Description of Energy Saving Options for Bard HVAC Units
Energy Recovery Ventilator (ERV)
The Bard Energy Recovery Ventilator (ERV) provides energy efficient, cost effective ventilation
to meet I.A.Q. (Indoor Air Quality) requirements while still maintaining indoor comfort and
humidity control for a variety of applications such as schools, classrooms, lounges, conference
rooms, and others. It provides a constant supply of fresh air for control of airborne pollutants
including CO2, smoke, radon, formaldehyde, excess moisture, virus and bacteria.
The ventilator incorporates patented rotary heat exchanger technology to remove both heat
and moisture. The ERV reduces the costs of heating ventilated air in the winter by transferring
heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer,
the inside air cools the warmer supply air to reduce ventilation cooling costs. The ERV has an
approximate 66% efficiency rating in recovering the energy within the exhaust air leaving the
building by transferring it to the incoming fresh air.
CS2000A2 Energy Monitor
The CS2000A2 is an energy management controller that works in conjunction with a nonprogrammable
HVAC thermostat to optimize energy savings and occupant comfort. The
CS2000A2’s learning capability, occupancy detection, and self-adjusting time-base provides
effective control of HVAC systems without the need for user adjustments. There is no time
clock to set or adjust as the controller automatically learns the occupancy pattern by
observation and programs itself accordingly, and then automatically adapts to any schedule
changes or unplanned occupancy. Simply stated, the CS2000A2 gives authority to the room
thermostat in advance of learned first arrival to precondition the space and also during
occupied periods. During unoccupied periods, the CS2000A2 monitors room temperature
through its built-in thermistor and gives temporary authority back to the room thermostat long
enough to maintain the selected set-back or set-up temperature condition selected within the
CS2000A2. Additional control features of the CS2000A2 include the ability to operate
ventilation and lighting of the same conditioned space to save energy during unoccupied
periods.
Carbon Dioxide Detector
Conditioning the required ventilated fresh air to meet indoor air quality standards is a
significant amount of the load that a commercial HVAC unit must be sized to accommodate.
Via low voltage control wiring, typical HVAC setup provides for fresh air ventilation during the
normal fan operation. This setup results in fresh air being brought into the building any time
the HVAC unit is operating, without any real time reading of indoor air quality. This typical
setup often results in unnecessary ventilation during unoccupied or low building use periods. A
carbon dioxide (CO2) detector can be used to monitor indoor air quality by measuring CO2
levels, and when levels exceed the desired set point, the CO2 sensor will command the
ventilator open to bring fresh air into the room/building. This “commanded ventilation” based
on actual CO2 levels is an easy method to reduce the HVAC unit load by eliminating fresh air
ventilation when indoor air quality is at acceptable levels.
Note: The options above are the most common energy saving add-on options. Other methods
of energy savings is the use of high efficiency units which include, but are not limited to, step
capacity HVAC units, geothermal units, and other higher efficiency heat pumps.