Rockwell Automation FANM FanMaster Energy Saving Package - Manual (Page 7)

Allen-Bradley® FanMaster™ Energy Saving Package Installation Manual - Publication FANM-IN001B-EN-P – December, 2009 PN-65329
Chapter
1
FanMaster Overview
FanMaster Description FanMaster provides a means for improving the energy efficiency of
Constant Air Volume HVAC units. Constant Air Volume HVAC units
typically draw in room air and mix it with a small amount of outside air.
This mixed air is forced by a fan through heating and/or cooling elements to
provide supply air back to the room at a temperature that makes up for
heating or cooling lost to the surrounding environment. This maintains
comfortable conditions for the building’s occupants and contents.
FanMaster improves the efficiency of a basic HVAC unit by providing the
following two additional control features:
• FanMaster replaces a fixed speed fan motor starter with a Variable Speed
AC Drive which allows the fan speed to adjust to the actual HVAC
heating and cooling loads. The Law of Affinity states that the energy
required to operate a fan decreases by the cube of the actual speed
reduction. For example, a fan running at 80% of its maximum speed
requires about 50% of the energy needed to run the fan at full speed.
And, a fan running at 50% of its maximum speed requires only about
13% of the energy needed to run the fan at full speed. FanMaster’s ability
to monitor the HVAC operation and adjust the fan speed to the required
value provides considerable opportunity for savings.
• FanMaster regulates the amount of outside air drawn into the HVAC unit
for the purpose of ventilation by monitoring the actual Carbon Dioxide
(CO
2
) level in the serviced space. This feature, known as Demand
Ventilation, maintains air quality while reducing the cost of heating or
cooling the outside air by reducing its volume.
The typical Constant Air Volume HVAC unit selected by the building's
original designer provides adequate heating, cooling, and ventilation for
worst-case conditions. The heating and cooling capacity are selected for the
coldest and hottest days anticipated and the ventilation capacity is designed
for maximum human occupancy. Since the weather is seldom at the
extremes in most locations and buildings are often occupied at less than full
capacity, FanMaster provides a savings opportunity by reducing the fan
speed and ventilation used by the HVAC unit when they are not required. In
addition, when the weather extremes do require maximum heating or
cooling or the CO
2
level indicates the need for maximum ventilation,
FanMaster returns the fan to its original full speed and ventilation to the
original designed value until conditions are such that it can once again
reduce the fan speed and amount of outside air ventilation.
FanMaster has been designed for installation into an existing HVAC system
with minimal interface with the existing controls. FanMaster does not
replace or interfere with the existing controls which continue to regulate
room temperature. In addition, FanMaster can also be installed and used in
an evaluation only mode (without a fan drive). This mode allows the
FanMaster energy savings calculator to provide an estimate of potential
savings, prior to performing a full installation.