we are doing energy modeling for a mixed used tower (residential 30 flrs and office 6 floors and 5 floors parking under ground) can any one help in determining the following:
a- baseline case:
1-the envelope requirements should be residential or non residential.
2- how to model different floors in equest.
3-i m going to rotate the building as requested but how to average the values.
4-zoning in the residenatial area can it be per bedrooms or is there a preferred way.
5-what s the hvac system type to model.
6-ashare is talking about 25% factor of safety in cooling and 15 % in heating.what value shall i use in cooling load because in proposed case ashare is talking about actual equipment size (do they mean i should provide a factor of safety).
7-service water heating design shall i follow ashrae fundamental chapter or any preffered method.
8-landscape lighting is included in which section lighting or process load.
regarding proposed building:
1-automatic shades how to provide a schedule for it (residential and offices)
2-parking lighting system how to benefit from motion sensors (and same for all areas.
3-hvac system modeling using part load curves...where to get these curves.
finally can anyone provide me an actual modeling example documented and commented as here the documentationprovided when we don't have a simulation.
sorry for this long email.
regards,
tarek
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
July 19, 2010 - 9:10 pm
Let's see what we can do here:
a-baseline case
1 - envelope requirements - both! residential floors get modeled with residential envelope requirements, non-residential with non-residential
2 - modeling different floors in eQuest - easy to do, just create separate blocks in the wizard mode. Sorry, I can't give eQuest lessons here.
3 - how to average - add the results, divide by 4
4 - zoning - zoning in the base case should match actual zoning design (See Table G3.1 sections 7 & 8, of Appendix G, ASHRAE 90.1-2007)
5 - Read Section G3.1.1 - assuming the office is at least 20,000 sf, it needs to get modeled as a separate system. Depending on your heating source, you are probably System 1, for the residential areas, and System 7 for the Office.
6 - The base case systems get autosized by the program, but you are allowed to add a safety factor to their sizing. It is an input in eQuest. As you mentioned, the design case sizing is per the drawings.
7 - DHW - not clear on the question - read Table G3.1, section 11 - it will answer your question.
8 - landscape lighting - you can calculate exterior lighting separately if you like - in a spreadsheet. Base case should be based on the prescriptive requirements in section 9.4.5 of 90.1
Proposed Building
1 - automatic shades - I don't remember - does eQuest allow automatic shades to be modeled? I would schedule them just like you do any other item in eQuest, but I'm not 100% sure it is in the program - I'll get back to you on that.
2 - parking garage lighting - this likely requires an exceptional calculation measure - I would do this on a spreadsheet, and be careful about documenting your assumptions.
3 - equipment curves - decent curves are already in eQuest, or you can ask the manufacturer.
whew! I'm tired.
Tarek Dalati
Sustainbility managerCRHI
92 thumbs up
July 20, 2010 - 2:39 am
cristopher thank you for your reply.i hope you feel better now.
regarding the saftey factors in the proposed building.if hap is used for hvac load calculation and the factor of safety can be what ever we want.what it s usually a common practice(we usually use 10% for sensible cooling and 5 % for latent cooling and 0% heating (as no heating is required in dubai)
regards,
tarek
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
July 24, 2010 - 6:58 am
Yes, you can size your proposed system however you like. Generally oversizing carries with it an efficiency penalty. But the base case that you compare to must be autosized by the modeling program using the safety factors described. If you can live with smaller safety factors in your proposed design, good for you - it may show improved performance compared to the base case.