Sensible Temperature

Hi

I need to install and program a PLC to control fans in a chicken house.
The old system to be replaced display's the real temp as well as the "Sensible Temp"
According to Google, sensible temp can be calculated by the formula "hs = cp * rho * q * dt"

Has anybody done this and what does the "dt" represent?
Obviously difference in temp, but difference between What?

Thank you

dt = delta T, change in temperature.
The formula you list, is not sensible temp, it is for sensible heat. (Not the same thing)

Hi Ken
Thanks for the reply. If this is not the same thing, do you know what the correct formula is? I do realize that delta T is the change in temperature, but the change between what? one would most probably be the real temp, what would the other be? Temp after a fan started? If no fan is running, sensible temp would then be equal to real temp according to formula but this is not true.

Hi

It seems that I was wrong about this, I think I need to look at Apparent Temp.


AT=T_a+0.348*e-0.70*ws+(0.70*(Q/(ws+10))-4.25
where
Ta = Dry bulb temperature (°C)
e = Water vapour pressure (hPa) [humidity]
ws = Wind speed (m/s) at an elevation of 10 meters
Q = Net radiation absorbed per unit area of body surface (W/m2)

In the current system there is no device measuring humidity or wind speed.
I assume Wind speed is being calculated based on the amount of fans running and that an assumption is made regarding humidity.

Any experts please, was this a matter of BSh@t baffles brains all along or is there some sense to this?

https://energyeducation.ca/encyclopedia/Sensible_heat

I suspect that the original system was trying to tell you
- the apparent/actual temperature, that is what a thermometer will read. This is probably inside temperature?
- the "feels like" temparature, which is analagous to wind chill in the winter. I don't think poultry sweats, but as relative humidity (wet bulb or water vapor pressure) increases it may affect the chickens ability to dissipate body heat. They may increase the ventilation rate in that case. IF wind speed is included then I suspect this is a reading of outside conditions.

Tom Jenkins said:

https://energyeducation.ca/encyclopedia/Sensible_heat

I suspect that the original system was trying to tell you
- the apparent/actual temperature, that is what a thermometer will read. This is probably inside temperature?
- the "feels like" temparature, which is analagous to wind chill in the winter. I don't think poultry sweats, but as relative humidity (wet bulb or water vapor pressure) increases it may affect the chickens ability to dissipate body heat. They may increase the ventilation rate in that case. IF wind speed is included then I suspect this is a reading of outside conditions.

Click to expand...

They don't sweat, the wattle, combs, and legs are most used to help regulate temperature, along w/ ruffling of feathers to trap heat or raising wings to try and dissipate heat.
They do 'pant' to reduce heat load.
Iirc from my childhood farm experience, it was mostly dry-bulb temperature that was a concern.

Doing a quick bit of reading, the caveat there is the RH should be > 30% to avoid respiratory issues w/ bedding and whatnot.