Complete zone control

Controlco has undertake a project for Gloucester City Council to upgrade its non BMS controls systems at its head office, Council office and buildings – Herbert, Kimberley and Phillpots warehouses – located in the historic city docks.
Shaun Williams of Controlco explained: “This was a big task so we decided to use Seachange controls for the new boiler house and main chiller plant refurbishment, servicing all three buildings and all air handling plant. The modular nature of the Seachange control system provides flexibility and ease of use for such a project, with the best end results for the client.”

Each of the three buildings has seven floors. Each floor is controlled by fan coil units with heating and cooling valves and tempered make up air is supplied by two air handling units (AHU) on opposite sides of each building.

Controlco has installed a zone controller on each floor to enable the floor’s occupancy pattern to be set and the optimum start of the fan coil units, prior to occupancy.

The heating and cooling demand from each of the floors is collated to start the boiler plant or chiller plant as required. These are used to reset the tempered AHU set point such that if the demand from the building’s floors is predominantly a cooling requirement then the AHUs supply air set point is lowered to assist the cooling requirements. Vice versa, the set point is raised if there is a predominantly heating requirement.

The zone controllers have a dead zone between a heating and cooling set point where no demand for heating or cooling will inhibit the fan coils operation, and inhibit the central heating and chiller plant if there is no demand for energy.

Intelligent demand filtering is used to determine when the heating or chilled plant runs. This is achieved by selecting the minimum number of zones that need a heating or cooling demand before the respective plant is enabled. In addition to the zone numbers the minimum demand for any of the zones have to be achieved before the plant is used.

Chris Dobson, Council Engineer said: “The SeaChange interface is easy to use and allows the systems performance to be monitored by a central supervisor using a PC in the engineer’s department utilising doorway and site specific graphics.”

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