[Archived phorum post from squ1.com v2 by Caroline Prochazka]
Hello,
I am pursuing some modeling on existing Canadian buildings, to determine what role daylighting plays in the level of building sustainability (a cludgey way to explain it, but...).
What I would like to know is if Ecotect has the capacity to calculate an annual energy use (rather than hourly/monthly) for heating, cooling, AND lighting, whether as a single number or three separate numbers on one model.
Do the thermal calculations take into account the daylight, which can reduce electric lighting use, and hence reduce some interior heat-gain?
What I am trying to do is to generally determine what is/are the limit(s) to pay-offs for using daylighting (hence reduced lighting energy needs vs. changes in heating and cooling demands).
If I understand correctly I will need to carefully model zones, in order to calculate thermal loads. For my daylight level analyses, must this be a separate (albeit simpler to construct) model, or is is possible to do both thermal and lighting in the same model?
Thanks in advance,
Caroline P.
M.Arch candidate
University of Waterloo
Re: Whole Building Energy Use
[Archived phorum post from squ1.com v2 by Andrew]
Hi Caroline,
When you calculate monthly energy use values, the text box immediately below the graph also contains the total annual heating and cooling values - as well as peak instantaneous loads.
You can also use the Resource Consumption calculation to compare total energy use. As an example, the graph below compares heating and cooling loads, electricity use, gas use and fossil fuel use - which can be displayed as KWh or as kgCO2.
The electricity loads are generated by any appliances, lights and speakers in the model. Thus, if you were wanting only lighting energy, then only put lights in the model and you can use the one model for thermal and lighting.
Your big problem is how to calculate potential energy savings from daylight. If you have a room with a single light in the middle, it doesn't matter how well-lit the perimeter near the windows is, if it's dark further in the light will always be on and there will be no savings. Similarly if there are multiple lights but only one switch. Thus you will have to decide on which theoretical model to use and then get to grips with the assumptions it is based on. The Daylight Automony functions in ECOTECT will be good as a first take, but they only really indicate potential savings - you will still need to look closely at behavioural aspects and the specifics of the lighting design.
You should consider generating your model in ECOTECT and then exporting it to EnergyPlus for your final thermal and daylight analysis. You will find it relatively easy and allows you to take advantage of the modelling and visualisation functions of one tool and the analysis potential of the other.
Hope that helps...
Regards,
Andrew
Dr. Andrew Marsh
Square One research Pty Ltd
DaySim - works like a charm with Ecotect
Hello Caroline,
Your question sounds very much like one I had for my project as part of an MSc in Energy. I ended up using three programs to investigate the question - Ecotect (for the wonderful geometrical modeling), ParaSol (for the simple office I was investigating for heating and cooling energy - this one can handle heat recovery), and DaySim for the annual daylight/electricity analysis.
You can find DaySim at http://irc.nrc-cnrc.gc.ca/ie/lighting/daylight/daysim_e.html
DaySim is free from Natural Resources Canada and uses the Radiance calculation engine. It's strength compared to other programs is that it gives annual natural daylighting metrics and lets you know how much electricity you can save.
Regards,
Wendy