ASHRAE 90.1-2010

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Just wanted to reserve some space for some awesome data I received yesterday.... Bob you may want to sit down for this...No more heat pumps in Electric rooms. Starting with spaces such as toilet rooms, storage, mech/elec rooms, stairs, vestibules...will be allowed to modeled as heating and ventilation only units Sys#10&11. No longer will the cooling be required to be included even if not providing mentioned in Appendix G Table 3.1. {More to come}

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90.1-2010 is only claiming 20% improved performance over 2004 levels. I'd thought they'd push harder since I'm going for 40% better than 2007 all the time...

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This is really good stuff. I would love to start a 90.1 directory where we classify stuff like this. If only more users had your bounty hunter skills when hunting down 90.1 issues.
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[quote=Bobba_Fett]Economizers (airside): Will be required in all Climate Zones except 1A and 1B down to 54MBH equipment. With inclusion of 90.1-2007 Addendum AU, BU, and CY[/quote] One exception is if you have more efficient equipment. There is a table by climate zone stating what higher level efficiency is required for that climate zone to allow no economizer. Frankly the increased efficiency requirements are so high for the colder climate zones it would make no sense to NOT use an economizer.
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Economizers (airside): Will be required in all Climate Zones except 1A and 1B down to 54MBH equipment. With inclusion of 90.1-2007 Addendum AU, BU, and CY

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Ventilation Rate: Per LEED v2.2 and the current v3.0 it is unclear as to what rate means. The overall end total sumation of all the ventilation rates of the baseline and proposed equipment, or space by space rate per person plus per square foot. Either can and has been argued to comply, since the other EQ prerequisite minimum ventilation per ASHRAE 62.1 is met and would correlate to the rates within your supporting documention of EAc1 for the Proposed Design. Until ASHRAE 90.1-2007 Addendum DA Exception (b.) the term "rate" was undefined. Exception b. now requires that the baseline building model follows the Ventilation Rate Procedure of 62.1 using the rates listed in the Ventilation Rate Table, and comply with the corrected outdoor air fraction. So if you have a non-residential 5-story building like I did, you van no longer take the total Proposed CFM and divide it by the Squarefoot and lambaste it in the Baseline Model ventilation rates. You will need to go through the iterative process to get the Cooling and Heating ventilation rates to equalize, by various methods (increasing the min VAV setting beyond 90.1 Appendix G min 0.4cfm/sf). Once they equalize, stop. Any further efforts will reduce the ventilation more and start increasing you Heating supply air (SACFM). This will show a benefit to the Dedicated Outdoor Air Systems now, and I think it should. This great and wonderfull system should not be penalized or neutralized by having energy neutral ventilation among the two models. So iterations are fun, I know, but stick with it ;-)

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Unmet Hours: 90.1-2007-An hour in which one or more zones is outside of the thermostat setpoint range AND Appendix G allows up to 300 unmet hours and within 50 unmet hours between Baseline and Proposed designs....90.1-2010-An hour in which one or more zones is outside of the thermostat setpoint plus or minus 1/2 of the temperature control throttling range. Any hour with one or more zones with an unmet cooling load or unmet heating load is defined as an unmet hour AND Appendix G will only allow up to 300 unmet hours, no delta 50 unmet hours.|||||Throttling Range 2°F (1/2=1°F) Setpoint at 75°F, Thermostat Setpoint Range 74°F - 76°F (DoD UFC's AR-420-1 require Barracks at 72°F - 74°F ±2°F).

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[quote=Bobba_Fett]Just wanted to reserve some space for some awesome data I received yesterday.... Bob you may want to sit down for this...No more heat pumps in Electric rooms. Starting with spaces such as toilet rooms, storage, mech/elec rooms, stairs, vestibules...will be allowed to modeled as heating and ventilation only units Sys#10&11. No longer will the cooling be required to be included even if not providing mentioned in Appendix G Table 3.1. {More to come}[/quote] Who's Bob? What you've stated is not necessarily true. The PREDOMINANT spaces and conditions will dictate THE baseline system type. Exceptions to G3.1.1 allows additional baseline systems. Systems 10 & 11 will be used for mostly heating only building types (i.e. warehouses) or additional baseline systems per the exceptions to G3.1.1.
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Only speaking from my experience with USGBC on a couple Office designs that was under their review. One of the designs passed, even though it was a single communications room, under 20,000sf, (App-G exception for secondary systems) as I understood their CIR ruling for someone else's design. The 2nd building needed clarification, since the reviewer didn't understand why I modeled Elec Rooms and Comm Rooms with Split HP for heating and cooling. After a brief explaination of where I was coming from, he accepted the design. BUT it seems that LEED was confusing the matter with their CIR ruling, basically saying that even if the space does not qualify for a secondary HVAC system, they still wanted to see it modeled differently. Now 90.1 is clarifying the matter for all. Which brings me to what came out fo the Webinar I attended, without having 90.1-2010 in front of me, their words were that rooms that are heated only can be modeled as heating only, as defined by 90.1's definitions for heated or semi-heated spaces. You don't need to model an electric room with no exterior walls with having an electric unit heater, it can just be exhausted if that is all it takes. Again, wasn't speaking on warehouses. As for Bob F. he's a great resource to go to.

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