SHR - STULZ answers
The Sensible Heat Ratio (SHR) reflects the ratio of the sensible (perceptible) heat load (Qsensible) and the total heat load (sensible & latent).
A cooling system emits a total amount of heat of 20 KJ/kg to cool the cabin at atmospheric pressure from 35 °C to 26 °C. The air inside the cabin has an average heat of CP of 1.050 KJ/kg.
Qtotal = 13 KJ/kg
Tinitial = 32 °C
Tfinal = 26 °C
CP = 1.050 KJ/kg
The total heat load (Qsensible) can then be calculated:
QSensible = CP (Tinitial – Tfinal)
QSensible = 1.050 (35 – 26)
QSensible = 9.450
Then the SHR is calculated as follows:
SHR = Qsensible / Qtotal
SHR = 9.450 / 13
The SHR amounts to 0.726
An SHR lower than 1 means that due to dehumidification of the air, the air conditioning system in a data centre is less efficient than it should be. Typically, dehumidification in a DC is not necessary.