Case Study

New England Business Service  (NEBS) - Townsend, MA

New England Business Service's Townsend Massachusetts facility is a paper forms printing plant.

The building's major mechanical systems include:

This project involved replacing the existing DDC system with a Delta Controls ORCA Series DDC system.  While updating the equipment, corporate and local facility management put forth a list of goals that they wanted to accomplish during the replacement. These included:

1. Minimize operating and energy expenses.
2. Track the buildings mechanical performance.
3. Control the 9 new York heating/cooling units.
4. Control the ventilation requirements using motorized dampers and Carbon Dioxide sensors.
5. Control the buildings internal static pressure.
6. Install a Graphical Operator Interface.
7. Reduce the operator workload in the day-to-day operations of the HVAC system.

R. L. Shields Associates, Inc. installed a Delta Controls ORCA Series DCU Controller to replace the existing Andover Control's AC256 system.  The 9 new York heating/cooling units as well as the 16 existing heating/cooling units are being controlled by Delta Controls Zone Controllers.  They are networked together and connected to the DCU Controller. 

To control ventilation requirements, Carbon Dioxide (CO2) sensors were installed in the production and warehouse areas.  As CO2 levels rise, the outside dampers modulate open to keep the CO2 readings below maximum acceptable levels.  Carbon Dioxide has become an acceptable method of controlling ventilation requirements and is recognized by ASHRAE as one method of monitoring air quality.

To control building static pressures, a network of sensing ports was installed around the four sides of the building.  This building has a history of running a negative static pressure.  This was a concern because of drafts and blowing paper.  Since the Delta Zone Controllers allowed full control over the dampers in the 9 new York units, as the static pressure starts to go negative, the dampers begin to modulate open to allow outside air to enter the building through the cooling units rather than the doors.

Some special software was developed by R. L. Shields Associates for use on this site and others.

1. Demand Side Management Software - This software is used to calculate the electrical demand, consumption and projects demand based on a minute by minute calculation. This enables the computer and operator to make changes in operation to avoid setting demand peaks.  To better understand Electric Demand, click here.
2. Sunrise/Sunset Time Calculation - This controls the parking lot and building exterior lighting based on Sunrise and Sunset. The eliminates the problems associated with power failures skewing the time clocks and provides for the adjustment to Daylight Savings Time and Daylight Standard Time.
3. Humidity Control Software - In the printing business, humidity plays a very important roll.  When multi-part forms are printed, paper stretch is very important.  In many cases, the first sheet is printed at a different time from the second, third, fourth, etc. sheets.  If the stretch is different from one run to the next, the sheets won't line up when assembled.   Special software was created to control the humidifiers when adding moisture, and controlling the HVAC units when dehumidifying.   Because the building will be using some energy savings strategies, this software will be using both relative humidity and dewpoint as control references.  To better understand Humidity, click here.
4. Building Pressure Control Software - Building static pressure was always negative when referenced to outside pressure.  At times it was very difficult to open doors.   Special software was created to use the economizer dampers as air inlets to equalize the inside pressure of the building.  If the roof top units fans are running, the building can actually be pressurized slightly.  This eliminated strong drafts and provided filtered air to the facility.  The building now runs approximately .05 inches of water column positive pressure as a result of this software, which is the desired result. 

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