Several solutions were discussed here and on other threads so I tried a few. Here are my results in case anyone is interested.
- Outdoor Feels Like (Feels Like Suite) @ masterkenobi
- SensorX Real Feel @ Petrica
- Limych Feels Like @ Limych
They all follow nearly the exact same pattern but have significant offsets. Not to criticize anyoneās work, but IMO āSenxorX Real Feelā felt the closest to my expectation of temperature experience.
Sorry to spoil the party, but it seems any computation should consider the impact of humidity on insulating value of clothingā¦
http://agron-www.agron.iastate.edu/courses/Agron541/classes/541/lesson06a/6a.3.html
Hi,
Perhaps heat index and apparent temperature are relatively different concepts with different scope of application ?..
First about Heat Index:
Heat Index shows how much hotter the air seems to be than the ambient dry-bulb temperature due to the influence of humidity.
I found that the formula of the multiple regression analysis conducted by Lans P. Rothfusz is limited by temperature >~27C. Accordingly, for lower temperatures, the result may have large discrepancies relative to the original tables by Steadman. Although a simplified expression ( HI = 0.5 * {T + 61.0 + [(T-68.0)1.2] + (RH0.094)}) is given to circumvent this limitation.
On the other hand, the Apparent temperature has a wider range of acceptable values of dry-bulb temperature values (>20C).
Therefore, it may make sense to combine formulas. However, it should be borne in mind that the heat index / apparent temperature graphs intersect at different temperatures.
After a long study, I came to the conclusion that it is necessary to strictly distinguish between the purposes for which these calculations are used. Since these dependencies are completely different for the outdoor and indoor conditions.
In addition, humidity is only one of the secondary parameters that affects the perceived temperature. I was interested in the room conditions, and in this case, humidity, as it turned out, has a very weak effect on the perceived temperature (approximately 0.3 C per 10% humidity change). Much more important is the influence of the sun entering the room, the temperature outside, the speed of air movement (for example, fans), clothing and human metabolism. The main metric that allows you to combine all these microclimate parameters is PMV. It shows empirically the effect of each parameter.
Fortunately, this issue is deeply elaborated in the building regulations (ISO 7730, ASHRAE 55) Š°nd thereās even an online calculator.
The only problem is that PMV is a qualitative indicator and it is not expressed in degrees Celsius. Therefore, PMV can only be used for feedback - to show how the indoor climate feels, but not as a temperature sensor for HVAC
I managed to port the code of an iterative solver that determines this indicator.
Indoor Thermal Comfort Tool.
This may be too difficult for some, but it is the only scientifically sound way. On the other hand, if you try to get some kind of āFeelsLikeā sensor based on humidity alone, this is just the tip of the iceberg.