Wed, October 11, 2017 10:09 AM
Option 1 - No. I think the measure should be defined narrowly enough so the savings represents the efficiency of installing the measure in the ventilation only mode in the "on" setting. If there is a question about the baseline setting, then the research plan could try to address this.
Wed, October 11, 2017 4:09 PM
Kevin, you're right about there being a question about the baseline setting. Any time the pre-existing fan setting is in "auto" mode (ventilation-only mode is "off), the question is whether, for purposes of estimating savings, we should assume for the baseline that the fan is set to "on" or "auto". Are you suggesting the research strategy should ask about the building occupants' intentions ("without the measure, would you have set it to "on"), or are you suggesting the research strategy would simply look at the pre-existing setting and reduce savings where the fan was in "auto"?
Thu, October 12, 2017 8:51 AM
I am not suggesting asking about their intentions. And, I'm not even that concerned about the pre-existing setting, but it seemed like there is enough concern about this among RTF members. If they are going from inadequate ventilation to adequate, but efficient ventilation then I think the measure is fine and no discounting/reduction is needed.
Energy Trust of Oregon
Thu, October 12, 2017 11:40 AM
Regarding research plans: We should all be aware that there is no guarantee that any research plan this team designs will ever be implemented. At this point, I'm not aware of any group that has plans to do this work. And if anyone does choose to research the measure, they are not beholden to the plan. I worry that we're putting too much time into the details of a plan and too much confidence that it'll be followed.
Wed, October 11, 2017 10:41 AM
Option 2, Reason 3. The baseline “building’s decision-maker/T-stat setter's understanding” was that the indoor conditions were fine with the fan in Auto, or perhaps there was just no knowledge. However, if the building indoor conditions seemed stuffy or otherwise uncomfortable, chances are that somebody would have changed the T-stat. Unless the fans never run, there is ventilation, it just isn't constant, so the text shouldn't refer to "unventilated" cases. The ventilation when the fan is on for space conditioning could be totally sufficient. Also, for purposes of IAQ, air changes separate from mechanical ventilation are important. Retail stores often have their doors open during moderate conditions, which contributes. We don't know the baseline ventilation, but there is some, so the research plan should try and determine (1) the percentage of applicable zones for which the fan is in Auto, and (2) for those zones, the acceptability of the indoor air conditions, likely relative to ASHRAE Guideline 62. Then a determination could be made as to whether and how much any increased ventilation is needed, and calculate the appropriate baseline fan energy.
Wed, October 11, 2017 4:16 PM
Bill, you're right about my incorrect use of the word "ventilated" or "not ventilated". Even a building without any mechanical system has some (natural) ventilation. To clarify, any time we talk about ventilation with respect to this question, we're talking about the fan setting: is it set to operate in a ventilation-only mode ("on") or not ("auto"). Thanks for clarifying that. With that out of the way, it sounds to me like your opinion on this question is to set the baseline energy consumption independent of what the building operator is doing, but instead set the baseline energy consumption at what level of ventilation the building/space should have (per ASHRAE, maybe). Is that right?
Wed, October 11, 2017 4:41 PM
" your opinion on this question is to set the baseline energy consumption independent of what the building operator is doing, but instead set the baseline energy consumption at what level of ventilation the building/space should have (per ASHRAE, maybe). Is that right? " That is the ideal. It would incorporate, then, the need for ventilation for health. I suspect that will be very hard to get, so my default would be the pure existing conditions, since if they were clearly/obviously objectionable somebody would change the Tstat fan setting.
Wed, October 11, 2017 4:18 PM
Bill, I forgot to ask: For the provisional estimate of savings, what number would you put in the blank percentage in option 2?
Wed, October 11, 2017 4:47 PM
I don't know what it should be. I suggest we go with what we know from CBSA, if that is at all sufficient for a semi-reliable or reasonably number. Absent that, guess 25%. I think it will vary significantly based on building type, zone type, and perhaps zone/RTU size.
Wed, October 11, 2017 1:52 PM
I think I choose option 1, although the wording is confusing. There is no 'ventilation only' mode, just fan auto or fan on. This is consistent with the way the measure is delivered in that the control will not be installed until the unit is brought up to code and all repair needed are made. Health and safety code requirements always override energy. I don't think any verbiage is needed in the specification about whether the owner knows about possible increased energy use. We can assume that owners intend to follow code.
Wed, October 11, 2017 4:28 PM
Janice, I'm sorry for the confusing wording. By "ventilation-only" mode, I mean that the fan is allowed to operate/set to operate without heating or cooling, for the purposes of ventilating (only). This is the "fan on" mode. With that clarified (hopefully), I'd like ask you about your health/safety comment. I wasn't aware that existing commercial buildings were required to ventilate under a health/safety code. I knew new buildings were required to meet the code, but can you point to me where it says (in Oregon, for example) existing buildings are required to meet a certain mechanical ventilation standard?
Thu, October 12, 2017 11:37 AM
Adam, OR and WA at least have adopted the International Mechanical Code which you can see here; https://codes.iccsafe.org/public/document/code/549/9788118 The ventilation section states: "The ventilation system shall be designed to supply the required rate of ventilation air continuously during the period the building is occupied, except as otherwise stated in other provisions of the code" The only exception I could find was for low rise residential. It says more or less the same thing under controls in section 405.1
Fri, October 13, 2017 3:49 PM
There is a thread in these comments that implies that the ventilation rate is fixed by the code and that it can be predicted using the code values. This is probably overstating the impact of code on engineering design let alone ad hoc HVAC installations that are placing RTUs. The Oregon mechanical code, for example, allows the ventilation to be supplied with operable windows. It also states the the table values are designed to be the capability of the equipment not the operation of the equipment. Thus a code compliant RTU could have a minimum damper setting but still have a a complying system even though the fan is not running continuously. This "capability" language is also in the Washington code. How we interpret this section could be that the minimum flow rates are as described in the table and are supplied continuously during occupied periods, but the code definitely doesn't say that. The second problem here is that there is no air flow sensor measuring delivered air flow in RTU equipment. The damper setting might be fixed at some percent opened but the air flow is not regulated. In effect this means (in the absence of a flow measurement device) you cannot assume that the ventilation provided meets, exceeds or is non-compliant. As a practical matter the measure (if it includes the DCV) will normalize this situation as long as the fan is operating. The occupant could still intervene and force a "fan auto" setting. The PSE data (from 2005) measures total air flow and OA flow at the units as found. The implication here is that the amount of ventilation delivered is about 25% of the total airflow. In about 15% of the cases the damper is probably closed and we only have leakage. That group delivers about 5% of the air flow as OA. I reviewed the CBSA data on RTUs and it records intermittent fan operation in 58% of the cases were any fan control was identified. In that case the minimum damper setting would provide ventilation whenever the thermostat requested conditioning. As near as I can tell that would meet the IMC requirements as long as the damper setting delivered outside air at some percentage of the air flow. It is inherently unenforceable to go beyond that. .
Energy Trust of Oregon
Thu, October 12, 2017 11:35 AM
I'm still undecided. I would like to suggest option 1, reason 2 with the assumption that the building's decision maker called a contractor to do the work of improving the HVAC system and if the contractor wasn't installing this measure, they'd be doing other work probably including correcting any ventilation problems. Under this assumption, incremental costs would be the difference between the controller and some other option. This assumption does not apply to scenarios where programs initiate the measure such as direct install programs.
Thu, October 12, 2017 12:33 PM
I don't quite understand the questions or agree with the answers as laid out above. I think the question is whether ventilation is viewed the same as productivity gains we would have for industrial. I think there is a distinction between output and productivity and things like ventilation rate and increased comfort. I would keep these distinct and not muddy them together. I think the Act, as interpreted by the Council lawyers, has conservation as something that can increase consumption when the energy intensity declines. That is tangible and can be quantified. But for ventilation, thermostat settings and comfort measures, I do not think it is tangible and clear in the same way. While utilities are in the business of providing power to economic growth (hence why energy intensity is clearly in scope), it is less clear that it is utility business to improve ventilation practices. If ventilation practices improve, but we have no energy reduction, is this an appropriate place to claim savings? Ventilation seems one step removed from energy intensity, and falls into squishy land of comfort and preference. For instance, if people add a bunch of light sockets, making their LPD constant, who’s to say whether that is better light quality or wasteful? I would check in with the Council lawyers on this one for the definition of efficiency, which I don’t think is a guidelines decision. They have some clarifying memos on what efficiency is, and it seems like this would fall under that purview of a definitional question appropriate for them, versus the RTF and CATs. My personal judgment is that we should not adjust savings for changes in ventilation in a pre-conditions baseline measure.
Thu, October 12, 2017 2:19 PM
While I was unable to attend the last call I am convinced that this is the wrong question. The data collected in 2005 from the original PSE RTU program included baseline air flows and fan settings on 212 RTUs in about 19 establishments. 78% of fans were on continuously (at least during occupancy). 20% of fans were on regardless of occupancy including the morning warmup cycle. Approximately 15% of all fans had no flow (<10% OA fraction) when the damper was closed. This fraction does not vary with "fan on" status. The damper was always closed unless there was an economizer call. For all cases that had some flow at minimum damper setting the OA fraction as a percent of max CFM was about 25% if the OA was set above zero. The fundamental assumption in this question is that the operator has control of the ventilation rate and can select based on some rational assessment of the ventilation requirements of the building. This is almost certainly not true. The damper settings are typically constant ones the equipment is installed. This means that the installer selects the occupancy rate based on a combination of judgement, bias, and ignorance. In short the fundamental assumption is flawed. The "fan on" setting is under occupant control but this usually is set to insure some sort of distribution and mixing. Ventilation is a secondary consideration. All this suggests that measure identifiers should be used. This could be fairly simple such as : if the "fan on" setting used? Is the minimum damper setting "closed"? Is there an existing schedule for the temperature? These could be Yes/No categories and in those categories we could set the assumptions based on this data of CBSA or some other form of tea leaves. I am quite syure that no one set the ventilation rate using any particular understanding of the occupancy, the effect of their damper setting, or any concern about the status of the fan setting. To argue that it is otherwise is to ascribe to this occupancy a level of understanding and concern that is more illusion than analysis.
Thu, October 12, 2017 3:31 PM
I have to admit that I'm still confused by the Options; perhaps it's just the wording, but I think the main issue is less one of pre/post ventilation rates but instead the status of air handler control in the base case. This is the primary savings for ARC-lite. The data Dave brought up for the early part of the PSE rooftop program suggests a high fraction of cases with the air handler running in non-AUTO mode. The most recent CBSA suggested that perhaps half of cases had 'intermittent' air handler operation (but we're not sure yet what 'intermittent' means). I'm also trying to find out what the air handler duty cycle was for the 200 sites that were studied by Cadmus in 2009. I think using the best possible empirical estimate of the base case fan control strategy is the best way forward to estimating savings from the fan control portion of the measure.