SHF,RSHF & GSHF are elements used in heat load calculation & which affects the psychrometric properties of the air.

## SHF – Sensible Heat Factor

- The thermal properties of air can be separated in to latent & sensible heat.
- The term
*sensible heat factor*is the ratio of the sensible heat to total heat, where the total heat is the sum of sensible & latent heat

## RSHF – Room Sensible Heat Factor

The *room sensible heat factor* is the ratio of room sensible heat to the summation of room sensible & room latent heat. this ratio can be expressed as:

- The supply air to the conditioned space must have capacity to offset simultaneously both the room sensible & room latent heat loads.
- The room & the supply air condition to the space may be plotted on the standard psychrometric chart & this point can be connected by straight line 1-2.
- This line represents the psychrometric process of the supply air within the conditioned space & is called the room sensible heat factor line

- The slope of the RSHF line illustrate the ratio of sensible to latent loads within the space & it is shown in figure as ∆h
_{S}(sensible heat) & ∆h_{l}(latent heat). - Thus if adequate air is supplied to offset these room loads, the room requirements will be satisfied, provided both the dry bulb & wet bulb temperature of the supply air falls on this line.

## GSHF-Grand Sensible Heat Factor

The *Grand sensible heat factor *is the ratio of the total sensible heat to the grand total heat load that the conditioning apparatus must handle including the outdoor air heat loads.

- Air passing through the conditioning apparatus increase or decrease in temperature and/or moisture content.
- The amount of rise or falls is determined by the total sensible & latent heat loads that the conditioning apparatus must handle.
- The condition of the air entering the apparatus (mixture condition of outdoor & return room air) and the condition of the air leaving the apparatus can be plotted on the psychrometric chart & connected by straight line 1-2.
- This line represents the psychrometric process of the air as it passes through the conditioning apparatus & is referred as the grand sensible heat factor line.

- The slope of the GSHF line illustrate the ratio of sensible & latent heat that the apparatus must handle & it is shown in figure as ∆h
_{S}(sensible heat) & ∆h_{l}(latent heat).

## 2 thoughts on “Sensible Heat Factor – SHF, RSHF & GSHF”