Not so long ago a telephone had but one function, to enable people great distances apart to speak with each other. Today, with the aid of clever technology such as Bluetooth, we use them to send text messages, take and send photographs, for video messaging, play computer games, receive FM radio, connect to the internet for email services, and some models even double-up as MP3 players. Similarly, building controllers are getting smarter and, just as in the telecommunications industry; it is the consumer (building occupier) that is benefiting.

A modern local controller can offer more than just regulating the room temperature. It can detect if a room is occupied thereby reducing energy consumptions, manage the lighting system including dimmer control, adjust the sunblinds, of course control the HVAC systems, provide extension services when working outside normal hours, and even provide data relating to room and outside air temperatures. And it is smart enough to understand how each of these systems impacts on the others.

For example, on a warm summer’s day as internal building temperatures begin to increase, the local controller may well deal with a rising room temperature by adjusting the sun blinds for maximum shading. However, this one action will affect at least two other systems: air conditioning and lighting. With greater shading to the room it may be possible to reduce the air conditioning supply; a building’s biggest energy consumer. Meanwhile, due to the increased shading, light levels will need to be checked and if necessary adjusted.

“At Priva Building Intelligence we have taken this one step further,” states Anders Norén, Managing Director of the UK operation. “Available within our controllers is the ability to calculate the position of the sun in accordance with the geographic locality of the building, the season and the time of day. The engineer simply has to enter the building’s longitude and latitude, together with the current time and date, and the controller will calculate the best angle for the sun blinds, as well as the heating/cooling and light levels required by the interior space. For example, when the sun is low on the horizon and likely to be a nuisance to tenants by shining directly onto their PC screens or into their eyes, then the controller will automatically adjust the blinds accordingly, taking into consideration how this will effect other building services. This type of intelligent thinking is a standard feature of the system.”

Dutch integration

In the West Netherlands, Priva is currently engaged on an integration application for the Dutch Government. The building, which was constructed in 1984 and is situated between a residential district and the heart of the city, has been partially vacated leaving two-thirds of it unoccupied. Planned renovation work is expected to be complete in 2007 and will encompass all of the building’s mechanical, electrical and control systems. Part of that refurbishment work includes the installation of an Ethernet, which will allow the Priva building management system to take full advantage of system integration. The building is fully air conditioned employing fan coil units supported by a perimeter heating system, but acknowledges the need for energy conservation by incorporating ground source heat pumps and automated sun blinds.

“Control intelligence will be distributed throughout the building via a series of Compri HX8 controllers, complete with built-in web servers,” explains Anders Norén. “Local control will be provided by Comforte CX controllers managing the HVAC services, lighting and sun blinds in each designated area. In total, some 1,600 Comforte CX controllers are to be installed linked to a series of Comset CX room controllers. Main voltage (Wieland GST 18) connectors will be used for controlling the lighting and sun blinds and the systems will utilise the building’s Ethernet to communicate with the Compri HX8 controllers; while interface of the building’s pumps, chillers, frequency converters, and energy meters will be via the Modbus RTU protocol.”

Communication

The foundation to system integration is communication. The Priva Building Intelligence Comforte CX multi-functional controller and the Comset CX room controller are native BACnet Application Specific Controllers (B-ASC). They communicate with other controllers via the BACnet CX network using BACnet MS/TP (Master Slave/Token-Passing).

But it does not stop there. The development work carried out on the Compri HX range means that the Priva system can communicate with other protocols; XML, KNX/EIB,

Echelon/LonMark, M-bus, Modbus, and OPC are all supported. Both internet/intranet applications and cordless communications are possible.

Comset CX and Comforte CX work in partnership to provide personal comfort conditions for people working in both cellular offices and open plan areas. Churn is a fact of life in the commercial world; moving people and their furniture and equipment to make the most efficient use of space. Modern internal partitioning techniques can result in a whole floor of cellular offices being quickly redesigned into an open plan area - or vice versa. The mix is constantly changing as staff levels rise and fall and business practices change making different demands on the available space.

Clustering

Because the Comforte CX units are able to communicate with each other it is possible to create ‘clusters’ so that whole areas can be regrouped without the need for physical installation, thus avoiding complex and expensive infrastructure changes. This is achieved by grouping selected control units within a single BACnet CX network in software-defined clusters.

The principle of creating clusters within the HVAC, lighting and sun blinds services is based on the master/slave concept, but in this case a three dimensional master/slave arrangement. This means that a single controller may be the HVAC ‘master’ for a group of designated zones and also be the ‘slave’ to the sun blinds controller.

Take, for example, an open plan office area that has been divided into four zones: north-east, south-east, north-west, and south-west. A master temperature controller manages the average temperature within each of the four zones; the lighting has been zoned in bands from the perimeter windows into the core of the building, as the centre of the open plan area will require greater illumination; meanwhile, sun blinds have been fitted to the south-facing wall only providing shading to the south-east and south-west zones. Because the controllers communicate on a peer-to-peer basis, all the controllers serving the area have the ability to give commands (master) or take orders (slave) dependent on the changing temperature or lighting demands within the space; they do not rely on a network supervisor to manage their operation.

“Designing clusters and adapting them later is a programming operation,” said Anders Norén. “Initially, the various cluster configurations are programmed in software during the commissioning stage, avoiding any additional work being carried out during system installation. Once operational, the end-user will, in the future, adapt and change clusters using the web browser available within TC WebVision. Consequently, the building is no longer restricted by its services - indeed the reverse. Previously, arranging for a group of services to interact as a single system meant physically replacing or adding new communications cabling, which in turn inevitably meant staff disruption, damage to the internal décor and an unbudgeted cost. Now, with new integration applications, the work can be completed within a few minutes and all with the aid of a common web browser.”

Integration

Integration is the foundation of Priva control and has been designed into its range of building controls. As a result, system integration becomes almost an intuitive process, requiring only the agreed settings to be downloaded in order to achieve a sophisticated

level of interaction between plant and equipment. Time required to design and engineer a building management system is cut, time required to integrate the building services is cut, and time required to commission the system is cut; which means engineering costs are greatly reduced and system security is enhanced as the pre-programmed control routines have been fully tested and proven in the field.

Savings are also achieved on equipment procurement. Integration means that one communications network replaces the three required when the HVAC, lighting and sun blinds operated separately. Similarly, one controller (not three) can manage all three systems.

Integration is no longer an industry buzz-word. The products and methodology have been tried and tested in the laboratory and in the real world - and they work. In addition, studies have been carried out that show energy can be saved by linking the building services. Energy prices are on the rise and forthcoming government legislation has once again placed energy management high on the end-user’s ‘must do’ list. Integrating the services is a viable option to improved facility management, improved building performance and energy conservation.

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