Specification Data. General:

Transcription

1 Specification Data General: Zone Units (ACU s) will be draw through vertical type having double skin construction. All Zone Units will have all necessary components such as control valves and motors to achieve the described control sequence. For Zone Unit capacities refer to schedules and schematic drawings. Units will take return air via the top face either directly from the room or via a top mounted unit matched section from the suspended ceiling. Cabinet & Panels: Zone Unit frames and panels are manufactured from non corroding Aluzink. The rigid frame will be of maximum 2mm thick sheet steel. The front panels will hinged to ensure easy access for maintenance of electrical and mechanical components entirely from the front of the unit. A specialized key is required for the ¼ turn compression locks to prevent access to unauthorized personnel. The panels will be lined with class O non eroding insulation material 25mm thick with 80 kg/m3 density. Filter Section Zone Unit filters are disposable, low velocity, deep pleated, synthetic fabric mounted in galvanized metal frames coupled with fine mesh net made of synthetic material. Filters are to EU5 grade with additional G2 pre-filter to Eurovent 4/5. The filters are fitted in the return air stream, held by quick release retaining clips, and are fully accessible from the front of the unit. A differential pressure switch is fitted which, through the alarm facility in the microprocessor controller, will indicate when the filters need changing. Drain Pan and Drain lines Zone Units drain pan is manufactured from 316L, hygiene quality stainless steel, and cover the coil footprint and headers with appropriate over laps. Drain pan will be internally attached to coil casing and complete with pipe connection. The slope of the drain will be designed for a minimum drainage efficiency of 95%. Traps drain line with a water seal at least 25mm deeper than the suction pressure of the fan, pitched 21mm/meter to an indirect point. The drain tray will be insulated to prevent condensate forming. Fan Section Zone Units are fitted with two or three fans. The fans are quiet low speed centrifugal, double inlet, double width, forward curved with statically and dynamically balanced impellers with lifetime lubricated bearings for quite vibration free operation, fans are specifically designed and suitable for service indicated with non-over loading operating characteristics, complete in all respects with integral variable speed independent electric motor IP 56 with class F insulation, single phase 6 pole with built in thermal protection. The fan speed is modulated through fan speed regulator by use of integral inverters which are less noisy, audibly and electronically than phase cutters. The motor shall be fitted with automatic re-settable temperature sensing device.

2 A differential pressure sensor is fitted to monitor airflow; failure will result in an alarm and automatic disabling of all functions. The fans will automatically modulate dependent upon return air conditions and shall have an easily re-settable upper and lower air volume limit for cooling (and heating) mode(s). A low speed shall be assigned for dehumidification mode where required. Coil Section Zone Unit coils are rated for 300 psig working pressure. The coils will be manufactured from 3/8" O/D copper tubes with mechanically bonded aluminium fins. Coils will be 2, 3 or 4 rows (depending on the coil selections) with 12 fins per inch. Units are fitted with 2 way control valve. Overall unit chilled water pressure drop including coil and valve is stipulated in the associated unit selection supplied as part of this submittal. Each unit shall be provided with a purpose made base frame constructed from angle 34x34mm. The base frame shall be supplied for the required configuration to suite the site condition and shall have scope for height adjustment +/- 50mm for final cutting in level with the access floor. Electric Board The Zone Unit electric board is factory wired and compliant with IEC standards. It is completely isolated from the air stream and accessible from the front panel via a door interlocked mains isolator to prevent access to live components. All terminals within the unit with power supply higher than 24 volts are touch proof an additional cover will be provided to further protect the electric components. The electrical board will include mains isolator switch, transformer, miniature circuit breakers, automatic safety switches, fan motor contact, fan motor speed controllers, additional contacts for remote signaling of alarms etc. Cabling shall be colour coded and numbered, and neatly run in trunking segregating high and low voltages. All wiring shall comply with BS EN Part 1. Controls Each Zone Unit is fitted with an independent microprocessor controller with LCD display to check the main parameters. A separate main microprocessor is not required. The microprocessor within the Zone Unit is sufficiently powerful to control each Zone Units and associated LECU s on its network and communicate directly to a PlantWatch Pro colour touch screen display situated on each floor providing both remote and local control. The system is controlled as standard by the return air to the Zone unit, Visualization of the controls shall be achieved directly at each Zone Units or through the PlantWatch Pro controller. All of which shall provide easy access to set point adjustment and all other built in functions. A PlantWatch Pro controller module has been allowed for each independent floor. Plus two Plant Watch Master Controllers either in PC format or via a touch Screen Display these will be located in the designated Maintenance Control Room. Full Links for the BAS are available via the PlantWatch Pro

3 Each PlantWatch Pro will be fitted with an Ethernet card which via connection to the client s Local Area Network (LAN) will interface with the Local Intranet to permit PC adjustment of the Zone Unit set points and individual Local Environmental Units (LECU/Fan Tiles) fan speed and set point for each individual user by on-screen pop up display (TCP/IP based - all PlantWatch Pro units would have to be assigned fixed IP addresses by the onsite IT Engineer). Software required for the above function will be supplied and installed by GEA-Denco at the commissioning stage in association with the client. There will be no requirement for software licenses or ongoing license renewal provided each user s PC is supplied with an internet browser. The IT department of the client shall supply the required IP addresses necessary for each PlantWatch Pro unit. Through an interface provided by Denco it will be possible to link the complete Officecool air conditioning system to the central BMS for specific tasks of plant co-ordination, alarm recognition and out of hours operational override provided the BMS is a Modbus enabled system, although other protocol systems are available. The Officecool system shall be capable of standalone operation in the event of BMS shut down or failure. Any software required for the acquisition and display of data on the BMS shall be supported by GEA-Denco with the software supplied by the BMS manufacturer. The Officecool system is factory prepared by GEA-Denco and requires no software writing on site. Leak detection system comprising a condensate tray water level sensor and a 5 metre underfloor sensing tape will be provided for each unit with required accessories for proper operation, this is offered as an optional extra. In the event of a fire the complete Officecool air conditioning system shall be closed down by the operation of contactors on the power supplies to the Zone Units and LECU. Such signal shall not be overridden until the fire alarm is re-set. Control Sequences Each Zone Unit will communicate with its group of LECU via the communication bus data network. LECU shall control the selected temperature in their space by:- utilising a fully modulating damper according to the suitability of the supply air temperature under the floor. by making full use of the available Officecool temperature until this reaches the minimum supply temp, after which, an electric heater will be energized to raise the supply temp to the LECU Automatically varying the LECU damper to control the temperature Zone Units will communicate with the LECU via this network to determine damper position and shall adjust the volume flow by fan speed control located in each Zone Unit accordingly in line with the prevailing temperature demand. Further the Zone Unit shall adjust the temperature of the supply air according to the demand of the LECU and to the degree of off set to the room temperature from the set point. The Zone unit controller will connect directly to the BMS with no need for duplicate additional PC based systems. This will provide set point adjustment of each Zone unit and system monitoring.

4 The Facilities Manager will have several ways in which to monitor and control the systems as detailed below: utilizing the Zone Unit mounted microprocessor controller with door mounted LCD display utilizing any individual floor PlantWatch Pro colour touch screen display utilizing the main PlantVisor system with colour touch screen display supplied to the Facilities Manager s office The system can be further integrated with the main Building Management System (front end dependant) to provide a common point for plant timing co-ordination, and alarm recognition. Whilst the BMS may originate the normal timing for operation, each zone will have a local override facility which will be communicated to the BMS in order to start up related central plant such as Chillers and ventilation plant via a network, either Ethernet, or own integrated network therefore the additional supply of volt free contacts is not required. Each Zone Unit is fitted with a user-friendly LCD display for visualization, data entry and timer functions shall communicate with up to minimum 16 units. The display shall be fitted to the front access panel of each Zone Unit. The display shall be 107 x 35 mm, 240 x 64 pixels. It shall be possible to set different control parameters for each Zone Unit by means of the display. This display shall check and set all the parameters of the terminal units and will perform the following functions (for Zone Units): auto-restart after power off, zone set point, room humidity set point, fan speed selection, alarms, timer setting, cooling proportional band, heating proportional band, alarm selection, LECU setting, valve control, manual mode for service purposes, sensor calibration, etc. Temperature Sensors The zone air temperature is measured by the return air sensors fitted to the Zone Units located in the return air side of the unit and by the sensors fitted in each LECU unit. Control of Zone Unit on, return air to the Zone Unit, or on the average value of the Zone temperature is possible. The system is capable of varying the supply air temperature depending upon the deviation between the zone set point and the zone measured room temperature. The Facility manager can decide to give different priority to the various sensor values in order to choose between a close control of zone temperature and total freedom to the users for modifying their own micro-climate. Local Environmental Control Unit (LECU/Fan Tile) LECU will be manufactured from a ignition resistant Acrylonitrile Butadiene Styrene (ABS) and will not extend more than 220 mm into the floor void depth from the underside of the floor panel. The LECU is an intelligent fan tile, easily positioned anywhere in the floor of an adaptable work space and capable of operating at noise levels as low as NR18. The LECU maintains the local desired set temperature by re-circulating a varying mixture of air from the room and conditioned underfloor air.

5 Each LECU will contain a sinlgle slow speed low noise centrifugal scroll fans driven from a single motor, fully modulating control dampers, 500w electric heating coil (where stipulated), and a self contained on board control system with full intelligent data link to the Zone Unit. Each LECU will be supplied with supply and recirculation grilles with inbuilt variable height adjustment capability incorporating vibration and movement isolation with load bearing on the pedestal heads and not on the stringers or LECU frames. The motor shall be IP20. The damper will be fully modulating (to avoid large swings in air off temperature which can happen with ON/OFF control) and will be operated by an electrical actuator, which under the dictates of the onboard controller, shall modulate the damper position to allow varying amounts of air from the void to be drawn into the room. The modulating damper incorporates a permanent air bleed from the floor void in order to ensure a continuous fresh air supply to the room during conditions where the damper is fully closed. Built in thermal protection, with automatic reset after tripping is provided. The units shall have no ductwork or pipework connections. Each unit shall be easy to relocate and require no more than one additional tile to be lifted to permit removal or relocation. A standard factory fitted power cable of minimum 4.5 m, rated at 5amp minimum shall link the unit to a segregated power supply. This power shall be controlled via the PlantWatch Pro and contactor control to enable a default function on fan speed to be utilized and fire shut down via the Zone Unit. The unit shall be supplied with a 13amp fused plug for connection to the power track dedicated to the LECU circuits. Due to our control system a 3 core RS485 data cable is all that is required to link the LECU unit back to the Zone Units to provide monitoring and control options. No LECU will cause any electromagnetic interference with other communication data cables and shall not produce any noise. There will be no requirement for filters to avoid any electromagnetic interference. The LECU shall be fitted with two air temperature sensors sensing both the local room temperature and the underfloor air temperature, the intelligent controller shall modulate the control damper to allow more or less cooling/heating air from the floor void to maintain the desired room condition. The LECU can operate as standard as a standalone unit and does not require a connection to the Zone Unit. Each LECU will be supplied with two straight bar grilles. They comprise solid parallel aerofoil blades supported with transverse bars and coated in neutral silver anodized finish as standard. These will be mounted on top of the LECU and will be designed for the general office environment. These grilles will be providing supply and recirculation air to the room. Each grille shall be 200mm x 600mm and shall be supplied to fit flush or below the raised floor finishes dependent upon surface finish and will be height adjustable. The insert piece between grilles shall be cut from floor panels by the flooring installer.

6 The systems are also provided with bleed grilles to the same design and will have the same height adjustment feature as the LECU grilles for easy alignment with the final floor covering. Each grille shall be 200mm x 599mm x30mm. Typical Noise Level Data Zone Unit (ACU) Freefield

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8 Typical Noise Level Data LECU - tested in Anechoic Chamber at South Bank University, London

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