WINNER: AIRAH 2022 Product of the Year

The world’s only VAV diffuser with inbuilt IEQ sensors and AHU optimisation controls.

Suitable for both equal and unequal duct pressure distribution.

Unique Features:

• Low Profile: 200 mm minimum side- or top-entry plenum box height
• Wide Operating Pressure: 10-80 Pa (130 Pa with BMS-networked Actuation Pressure Control)
• Low Pressure Loss: 20-30 Pa typical design static pressure
• Multi-Max Flow: five-fold damper sizing / design flow air balancing from room (40-220 L/s)
• Wide VAV Range: pressure-independent turndown to ≤15% from full five-fold Multi-Max Flow range; full shut-off
• Low Flow Throw Boost: variable geometry extended coverage when turned down
• Multi-Pattern Blow: horizontal swirl pattern adjustable from room (360°; 270°, 180°, 2×90°)
• Factory Calibrated Flow: minimum and design airflow rates programmable at diffuser or BMS
• Vari-Smart Controls™ – Highlights:
  • Thermal-Capacity VAV: inbuilt supply temperature- and static pressure-independent thermostatic control
  • Demand-Controlled Ventilation: CO₂-based and/or PIR-based
  • System Excess-Pressure Relief (BMS-networked): via motorised relief air damper (by others) or diffuser minimum airflow reset
  • Scalable Controls (BMS-networked): smart, stand-alone; scalable via comms connection and simple third-party BMS programming into a distributed controls network
  • AHU Control (BMS-networked): supply air temperature, pressure, fan speed and economiser optimisation
  • Onboard Sensors:
    • Supply & room air temperature
    • Air pressure (diffuser flow & AHU/FCU fan speed)
    • PIR (occupant detection) – optional
    • IAQ (room CO₂+RH or VOC) – optional

Vari-Smart Controls – Variants:

1. Stand-alone: A single Vari-Smart VAV Diffuser or master-slave group of Vari-Smart VAV Diffusers (daisy-chain comms connected) each with inbuilt, intelligent Vari-Smart Controls™  that provide thermal-capacity VAV modulation (supply temperature- and static pressure-independent) and zone-level demand-controlled ventilation (DCV); OR
2. BMS-Network: 1. above; but with Vari-Smart VAV Diffusers networked to BMS (by others), providing highly scalable, BMS-integrated Vari-Smart Controls™ with AHU optimisation of supply air temperature and pressure, fan speed and economiser modulation.

	Location – above:  Discharge height: 2.4 – 4.5 m Flush with a closed ceiling or freely suspended
	Mixed flow discharge: Airflow: 6 – 220 L/s (22 – 792 m³/h) Nominal diameter: DN355
	Swirl induction: suitable for draught-free comfort (ADPI ≥ 90%) from cold-air distribution systems (CADS) with low-temperature supply air ≳7 °C, and for heating at ≤+10 K from 2.7 m height.
	Adjustable pattern: radial swirl pattern configurable through diffuser face (4/3/2-way blow).
	Constant throw VAV: variable geometry discharge provides extended coverage, even when turned down to 15%.
	Vari-Smart™ VAV Diffuser: Electronic VAV diffuser with integrated Vari-Smart Controls™; operates: Stand-alone (pressure-independent) or BMS-networked (additionally optimises AHU operation)
	Electric adjustment: stepper motor VAV damper adjustment.
	Square face shape: lay-in tile, suitable for ceiling grids with 600 mm centres.
	Radial face pattern: flush-face, offset-radial vane pattern matches Fixed Helical Swirl Diffuser (HSC-FD), Adjustable Helical Swirl Diffuser (HSC-AD) and Multi-Swirl Diffuser (MSC-FD).
	Metal face: powder coated galvanised steel.
	Plenum: Square, R1 insulated, rigid-foam, side-entry connection box (cushion head) c/w perforated distribution plate.
	Integrated sensors & Vari-Smart Controls™: Terminals for 24VDC power supply. Terminals suitable for optional comms (Modbus RS-485) daisy-chain to BMS /  System Controller (by others). Diffuser perforated cap, removable from room, houses controls hub with: Sensors: Troom; Tsupply; Pstatic PC board, Bluetooth enabled Stepper motor Plug-in sockets suitable for: PIR; CO2+RH or VOC P or PI thermal-capacity room temperature control, plus zone-level demand-controlled ventilation (DCV) sequences for optional PIR and/or CO2/VOC sensors.

Options

	Mounting frame: suitable for framing a square ceiling cut-out. Compatible with HSC-VS-S (ie square face) only.
	Reduced square face: lay-in tile, suitable for ceiling grids with 500 mm centres.
	Circular face shape: 500 mm face diameter, suitable for round ducting or a cylindrical connection box.
	Plenum options: low profile (≥200 mm); acoustic lining opposite spigot; up to R2 thermal insulation; top-entry or multiple side-entry spigots; metal casing; cylindrical shape.
	Optional sensors & Vari-Smart Controls™  functions: Optional Integrated Sensors (plug-and-play from room): IAQ: CO2+RH or VOC Occupant detection: PIR Remote Options (wired or Bluetooth): HMI Troom Indoor air quality: PM2.5; CO2; RH; VOC Occupant detection: PIR Key Advanced Functions (BMS-networked only): System excess-pressure relief (via motorised relief air damper by others, or biased towards low-priority Vari-Smart VAV Diffusers) System under-pressure prevention (for highly diversified systems) Actuation pressure control (prevents excessive pressure during stepper motor operation) AHU/FCU fan speed dynamic reset AHU/FCU supply temperature dynamic reset Supply air pressure optimisation (minimises duct pressure) Supply air temperature optimisation (minimises supply temperature) Economy cycle optimisation & reset (extends free-cooling range; controls supplementary cooling)

SMARTEMP Helical Vari-Swirl Diffuser™ HSC-VS

VARI-SWIRL^® and VARI-SMART^® are registered trade marks

Smarter Design / Smarter Engineering / SMARTAIR DIFFUSION™

Known as the Vari-Swirl™, the Helical Vari-Swirl Diffuser™ (HSC-VS) is a Vari-Smart™ electronic variable air volume (VAV) ceiling swirl diffuser for space cooling and heating, indoor air quality control, and AHU optimisation.

Vari-Smart VAV Diffusers

Vari-Smart VAV Diffusers incorporate key onboard smarts: sensors for room air temperature, supply air temperature and supply air pressure; optional sensors for PIR and IAQ (CO₂+RH / VOC); motorised VAV damper operation; and intelligent Vari-Smart Controls. They provide stable room temperature control, independent of supply air temperature and pressure variations. They also improve energy efficiency, enhance thermal comfort, elevate indoor air quality, and increase flexibility to tenancy changes.

Each Vari-Smart VAV Diffuser operates as a small and independent thermal comfort and IAQ zone. By following shifting loads across multiple small diffuser zones, supply of thermal capacity and fresh air is finely targeted, both leveraging load diversity to save energy, and enhancing comfort and IAQ where needed.

The Vari-Smart Controls in each Vari-Smart VAV Diffuser may operate stand-alone, or networked to integrate with the BMS. They include AHU optimisation strategies that distill complex data processed at each Vari-Smart VAV Diffuser into simple data sets for collation by the BMS. Uncomplicated BMS sequences may, hence, be used to optimally control set-points for supply air temperature, pressure, fan speed and economy cycle free-cooling. This applies largely irrespective of the number of Vari-Smart VAV Diffusers in the system (or that may subsequently be added or removed). Sophisticated AHU optimisation is realised, along with simplified BMS programming and flexiblity for the future.

Vari-Smart VAV Diffuser Advantages: system flexibility to load range and location is increased; thermal capacity and fresh air supply are targeted; thermal comfort and IAQ are enhanced; plant size and outdoor airflow are reduced; BMS programming is simplified; and AHU optimisation and energy savings are achieved. Crucially, Vari-Smart systems adapt and optimise operation not only as loads shift, but also as tenancies and the climate change, future-proofing design.

Vari-Smart Controls

Vari-Smart Controls provide energy efficient, diffuser-specific zoning with advanced thermal-capacity VAV control. Optional wired or wireless, wall mounted temperature set-point adjustment allows personalised control of the local environment. IAQ enhancement – through zone-level demand- controlled ventilation (DCV) and air-flush sequences – is also provided. Personalised, premium thermal comfort with superior indoor air quality is achieved, when and where required, whilst realising energy savings by relaxing conditions in zones that are unoccupied.

Vari-Smart Controls operate stand-alone (single or as a master-slave group), or BMS-networked via Modbus RS-485. They provide highly responsive VAV thermostatic control to changes in zone thermal demand (not just temperature), achieving thermal capacity modulation that is both supply temperature-independent and static pressure-independent. Zone temperature control is decoupled from supply air temperature and static pressure shocks. Such system shocks typically occur if the thermal load on the index diffuser changes sharply, or if there is an abrupt change in supply air temperature, such as due to a change in weather during economiser operation, or due to oil return function activation in VRF/VRV systems.

Bio-inspired by the nine brains of the octopus, the patent-pending intelligent Vari-Smart Controls reside in each Vari-Smart VAV Diffuser micro-controller as standard. When Modbus-networked to the BMS (no additional central controls required) dispersed components with considerable functional autonomy are formed via a modular, configurable and highly adaptable system of distributed processing direct digital control (DDC). The resultant distributed controls system (DCS) achieves advanced functionality – in particular of high-end HVAC plant optimisation strategies – that is both resilient and that scales with project size (up to thousands of diffusers). BMS integration facilitates overall HVAC system control and monitoring, and provides Vari-Smart AHU optimisation by dynamically resetting set-points for supply air temperature, pressure, fan speed and economiser free-cooling. Vari-Smart Controls broadly target minimal supply air pressure (as load reduces, pressure is reset downwards, with the index Vari-Smart VAV Diffuser typically operating at its minimum of just 10 Pa for most part-load conditions) and a low supply air temperature (saving fan energy when cooling, and reducing stratification when heating), and allow the supply air temperature to largely “float” in economiser mode (extending the free-cooling range). Due to often conflicting criteria, Vari-Smart Controls reset AHU fan speed, supply air pressure and temperature, and economiser operation to achieve balance between fan energy, cooling/heating plant energy, dehumidification, space ventilation, comfort, competing thermal zones, and zone over-cooling/heating.

Benefits of Vari-Smart Controls include increased cost effectiveness and reliability, superior system efficiency, open protocol interoperability, and commissioning simplicity. Exceptional flexibility to tenancy fit-out changes is also provided, as is the safety of ongoing VAV airflow control in the event of network failure.

Vari-Swirl – Onboard Sensors

In addition to inbuilt T_room, T_supply and P_static sensors as standard, allowing precise airflow rate and individual thermostatic temperature control to be achieved, IAQ sensors (CO₂+RH or VOC) and a PIR sensor (occupant detection) may be plugged into the hub of the Helical Vari-Swirl Diffuser to enhance indoor air quality and tighten temperature control, when needed. No wall-mounted thermostat or remote sensors are required, as forced induction from a powerful, inbuilt induction system actively draws a strong flow of room air into the controls hub, ensuring accurate room air sensing.

The passive infrared (PIR) motion sensor, and the volatile organic compound sensor (VOC) or combined zone carbon dioxide and humidity sensor (CO₂+RH) allow Vari-Smart VAV Diffuser minimum airflow to be dynamically reset by the Vari-Smart Controls. Zone-level demand-controlled ventilation (DCV) and targeted IAQ delivery are achieved. The latter is especially well-suited to saving energy in highly diversified dedicated outdoor air systems (DOAS). These sensors may also be used by the BMS for AHU system-level DCV.

Vari-Swirl – IEQ & Diversity

The variable air volume (VAV) control of each Helical Vari-Swirl diffuser allows it to operate as both a small independent thermal zone and a small independent air quality zone. Integrated IEQ sensors (room air temperature, PIR, and VOC or CO₂+RH) determine both the degree and location of shifting thermal and indoor air quality loads. Many small diffuser zones of individual control enhance system response to thermal and air quality diversity. Highly targeted indoor air quality and comfort are delivered, improving the indoor thermal quality (ITQ) and indoor air quality (IAQ) where needed. The greater the diversity, the less the required total AHU design airflow capacity relative to the combined design aiurflow rate of all Vari-Smart VAV Diffusers in the system. Enhanced diversity, therefore, allows plant size to be reduced. Diversity also saves energy: fan energy is not wasted discharging more air than is required; thermal capacity is not wasted over-cooling/heating zones with low loads or on tightly conditioning spaces with no occupancy; and conditioned fresh air is not wasted providing excessive air quality.

Vari-Swirl – High Comfort

The swirl discharge of the Helical Vari-Swirl Diffuser produces intense mixing with high induction. This entrains large quantities of room air into the supply air stream, strongly equalising the supply-to-room temperature differential and producing rapid discharge velocity decay. The risk of dumping and draughts is greatly reduced. So, too, is the risk of stagnation further afield. This is because high induction greatly increases the mass flow rate of the supply air stream due to the large quantities of entrained room air, thereby ensuring sufficient momentum for coverage over large areas even though the air stream velocity rapidly decelerates to be low. High levels of both draught-free and stagnation-free comfort are achieved, with ADPI ≥ 90%, even for a supply air temperature as low as 7 °C.

Vari-Swirl – One-Size-Fits-All

The Helical Vari-Swirl Diffuser comes in one neck size only – viz DN355 – connected to a low pressure loss, low-profile, side-entry plenum (top-entry is optional). Its patent-pending cyclone swirl damper makes it the industry’s highest capacity electronic VAV swirl diffuser. It is also the only VAV diffuser with an effective damper size that is adjustable: cyclone damper doors can be individually locked shut on site, reducing the effective damper area to as little as 20% for a design airflow rate as low as 20% of the diffuser maximum. Consequently, multiple neck/damper sizes are simply not required. This allows the Helical Vari-Swirl Diffuser to boast a wide design flow rate range of 40 L/s to 220 L/s – adjustable through the face via the Multi-Max Flow feature. Motorised damper door aperture adjustment provides airflow rate turndown to ≤15% of any design flow rate within that range. Low turndown is achieved even if diffuser static pressure rises dramatically, as typically occurs when a VAV diffuser throttles. Full shut-off, too, is provided.

The lockable cyclone damper doors allow the radially projecting discharge pattern to be adjusted through the diffuser face (360°, 270°, 180° or 2×90°), providing Multi-Pattern Blow flexibility to tenancy layout changes.

The Helical Vari-Swirl Diffuser is a one-size-fits-all solution that may truly be varied in almost every way. It is the most adaptable VAV diffuser on the market, perfect for both base-building design and changing fit-out applications.

Vari-Swirl – Static Pressure

The Helical Vari-Swirl Diffuser’s factory calibrated airflow rates are calculated from VAV damper position and static air pressure in the supply air plenum measured relative to the room. This is in contrast to some alternative brands that measure pressure relative to the ceiling void, which is less accurate due to air pressure fluctuations when the ceiling void functions as a return air plenum. As a result, the Helical Vari-Swirl Diffuser’s calculated airflow rates are extremely accurate. This applies if a supply duct bend is directly connected to the diffuser, or at very low airflow rates when air velocity or dynamic pressure airflow measurements (as used by some alternative brands) would yield poor results.

The Helical Vari-Swirl Diffuser’s static air pressure sensor, in combination with its supply air temperature sensor, is additionally used to optimise AHU supply air fan speed, pressure and temperature. For BMS-networked systems, simple BMS sequences may be programmed to use data sets provided by the Vari-Smart Controls to minimise system supply pressure (targets operating at least one VAV damper fully open) at a low supply air temperature (saves fan energy when cooling and minimises stratification when heating). This is done in balance with other – often conflicting – constraints, such as humidity, indoor air quality, zone over-cooling/heating, and economiser mode extended free-cooling optimisation.

Vari-Swirl diffusers have been designed for use in non-static regain (ie unequal static pressure) duct systems. In comparison to duct systems for conventional VAV diffusers, Vari-Swirl diffuser systems permit both the largest pressure difference between VAV diffusers and the highest operating pressure at VAV diffusers. This is an important distinguishing feature, as static regain duct design is, therefore, generally not required (although always preferred, saving fan energy) and the likely need for pressure control dampers in systems with long or convoluted duct runs is greatly reduced. With Actuation Pressure Control (BMS-networked systems only), operating pressure may rise as high as 130 Pa (or to 80 Pa without it), subject to acoustic constraints. This means that up to 100 Pa may be available for duct system pressure losses between the highest pressure and the index Helical Vari-Swirl Diffusers, based on 30 Pa diffuser design pressure. In constrast, conventional VAV diffusers typically have a maximum permissible operating pressure of just 60 Pa. They also require ducting with substantially equal static pressure distribution to prevent excessive VAV damper throttling of non-index VAV diffusers when delivering design flow. Excessive throtting at design flow compromises available turndown, leading to poor part-load thermal control and resulting in over-cooling/heating and energy wastage.

Vari-Swirl – Multi-Max Flow

Multi-Max Flow cyclone swirl damper effective area (not aperture) adjustment across a 100% to 20% range provides Helical Vari-Swirl “diffuser sizing” and air balancing from within the room (via Allen key access through the diffuser face) to suit the required design flow and actual operating pressure. VAV damper authority is preserved across a five-fold design flow range – despite the Helical Vari-Swirl Diffuser having just a single neck size – achieving pressure-independent turndown to 15% (or less) of any design flow rate between 40 L/s and 220 L/s at up to 80 Pa static pressure (or up to 130 Pa with Actuation Pressure Control, if BMS-networked; subject to acoustic constraints). This greatly facilitates the use of Helical Vari-Swirl Diffusers in unequal pressure duct systems, such as equal friction design. Low turndown under high pressure conditions is important, as diffuser static pressure typically rises exponentially during VAV diffuser turndown due to pressure losses to the diffuser (from flexible ducts and manual balancing dampers) reducing by the square of the change in airflow rate. Consequently, conventional manual air balancing dampers become ineffective as the flow reduces. The negative effects may be considerable, especially in equal friction duct systems with long duct runs or multiple bends that cause significant pressure losses. In such systems, the static pressure to non-index diffusers may rise sharply when the VAV diffusers throttle, leading to noise issues, the inability to fully turn down, and poor zone temperature control.

For each Helical Vari-Swirl Diffuser, Multi-Max Flow air balancing is done on site, in lieu of both sizing the diffuser neck during design and subsequent on-site conventional air balancing via a separate balancing damper. The airflow-pressure relationship of each Multi-Max Flow setting is factory calibrated, making air balancing a breeze. Multi-Max Flow allows a single diffuser size to suit widely varying design flow rates or duct pressure applications, each with a broad turndown range, if required. Low turndown is prserved, ensuring propoer zone temperature control. It’s a one-size-fits-all solution that aids duct design, whilst realising a uniform architectural aesthetic, simplified project and on-site co-ordination, and exceptional adaptability to tenancy fit-out changes.

Vari-Swirl – Low Flow Throw Boost

Helical Vari-Swirl Diffusers are suitable for low supply air temperature systems (cold-air distribution) with a supply air temperature ≥ 7 °C and a wide VAV range of operation.

During turndown, elevated discharge velocities are maintained by variable geometry cyclone swirl damper aperture throttling in close proximity to the discharge face, preventing dumping and achieving superior throw coverage. This ensures air movement with good mixing and a high air change effectiveness (ACE) in the space. Premium comfort, with an ADPI ≥ 90%, is realised, as is good mixing of fresh air, even when airflow is throttled to 15% at a specific airflow rate of just 0.4 or 0.5 L/s/m² and ΔT ≈ ‑10 or -15 K, respectively.

Low Flow Throw Boost also benefits heating, which is permitted at up to +10 K from 2.7 m height.

Vari-Swirl – Multi-Pattern Blow

The horizontally projecting “radial” swirl pattern of the Helical Vari-Swirl Diffuser may be set on site, via Allen key insertion through the diffuser face, to 360°, 270°, 180° or 2×90° (ie 4-way blow, 3-way blow or 2-way blow). This provides adaptability to unique space architecture and to fit-out changes. Superior ease of conversion from base-building design to tenancy fit-out is achieved, with exceptional on-going flexibility to change of use.

Vari-Swirl – Silent Swirl

Bio-inspired “barbed and barnacle blade” features on the swirl vanes and cyclone swirl damper doors of the Helical Vari-Swirl Diffuser provide aero-acoustic noise suppression for quiet operation, even at 80-100 Pa static pressure, enabling use in non-static regain – such as equal-friction – duct design systems.

Vari-Swirl – Low Profile Height

A shallow (200 mm minimum) side- or top-entry supply plenum box, complete with perforated distribution plate, and optionally with multiple spigots and/or acoustic matting, facilitates co-ordination of the Helical Vari-Swirl Diffuser within tight or low-height ceiling void spaces. Airflow into the cyclone swirl damper is largely unrestricted, allowing high capacities to be achieved at a low pressure loss.

Vari-Swirl – Accessible Electronics

The stepper motor, Bluetooth-enabled PC board, and all integrated sensors (supply air static pressure; supply air temperature; room air temperature; PIR; CO₂+RH or VOC) are removable through the face of the Helical Vari-Swirl Diffuser, providing ease of maintenance and plug-and-play upgrades.

Vari-Swirl – Electrical Components, Sensors & Controls  

Each Helical Vari-Swirl Diffuser includes:

• Terminals for 24V power supply
• Terminals suitable for comms daisy-chain or loop
• Room air induction system, plus perforated cap with controls hub removable from the room, housing:
  • Standard Integrated Sensors: room air temperature, supply air temperature, supply air static pressure
  • PC board, Bluetooth enabled
  • Stepper Motor
  • Optional Integrated Sensors (zone CO₂+RH or VOC; PIR)
• PC board controls:
  • Adjustable set-points: room air temperature; design airflow rate; minimum airflow rate
  • P or PI zone temperature control with thermal-capacity VAV modulation provides supply temperature- and static pressure-independent zone temperature control
  • Zone-level DCV and DOA sequences suitable for optional PIR and/or CO₂/VOC sensors
  • Suitable for implementation of diffuser-plant-integrated controls (refer to 2. BMS-Network, below)
• Optional HMI:
  • Wired or Bluetooth connected to a Master Vari-Smart VAV Diffuser
  • Wall-mounted adjustable thermostat with T_room sensor
  • Diffuser-specific temperature set-point adjustment (typically within a preset range)
  • Optional touchscreen
  • Optional sensors: PM2.5; RH; CO_2; VOC; PIR
  • Optional quick access for commissioning (eg design flow, minimum flow & DCV set-points)

Vari-Smart Controls – Variants

1. Stand-alone:

• Stand-alone Single: a single Vari-Smart VAV Diffuser that is not comms connected to other Vari-Smart VAV Diffusers or devices is automatically designated as a Vari-Smart Master Diffuser.
• Stand-alone Group: a group of Vari-Smart VAV Diffusers, comprising a designated Vari-Smart Master Diffuser, with remaining diffusers designated as Vari-Smart Slave Diffusers, interconnected by a Modbus RS-485 comms daisy-chain to operate as a stand-alone group of Vari-Smart VAV Diffusers in which the Vari-Smart Slave Diffusers largely mimic the commands of the Vari-Smart Master Diffuser. The Stand-alone Group may not be networked to any other Vari-Smart VAV Diffusers or devices.

2. BMS-Network:

As for 1. above; but with Vari-Smart VAV Diffusers connected by a Modbus RS-485 comms daisy-chain network to a BMS (by others).

Distributed Vari-Smart Controls, when BMS-networked, are intelligent diffuser-plant-integrated controls. They make intelligent building- and HVAC plant-related decisions based on complex information available from every Vari-Smart VAV Diffuser to optimise operation for energy efficiency, indoor air quality and comfort. Additionally, building HVAC conditions – both globally and locally – can be controlled and modified centrally from the BMS.

Designed for building automation, minimal third-party BMS programming is required – with no additional central controls needed – to harness advanced Vari-Smart Control sequences for AHU/FCU control and optimisation.

Vari-Smart VAV Diffusers:

• • Multiple Vari-Smart Master Diffusers permitted
  • Vari-Smart Slave Diffusers may be assigned to any Vari-Smart Master Diffuser

BMS / System Controller:

General:

• • Supplied and programmed by others
  • Has visibility of all sensors
  • Global set-points (room temperature; CO₂; RH thresholds)
  • AHU supply air temperature set-point band
  • AHU/FCU cooling/heating changeover (weighted by thermal zone priority)

Vari-Smart VAV Diffuser Management:

• • Local set-points (room temperature; CO₂; RH thresholds)
  • Minimum airflow rate per Vari-Smart VAV Diffuser
  • Design airflow rate per Vari-Smart VAV Diffuser
  • Damper position override per Vari-Smart VAV Diffuser
  • Master/Slave diffuser assignment
  • Thermal zone prioritisation: premium; high (default); medium; low

Distributed Controls – advanced functions

• • Trim heater operation (controlled via a single or multiple Vari-Smart VAV Diffusers downstream of a trim heater)
  • Riser/zone pressure control damper operation (controlled via a single or multiple Vari-Smart VAV Diffusers downstream of a pressure control damper)
  • System excess-pressure relief (when BMS-networked) via motorised relief air damper (by others) or Vari-Smart VAV Diffuser minimum airflow reset (biased towards low-priority Vari-Smart VAV Diffusers)
  • System under-pressure prevention (damper modulation to maintain minimum permissible pressure at Vari-Smart VAV Diffusers)
  • Actuation pressure control (temporarily reduces AHU fan speed and system pressure for stepper motor actuation within permissible upper pressure limits)
  • AHU/FCU supply temperature set-point dynamic reset
  • Supply air temperature optimisation (minimises supply air temperature, reducing fan energy when cooling and stratification when heating)
  • AHU/FCU supply pressure / fan speed dynamic reset (modulating or stepped)
  • Supply air static pressure optimisation (targets at least one Vari-Smart VAV Diffuser VAV damper fully open to minimise duct pressure)
  • Economiser supply temperature set-point dynamic reset (for supplementary cooling / dehumidification)
  • Economiser optimisation: allows supply air temperature to largely float in a broad, dynamic dead-band (maximises free-cooling potential)
  • Optimum RH band: increased/decreased dehumidification via supply air temperature dynamic reset (cooling & economiser modes only)
  • Over-cooling/heating mitigation (via supply air temperature dynamic reset)
  • Room temperature dead-band relaxation or airflow shut-off when unoccupied (PIR-based)
  • Air-flush – rapid contaminant purging upon not-occupied status activation (PIR-based)
  • Zone-level demand-controlled ventilation (DCV) sequences (PIR- and/or CO₂-based)

Safeties:

• • Diffuser over-pressure bleed (VAV modulation setpoint: P_static = 150 Pa)
  • Diffuser high pressure relief (VAV fully open if P_static ≥ 200 Pa)
  • Rogue zone identification
  • Ignored zones (rogue- and/or percentile-based) are removed from supply air temperature and pressure/fan reset decisions
  • Sensor failure – automated sensor failure detection and response

SMARTEMP Helical Vari-Swirl Diffuser™ HSC-VS

VARI-SWIRL^® and VARI-SMART^® are registered trade marks

Smarter Design / Smarter Engineering / SMARTAIR DIFFUSION™

Patents Pending

1.  Cyclone Swirl Damper:

• Integrated IAQ
• Silent Swirl
• Low Flow Throw Boost
• Multi-Max Flow
• Multi-Pattern Blow

2. Thermal-Capacity Control:

• VAV damper thermal-capacity control, independent of supply air pressure and supply air temperature variations.
• AHU constant thermal-capacity supply air temperature and airflow dynamic reset to:
  • optimise duct pressure by targeting at least one VAV damper fully open
  • optimise supply air temperature by offsetting available static pressure
  • mitigate zone over-cooling/heating
  • boost IAQ ventilation
  • enhance/diminish dehumidification (cooling & economiser modes only)
• Economiser mode supply air temperature float function to maximise free-cooling potential.

SMARTEMP Helical Vari-Swirl Diffuser™ HSC-VS

VARI-SWIRL^® and VARI-SMART^® are registered trade marks

Smarter Design / Smarter Engineering / SMARTAIR DIFFUSION™