Wish: Psychrometric chart - shading strategy

[AbrahamYezioro]

Hi @chris,
We are getting closer, i think. You are convincing me … and i want to propose something.

1. What we agree on: This is fine.
2. What we need a consensus:

@chris

1. Does a psych chart strategy represent the hours that are made comfortable by the strategy or the hours helped by it? Alternatively, does it matter that we enforce a consistent definition for what a strategy is?

I believe we can agree that the former is the right one. This is the accepted approach so we don’t need to challenge that at this point.

@chris

But I just feel that we have an opportunity to keep things consistent here and so I don’t really understand why we should make an exception for Shade and not some other strategies.

I see your point and i’m for keeping consistency.

@chris

2. What type of shade does the Shade Line represent? Is it Shading on a passive building in which the occupant sits? Or is it more like a beach umbrella that directly blocks sun falling on the occupant?

I would say that it is a combination. I’ll try to explain after the next quote.

@chris

And the logic follows that, even if it’s 15 C outside, conditions within an insulated all-glass greenhouse blasted by the sun can be so warm that it’s just not comfortable for people.

You are right on this BUT you are denying the possible use of ventilation. When you check winter time in the chart, the cooling options are off. What you suggest is provide shading as an option, which is fine, but not the only option i can apply. I’m trying to think what i would do in the case that in mid january i get lots of sun in the space i am in. Open a window or close the shades? Myself will probably open the window.

@chris

I’m guessing they were imagining that this Shade was more like a beach parasol that was applied directly to the human and not the the passive building in which they were sitting. And so they put the line at the “human balance point” of the comfort polygon instead of the “building balance point”.

Exactly. So here is what i propose, based on what i just found in the Lechner’s book (Heating, Cooling, Lighting: Sustainable Design Methods for Architects):

The key part is

… to the right of the vertical shade line, the sun should be prevented from entering windows

So maybe this should be the approach: the shade line is not a strategy but rather a recommendation. The counting of the hours that fall to the right of it (not counting the comfort polygon ones) represent the potential severity of the situation (i know you don’t like the potential word in this context … ) and not a strategy by itself.

@chris

So, if “Capture Internal Gains” is plotted on the chart, we can show the shade line at the building balance point. Otherwise, we can show it at the human balance point on the lower part of the comfort polygon. What do you think?

This can be a good option, you can explain that to people and makes sense.

Saying that, what do you think about the quote of the book. Right now i can live with either of the options.

Thanks @chris. I see the intellectual effort you are putting here and the responsibility you feel towards this. This is great!! I appreciate it very much.

-A.