This technology, which has originated from the computer sector, was first used in industrial applications engineering. In the field of building technology, installation bus systems were used, initially, in industrial facilities. No more than a few years ago, an increase in applications in the residential building sector could also be observed. Some basic cases are described in the following sections, which are partially executable by means of conventional electrical installations. The application of bus systems, however, will facilitate the execution; in some cases, bus systems are essential to solve a specific problem.
Concerning the control of lighting in apartments or residential buildings, the bus technology provides several functions, which - compared to conventional solutions - clearly require less expense for wiring and devices. These functions include:
• time-switching (the control clock may be installed anywhere along the bus line);
• control of the brightness level (likewise with arbitrary positioning of the brightness sensor in the bus line);
• occupancy-dependent lighting control;
• the allocation of keys/push buttons and luminaries that are freely programmable and may easily be modified afterwards;
• the control and supervision, from one central place, of the entire lighting system, the position of which can also be modified;
• simulation of occupancy by means of artificial lighting, implying increased security;
• the allocation of push buttons and luminaries that may be modified, simply by reprogramming, without creating the need for further (re)wiring;
• demand-adapted and brightness-controlled lighting, which saves electric energy.
The scope of lighting applications must not be viewed separately, ignoring other domains where the installation bus technology is used. It is only in conjunction with other sectors that major advantages (for instance, by multi-use sensors) will be achieved by means of the installation bus compared to conventional systems of electrical installation.
15.4.2 Controlling louvers, blinds and windows
The number of electrically controlled and operated louvers, blinds and windows is steadily increasing. In conjunction with an installation bus, the electromotive control of louvers and blinds facilitates many functions that are similar to lighting control:
• clock-controlled switching;
• brightness control (for example, depending on solar radiation);
• louvers and blinds that can be controlled or monitored from one central spot;
• simulation of occupancy; and
• security functions, such as raising louvers at a gale alert or closing windows when raining.
By analogy with lighting, increased security can also be included in the list featuring further advantages. Energy savings due to consequently closing the blinds during nighttime hours of the winter season are only marginal, as modern windows have a high level of thermal insulation.
By ensuring optimized control of the heating system, a bus system can help to save heating energy:
• It is possible to adjust the requested temperature for each individual room by using EIB thermostats for room temperature control and a corresponding connection of the valve actuators for individual room control. By means of a bus, the room temperature controller will control all actuators inside the room.
• In addition, EIB-compatible central heating controls help to save more energy. The controller for the central heating boiler will poll all of the valve actuators that are connected to the EIB system. If all valves are closed, the circulation pump can be switched off and the flow temperature can be set back. Accordingly, precisely the amount of heating energy that is actually required will be supplied to the flat (by adjusting the flow temperature).
• Time-dependent heating control (such as nighttime or weekend setbacks) can be programmed individually for separate rooms.
• The remote enquiry of energy consumption rates is relevant for rental housing construction. Since onsite meter reading is no longer necessary, there is no more need to make appointments with the tenants, and the billing (procedure) for consumed energy will become more cost efficient.
Since transmission heat losses are increasingly reduced due to the provision of improved thermal insulation for the envelope components, the heat losses caused by ventilation are becoming more and more important. By using the bus technology, it is possible to save energy in this sector:
• Ventilation heat losses can be minimized if the radiator valves will be automatically (by means of window contacts) reduced to anti-icing temperatures when a window is opened. These window contacts can also be used for protection purposes - for example, for burglary prevention (multiple-shift usage of sensors).
• If a balanced ventilation system with heat recovery has been installed, the system can be switched off while windows are open.
• Similar to the individual control of space heating, the same procedures are also possible for individual ventilation of spaces.
• Using appropriate sensors, it is possible to determine the indoor air quality. The volume flows of supply and extract air can be controlled on the basis of these data.
The functions featured above are also achievable without installing a bus system. However, if a bus has been installed, it would be preferable to control these functions via the bus system.
Load management implies taking measures for a most economical use of the energy supplied by power utilities, as well as measures to prevent the circuit system from switching to overload. Load management is most common in industrial facilities; but there are some interesting approaches to be found in the residential building sector - namely:
• shifting the operation of energy-intensive domestic appliances to periods of low price rates (for example, nighttime rates) offered by many power suppliers; and
• switching off electric circuits that are no longer required (this will reduce the amount of power consumed in the standby mode).
By utilizing the bus technology, load management in residential buildings will become more cost efficient.
The safety of a building is of increasing concern. The application of a bus system makes it possible to supervise the building envelope, to provide for occupant-induced monitoring of the building interior, and to protect the building against damages by fire and adverse weather influences. In this context, components of the bus system can be used to perform several functions - for instance, the same bus line that connects the lighting actuators could also be used to integrate sensors for the building security within the system. Such functions of securing the building include:
• warnings concerning the status (open/closed) of windows and doors;
• occupant-induced monitoring by means of motion sensors from spaces inside the building and from sectors outside;
• simulation of presence (by operating the lighting and moving the louvers and blinds, the security level may be increased); and
• the transmission of an internal alarm from the internal building network to an external network.
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