the proposed
design. I?m getting very nice energy savings overall, but since my
electricity use for the proposed case is actually higher than that of the
reference, the cost has not gone down much at all (electricity is a lot
more expensive here than natural gas.)
Is there any way to get EE4 to model the electric zone reheat capacity in
its reference case?
I have the RTU?s defined with electric zone reheat coils.
Thanks!
Alex Blue, EIT
P.S. I?m new to the list, so hi! Nice to meet you all.
Review the section "Determination of Principal Heating Source" in the EE4 modelling guide. Essentially you should use the fuel source with the highest energy source adjustment factor which contributes at least 10% to the total heating capacity of each zone (including both terminal and system capacity). Since electricity has a higher ESAF than natural gas, if your electric reheat contributes at least 10%, then the principle source will be electric.
The heating source is entered at the zone level.
Kyle
Hi Alex,
You can not modify reference case in EE4 but you can modify it in DOE.
Reference case is based on MNECB and to have a
electric heat in the reference case, the propose
building have to use electricity more than 50% for heating.
Martin Roy, ing. PA LEED
question on EE4 1.7 to model heating only (electric baseboard with gas make up air unit for high rise residential):
Does the EE4 calculation heating only performance? or cooling has to be met under 100 hours even no cooling in the building?
After I calculate, waring shows 3000+hours unmet cooling load, which to me make sense that I don't have cooling in the building at all.
But when I try to print report, it says" The energy use results needed for the report are not available...click yes to print report without any results, it has generated 29% better than MNECB, but on summary report $ saving is only $8697/95656 (proposed $86956, reference $95656).
Should I use the number generated in the summary report and energy cost summary manully calculate the % savings? my case 8697/95656= 9.1% to tell client that the building is not comply with LEED2009 requirement?
Thank for input