Room Sensible Heat Ratio Line

Q sr sensible heat load in room kw btu hr.

Room sensible heat ratio line. The room sensible heat factor rshf expresses the ratio between sensible heat load and total heat load in a room. The percentage of the capacity that goes toward sensible cooling at a given set of conditions for a given piece of equipment or space is called sensible heat ratio shr. Shr sensible heat ratio ratio of sensible heat load to total heat load q s sensible heat load kw btu hr. This means that if the air supply to the room has a condition that falls on the line it can absorb sensible heat and latent heat in the ratio 80 20 according to figure 1.

The summer room sensible total heat ratio will be 5 0 5 0 1 2 0 81 and since this is a coincident sensible cooling and latent cooling load the gradient of the room ratio line rrl is taken from the bottom quadrant of the protractor on the psychrometric chart and is drawn through summer room point r s the intersection of this line with the specified value of θ sc ie. If you followed the previous advanced psychrometrics article you now know how to use a psych chart to plot a room sensible heat ratio rshr line and how to calculate design room cfm. Starting to study for the mechanical hvac refrigeration pe exam. It is defined as the ratio of room sensible heat to room total heat.

Shr q s q t q s q s q l 1 where. This line ab represents all the points that will satisfy the required ratio of room sensible heat to room total heat. Rshf room sensible heat factor. 37 by δ h s sensible heat and δ h l latent heat.

So for example if a room sensible heating load was 6kw and the room latent load was 3 23kw the room sensible total heat ratio would be 6 6 3 23 0 65 the slope of the rrl may then be determined from the protractor printed on the chart and shown in figure 6. Thus if adequate air is supplied to offset these room loads the room requirements will be satisfied provided both the dry and. Click here to get access to my free daily insights course. The slope of the rshf line illustrates the ratio of sensible to latent heat loads within the space and is illustrated in fig.

Q tr total heat load in room kw btu hr 1 can be modified to. It can be expressed as. However if you followed that exercise you will note the absence of real world variables such as ventilation and bypass factors. Rshf q sr q tr 1.

The supply air having conditions given by any point on this line will satisfy requirements of the room with quantity of air supplied different for different points. The room sensible heat factor line.