Overview Building Features Grade JK-6 Grade 7-12

System Description of Operation

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General System Information


System Communications

WAN

An Ethernet wide area network provides a high-speed communication link between all sites and workstations. A fileserver provides a common database so that any modification to a site is updated at all workstations. Workstations can access and adjust data simultaneously at multiple sites. Site databases can be saved, modified and restored from any workstation that has administrative capabilities. Access to sites, areas and capabilities is restricted according to user passwords.
The Ethernet network components consist of a Continuum Workstation and Server at the Eugenie Street Office and Continuum network controllers in the schools.

Infinet Network

The infinet network within each building provides a high speed token passing communication link between all application controllers, communication, access, and security controllers so that information can be shared where required and the building operator can review and adjust operating parameters.

Application Controllers

A wide variety of application controllers for temperature control, lighting control, card access, intrusion and industrial applications are available. All can be networked on the same infinet but operate in a standalone mode according to their customized application programCommunication Controller

Communication Controller

The communication controller provides the operator interface to the Continuum Workstation so that information can be viewed, operating parameters adjusted, programs modified, points added, and access control managed via an Ethernet connection.  Access to the system is controlled by user passwords.  The communication controller also provides the communications to power metering and lighting controllers.

Continuum Workstation

The Continuum software operating on a personal computer provides a comprehensive user interface to the system consisting of databases for all controllers, reports, graphics, charts, logs, and access control information. The software is capable of communicating with controllers in a transparent manner.

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Air Handling Units (AHU-1 and AHU-2) Description of Operation


These 100% outdoor air handling units are comprised of a supply and return fan both equipped with variable frequency drives (VFD’s), split hydronic heating/cooling coil section, total enthalpy recovery wheel section, passive dehumidification recovery wheel section, MERV 13 filtration on supply air side, and MERV 8 filtration on exhaust air side.

Air handling units are started and stopped according to an operator programmed time schedule or manually through the operator workstation. The Supply and Return Air Fans are monitored by current sensors. The air handling units operate in conjunction with the VAV boxes to maintain space ventilation rate.

When the unit is in the occupied mode the outdoor air dampers are opened to allow 100% outdoor air flow rate.
The supply air fan speed is modulated by the VFD to maintain the duct system static pressure set point.  The set point is at a level that ensures the VAV Box demands are met and at least one box is open 100%. Static pressure is reset using Trim and Respond logic within the range 0.15 in w.c. (adjustable).  When the fan is off, the set point is 0.5 in. w.c. (Adjustable).  When the fan is proven on, every 2 minutes (Adjustable), the set point is trimmed by 0.04 in. w.c. (Adjustable).  The set point is increased by 0.03 in. w.c. times the number of pressure requests but no more than 0.12 in. w.c. (Adjustable).

Return air fan speed is modulated by the VFD to maintain the return air duct system static pressure set point.  The set point is adjusted to ensure the farthest exhaust damper is open 100%.

Occupied Heating Mode:

The hydronic coil control valve modulates to maintain a minimum discharge supply air temperature of 68°F (adjustable) and the in-floor heating control valves shall modulate to maintain the space set point. The two-way control valve which serves the unit four-row cooling coil closes enabling the two-row coil section for heating control.

The enthalpy wheel functions as first stage heating and operates in heating mode to recover energy from exhaust air and pre-condition incoming outdoor air. When the outdoor air is below 32°F, the VFD on the enthalpy wheel is operated to achieve an exhaust temperature setpoint of 33°F to prevent the wheel from freezing.

The passive dehumidification recovery wheel is stopped and the corresponding section bypass dampers fully opened.

Occupied Cooling Mode:

The hydronic coil control valves dedicated to each coil are modulated in sequence to maintain the required saturated air condition prior to entering the passive dehumidification wheel section.

The supply air temperature set point shall be reset from 68°F down to 65°F (adjustable) as determined by occupied classroom calls for cooling; if more than 30% (adjustable) of the classrooms are calling for cooling, the discharge air temperature is lowered by 1F°.
The enthalpy wheel operates in cooling mode to discharge energy to exhaust air and pre-condition incoming outdoor air. If the outdoor air enthalpy is less than that of the building exhaust air, the enthalpy wheel cycles off and the corresponding section bypass dampers is fully opened.

When the enthalpy wheel speed is at 100%, if the required supply air temperature setpoint cannot be maintained, the three-way heating/cooling coil control valve is modulated to maintain the cooling control supply air temperature set point.  When the three-way heating/cooling valve is at 100% open, the two-way cooling only valve shall be opened to further control the supply air temperature set point.  As the system cooling requirement is reduced, the cooling control sequences shall reverse accordingly.
Outdoor air absolute humidity is referenced to create a control curve for the operation of the passive dehumidification wheel.  The passive dehumidification recovery wheel is modulated with VFD control as required to achieve a discharge air humidity condition of 50 gr/lbm maximum during cooling operation. The cooling coil is used to achieve the required sensible air temperature set point. The section bypass dampers are fully closed during wheel operation.

While unit is in operation, if the discharge air humidity condition of 50 gr/lbm cannot be maintained, a cooling start command will be issued to the respective heat pump unit (HPW-1/HPW-2) for dehumidification and the heating/cooling valve and the cooling valve will be utilized with the passive dehumidification recovery wheel to maintain a discharge air humidity condition of 50 gr/lbm.
Air handling units remain off during morning warm-up or evening cool down.

If the system’s internal air temperature falls below 50°F with the heating section energized, the supply air flow limit controller (freeze stat) shall stop the unit. If the unit’s supply air temperature rises above 180°F, the supply air high limit controller shall stop the unit.

Unit Unoccupied Mode:

The fans shall be off and the outdoor and exhaust dampers shall be closed.  When the outdoor air temperature is below 40°F, the two-way heating/cooling valve will be modulated to maintain an AHU unit internal temperature of 40°F. A 60°F space set point temperature is maintained by utilizing the in-floor heating system.

Logged Points:

Alarm Points:

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Air Handling Unit (AHU-3) Description of Operation


This 100% outdoor air handling unit is comprised of a supply and return fan both equipped with variable frequency drives (VFD’s), split hydronic heating/cooling coil section, total enthalpy recovery wheel section, passive dehumidification recovery wheel section, MERV 13 filtration on supply air side, and MERV 8 filtration on exhaust air side.

The unit is started and stopped according to an operator programmed time schedule or manually through the operator workstation. The Supply and Return Air Fans are monitored by current sensors. The air handling unit operates in conjunction with the VAV boxes to maintain space ventilation rate and to provide both first and third stage cooling.

When the unit is in the occupied mode the outdoor air dampers are opened to allow 100% outdoor air flow rate.
The Unit is coupled with a transpired solar collector (solar wall). The solar wall intake air temperature is continuously monitored and recorded for performance analysis.

The supply air fan speed is modulated by the VFD to maintain the duct system static pressure set point.  The set point is at a level that ensures the VAV Box demands are met and at least one box is open 100%. Static pressure is reset using Trim and Respond logic within the range 0.15 in w.c. (adjustable).  When the fan is off, the set point is 0.5 in. w.c. (Adjustable).  When the fan is proven on, every 2 minutes (Adjustable), the set point is trimmed by 0.04 in. w.c. (Adjustable).  The set point is increased by 0.03 in. w.c. times the number of pressure requests but no more than 0.12 in. w.c. (Adjustable).

Return air fan speed is modulated by the VFD to maintain the return air duct system static pressure set point.  The set point is adjusted to ensure the farthest exhaust damper is open 100%.

Occupied Headint Mode:

Supply air heating setpoint will be set to 68°F (adjustable).

First stage of heating will be the solar wall.  When heating is required, the solar wall intake damper shall be modulated open while the outdoor air damper is modulated closed to maintain the supply air temperature setpoint.

Second stage heating is the enthalpy wheel operating in heating mode to recover energy from exhaust air and pre-condition incoming outdoor air. When the outdoor air is below 32°F, the VFD on the enthalpy wheel is operated to achieve an exhaust temperature setpoint of 33°F to prevent the wheel from freezing.

Third stage heating is the hydronic coil control valve modulating to maintain the supply air temperature setpoint.

Occupied Cooling Mode:

First stage cooling is the enthalpy wheel operating in cooling mode to discharge energy to exhaust air and pre-condition incoming outdoor air. Should the outdoor air enthalpy be less than that of the building exhaust air, the enthalpy wheel shall cycle off and the corresponding section bypass dampers are fully opened.

Second stage cooling is provided by the hydronic coil control valve modulating to maintain the required supply set point temperature of 65°F (adjustable) to provide tempered ventilation air.  Additional space cooling is by the space DX fan coil units.

Space ventilation rates are minimum rates as scheduled and supplied during occupied periods. The air flow rate supplied to each space is monitored at the VAV box.

Air handling units remain off during morning warm-up or evening cool down.

If the system’s internal air temperature falls below 50°F with the heating section energized, the supply air flow limit controller (freeze stat) stops the unit. If the unit’s supply air temperature rises above 180°F, the supply air high limit controller stops the unit.

Unit Unoccupied Mode:

The fans shall be off and the outdoor and exhaust dampers shall be closed.  When the outdoor air temperature is below 40°F, the two-way heating/cooling valve will be modulated to maintain an AHU unit internal temperature of 40°F. A 60°F space set point temperature is maintained by utilizing the in-floor heating system.

Logged Points:

Alarm Points:

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Air Handling Unit (AHU-4) Description of Operation


This 100% outdoor air handling unit is comprised of a supply and return fan, hydronic heating/cooling coil section, total enthalpy recovery wheel section, MERV 13 filtration on supply air side, and MERV 8 filtration on exhaust air side.

The unit is started and stopped according to an operator programmed time schedule or manually through the operator workstation. The Supply and Return Air Fans are monitored by current sensors. The air handling unit is a constant volume system.

When the unit is in the occupied mode the outdoor air dampers are opened to allow 100% outdoor air flow rate.

The unit is equipped with an earth tube air intake system.  The intake temp from the earth tubes shall be monitored and logged for performance.  When possible, the outdoor air intake damper will be closed and the earth tube intake damper will be opened to satisfy the unit.

Occupied Heating Mode:

First stage heating is the enthalpy wheel operating in heating mode to recover energy from exhaust air and pre-condition incoming outdoor air.  When the outdoor air is below 32°F, the VFD on the enthalpy wheel is operated to achieve an exhaust temperature setpoint of 33°F to prevent the wheel from freezing.

Second stage heating is the hydronic coil control valve modulating to maintain a minimum discharge supply air temperature of 68°F (adjustable) and the in-floor heating control valves modulate to maintain the space set point.  When the space heating valve is 100% open and there remains a space call for heating, the room sensor overrides the discharge air sensor and the heating control valve modulates to maintain the required space temperature.

Occupied Cooling Mode:

First stage cooling is the enthalpy wheel operating in cooling mode to discharge energy to exhaust air and pre-condition incoming outdoor air. Should the outdoor air enthalpy be less than that of the building exhaust air, the enthalpy wheel shall cycle off and the corresponding section bypass dampers are fully opened.

Second stage cooling is provided by modulating the hydronic coil control valve to maintain the required set point temperature of 63°F (adjustable) to provide space cooling.

This system maintains washroom exhaust rates and corresponding make-up air during occupied hours.

Air handling units remain off during morning warm-up or evening cool down.

If the system’s internal air temperature falls below 50°F with the heating section energized, the supply air flow limit controller (freeze stat) stops the unit. If the unit’s supply air temperature rises above 180°F, the supply air high limit controller stops the unit.

Unit Unoccupied mode:

The fans shall be off and the outdoor and exhaust dampers shall be closed.  When the outdoor air temperature is below 40°F, the two-way heating/cooling valve will be modulated to maintain an AHU unit internal temperature of 40°F. A 60°F space set point temperature is maintained by utilizing the in-floor heating system.

Logged Points:

Alarm Points:

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Air Handling Unit (AHU-5) Gymnasium Description of Operation


This 100% outdoor air handling unit is comprised of a supply and return fan both equipped with variable frequency drives (VFD’s), hydronic heating/cooling coil section, total enthalpy recovery wheel section, MERV 13 filtration on supply air side, and MERV 8 filtration on exhaust air side.

The unit is started and stopped according to an operator programmed time schedule or manually through the operator workstation. The Supply and Return Air Fans are monitored by current sensors. The air handling unit operates in conjunction with the VAV boxes to maintain space ventilation rate.

When the unit is in the occupied mode the outdoor air dampers are opened to allow 100% outdoor air flow rate.  The unit and associated VAV boxes operate to maintain return air CO²  for ventilation control.

Occupied Heating Mode:

First stage heating is the enthalpy wheel operating in heating mode to recover energy from exhaust air and pre-condition incoming outdoor air.  When the outdoor air is below 32°F, the VFD on the enthalpy wheel is operated to achieve an exhaust temperature setpoint of 33°F to prevent the wheel from freezing.

Second stage heating is provided by modulating the hydronic coil control valve to maintain a minimum discharge supply air temperature of 68°F (adjustable) and the in-floor heating control valves modulate to maintain space set point.  When the space heating valve is 100% open and there remains a space call for heating, the room sensor overrides the discharge air sensor and the heating control valve modulates to maintain the required space temperature.

Occupied Cooling Mode:

First stage cooling is the enthalpy wheel operating in cooling mode to discharge energy to exhaust air and pre-condition incoming outdoor air. Should the outdoor air enthalpy be less than that of the building exhaust air, the enthalpy wheel shall cycle off and the corresponding section bypass dampers are fully opened.

Second stage cooling is provided by modulating the hydronic coil control valve to maintain the required set point temperature of 65°F (adjustable) to provide tempered ventilation. Additional space cooling is by the space water to air heat pump units.

Space ventilation rates are minimum rates are determined by return air CO²  levels and supplied during occupied periods. Air flow rate supplied to each space is monitored at the VAV box.

Supply air fan speed is modulated by the VFD to maintain the duct system static pressure set point.  The set point is reset to maintain a VAV box at 100% open.  The return fan speed is modulated to track the supply fan.

The air handling unit remains off during morning warm-up or evening cool down.

If the system’s internal air temperature falls below 50°F with the heating section energized, the supply air flow limit controller (freeze stat) stops the unit. If the unit’s supply air temperature rises above 180°F, the supply air high limit controller stops the unit.

Unit Unoccupied Mode:

The fans shall be off and the outdoor and exhaust dampers shall be closed.  When the outdoor air temperature is below 40°F, the two-way heating/cooling valve will be modulated to maintain an AHU unit internal temperature of 40°F. A 60°F space set point temperature is maintained by utilizing the in-floor heating system.

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Variable Air Volume (VAV) Terminal Units Description of Operation


Upon detection of space occupancy, the associated VAV box is modulated open to the minimum ventilation setting. The return air control damper is opened to the calculated air flow position. The VAV box and return air control damper close after a preset time of 10 minutes (adjustable) if no occupancy is detected in the room.

During unoccupied periods the VAV box and return air control damper are closed. A 60°F (adjustable) set point temperature in heating season is maintained by activation of the in-floor heating system.

During start-up of the it’s respective AHU, each VAV box will modulate open to the minimum flow position and the return air control damper will open to the calculated air flow position.  After a period of 30 minutes each VAV box and return air control damper will be allowed to operate based on the occupancy detected in each room.

Cooling VAV Boxes (VAV1-1, 1-2, 1-8, 1-9, 2-4, 2-15, 2-19 and 5-3)

VAV boxes modulate further open from minimum ventilation set point as required to maintain space temperature.

Classroom Economizer (VAV Boxes connected to AHU1 and 2)

During favourable outdoor air conditions, sensible temperature between 60°F-75°F (adjustable), enthalpy less than 39.0 Btu/lbm (adjustable) and dew point less than than 55°F (adjustable), the Building Automation System sends a signal to the LED driver to illuminate a signal light (green) that the classroom windows may be opened.

In the event that the occupant chooses to open the windows, the corresponding supply air VAV is closed and the return air damper from the classroom remains open. The hydronic control valves which control the in-floor heating/cooling system close.

Each classroom operable window is provided with a closure contact device. A minimum of two windows must be opened for the Building Automation System to initiate classroom economizer mode.

During unfavourable outdoor air conditions (outdoor of the parameters identified above), the classroom signal light indicates red that all windows must be closed.

In the event that any window is left open during unfavourable outdoor air conditions, the classroom signal light shall flash (red) until all windows are closed. The hydronic control valves close. If this event occurs and the space is occupied, the hydronic control valve closes if operation is in cooling season or remains full open if in heating season. Should this situation remain unchanged for a period of 15 minutes (adjustable) then an alarm is initiated by the Building Automation System.

Demand Control Ventilation (VAV Boxes 2-1 & 2-3)

During occupied hours, a space CO² sensor is used to modulate a corresponding VAV box to below the minimum occupied ventilation rate during periods when the space CO² levels are within the acceptable CO² set point of 700 ppm (adjustable) above the outdoor ambient concentration level.

Demand Control Ventilation (Administration VAV Box 3-1)

During occupied hours, the box operates interlocked with EF-1 to provide 235cfm of ventilation air.

Demand Control Ventilation (Gymnasium VAV Boxes 5-1, 5-2)

During occupied hours, a return air CO² sensor is used to modulate a corresponding VAV box to a lower ventilation rate of 100 cfm during periods when the space CO² levels are within the acceptable CO² set point of 700 ppm (adjustable) above the outdoor ambient concentration level.

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Gymnasium Natural Ventilation Control Description of Operation


During favorable outdoor air conditions, sensible temperature between 60°F-75°F (adjustable), enthalpy less than 39.0 Btu/lbm (adjustable) and dew point less than 55°F (adjustable), a ventilation button located at occupant level that is interlocked with high level motorized ventilation louver is enabled.  Favorable conditions will be indicated with a green LED.

In the event that the occupant chooses to activate the louver, the corresponding supply air VAV box is turned off and AHU-5 is cycled off. The hydronic control valves which control the in-floor heating system closes.

Each gymnasium exterior door is provided with a closure contact device. The corresponding door must be propped open for the corresponding louver to open.

During unfavorable outdoor air conditions (outdoor of the parameters identified above), the ventilation louver closes automatically.
In the event that any exterior door is left open during unfavourable outdoor air conditions, the gymnasium LED (mounted next to the temperature sensor) will flash red until all doors are closed. The hydronic control valves shall also be closed. If this event occurs and the space is occupied, the hydronic control valve shall be full open if in heating season to maintain minimum heating set point.  Should this situation remain unchanged for a period of 15 minutes (adjustable) then an alarm is initiated by the Building Automation System.

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Split System Air Conditioners Description of Operation


Split system air conditioning units AC-1 and AC-2 and the respective remote air cooled condensing units ACC-1 and ACC-2 are started and stopped by electronic thermostat provided with unit. BAS monitors and logs space temperature.

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Variable Refrigerant Volume (VRV) Air-Conditioning System Description of Operation


The VRV Air-Conditioning System consists of DX fan coils FC-1 to FC-11 and indoor water-cooled condensing units WCC-1a and WCC-1B. This system utilizes the manufacturer’s controllers and sequences and is enabled by the BAS. The BAS monitors points provided by the manufacturer’s controller through the BACnet interface and also indicates alarm status.

BAS monitors and logs space temperature.

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Exhaust Fans Description of Operation


Exhaust fans are started and stopped and associated motorized dampers are opened and closed according to a programmed time schedule or manually through the operator workstation. Fan status is monitored by a current sensor.

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Mechanical Room Heating and Ventilation Description of Operation


On a rise in space temperature above set point, the exhaust fan activates and the corresponding motorized damper opens. On a fall in space temperature below set point, the dampers close and the fan cycles off.

If the space temperature falls below the set point, then the unit heater fan is cycled on until the space temperature reaches set point.

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Solar Domestic Hot Water System Description of Operation


The Domestic hot water heater operates on factory built in controls. The BAS starts and stops recirculation pump P-11 in accordance with operator programmed time schedule or manually through the operator work station.  Pump status is monitored by a current sensor.  BAS monitors domestic hot water supply temperature.

The temperature of the solar heated water storage tank is monitored and when the temperature is above the set point (Adjustable) the ground source isolation valve is opened and the associated pumps started until the tank temperature is 10° below set point.

The command and status of the solar system pump is monitored through a parallel relay to the pump start signal and a current sensor installed on the power lead to the pump.

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Ground Source Loop Flow Control (P-1 and P-2) Description of Operation


The ground source loop flow is initiated automatically on a call for heating or cooling from any ground source connected mechanical unit (HPW-1, HPW-2, HPW-3, HPW-4, HPA-1, HPA-2, WCC-1a, and WCC-1b).

Once the lead pump has been activated and flow is established in the ground source loop, the respective ground source mechanical unit continues through its respective sequence of operation.  Loop flow is established by speed feedback from the pump VFD’s, pump current and loop differential pressure sensors.

Each pump is modulated by a VFD to maintain the system differential pressure set point; there is a heating season system set point of 20psi (adjustable), and a cooling season system set point of 25 psi (adjustable).

If a no flow condition is indicated by the ground source loop flow switch then the lead pump is stopped and the lag pump is started. If a no flow condition still remains, then an alarm is initiated at the BAS and all ground source connected mechanical units will be disabled to prevent high head pressure faults. Every 7 days (adjustable) the lead and lag pumps are alternated.

The system pumps operate in a standby mode for system flow up to 200GPM (adjustable) and operate in parallel for system flow exceeding that value.  The lead pump will run its speed up to 95% and if loop differential pressure cannot be maintained, the second pump will be started.  The speed of both pumps will be controlled from one PID loop, so that when both pumps are operating there is one speed setting to maintain pressure.  If during parallel pump operation the speed required to maintain loop pressure differential falls below 55% (adjustable) then the lag pump will be stopped and the lead pump will continue to operate.

In the event that the system flow requirement exceeds the peak ground heat exchanger differential pressure set point 20 psi (adjustable), the ground loop recirculation valve begins to modulate open as required to maintain the system differential pressure set point. As the ground source system flow requirement decreases, the bypass valve modulates to closed first prior to modulation of the pump ground heat exchanger VFDs.

The BAS continually monitors ground heat exchanger supply and return temperatures as well as supply temperature to the ground source mechanical units (temperature sensor installed on discharge side of pumps P-1/P-2).

In the event that the ground source supply temperature fall below 40°F (adjustable) during heating season, a low water temperature alarm is initiated by the BAS.

In the event that the ground source supply temperature rises above 85°F (adjustable) during cooling season, a high water temperature alarm is initiated by the BAS.

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Hydronic Plants (East and West Loop Heat Pumps; HPW-3 and HPW-4) Description of Operation


Cooling Plant Operation

The cooling plant operation will be enabled when the outdoor air temperature is above 65°F (adjustable).  On call for cooling from a classroom or a dehumidification call from AHU 3, AHU4 or AHU-5, the respective water source heat pump unit (HPW-3/HPW-4) is activated. Chilled water plant operation is set to supply a 58°F supply water temperature during cooling operation. Heat pump unit and corresponding circulating pump status is monitored by current sensors.

When the plant has been activated then the lead hydronic system pump and respective circulating pumps are started. Flow must be established in both the source side heat pump loop by its flow switch and load side heat pump loop as indicated by pump status prior to activation of the heat pump compressor.  Water temperature setpoint will be maintained by cycling the 1st and 2nd stage of the heat pumps to maintain loop temperature set points and anti-cycle timers to prevent short cycling of the equipment (anti-cycle timers initially set at 5 min).

Each hydronic system pump is modulated by a VFD to maintain the system differential pressure set point of 25 psi (adjustable).  Pumps P-3 and P-4 and P-5 and P-6 operate lead/lag. The lead pump will run its speed up to 95% and if loop differential pressure cannot be maintained, the second pump will be started.  The speed of both pumps will be controlled from one PID loop, so that when both pumps are operating there is one speed setting to maintain pressure.  If during parallel pump operation the speed required to maintain loop pressure differential falls below 55% (adjustable) then the lag pump will be stopped and the lead pump will continue to operate.
.Load side return water temperature sensor modulates a 3-way valve to ensure incoming water temperature does not exceed 60°F (adjustable).

Heating Plant Operation

The heating plant operation will be enabled when the outdoor air temperature is below 60°F (adjustable).  On a call for heating from a classroom or the gymnasium, the respective water source heat pump unit (HPW-3/HPW-4) is activated. Heating water plant operation is controlled automatically with an outdoor air reset schedule. When the outdoor air temperature fails below 60°F (adjustable), the hydronic plant operates to supply a system temperature of 80°F (adjustable). As the outdoor air temperature proceeds to 40°F (adjustable), the system water temperature resets to 90° (adjustable).

When the plant has been activated then the lead hydronic system pump and respective circulating pumps are started. Flow must be established in both the source side heat pump loop by its flow switch and load side heat pump loop as indicated by pump status prior to activation of the heat pump compressor.  Water temperature setpoint will be maintained by cycling the 1st and 2nd stage of the heat pumps to maintain loop temperature set points and anti-cycle timers to prevent short cycling of the equipment (anti-cycle timers initially set at 5 min).

Each hydronic system pump is modulated by a VFD to maintain the system differential pressure set point of 20 psi (adjustable).  Pumps P-3 and P-4 and P-5 and P-6 operate lead/lag. The lead pump will run its speed up to 95% and if loop differential pressure cannot be maintained, the second pump will be started.  The speed of both pumps will be controlled from one PID loop, so that when both pumps are operating there is one speed setting to maintain pressure.  If during parallel pump operation the speed required to maintain loop pressure differential falls below 55% (adjustable) then the lag pump will be stopped and the lead pump will continue to operate.

Transition between Heating/Cooling Plant Operation

To transition from heating plant operation to cooling plant operation, there are two conditions which need to be met: 1)That the outdoor air be above the cooling lockout setpoint of 65°F (adjustable) and 2) That there is a cooling call from one of the respective classrooms.  The first stage of cooling, if available, will be the ground source water economizer control.  If the ground source water economizer control cannot maintain the temperature setpoint, then the heat pump unit (HPW-3/HPW-4) will be started and the respective ground source mechanical unit continues through its respective sequence of operation.

To transition from cooling plant operation to heating plant operation, there are two conditions which need to be met: 1) That the outdoor air be below the heating lockout setpoint of 60°F (adjustable) and 2) That there is a heating call from one of the respective classrooms.  The first stage of heating, if available, will be the ground source water economizer control.  If the ground source water economizer control cannot maintain the temperature setpoint, then the heat pump unit (HPW-3/HPW-4) will be started and the respective ground source mechanical unit continues through its respective sequence of operation.

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Ground Source Loop Water Economizer Description of Operation


In the event that the ground loop temperature is within the hydronic system set point conditions (58°F in cooling; 80°F or greater in heating), the plant heat pump compressors are disabled, and the water economizer three-way control valve modulates source water through the respective heat exchanger to achieve system set point.

Once the lead pump has been activated and flow is established in the ground source loop, the respective ground source mechanical unit continues through its respective sequence of operation.

Each hydronic system pump is modulated by a VFD to maintain the system differential pressure set point; there is a heating season system set point of 20 psi (adjustable), and a cooling season system set point of 25 psi (adjustable).  Pumps P-3 and P-4 and P-5 and P-6 operate lead/lag. The lead pump will run its speed up to 95% and if loop differential pressure cannot be maintained, the second pump will be started.  The speed of both pumps will be controlled from one PID loop, so that when both pumps are operating there is one speed setting to maintain pressure.  If during parallel pump operation the speed required to maintain loop pressure differential falls below 55% (adjustable) then the lag pump will be stopped and the lead pump will continue to operate.

If a no flow condition is indicated by the heat pump loop flow switch then an alarm is initiated at the BAS.

If a no flow condition is indicated by the hydronic system loop flow switch then the lead pump is stopped and the lag pump is started. Every seven days the lead and lag pumps are alternated.

The plant heat pumps are complete with their own operating and safety controls. Optimum supply water temperature is maintained by cycling compressor operation.

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Dedicated Air Handling Unit Water Source Heat Pumps (HPW-1 and HPW-2) Description of Operation


Heat Pump Unity Cooling Operation

On a call for cooling from the air handling unit discharge air sensor, the respective water source heat pump unit (HPW-1/HPW-2), flow control valve and corresponding circulating pump are activated. The heat pump unit is set to supply a 42°F (adjustable) chilled water temperature during cooling operation. Heat pump unit and corresponding circulating pump status is monitored by a current sensor.

Heat Pump Unity Heating Operation

On a call for heating from the air handling unit discharge air sensor, the respective water source heat pump unit (HPW-1/HPW-2) is activated. The heat pump unit is set to supply a 98°F (adjustable) hot water temperature during heating operation. The heat pump unit and corresponding circulating pump status is monitored by a current sensor.

In the event that hydronic heating loop calls for heating, the hydronic control valve modulates to a preset position. The AHU coil 2-way control valve modulates open to maintain the AHU discharge air sensor set point.

Flow must be established in both the source side heat pump loop by its flow switch and load side heat pump loop as indicated by pump status prior to activation of the heat pump compressor.

If a no flow condition is indicated by the source side or load side heat pump loop flow switch then an alarm is initiated at the BAS.
The heat pumps are complete with their own operating and safety controls.

Water temperature setpoint will be maintained by cycling the 1st and 2nd stage of the heat pumps to maintain loop temperature set points and anti-cycle timers to prevent short cycling of the equipment (anti-cycle timers initially set at 5 min).

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Air to Water Source Heat Pumps (HPA-1 and HPA-2) Description of Operation


The air to water source heat pumps serve the gymnasium and operate to provide supplemental cooling operation. This manufacturer’s controller and sequences are utilized and are enabled by the BAS. The flow control valve is opened when the unit is activated. The BAS monitors points provided by the manufacturer’s controller and also indicates alarm status.

The units will be cycled to maintain gym temperature at cooling setpoint when the gymnasium is operating in cooling mode.  Heat pump operation is verified via a current sensor.

BAS monitors and logs space temperature.

Logged Points:

Alarms:

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Heating Control Valves (Convectors) Description of Operation


The two-way control valve serving the radiation and hydronic systems which are not interlocked with any other equipment or systems is controlled by a space sensor to maintain the desired set point.

Logged Points:

Alarms:

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Radiant In-floor Heating/Cooling System Description of Operation


The space thermostat controls the radiant in-floor heating/cooling system serving the heating zone.  The scheduling of the in-floor manifolds will be based on the operating schedule of the building.  The in-floor manifolds will be scheduled occupied for a period of 3 hours (adjustable) prior to the main occupied flag being turned on by the occupied schedule.

Heating

On a fall in space temperature, the corresponding manifold zone valves open. When space temperature is satisfied, zone valves close.

Where all in-floor loops in a given manifold serve a common space, one modulating control valve is used to control the manifold.

Each heating manifold has a flow control valve which is closed when the in-floor system is in the cooling mode.

Cooling

On a rise in space temperature, the corresponding manifold zone valves modulate open. When space temperature is satisfied, corresponding zone valves close.

Where all in-floor loops in a given manifold serve a common space, one modulating control valve is used to control the manifold. 

Logged Points:

Alarms:

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Unit Heaters and Cabinet Unit Heaters Description of Operation


If the space temperature falls below the set point temperature then the unit heater fan is cycled on until the space temperature rises to set point.

All unit heater two-way control valves are closed during cooling season.

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Non-Potable Domestic Water System (P-12 and P-13) Description


Non-potable domestic water pumping system is enabled at all times. Pump status is monitored by a current sensor.
Upon positive detection of the water level in the interior rainwater collection manhole from the level sensor, the lead pump may be activated. The level sensor disables the pumps upon detection of low water level and alerts the BAS; the solenoid connected to the makeup domestic water connection opens. When cistern level rises above the restart level, the domestic water solenoid valve closes and the pumps are activated.

In the event that the solenoid connected to the makeup domestic water is open, the wall hydrant control valves serving the west school hydrant (by Servery Rm 121), the front school hydrant (located in front of mech rm 148) and the hydrant serving the green roof shall be closed until the makeup water solenoid closes.

In the event that a high water level is detected, an alarm is initiated by the BAS. Cistern water level is continuously monitored and logged.
Each pump is modulated by a VFD to maintain the system pressure set point of 40psi (adjustable) as measured from the pressure sensor in Mechanical Room 148.  If, at low VFD speed, the system pressure goes 5psi (adjustable), the pump VFD will be stopped until the system pressure falls below the system pressure setpoint.

If a low pressure condition (set initially at 30 psi, adjustable) is indicated by the system pressure sensor then the lead pump is stopped and the lag pump is started. If a low pressure condition still remains, then an alarm is initiated at the BAS and the make up water solenoid is opened. Every 7 days (adjustable) the lead and lag pumps are alternated.

UV filter lamps are enabled at all times as indicated by the UV light manufacturer.

Bag filter pressure drop is monitored. A BAS alarm occurs when the bag filter pressure drop exceeds 2 psi (adjustable).

Logged Points:

Alarm Points:

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Living Wall System Control Description of Operation


Water Control

Living wall water circulation system is started and stopped according to an operator programmed time schedule or manually through the operator workstation. Pump status is monitored by a pressure switch.

Make up water solenoid valve opens during pump operation.

A conductivity sensor in the pump supply line is used to measure and control the water conductivity.  When water conductivity level is above the system set point, the bypass line solenoid valve opens to the living wall sump; old water will drain into the overflow.

A high water level sensor disables water supply to the system and initiates an alarm to the BAS.

A mechanical float valve maintains minimum sump water level during regular system operation.

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Air Flow Control (FC-7) Description of Operation


Living wall air flow control is started and stopped according to an operator programmed time schedule or manually through the operator workstation. Fan status is monitored through the manufacturer provided fan coil controller.

Living wall air flow control is by FC-7; this fan coil continuously circulates air during living wall operation.

VOC, CO², and humidity levels in the return air ductwork are monitored, measured and compared with ambient space levels for the purpose of demonstrating performance of the living wall.

In the event that return air humidity level exceeds 60% RH (adjustable) during non-cooling operation of FC-7, the duct bypass damper opens and the damper in the return air connection closes thereby facilitating complete air bypass from the living wall filtration.

Logged Points:

Alarm Points:

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Water Meter Description of Operation


BAS monitors and logs the water meter utilizing pulse output from water utility.

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Electric Meter Description of Operation


BAS monitors and logs the electric meter utilizing standard communication protocol.

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Lighting Description of Operation


During occupied hours and when there is an adequate amount of natural light already present in the classroom, as sensed by the light level sensor, the classroom lighting is activated by a pushbutton on the classroom temperature sensor; occupancy must be sensed in the room for the pushbutton to be active.  If there is not an adequate of natural light available in the classroom, the occupancy sensor, upon detection of occupancy, will automatically turn the lights on.

The BAS (via the light level sensor) dims the exterior row of fixtures in response to the available natural light with a 0-10 VDC signal.
Classroom lighting may be overridden to off by activating the sensor pushbutton.

If no occupant is sensed in the space for an operator adjustable time interval, the lights are shut off.

During unoccupied hours the lights are shut-off. If an occupant is sensed in the space the lights are turned on or they may be turned on by the local switch. If no occupant is sensed in the space after an operator programmed time interval, the lights are turned off.
Common area lighting is controlled via the Clipsal Lighting Controls.

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Door Access Controls Description of Operation


Door access control is done through the BAS system using AC1 card access modules with HID ProxPoint proximity card readers. The security panel and BAS is interfaced with contact closures; one from the security panel for indicating the system is armed and one from the Andover BAS for remote disarming.

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Greater Essex County District School Board