Honeywell LCBS Connect, Руководство по применению, Страница: 9 / 44

LCBS CONNECT SOLUTION
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Method #3: Dehumidification extended cooling minimum run time
This alternate dehumidification sequence works in conjunction with the dehumidification strategy described above. If
there is a call for dehumidification and there is also a call for cooling, the DX refrigeration will continue to operate and
functionally runs for specified time. We are ensuring that a cooling stage is on long enough so that it reaches a cold
enough temperature to remove moisture. This will cause fewer compressor cycles of longer duration, which may result in
slightly larger temperature swings around the set point.
Cooling and Dehumidification Summary
LCBS Connect controllers have numerous cooling and dehumidification options as described in this section.
If you are commissioning a simple single cool conventional system, the LCBS Controller will work "out of the
box." It will be designed to work at 76°F occupied setting and 82°F unoccupied set point setting. You will
have access to changing proportional band, integral gain, and derivative gain if you wish. It is HIGHLY RECOMMENDED
that you DON'T alter these parameters unless a Honeywell LCBS Connect support professional tells you to do so. You will
need to make some basic changes to the device if you are commissioning a dehumidification loop. There are a number of
options described in this document that will allow you to alter basic dehumidification operation. Do not change
preconfigured parameters unless you discuss this with an LCBS Connect support professional.
FRESH AIR ECONOMIZER CONTROL
Theory and Operation Economizer
There are two key operational objectives for economizer. First, we have an objective to keep building occupants alert,
healthy, and safe by making sure that fresh outdoor air is continually provided to the building space. Technically, this is
referred to as "ventilation." In the North American geography, there are many areas that cool, dry outdoor air can be used
to cool building spaces and augment the mechanical cooling process. This apparatus, system, collection of sheet metal
and controls is called an "economizer system. "
Economizer Function
Three high level strategies are supported by LCBS Connect to address control economizer functions.
— None. First, for units that do not feature integrated economizer at all, LCBS connect offers a "none" selection.
There are some parts of North America that allow make up air to be provided to building spaces in an alternate
manner; not using the economizer apparatus. Please refer to ASHRAE Standard 90.1 - 2010 Section 6.5.1 or to
your local building code for ventilation and economizer codes. This choice would also be used for systems that
aren't connected to a fresh air, ventilation function, like many commercial split systems.
— Enable Economizer Function. Second, there are hundreds of thousands of economizers that are "controlled" by a
stand-alone collection of economizer controls, typically provided by Honeywell for the last 20 years through com-
panies like MicroMetl, Cambridgeport, and Canfab to name a few. The resulting control sequence is super simple.
If there is a call for cooling via a thermostat of contractor and building owner's choice and the economizer control
system indicates that outdoor air is cool and dry enough, the economizer controls operate, providing as much as
100% outdoor air to cool the building space. If outdoor air becomes unacceptably warm, the electronic thermostat
takes over control and controls mechanical cooling. Lastly, a time of day signal is provided to the economizer con-
trol system so that the outdoor air damper is able to close 100% to avoid equipment damage and potential exces-
sive energy use.
— Integrated Economizer. The third strategy that is supported is full control of the economizer function by the LCBS
Connect controller. If this option is suggested, you have also enabled the LCBS Connect controller to perform
"Demand Controlled Ventilation (DCV)." DCV will be described in the next section. This is clearly the preferred
selection. This results in optimum comfort for customers and can also result in efficient operation, supporting
cost avoidance for building owners. Service contractors also benefit from full Cloud based remote control of the
economizer function, allowing him or her to troubleshoot the economizer from the ground, rooftop unit, or their
service truck.
General Economizer Operation
We refer to the economizer section of a rooftop in many ways. When we refer to the "economizer damper," we're typically
referring to the combination of outside air damper and return air damper. In our area of interest in the light commercial
marketplace and more specifically, 3 to 25 ton CVAHU units, the outside air damper system is typically operated by an
actuator directly coupled to mechanical linkages and to dampers. The outdoor air damper is normally closed and return
air damper is normally open. For most installations, the outdoor air damper is interlocked mechanically to the return air
damper. The outdoor air actuator is almost exclusively a "spring return device" that is designed to "spring closed" in event
of a loss of control signal power failure. The spring return apparatus in an actuator is provided to combat the potential
damage to HVAC coils, compressors, and to building plumbing.