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**Hasni** Can someone tell whether latent load contributes to the total cooling load of a building or not.if it does, tell which way, and how it should be looked at during load calculation of a building.Also if possible display a perfect, easily understood definition of latent heat.Thanks

Latent heat does contribute to the total cooling load of a building. Your chiller capacity will be equal to the sum of latent and sensible heat (total heat)

Air is mixture of several gases but for engineering purposes we can assume that air is a perfect mixture of dry air and water vapour. Latent heat is energy required to evaporate water in to the water vapour contained in dry air- water vapour mixture.

In other words if you are adding latent heat to your space it means you are adding water to the air inside your space.

Latent heat is responsible for air humidity.

When you cool air to keep temperature in the space at certain level some of that water in air will condense so your coil has to be sized to deal with sensible heat (to reduce the air temperature) and latent heat (to reduce the water content)