Product(s):	Hevacomp Design Database
	Version(s):	V8i (V26)
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A

Overview

The CIBSE gain calculation contains an option to allow the temperature to rise.

 This allows the "peak cooling capacity to be reduced if the room temperature is allowed to rise above the room set point for a period sufficiently short that the effect on the mean temperature is small." (CIBSE Guide A, Section 5.A2.5)

Notes

• The permitted temperature rise should be used with care. The method is only accurate for rises of up to 2 or 3°C

If temperature is allowed to rise by 2°C, why are the calculated room loads different when room design temperature by are increased by 2°C?

• Allowing a swing of 2°C will generate a different peak cooling load than changing the room set point by 2°C as the mean room temperature will be different for each case. In the example below, comparison can be made between a 24°C set point and a 22°C set point with a 2°C allowance for temperature rise.
  

Why do I only see a single sensible load rather than separate component loads in results?

• While calculating, sensible gains are combined as they are passed through the equations noted in CIBSE Guide A, Section 5.A2.5. This is reflected on the results page, with a single sensible gain column showing combined figures.

Why does the room peak appear at the same time for each room, regardless of actual room peak?

• The room peak indicated in the results will show the plant peak cooling load hour, and not the room peak hour.