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Adaptive tab #135

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JoseAliPorras-Salazar opened this issue May 18, 2022 · 12 comments
Open

Adaptive tab #135

JoseAliPorras-Salazar opened this issue May 18, 2022 · 12 comments
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enhancement New feature or request

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@JoseAliPorras-Salazar
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It will be great to have the chart showing points (8760) instead of bars, like the one below:
image
Then it will be nice for the user to select the occupancy hours and set the air velocity in the room. Finally, it will be super great to have a summary table with the monthly percentage of time above and below the comfort limits (both 80% and 90%).

Thanks in advance!
@giobetti
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Hi Jose, thanks for the feedback.
What would be the use case/practical application?

Currently there are a few assumptions that we had to bake in the chart:
For a “generic” indoor environment we assume that:

  • MRT always equals DBT
  • Air speed is constant at 0.5 m/s
  • If the average DBT for any day is outside of the applicability limits for the adaptive thermal comfort (lower than 10°C or higher than 40°C), the values are capped at 10° or 40°C respectively. This is done to be able to always display a comfort range, rather than an error message.

we could expose the air speed as a parameter within the range of acceptability.
Probably this should be a feature for one of the advanced tabs.

I assume you are familiar with the CBE Comfort tool
https://comfort.cbe.berkeley.edu/

@FedericoTartarini
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Hi @giobetti I think there is an issue in the adaptive code. Currently we are using the following if statement:

        if dbt_day_ave[i] >= 40:
            dbt_day_ave[i] = 40
        elif dbt_day_ave[i] <= 10:
            dbt_day_ave[i] = 10

which basically sets the daily outdoor temperature to 40 or 10°C if the original values exceeds 40 or it is lower than 10°C, respectively. This I believe it is incorrect. We should not change the daily average temperature values. I believe this if was meant to check the value of running mean outdoor temperature. It should read as follows:

        rmt = running_mean_outdoor_temperature(last_days, alpha=0.9)
        if rmt >= 40:
            rmt = 40
        elif rmt <= 10:
            rmt = 10
        r = adaptive_ashrae(
            tdb=dbt_day_ave[i], tr=dbt_day_ave[i], t_running_mean=rmt, v=0.5
        )

@FedericoTartarini
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Hi @giobetti let me add a bit more context to Jose's comment. he is a colleague of mine and he verbally explained to me his suggestions.

  1. He was suggesting to show each point so visually you can see the data distribution. Currently, we are showing a box which depicts the max an min value but we do not know for how long each day the temperature was close to the max value. Using a scatter chart allows the user to visualize all the 24 readings.
  2. Occupancy hours are also useful since most of the buildings are not utilized 24/7. It would make sense to allow the user to see for how many hours the building is within the adaptive thermal comfort region between XX am an YY pm.
  3. Allowing the user to control the airspeed would also be beneficial. Higher value of airspeed move the adaptive comfort region up. This would allow the user to check if natural ventilation + air movement alone would suffice during warm days.
  4. The summary table is very useful too. At this stage we are only showing the data but for the user it is impossible to tell how many points are above, within, and below the adaptive thermal comfort region. The summary table would provide all those info.

Why don't we include all the above, maybe leaving out point 1, in the Natural Ventilation tab?

@giobetti
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giobetti commented Jun 6, 2022 via email

@FedericoTartarini
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Yes, we could add one or two graphs to the natural ventilation tab. One may suffice since we can show the data and the percentages in the same figure. The current chart is very beautiful but in its current form it is not practical to extract information from it, it could be changed into the following

image

In which we depict the percentage of time the temperature is between the 80% and 90% adaptive comfort region. Alternatively, the percentages can be presented in a table below the chart.

One way would be to extend the functionalities of the current one where the upper boundary for natural ventilation is not set as a static value but (optionally?) tracks the adaptive comfort zone with (optionally?) a maximum indoor wind speed allowed.

This is what I had in mind. The user specifies a Max airspeed then the adaptive region can stretch up if the outdoor temperature is hot, but the bottom range does not change as in the CBE comfort tool. The table below would show the new percentage of time during which the outdoor temperature is within the comfort region.

@giobetti
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giobetti commented Jun 7, 2022

Hi Federico, lots of good comments here I'll try to think how this might look like once we put all together.
In the meanwhile I was l looking at the temperature graph and noticed that the comfort zone disappears now?
image

I think this is because of the change to the MRT statement.
Is this the desired behavior?

@giobetti
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giobetti commented Jun 7, 2022

Hi Federico,
So I guess we are thinking about a complete overhaul of the Nat vent tab. This is what I think makes sense, please let me know what you think.
The natural ventilation tab will have 3 connected graphs, like the 3 below.

image

The first one is new. It is similar to the temperature graph but the difference is that the grey band at the back doesn’t show the comfort zone but our newly defined Natural Ventilation Potential Range (NVPR?).
I would suggest that we implement different methods to define the NVPR.

  1. The one we currently adopt: a fixed upper and lower boundary (i.e. between The NVPR can be defined in a couple of different way and s deg C).
  2. One based on the (90%?) ashrae adaptive comfort
    In the second case the user would be able to calculate (independently for the upper and lower boundary) the comfort zone based on different air speeds and specify different fixed temperature offsets.
    For example, the top condition could be defined as the ashrae adaptive upper limit minus 2deg C (to account for internal gains that can’t be fully offset even at high ventilation rates). The lower might be based on the ashrae adaptive lower limit minus 10deg C (to account for internal gains with a lower ventilation rate).
    For the upper and lower bound we could also le the user specify different design air speeds. This would allow to further push up the upper boundary by specifying a higher indoor air speed for it, while still leaving the lower bound based on an air speed of maybe 0,1m/s.
    The user would also still have access to the current controls to specify times and check for condensation risk.
    I think this is an interesting model but it leaves open a few questions.
  3. Interface: there are a lot of options now to set up the upper and lower boundary of the NVPR. UI design is going to be challenging!
  4. Can we provide some guidance on the right temperature offset values and air speeds? Maybe there is a separate parametric thermal + natural ventilation study that can be set up to simulate typical office/ learning/ housing environments to figure out what realistic values for both temperature offsets and wind speeds are. That would be a very nice paper and might be a useful contribution for the design of naturally ventilated spaces based on the ashrae adaptive comfort model.
    What do you think?
    This is probably getting to complicated to be solved in a chat and we might have to arrange a call. I am not sure everything I’ve written makes sense! 😉

@FedericoTartarini
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I think this is because of the change to the MRT statement. Is this the desired behavior?

No technically I did not want that to happen, but this is how the graph should look like since before the results were incorrect. Let me know if you would like me to revert it back or keep as it is.

@FedericoTartarini
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I agree, the user should be able to:

  • see the percentage of time the outdoor is within the 90% of the adaptive comfort range.
  • specify the two offsets from the values calculated with the adaptive model to compensate for internal gains.
  • specify different design air speeds. This would allow to further push up the upper boundary by specifying a higher indoor air speed for it, while still leaving the lower bound based on an air speed of maybe 0,1m/s.
  • have access to the current controls to specify times, months, and check for condensation risk.

UI design is going to be challenging!

Agree but I am sure we can find an elegant solution.

Can we provide some guidance on the right temperature offset values and air speeds? Maybe there is a separate parametric thermal + natural ventilation study that can be set up to simulate typical office/ learning/ housing environments to figure out what realistic values for both temperature offsets and wind speeds are. That would be a very nice paper and might be a useful contribution for the design of naturally ventilated spaces based on the ashrae adaptive comfort model. What do you think?

This is a good idea, we should also consider the relative humidity outside as we did in this paper that I have published before. At the end of the day we want to use natural ventilation only when the entropy of the outside air is lower than the one indoors.

This is probably getting to complicated to be solved in a chat and we might have to arrange a call. I am not sure everything I’ve written makes sense! 😉

I think your message makes full sense to me and I hope I did not miss any key points. Let me know if I did. But I am more than happy to have a call with you whenever you are free.

@giobetti
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giobetti commented Jun 8, 2022 via email

@giobetti
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giobetti commented Oct 11, 2022 via email

@FedericoTartarini
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I can look into implementing them but I just change job last week and moved to Australia so I am a bit overwhelmed with work at the moment and I will not have much time to dedicate to this at the moment. i hope this is not a problem.

@FedericoTartarini FedericoTartarini added the enhancement New feature or request label Mar 17, 2023
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@giobetti @FedericoTartarini @JoseAliPorras-Salazar