Intelligent Building Systems - Lighting Automation - HVAC Automation

Intelligent Building Systems

The term Intelligent Building System refers to the integration of various building facilities by computer systems. Such a system provides a centralized control application for example for HVAC (heat, ventilation and air conditioning), security systems, lighting systems, energy management, access control and telecommunications [1]. In other words, Intelligent Building Systems try to integrate several building automation systems. As mentioned before, these systems are developed to control innovative technologies to increase energy efficiency as well as user benefits. Approaches of this kind address the fundamental issue of achieving reductions in energy demand in buildings without lowering the quality of in-building conditions for occupants. This is of special importance for the distribution of energy efficient technology, since it can also bring direct benefits for users, beside the positive environmental impact. To reduce energy consumption in buildings Intelligent Software Agents (ISA) can be installed at different levels of automation. The focus of this approach is set on individual climate control to adjust the conditions to user preferences by an optimal setting of parameters. This implies profound knowledge of the actual weather situation and data about the building like window orientations. An approach of this kind was tested in field in office buildings in the Netherlands [2]. Although this technology is still in research phase, it is a promising concept to deal with the trade-off between energy savings and individual comfort.

Lighting automation 

Lighting is responsible for about 20 percent of total energy demand in commercial buildings and for about 10 percent of energy demand in residential homes [3]. One possibility to reduce this energy consumption is to use more efficient illuminants, like light-emitting diodes (LED). On the other hand the inefficiencies in lighting of today’s buildings arise from light usage. Light should be turned on when it’s needed and should be turned off when it’s not necessarily needed. This approach can be named as occupancy-based lighting [4]. At this point automated lighting systems come to play. Modern lighting control systems are computer systems that allow automated control and optimization of lighting in office or private buildings, that maximize efficiency and therefore save energy. The energy savings from these control systems can be numbered as up to 70 percent of today’s energy demand for lighting [5]. The global potential of emissions savings by lighting automation is estimated by about 0.12 GtCO2e [4], which would bring a significant environmental benefit. Additionally there are important social and economic benefits, like improved and individually adjusted room lighting and lower operational costs due to lower energy consumption.
Typical features of modern lighting control systems are the following [5, 6]:

• Direct on/off and dimming controls provided to the occupants at a centralized control user interface. 
• Possibility of remote management of lighting control of all individual lights in a whole building or several buildings combined. 
• Scheduling functions and timers, switching lights on and off or dimming lights automatically at predefined times. 
• Integration of photo-sensors to detect illumination levels of natural lighting. This allows to adjust additional artificial lighting efficiently to meet the required illumination levels and save a significant amount of energy. 
• Occupancy sensors, to enable occupancy-based lighting, especially useful in areas with varying usage. 
• Functions for measuring and monitoring energy consumption of lighting, which provide real-time or historical data on energy usage for decision making. 

As already mentioned lighting control systems can not only provide energy savings, they can also bring advancements in lighting characteristics like illumination levels in respect to the requirements at different places. As an example, lighting can be individually adjusted to several specific workplaces in the same room. Beside environmental benefits, this induces significant economic and social improvements, since it is the sense of artificial lighting to improve the productivity and wellbeing of a buildings occupants. To achieve individuality in lighting and to adjust it to user preferences, a flexible structure of the lighting network is needed. This involves a multiple-circuits configuration with local and remote control functions and individually positioned luminaries at specific areas per room [7]. Approaches like this focus at ensuring that savings in energy are not achieved at the cost of performance. However a simple case study at a small office showed, that automated lighting control could lower energy usage to about 30 or 40 percent of energy usage without any lighting control facilities [7].
One problem for adoption of lighting control systems in existing buildings are the high costs of installation and rewiring [8]. Wireless technology could help overcome this hurdle, since it is better compatible with economic considerations due to lower investment expenses for retrofitting. In the case of wireless lighting control a network of wireless photo- and occupancy sensors, as well as wireless light switches and dimmers is installed, which means that “each endpoint is wirelessly enabled” [5]. Figure 1 shows a schema of a simple wireless lighting architecture, using wireless actuation modules for luminaries with dimming functions and a base server for lighting control. The system is designed as wireless networked intelligent lighting actuation system, to gain energy savings and satisfy the needs of individual occupants [8].

Figure 1: Wireless networked lighting architecture [8]

More complex wireless lighting networks use mesh-architectures, meaning that every endpoint can communicate with the controller by at least two channels, which makes the network more stable and more resistant to failures due to redundancy [5]. Beside the relatively low costs of retrofits, the major benefits of wireless lighting control are flexibility in placing lighting controls and reconfigurations of the network, as well as high scalability in respect of adding devices and expanding the network.

Heat, ventilation and air conditioning (HVAC) automation 

Similar to lighting control, heating, ventilation and air conditioning can also be automated by special building automation system (BAS). In this case the BAS is a computer network integrating the controls of heating, ventilation and air conditioning systems of buildings, which also can be automated [6]. A main goal of these systems is to adjust HVAC settings to occupants needs in order to save energy and improve room conditions. In China HVAC systems are responsible for more than 70 percent of total energy use in buildings [9]. Globally the automation of HVAC systems could save up to 0.13 GtCO2e [4].
The full potential of energy savings from improving HVAC systems in the building sector can be tapped by developing hybrid systems for heating and cooling that use efficient and low carbon energy sources. An example of a hybrid air conditioning system is a combination of a vapor-compression system, a desiccant dehumidification system and a indirect evaporative cooling system [9]. To achieve maximum efficiency of such combined systems information technology is needed to optimize and operate them. For proper and efficient building ventilation there are hybrid concepts too. These systems use a combination of natural ventilation and air conditioning [10].
Another approach of reducing energy demand for heating and cooling is to exploit geothermal energy. This brings significant environmental benefits, since this type of energy is carbonfree and widely available. The main principle of these systems is the heat pump, which works like a “reverse refrigerator” [11]. The ground heat is used for building heating in winter, since the soil is warm relatively to the air on the surface. In summer the soil can be used to cool the building by reversing this principle. Figure 2 depicts a simple schema of a heat pump system.

Figure 2: Ground source heat pump system for building heating and cooling [11]

Geothermal systems are often used in context of passive building concepts with a low grade of natural ventilation. These concepts often optimize energy consumption at the cost of room conditions. To improve room conditions, additional active ventilation systems are necessary, to achieve the required level of air exchange in these buildings. In contrast to this, there are approaches in research to use geothermal energy with the help of ground air collectors to realize active conditioning systems. The advantage of this method is, that the whole building construction is warmed by naturally preheated air in winter and cooled by natural cool air in summer [12]. The principle is similar to traditional heat pumps, but the main difference is that air is used to heat or cool the building instead of water. By collecting ground air a higher level of ventilation can be achieved to improve room conditions and the need for additional ventilation can be avoided.
Heating of buildings by traditional systems using fossil fuels has large environmental impact. In the UK tempering buildings accounts for about 49 percent of total carbon emissions [13]. There are several technology approaches for low carbon domestic and nondomestic heating, to lower this environmental impact. Such heating systems are called microgeneration heat technology, since they are built in small-scale factor and mainly used to heat single building units [13]. Some samples for microgeneration heat technology used for room and water heating are heat pumps, solar thermal hot water, biomass stoves and boilers fuelled by wood or pellets. Just as for other building technologies the role of ICT is to control these microgeneration heat systems, integrate them with other building automation systems and therefore optimize the efficiency.
A study from the UK about the use and adoption of low carbon microgeneration technology addressed the reasons for or against the adoption of these technologies [13]. The survey showed that a big part of the adopters of microgeneration heat technologies considered themselves as “environmentally conscious” and took also different actions to reduce their energy demand, like using public transport for example. Households in rural areas, with no children, or where children already left home, are more likely to adopt low carbon technology as well. The main reason for adoption is the idea to lower bills and carbon emissions. On the other hand, the largest barriers for adoption are mainly financial: high initial costs, uncertain and long payback periods, small subsidies [13]. In summary there are financial, regional and ideological factors that influence the decision for or against adopting new technology to lower the environmental impact of domestic heating systems. The uncertainty about payback periods and efficiency of these systems that prevents many households from adoption. Therefore a well-directed information campaign and higher incentives given by governments could help overcome these barriers and support a faster distribution of low carbon heating technologies.

References

[1] Diamond Electronic Systems Ltd. http://www.diamondsystems.co.uk/index.php?option=com_content&view=article&id=81&Itemid=84. Accessed: 2013-03-08.

[2] W. Zeiler, R. Houten, and G. Boxem.  Smart buildings:  Intelligent software agents.  In
Robert J. Howlett, Lakhmi C. Jain, and Shaun H. Lee, editors, Sustainability in Energy
and Buildings, pages 9–17. Springer Berlin Heidelberg, 2009.

[3] B. Metz. Controlling climate change. Cambridge University Press, 2010.

[4] The Climate Group. Smart 2020: Enabling the low carbon economy in the information age. Technical report, The Climate Group on behalf of the Global e-Sustainability Initiative (GeSI), 2008.

[5] Daintree  Networks,   Inc.      White  paper:    The  value  of  wireless  lighting  control.
http://www.daintree.net/downloads/whitepapers/smart-lighting.pdf.  Accessed: 2013-03-08.

[6] R. Wolsey.  Controlling lighting with building automation systems.  Lighting Answers, Vol. 4 Number 1:1 – 8, May 1997.

[7] G. Parise and L. Martirano.  Impact of building automation, controls and building management on energy performance of lighting systems.  In Industrial Commercial Power Systems Technical Conference - Conference Record 2009 IEEE, pages 1 –5, May 2009.

[8] Y.-J. Wen and A.M. Agogino. Wireless networked lighting systems for optimizing energy savings and user satisfaction. In Wireless Hive Networks Conference, 2008. WHNC 2008. IEEE, pages 1 –7, Aug. 2008.

[9] K. Sumathy, Li Yong, Y. J. Dai, and R. Z. Wang.   Study on a novel hybrid desiccant dehumidification and air conditioning system. In Robert J. Howlett, Lakhmi C. Jain, and Shaun H. Lee, editors, Sustainability in Energy and Buildings, pages 413–421. Springer Berlin Heidelberg, 2009.

[10] A. Elmualim. Integrated building management systems for sustainable technologies: Design aspiration and operational shortcoming. In Robert J. Howlett, Lakhmi C. Jain, and Shaun H. Lee, editors, Sustainability in Energy and Buildings, pages 275–280. Springer Berlin Heidelberg, 2009.

[11] B. Metz. Controlling climate change. Cambridge University Press, 2010.

[12] W. Zeiler and G. Boxem. Geothermal active building concept. In Robert J. Howlett, Lakhmi C. Jain, and Shaun H. Lee, editors, Sustainability in Energy and Buildings, pages 305–314. Springer Berlin Heidelberg, 2009.

[13] S. Caird and R. Roy. Adoption and use of household microgeneration heat technologies. Low Carbon Economy, 1(2):61–70, December 2010.