Enter the sensible heat (kW) and the total heat (kW) into the calculator to determine the sensible heat ratio.

SHR Formula

The following formula is used to calculate a sensible heat ratio (SHR). 

SHR = qs / qt
  • Where SHR is the sensible heat ratio
  • qs is the sensible heat (kW)
  • qt is the total heat (kW)

To calculate the sensible heat ratio, divide the sensible heat by the total heat.

What is a sensible heat ratio (SHR)?

Definition:

A sensible heat ratio, or SHR for short, measures the ratio of sensible heat to total heat that of an evaporator.

For example, if the sensible heat ratio were 1, the evaporator would use all of its energy to cool air and non for dehumidification. (Not feasible).

How to calculate a sensible heat ratio?

Example Problem:

The following example outlines how to calculate a sensible heat ratio.

First, determine the sensible heat load. This is the heat or power used to cool air by the evaporator. In this example, the sensible load is 100 kW.

Next, determine the total heat load. This is the total power consumed by the evaporator. In this case, the total heat load is 125 kW.

Finally, calculate the SHR using the formula above:

SHR = qs / qt

SHR = 100 / 125

SHR = .80 = 80%

FAQ

What is the difference between sensible and latent heat?

Sensible heat refers to the heat that causes a change in temperature of a substance without changing its phase, such as heating air. Latent heat, on the other hand, is the heat absorbed or released by a substance during a phase change, such as water vapor condensing into liquid water, without changing its temperature.

Why is the sensible heat ratio important in HVAC systems?

The sensible heat ratio (SHR) is crucial in HVAC systems because it helps in designing and sizing the equipment appropriately for both cooling and dehumidifying the air. A correctly calculated SHR ensures that the HVAC system can maintain the desired indoor temperature and humidity levels efficiently, providing comfort and saving energy.

Can the sensible heat ratio be greater than 1?

No, the sensible heat ratio (SHR) cannot be greater than 1. The SHR is a ratio of sensible heat to the total heat, which includes both sensible and latent heat. Since the total heat includes sensible heat, the SHR will always be a value between 0 and 1, indicating the proportion of the total heat that is sensible heat.