Resources
Product-Leaflet-SMARTEMP-HSC-VS.pdf[ uploaded: 2023-07-05 ]
Performance-Leaflet-SMARTEMP-HSC-VS.pdf[ uploaded: 2025-04-10 ]
Selection-Tool-SMARTEMP-HSC-VS.xlsx[ uploaded: 2026-01-08 ]
References
Helical Vari-Swirl™ Diffuser
Vari-Smart™ IEQ VAV
Vari-Smart™ IEQ VAV
Helical Vari-Swirl™ Diffuser
Vari-Smart™ IEQ VAV
Vari-Smart™ IEQ VAV
SMARTEMP HSC-VS
Overview
Description
Innovation
Overview
The world’s only VAV diffuser with inbuilt IEQ sensors and smart controls for comfort, indoor air quality and AHU/FCU optimisation.
Features:
- Low Profile: 200 mm minimum side- or top-entry plenum box height
- Cyclone Swirl Damper: compact, efficient, low noise VAV modulation
- Multi-Pattern Blow: horizontal swirl pattern adjustable through the diffuser face (360°; 270°, 180°, 2×90°)
- Multi-Max Flow: air balancing through the diffuser face across five-fold design flow (40-220 L/s)
- Broad VAV Range: pressure-independent turndown to ≤15% from full five-fold Multi-Max Flow range; full shut-off
- Low-Flow Throw Boost: variable geometry discharge extended coverage when turned down
- Low Pressure Loss: 20-30 Pa typical design static pressure
- Wide Operating Pressure: 10-80 Pa (130 Pa with BMS/VSC-networked Motor Pressure Control)
- Factory Calibrated Flow: minimum and design airflow rates programmable at diffuser or BMS/VSC
- Vari-Smart Microprocessor (VSM): decentralised thermostatic control (supply temperature- and static pressure-independent)
- 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
Controls – Vari-Smart™:
- Stand-alone: a single Vari-Smart VAV Diffuser or master-slave group of Vari-Smart VAV Diffusers (daisy-chain comms connected) provides VAV thermostatic control (supply temperature- and static pressure-independent) and zone-level demand-controlled ventilation (DCV); OR
- VSC-Network: a Vari-Smart Controller (VSC), providing AHU/FCU control of supply air temperature, fan speed, system pressure, spill air and economiser optimisation (BMS integration, via Modbus or BACnet, is optionally available), connected by a Modbus RS-485 daisy-chain to up to 16 off Vari-Smart VAV Diffusers (for standard VSC controls) or up to 30 off Vari-Smart VAV Diffusers (for bespoke VSC controls), with multiple interconnected VSCs permitted for the latter; OR
- BMS-Network: up to 30 off Vari-Smart VAV Diffusers daisy-chain networked (Modbus RS-485) to a BMS (by others), providing AHU/FCU control of supply air temperature, fan speed, system pressure, spill air and economiser optimisation.
 | Location – above:
|
 | Mixed flow discharge:
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 | 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: Low-Flow Throw Boost variable geometry discharge provides extended coverage, even when turned down to 15%. |
 | Vari-Smart™ VAV Diffuser: Electronic VAV diffuser with integrated Vari-Smart™ microprocessor controls; operates:
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 | 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 terminals, sensors & controls: Terminals for 24VDC power supply @ 16VA. Terminals suitable for optional comms (Modbus RS-485) daisy-chain to BMS/VSC. Diffuser perforated cap, removable from room, houses controls hub with:
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™ functions: Optional Plug-In Sensors:
Remote Options (wired or Bluetooth):
Key Optional Vari-Smart™ Functions (BMS/VSC-networked only):
|
SMARTEMP Helical Vari-Swirl™ Diffuser HSC-VS
VARI-SWIRL® and VARI-SMART® are registered trade marks
Smarter Design / Smarter Engineering / SMARTAIR DIFFUSION™
Description
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/FCU optimisation.
Vari-Smart VAV Diffusers
Vari-Smart VAV Diffusers operate as small and independent thermal comfort and IAQ zones. By following shifting loads across multiple small diffuser zones, VAV supply of thermal capacity and fresh air is finely targeted, both leveraging load diversity to save energy and enhancing comfort and IAQ where needed.
Each Vari-Smart VAV Diffuser requires a 24 VDC power supply and incorporates the following 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 a Vari-Smart Microprocessor (VSM) with intelligent, patent-pending controls.
Stable VAV room temperature control is provided, independent of supply air temperature and pressure variations, along with improved energy efficiency, enhanced thermal comfort, elevated indoor air quality, and increased flexibility to tenancy changes.
The onboard Vari-Smart Microprocessor (VSM) provides energy efficient, diffuser-specific zoning with advanced thermal-capacity VAV control 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 critical (lead thermal) 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.
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 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.
Stand-Alone or Networked
The intelligent Vari-Smart Microprocessor (VSM) in each Vari-Smart VAV Diffuser may operate stand-alone, or may be networked by a Modbus RS-485 daisy-chain directly to a Building Management System (BMS) or to a Vari-Smart Controller (VSC). The latter may, in turn, be integrated with the BMS via Modbus or BACnet. In each case, BMS integration facilitates overall HVAC system control and monitoring, and allows the benefits of SMARTEMP’s patent-pending Vari-Smart AHU/FCU optimisation control to be realised.
For networked systems, the BMS is supplied and programmed by others with associated functional descriptions provided by SMARTEMP. Alternatively, a VSC is supplied and programmed by SMARTEMP, suitable for on-site configuration by others.
If the Vari-Smart VAV Diffusers are directly connected to a BMS, each Modbus RS-485 daisy-chain may control up to 30 off Vari-Smart VAV Diffusers, with multiple daisy-chains permitted. Alternatively, if the Vari-Smart VAV Diffusers are directly connected to a VSC then up to 16 off Vari-Smart VAV Diffusers may be Modbus RS-485 daisy-chain connected to the VSC if one of three standard VSC programs is used for optimisation of a single AHU/FCU:
- VSC-CW-FCU: chilled water fan-coil optimisation
- VSC-VR-FCU: VRV/VRF fan-coil optimisation
- VSC-DX-PAC: direct-expansion packaged rooftop optimisation
Alternatively, a fourth option – VSC-special – is available for tailored VSC programming to realise bespoke or larger system AHU/FCU optimisation, in which case up to 30 off Vari-Smart VAV Diffusers may be Modbus RS-485 daisy-chain connected per VSC, with multiple VSCs permitted in communication with one another controlling multiple AHUs/FCUs.
In each of the above four cases, BMS integration is optionally available.
Distributed Vari-Smart Controls
Bio-inspired by the nine brains of the octopus, the controls architecture is distributed. Patent-pending Vari-Smart controls programs are integrated in each Vari-Smart Microprocessor (VSM) as standard. When Modbus-networked to a VSC/BMS, dispersed components with considerable functional autonomy are formed via a modular, configurable and highly adaptable system of distributed processing direct digital control (DP-DDC). The resultant distributed controls system (DCS) achieves advanced functionality – in particular of high-end AHU/FCU optimisation strategies – that is both resilient and that scales with project size (up to thousands of diffusers).
The Vari-Smart Microprocessor (VSM) in each diffuser distills complex local data into simple data sets, which are processed by the VSC/BMS to optimise AHU/FCU system operation. Standard, high-end sequences that reside in each VSM ensure that complex on-site programming – which would bring with it a high the risk of error – is not required, allowing central controller programming to be both simple to implement and flexible to suit bespoke, building-specific requirements. Excellent diffuser scalability with high-end control are achieved, realising minimal network size impact on VSC/BMS programming and ensuring ease of commissioning. Indeed, simple BMS programming with premium-level AHU optimisation and flexiblity for the future are hallmarks of the Vari-Smart system.
AHU/FCU optimisation is achieved by dynamically resetting set-points for supply air temperature, system pressure, fan speed and economiser free-cooling. Optimisation strategies largely aim to minimise both supply air temperature (saving fan energy when cooling and reducing stratification when heating) and supply air pressure (targeting at least one VAV damper fully open, and resetting the critical diffuser – wherever it may be – to operate at just 10 Pa under most part-load conditions). In economiser mode, supply temperature control changes to allow the supply air temperature to “float” within a dynamic band, extending the free-cooling range and minimising the need for supplementary cooling. Due to changing – and often conflicting – criteria, Vari-Smart controls dynamically reset AHU/FCU fan speed, system air pressure, supply air temperature and economiser operation to achieve balance between fan energy, cooling/heating plant energy, dehumidification, space ventilation, thermal comfort, competing thermal zones, zone over-cooling/heating, and spill air requirements.
Benefits of distributed Vari-Smart Microprocessors (VSMs) include increased cost effectiveness and reliability, superior system efficiency, open protocol interoperability, BMS programming simplicity, and ease of commissioning. Exceptional flexibility to tenancy fit-out changes is also provided, as is the safety of ongoing VAV airflow control in the event of comms network failure.
Onboard Sensors
In addition to inbuilt Troom, Tsupply and Pstatic 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 (although they are optionally available), 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 Microprocessor (VSM). 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 system-level DCV at the AHU.
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 (Troom, 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 airflow rate of all Vari-Smart VAV Diffusers in the system. Consequently, enhanced diversity allows plant size to be reduced. Diversity also saves energy: fan energy is not wasted discharging more air than is necessary; thermal capacity is not wasted over-cooling/heating zones with low loads or on tightly conditioning spaces with no occupancy (unoccupied zone temperature setback or shutoff is provided); and conditioned fresh air is not wasted enhancing air quality where not required.
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.
One-Size-Fits-All
The Helical Vari-Swirl Diffuser comes in one neck size only – viz DN355 – connected to a low pressure loss, 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 in situ, 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.
Airflow Rate, Static Pressure & Supply Temperature Control
The Helical Vari-Swirl Diffuser’s factory calibrated airflow rates are calculated from VAV damper position and supply air plenum static pressure relative to the room. This is in contrast to some alternative brands that measure pressure relative to the ceiling void, which leads to inaccuracies due to air pressure fluctuations when the ceiling void functions as a return air plenum. In contrast, the Helical Vari-Swirl Diffuser’s calculated airflow rates are extremely accurate. This applies even 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.
For networked systems, the integrated static air pressure sensor is additionally used to optimise AHU supply air fan speed and system pressure, and an integrated supply air temperature sensor is used to optimise AHU supply air temperature. Simple sequences in the VSC or BMS collate data from all VSMs to minimise supply air pressure (system pressure optimisation reset control targets operating at least one VAV damper fully open) and aims for a low supply air temperature (saving fan energy when cooliong and minimising 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.
Duct Design
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 (full or partial) static regain duct design is, therefore, less frequently 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 Motor Pressure Control (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 diffuser and the index diffuser, based on 30 Pa index 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 (typically within +20%/-10% pressure) to prevent excessive VAV damper throttling of high pressure 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. The Multi-Max Flow feature of the Helical Vari-Swirl diffuser overcomes this.
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 Motor Pressure Control, if 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 rapidly become ineffective as the VAV damper throttles. 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 higher system pressure diffusers may rise sharply when the VAV diffusers throttle, leading to noise issues and the inability to fully turn down, causing discomfort 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 preserved, ensuring proper 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.
Low-Flow Throw Boost
Helical Vari-Swirl Diffusers are suitable for low supply air temperature systems – also known as cold-air distribution systems (CADS) – with a supply air temperature ≥ 7 °C. CADS typically have extremely low specific airflow rates (L/s/m2) especially when turned down.
During turndown, the Helical Vari-Swirl Diffuser maintains elevated discharge velocities via “Low-Flow Throw Boost” 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.
Multi-Pattern Blow
The horizontally projecting “radial” swirl pattern of the Helical Vari-Swirl Diffuser may be set in situ, 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.
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.
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.
Accessible Electronics
The stepper motor, Bluetooth-enabled Vari-Smart Microprocessor (VSM), 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-in upgrades.
Electrical Components, Sensors & Controls
Each Helical Vari-Swirl Diffuser includes:
- Terminals for 24 VDC power supply @ 16 VA
- Terminals suitable for a Modbus RS-485 comms daisy-chain
- Terminals suitable for an HMI
- Active room air induction system
- Perforated cap with controls hub, removable from the room, housing:
- Vari-Smart Microprocessor (VSM), Bluetooth enabled
- Stepper motor
- Standard onboard integrated sensors: room air temperature, supply air temperature, supply air static pressure
- Optional onboard plug-in sensors (zone CO2+RH or VOC; PIR)
- VSM 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. VSC-Network and 3. BMS-Network, below)
- Optional HMI:
- Wired or Bluetooth connected to a Master Vari-Smart VAV Diffuser
- Wall-mounted adjustable thermostat with Troom sensor
- Diffuser-specific temperature set-point adjustment (typically within a preset range)
- Optional touchscreen
- Optional sensors: RH; CO2; VOC; PIR
- Optional quick access for commissioning (eg design flow, minimum flow & DCV set-points)
Vari-Smart – Variants
- 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 always designated as a Vari-Smart Master Diffuser.
- Stand-Alone Group: a group of Vari-Smart VAV Diffusers, comprising a designated Vari-Smart Master Diffuser and one or more 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.
Stand-alone diffusers are supplied standard with terminal connections suitable for Modbus RS-485 daisy-chain networking.
- VSC-Network:
When daisy-chain networked via a Modbus RS-485 daisy-chain to a Vari-Smart Controller (VSC), which in turn is in communication with the AHU/FCU, a distributed controls network of Vari-Smart Microprocessors (VSMs) is created providing diffuser-plant-integrated controls for up to 16 off Vari-Smart VAV diffusers per VSC for standard VSC programming, or up to 30 off Vari-Smart VAV diffusers per daisy-chain for bespoke VSC programming (multiple interconnected VSCs permitted). VSCs allow system operation to be optimised for energy efficiency, indoor air quality and comfort. Building HVAC conditions – both globally and locally – may be controlled and modified centrally. BMS integration is available via Modbus or BACnet.
- BMS-Network:
As for 2. above; but suitable for up to 30 off Vari-Smart VAV Diffusers, and with the VSC replaced with a BMS (by others), and the Modbus RS-485 daisy-chain directly connected to the BMS.
Designed for building automation, functional descriptions for minimal third-party BMS programming are provided – with no additional central controls needed – to harness advanced Vari-Smart control sequences for AHU/FCU control and optimisation.
Vari-Smart – Distributed Network Features
Vari-Smart VAV Diffusers:
- Multiple Vari-Smart Master Diffusers permitted
- Vari-Smart Slave Diffusers may be assigned to any Vari-Smart Master Diffuser
VSC/BMS:
General:
- VSC supplied and programmed by SMARTEMP; BMS supplied and programmed by others
- VSC & BMS configured on site by others
- Has visibility of all sensors
- Global set-points (room temperature; dead-band; CO2; RH thresholds, etc)
- AHU/FCU cooling/heating changeover
Diffuser Management:
- Local set-points (room temperature; CO2; RH thresholds, etc)
- 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
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 via motorised spill air damper (by others) and/or Vari-Smart VAV Diffuser minimum airflow reset (biased towards low-priority Vari-Smart VAV Diffusers)
- System under-pressure mitigation for highly diversified air supply systems (dynamic capping of maximum airflow to maintain at least 10 Pa at Vari-Smart VAV Diffusers)
- Motor 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)
- System supply air static pressure optimisation reset control (targets at least one 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)
- Unoccupied zone temperature setback or shut-off via room temperature dead-band relaxation or VAV damper shut-off (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: Pstatic = 80 Pa and 130 Pa for stand-alone and networked, respectively)
- Diffuser excess pressure relief (VAV fully open if Pstatic ≥ 100 Pa and ≥150 Pa for stand-alone and networked, respectively)
- 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™
Innovation
Patents Pending
1. Cyclone Swirl VAV:
- Silent Swirl
- Integrated IEQ
- 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 system 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™
Home / Products /
Helical Vari-Swirl™ Diffuser
Vari-Smart™ IEQ VAV
Vari-Smart™ IEQ VAV
Helical Vari-Swirl™ Diffuser
Vari-Smart™ IEQ VAV
Vari-Smart™ IEQ VAV
SMARTEMP HSC-VS
Overview
Description
Innovation
Overview
The world’s only VAV diffuser with inbuilt IEQ sensors and smart controls for comfort, indoor air quality and AHU/FCU optimisation.
Features:
- Low Profile: 200 mm minimum side- or top-entry plenum box height
- Cyclone Swirl Damper: compact, efficient, low noise VAV modulation
- Multi-Pattern Blow: horizontal swirl pattern adjustable through the diffuser face (360°; 270°, 180°, 2×90°)
- Multi-Max Flow: air balancing through the diffuser face across five-fold design flow (40-220 L/s)
- Broad VAV Range: pressure-independent turndown to ≤15% from full five-fold Multi-Max Flow range; full shut-off
- Low-Flow Throw Boost: variable geometry discharge extended coverage when turned down
- Low Pressure Loss: 20-30 Pa typical design static pressure
- Wide Operating Pressure: 10-80 Pa (130 Pa with BMS/VSC-networked Motor Pressure Control)
- Factory Calibrated Flow: minimum and design airflow rates programmable at diffuser or BMS/VSC
- Vari-Smart Microprocessor (VSM): decentralised thermostatic control (supply temperature- and static pressure-independent)
- 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
Controls – Vari-Smart™:
- Stand-alone: a single Vari-Smart VAV Diffuser or master-slave group of Vari-Smart VAV Diffusers (daisy-chain comms connected) provides VAV thermostatic control (supply temperature- and static pressure-independent) and zone-level demand-controlled ventilation (DCV); OR
- VSC-Network: a Vari-Smart Controller (VSC), providing AHU/FCU control of supply air temperature, fan speed, system pressure, spill air and economiser optimisation (BMS integration, via Modbus or BACnet, is optionally available), connected by a Modbus RS-485 daisy-chain to up to 16 off Vari-Smart VAV Diffusers (for standard VSC controls) or up to 30 off Vari-Smart VAV Diffusers (for bespoke VSC controls), with multiple interconnected VSCs permitted for the latter; OR
- BMS-Network: up to 30 off Vari-Smart VAV Diffusers daisy-chain networked (Modbus RS-485) to a BMS (by others), providing AHU/FCU control of supply air temperature, fan speed, system pressure, spill air and economiser optimisation.
| Location – above:
|
| Mixed flow discharge:
|
| 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: Low-Flow Throw Boost variable geometry discharge provides extended coverage, even when turned down to 15%. |
| Vari-Smart™ VAV Diffuser: Electronic VAV diffuser with integrated Vari-Smart™ microprocessor controls; operates:
|
| 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 terminals, sensors & controls: Terminals for 24VDC power supply @ 16VA. Terminals suitable for optional comms (Modbus RS-485) daisy-chain to BMS/VSC. Diffuser perforated cap, removable from room, houses controls hub with:
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™ functions: Optional Plug-In Sensors:
Remote Options (wired or Bluetooth):
Key Optional Vari-Smart™ Functions (BMS/VSC-networked only):
|
SMARTEMP Helical Vari-Swirl™ Diffuser HSC-VS
VARI-SWIRL® and VARI-SMART® are registered trade marks
Smarter Design / Smarter Engineering / SMARTAIR DIFFUSION™
Description
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/FCU optimisation.
Vari-Smart VAV Diffusers
Vari-Smart VAV Diffusers operate as small and independent thermal comfort and IAQ zones. By following shifting loads across multiple small diffuser zones, VAV supply of thermal capacity and fresh air is finely targeted, both leveraging load diversity to save energy and enhancing comfort and IAQ where needed.
Each Vari-Smart VAV Diffuser requires a 24 VDC power supply and incorporates the following 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 a Vari-Smart Microprocessor (VSM) with intelligent, patent-pending controls.
Stable VAV room temperature control is provided, independent of supply air temperature and pressure variations, along with improved energy efficiency, enhanced thermal comfort, elevated indoor air quality, and increased flexibility to tenancy changes.
The onboard Vari-Smart Microprocessor (VSM) provides energy efficient, diffuser-specific zoning with advanced thermal-capacity VAV control 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 critical (lead thermal) 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.
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 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.
Stand-Alone or Networked
The intelligent Vari-Smart Microprocessor (VSM) in each Vari-Smart VAV Diffuser may operate stand-alone, or may be networked by a Modbus RS-485 daisy-chain directly to a Building Management System (BMS) or to a Vari-Smart Controller (VSC). The latter may, in turn, be integrated with the BMS via Modbus or BACnet. In each case, BMS integration facilitates overall HVAC system control and monitoring, and allows the benefits of SMARTEMP’s patent-pending Vari-Smart AHU/FCU optimisation control to be realised.
For networked systems, the BMS is supplied and programmed by others with associated functional descriptions provided by SMARTEMP. Alternatively, a VSC is supplied and programmed by SMARTEMP, suitable for on-site configuration by others.
If the Vari-Smart VAV Diffusers are directly connected to a BMS, each Modbus RS-485 daisy-chain may control up to 30 off Vari-Smart VAV Diffusers, with multiple daisy-chains permitted. Alternatively, if the Vari-Smart VAV Diffusers are directly connected to a VSC then up to 16 off Vari-Smart VAV Diffusers may be Modbus RS-485 daisy-chain connected to the VSC if one of three standard VSC programs is used for optimisation of a single AHU/FCU:
- VSC-CW-FCU: chilled water fan-coil optimisation
- VSC-VR-FCU: VRV/VRF fan-coil optimisation
- VSC-DX-PAC: direct-expansion packaged rooftop optimisation
Alternatively, a fourth option – VSC-special – is available for tailored VSC programming to realise bespoke or larger system AHU/FCU optimisation, in which case up to 30 off Vari-Smart VAV Diffusers may be Modbus RS-485 daisy-chain connected per VSC, with multiple VSCs permitted in communication with one another controlling multiple AHUs/FCUs.
In each of the above four cases, BMS integration is optionally available.
Distributed Vari-Smart Controls
Bio-inspired by the nine brains of the octopus, the controls architecture is distributed. Patent-pending Vari-Smart controls programs are integrated in each Vari-Smart Microprocessor (VSM) as standard. When Modbus-networked to a VSC/BMS, dispersed components with considerable functional autonomy are formed via a modular, configurable and highly adaptable system of distributed processing direct digital control (DP-DDC). The resultant distributed controls system (DCS) achieves advanced functionality – in particular of high-end AHU/FCU optimisation strategies – that is both resilient and that scales with project size (up to thousands of diffusers).
The Vari-Smart Microprocessor (VSM) in each diffuser distills complex local data into simple data sets, which are processed by the VSC/BMS to optimise AHU/FCU system operation. Standard, high-end sequences that reside in each VSM ensure that complex on-site programming – which would bring with it a high the risk of error – is not required, allowing central controller programming to be both simple to implement and flexible to suit bespoke, building-specific requirements. Excellent diffuser scalability with high-end control are achieved, realising minimal network size impact on VSC/BMS programming and ensuring ease of commissioning. Indeed, simple BMS programming with premium-level AHU optimisation and flexiblity for the future are hallmarks of the Vari-Smart system.
AHU/FCU optimisation is achieved by dynamically resetting set-points for supply air temperature, system pressure, fan speed and economiser free-cooling. Optimisation strategies largely aim to minimise both supply air temperature (saving fan energy when cooling and reducing stratification when heating) and supply air pressure (targeting at least one VAV damper fully open, and resetting the critical diffuser – wherever it may be – to operate at just 10 Pa under most part-load conditions). In economiser mode, supply temperature control changes to allow the supply air temperature to “float” within a dynamic band, extending the free-cooling range and minimising the need for supplementary cooling. Due to changing – and often conflicting – criteria, Vari-Smart controls dynamically reset AHU/FCU fan speed, system air pressure, supply air temperature and economiser operation to achieve balance between fan energy, cooling/heating plant energy, dehumidification, space ventilation, thermal comfort, competing thermal zones, zone over-cooling/heating, and spill air requirements.
Benefits of distributed Vari-Smart Microprocessors (VSMs) include increased cost effectiveness and reliability, superior system efficiency, open protocol interoperability, BMS programming simplicity, and ease of commissioning. Exceptional flexibility to tenancy fit-out changes is also provided, as is the safety of ongoing VAV airflow control in the event of comms network failure.
Onboard Sensors
In addition to inbuilt Troom, Tsupply and Pstatic 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 (although they are optionally available), 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 Microprocessor (VSM). 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 system-level DCV at the AHU.
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 (Troom, 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 airflow rate of all Vari-Smart VAV Diffusers in the system. Consequently, enhanced diversity allows plant size to be reduced. Diversity also saves energy: fan energy is not wasted discharging more air than is necessary; thermal capacity is not wasted over-cooling/heating zones with low loads or on tightly conditioning spaces with no occupancy (unoccupied zone temperature setback or shutoff is provided); and conditioned fresh air is not wasted enhancing air quality where not required.
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.
One-Size-Fits-All
The Helical Vari-Swirl Diffuser comes in one neck size only – viz DN355 – connected to a low pressure loss, 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 in situ, 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.
Airflow Rate, Static Pressure & Supply Temperature Control
The Helical Vari-Swirl Diffuser’s factory calibrated airflow rates are calculated from VAV damper position and supply air plenum static pressure relative to the room. This is in contrast to some alternative brands that measure pressure relative to the ceiling void, which leads to inaccuracies due to air pressure fluctuations when the ceiling void functions as a return air plenum. In contrast, the Helical Vari-Swirl Diffuser’s calculated airflow rates are extremely accurate. This applies even 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.
For networked systems, the integrated static air pressure sensor is additionally used to optimise AHU supply air fan speed and system pressure, and an integrated supply air temperature sensor is used to optimise AHU supply air temperature. Simple sequences in the VSC or BMS collate data from all VSMs to minimise supply air pressure (system pressure optimisation reset control targets operating at least one VAV damper fully open) and aims for a low supply air temperature (saving fan energy when cooliong and minimising 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.
Duct Design
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 (full or partial) static regain duct design is, therefore, less frequently 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 Motor Pressure Control (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 diffuser and the index diffuser, based on 30 Pa index 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 (typically within +20%/-10% pressure) to prevent excessive VAV damper throttling of high pressure 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. The Multi-Max Flow feature of the Helical Vari-Swirl diffuser overcomes this.
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 Motor Pressure Control, if 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 rapidly become ineffective as the VAV damper throttles. 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 higher system pressure diffusers may rise sharply when the VAV diffusers throttle, leading to noise issues and the inability to fully turn down, causing discomfort 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 preserved, ensuring proper 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.
Low-Flow Throw Boost
Helical Vari-Swirl Diffusers are suitable for low supply air temperature systems – also known as cold-air distribution systems (CADS) – with a supply air temperature ≥ 7 °C. CADS typically have extremely low specific airflow rates (L/s/m2) especially when turned down.
During turndown, the Helical Vari-Swirl Diffuser maintains elevated discharge velocities via “Low-Flow Throw Boost” 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.
Multi-Pattern Blow
The horizontally projecting “radial” swirl pattern of the Helical Vari-Swirl Diffuser may be set in situ, 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.
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.
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.
Accessible Electronics
The stepper motor, Bluetooth-enabled Vari-Smart Microprocessor (VSM), 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-in upgrades.
Electrical Components, Sensors & Controls
Each Helical Vari-Swirl Diffuser includes:
- Terminals for 24 VDC power supply @ 16 VA
- Terminals suitable for a Modbus RS-485 comms daisy-chain
- Terminals suitable for an HMI
- Active room air induction system
- Perforated cap with controls hub, removable from the room, housing:
- Vari-Smart Microprocessor (VSM), Bluetooth enabled
- Stepper motor
- Standard onboard integrated sensors: room air temperature, supply air temperature, supply air static pressure
- Optional onboard plug-in sensors (zone CO2+RH or VOC; PIR)
- VSM 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. VSC-Network and 3. BMS-Network, below)
- Optional HMI:
- Wired or Bluetooth connected to a Master Vari-Smart VAV Diffuser
- Wall-mounted adjustable thermostat with Troom sensor
- Diffuser-specific temperature set-point adjustment (typically within a preset range)
- Optional touchscreen
- Optional sensors: RH; CO2; VOC; PIR
- Optional quick access for commissioning (eg design flow, minimum flow & DCV set-points)
Vari-Smart – Variants
- 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 always designated as a Vari-Smart Master Diffuser.
- Stand-Alone Group: a group of Vari-Smart VAV Diffusers, comprising a designated Vari-Smart Master Diffuser and one or more 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.
Stand-alone diffusers are supplied standard with terminal connections suitable for Modbus RS-485 daisy-chain networking.
- VSC-Network:
When daisy-chain networked via a Modbus RS-485 daisy-chain to a Vari-Smart Controller (VSC), which in turn is in communication with the AHU/FCU, a distributed controls network of Vari-Smart Microprocessors (VSMs) is created providing diffuser-plant-integrated controls for up to 16 off Vari-Smart VAV diffusers per VSC for standard VSC programming, or up to 30 off Vari-Smart VAV diffusers per daisy-chain for bespoke VSC programming (multiple interconnected VSCs permitted). VSCs allow system operation to be optimised for energy efficiency, indoor air quality and comfort. Building HVAC conditions – both globally and locally – may be controlled and modified centrally. BMS integration is available via Modbus or BACnet.
- BMS-Network:
As for 2. above; but suitable for up to 30 off Vari-Smart VAV Diffusers, and with the VSC replaced with a BMS (by others), and the Modbus RS-485 daisy-chain directly connected to the BMS.
Designed for building automation, functional descriptions for minimal third-party BMS programming are provided – with no additional central controls needed – to harness advanced Vari-Smart control sequences for AHU/FCU control and optimisation.
Vari-Smart – Distributed Network Features
Vari-Smart VAV Diffusers:
- Multiple Vari-Smart Master Diffusers permitted
- Vari-Smart Slave Diffusers may be assigned to any Vari-Smart Master Diffuser
VSC/BMS:
General:
- VSC supplied and programmed by SMARTEMP; BMS supplied and programmed by others
- VSC & BMS configured on site by others
- Has visibility of all sensors
- Global set-points (room temperature; dead-band; CO2; RH thresholds, etc)
- AHU/FCU cooling/heating changeover
Diffuser Management:
- Local set-points (room temperature; CO2; RH thresholds, etc)
- 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
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 via motorised spill air damper (by others) and/or Vari-Smart VAV Diffuser minimum airflow reset (biased towards low-priority Vari-Smart VAV Diffusers)
- System under-pressure mitigation for highly diversified air supply systems (dynamic capping of maximum airflow to maintain at least 10 Pa at Vari-Smart VAV Diffusers)
- Motor 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)
- System supply air static pressure optimisation reset control (targets at least one 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)
- Unoccupied zone temperature setback or shut-off via room temperature dead-band relaxation or VAV damper shut-off (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: Pstatic = 80 Pa and 130 Pa for stand-alone and networked, respectively)
- Diffuser excess pressure relief (VAV fully open if Pstatic ≥ 100 Pa and ≥150 Pa for stand-alone and networked, respectively)
- 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™
Innovation
Patents Pending
1. Cyclone Swirl VAV:
- Silent Swirl
- Integrated IEQ
- 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 system 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™
Resources
Product-Leaflet-SMARTEMP-HSC-VS.pdf[ uploaded: 2023-07-05 ]
Performance-Leaflet-SMARTEMP-HSC-VS.pdf[ uploaded: 2025-04-10 ]
Selection-Tool-SMARTEMP-HSC-VS.xlsx[ uploaded: 2026-01-08 ]
