Chapter 5.2.4.3 - Task Heating, Zoning, and Temperature Setback

Determination of setback sizing implications and requirements are critical to HVAC
conventional system design analysis. Equipment oversizing of 20 to 60 percent is
commonly recommended for convection systems operated with night setback, or
both day and night setback, respectively. Fast-acting, preinsulated radiant heat panel
systems do not require additional capacity or equipment for effective occupantoriented
setback. Recovery is not system, convection, or mass restrained. Recovery
is defined by radiant field restoration as defined for thermal comfort. Dynamic setback
capability is a standard feature of fast-acting radiant heat panel installations.
As their sizing accommodates normal setback, these strategies can always be pursued,
regardless of original installation and operational practice design.

Zoning or individual room or area control is a comfort and energy conservation
feature of fast-acting radiant panels. Direct source-to-object radiant heat transfer
enables restoration of comfort in open rooms and open areas. Migration of warmed
air, through natural convection or mechanical distribution, complicates convection
system zoning. Issues include enclosure of space to be zoned, air distribution pressure
balance, heat generation output reduction, duct zoning capability, and control
requirements. Achievement of savings through zoning with convection systems
requires careful system design and increased initial cost. Standard design practice
for fast-acting, preinsulated radiant panels incorporates individual room or area
control.The base cost is unaffected (Fig. 2.8).

The radiant fast-acting feature makes radiant heat panels suitable for task heating,
a form of hybrid system with energy benefits comparable with those achieved
with task lighting. Installation directly over occupied areas provides localized comfort
in the presence of lower air temperatures in surrounding areas.The magnitude
of difference between surrounding air and the required local heated area operative
temperature depends on the task being performed. The idea of heating people, not
space, though impractical for convection systems, is a practical and standard feature
of many radiant heaters, especially fast-acting panels (Fig. 2.9).

Determination of setback sizing implications and requirements are critical to HVAC
conventional system design analysis. Equipment oversizing of 20 to 60 percent is
commonly recommended for convection systems operated with night setback, or
both day and night setback, respectively. Fast-acting, preinsulated radiant heat panel
systems do not require additional capacity or equipment for effective occupantoriented
setback. Recovery is not system, convection, or mass restrained. Recovery
is defined by radiant field restoration as defined for thermal comfort. Dynamic setback
capability is a standard feature of fast-acting radiant heat panel installations.
As their sizing accommodates normal setback, these strategies can always be pursued,
regardless of original installation and operational practice design.

Zoning or individual room or area control is a comfort and energy conservation
feature of fast-acting radiant panels. Direct source-to-object radiant heat transfer
enables restoration of comfort in open rooms and open areas. Migration of warmed
air, through natural convection or mechanical distribution, complicates convection
system zoning. Issues include enclosure of space to be zoned, air distribution pressure
balance, heat generation...