[Bldg-sim] Heated Only Residential Zones in 90.1 Appendix G

Athalye, Rahul NOR RAthalye at noresco.com
Tue Jul 23 08:13:50 PDT 2019

Per 90.1-2016 Appendix G, table G3.1 (10.d), the proposed case should be modeled with the same cooling system as the baseline when the proposed design does not have a cooling system. For northern Europe, you are looking at system 1 (PTAC plus boiler). Assuming there is no cooling load, the cooling system would have no impact on your energy use. But if there is a cooling load in the baseline and not in the proposed (due to cooling load-reducing features), then the proposed design will get credit for it.


From: Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Chapin, Alex N via Bldg-sim
Sent: Tuesday, July 23, 2019 4:30 AM
To: Jim Dirkes <Jim at fsmgmt.co>; bldg-sim at lists.onebuilding.org; Omer Moltay <omoltay at mimtarch.com>
Subject: [External] Re: [Bldg-sim] Heated Only Residential Zones in 90.1 Appendix G

To follow up on this, I have some input.

I’m assuming you are using ASHRAE 90.1-2010, in which case, you would use System #1 or #2 with cooling in the Baseline model and the Proposed system as designed with the System #1 or #2 cooling system included in the Proposed model. This assumes that the residential spaces are considered “conditioned” as defined in section 3.2 of ASHRAE 90.1-2010 (using Table 3.1 the heating output of the Proposed system would need to be greater than or equal to the value listed for the climate zone). Then the cooling setpoint can be pretty much what you want as long as it’s the same in both the Baseline and Proposed. This means that even though cooling is required to be included in the models, it is not likely to be used very often between the cold climate and having the ability to set a high cooling setpoint.

If the spaces are not considered “conditioned” and are instead “semiheated” then you don’t need to include cooling in either model, but the Baseline Case system would be the same as the Proposed Case other than heating and motor efficiency improvements.

From: Jim Dirkes <Jim at fsmgmt.co<mailto:Jim at fsmgmt.co>>
Sent: Monday, July 22, 2019 11:43 AM
To: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>; Omer Moltay <omoltay at mimtarch.com<mailto:omoltay at mimtarch.com>>
Subject: Re: [Bldg-sim] Heated Only Residential Zones in 90.1 Appendix G

Mr. Moltay,
Hoping to get a discussion started.....

I agree that Systems 9 & 10 are inappropriate. I suspect that there is a natural ventilation cooling scheme, since it's unlikely that a multi-family building will have "nothing" for cooling.

If that's true, you do have a cooling system, it's just not a mechanical system. The Baseline system would then be System #1 or #2 and your challenge for the Proposed system will be to demonstrate that it maintains proper control of temperatures and ventilation.

ps, You do not need to maintain typical temperature setpoints for, say an enclosed shopping center. If the owner agrees that 30C is acceptable as a cooling setpoint, then model that.

James V Dirkes II, PE, BEMP, BCxP
Team Lead - Building Performance
616 450 8653
Foresight Management

Coffee Conversation:

If “freedom” is ability to do whatever we want, whenever we want and with whomever… that’s lawlessness or anarchy. Try that with traffic…. then think about what might happen if you try it with your life.

From: Bldg-sim <bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org>> on behalf of Omer Moltay via Bldg-sim <bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>>
Sent: Monday, July 22, 2019 6:57 AM
To: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org> <bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>>
Subject: [Bldg-sim] Heated Only Residential Zones in 90.1 Appendix G


This has been bogging us for a while, as we cannot figure out how to interpret the various issues in ASHRAE 90.1.

If in a multifamily building the residential units are only heated but not cooled in the actual design (climate is North Europe), how does the baseline get modeled? I suppose Systems #9 and #10 (Heating Only) would be out of the question as these are intended for ancillary spaces. So it would have to be System #1 or #2, but with cooling as well?

More importantly, would the Proposed residential units be modeled with additional cooling using identical systems as in Baseline?

Thank you in advance,

Mimta EcoYapi, LEED Proven Provider
Hekimsuyu Cad. 559. Sk.
No:39 34255 Kucukkoy Istanbul Turkey
Tel: 90-212-617-2296
Fax: 90-212-617-2297
Mobile: 90-533-957-1394

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