Specifications

3
The Smart Choice for Energy Efficiency
Th
he Smart Choice for Energ
MANY CHOICES, ONE SOLUTION
When choosing a HVAC system for a project, there are
four basic types from which to choose.
FAN COILS
Fan coil systems are comprised of water-to-air coil air
handlers connected via a two- or four-pipe insulated water
loop. Fan coils require complex chillers and boilers to
provide water loop fl uid in a particular temperature range
(i.e. chilled water for cooling and hot water for heating).
Two-pipe fan coils have a major disadvantage as control
is substantially limited to whatever mode the system is
currently set at (i.e. cooling or heating). A four-pipe version
can be installed that requires both chilled and heated
water to be available at the same time. Four-pipe systems
also require twice the piping and twice the circulation
equipment of a two-pipe system, which makes a four-pipe
system one of the most expensive systems to install.
VARIABLE AIR VOLUME (VAV)
Variable Air Volume, or VAV, is one of the most common
types of HVAC systems used in large commercial
buildings today. A typical system is usually comprised of a
large air handler, central ductwork system, and a relatively
large equipment room. Conditioned air is distributed
throughout the building via a central ductwork system
and is regulated via dampers in each space. VAV systems
typically have a higher fi rst cost than Water-Source Heat
Pumps, and may have similar operating costs, resulting in
overall increased life cycle costs.
ROOFTOP
Rooftop systems are similar to VAV systems in that they
use a central ductwork system to distribute conditioned
air into the building space. However, instead of one
central unit, the system is comprised of multiple
units which can be tasked for different conditioning
requirements. Rooftop systems usually require
additional structural reenforcement as well as cranes or
other lifting equipment to place the units. Control in a
particular zone is limited to what the system is currently
set to (i.e. cooling or heating). Rooftop installation
costs are low to moderate, but operating costs are
typically 50% higher than Water-Source Heat Pumps.
Additionally, the systems are exposed to the elements
and are subject to damage and vandalism.
WATER-SOURCE AND
GEOTHERMAL HEAT PUMPS
Water-Source and Geothermal Heat Pump systems are
comprised of individual packaged units that transfer
heat via a single- or two-pipe water loop. Each unit can
be used in either heating or cooling mode year-round
and loop temperature is maintained via a boiler/tower
combination or earth-coupled loop. Each zone has
complete control of its heating/cooling mode and
each unit is independent from the others. This means if
one unit goes down, the whole system is not affected.
Controls can be as simple as one unit, one thermostat.
Water-Source and Geothermal Heat Pump systems are
the most energy, cost, and space effi cient of any system
in the industry.
SYSTEM COMPARISON
System
Ease of Design
Ease of Installation
Installation Space
Installation Cost
Maintenance Requirements
Maintenance Costs
Future System Expansion
Sound Levels
Operating Costs
Total Zone Failure Chance
Individual Tenant Control
Options
Additional Auxiliary
Equipment Needed
Structure
Modifi cation Needs
System Longevity
Two-Pipe Fan Coils Low Low High Med High High Low Low Med High Low Low High High Med
Four-Pipe Fan Coils Low Low High High High High Low Low High High Low Low High High Med
PTAC / PTHP Low Low Low Low High High Med High High Low Med Low Med High Low
VA
V Low Low High Med High High Low Med Med High Low Low High High Med
Rooftop Low Low High Low Med High Low Med Med High Low Low Med High Med
Water-source Heat Pumps High High Low Low Low Low High Low Low Low High High Low Low High
Geothermal Heat Pumps High
High Low Low Low Low High Low Low Low High High Low Low High