2 The Big Picture
Home automation, at the intersection of rapidly developing technologies such as Internet, mobile communication, and renewable energies, has changed considerably over the course of the past years. The developments relate to all major aspects of a smart home, such as
- the capabilities of home infrastructure and controlled device
- the usability of mobile and stationary user interfaces
- the motivation for investing in automation and control technologies
Up to recently, home automation was mainly focused on installing controllable power-outlets or light switches and wiring infrared (IR) controls around the house. Technologies developed in the early seventies of the past century, which from today’s perspective are slow, unreliable, and insecure, were at the heart of building control.
The rapid developments in mobile communications have introduced a technological leap forward in home automation since. Wireless networks (3G, LTE, Wi-Fi, LoRa) and smart devices, with wireless communication interfaces (Bluetooth, ZigBee, Wi-Fi), are omnipresent, and allow the user to take home control and building automation to the next level. Instead of simply switching power outlets on and off, specific and meaningful functions of consumer electronics, household devices, or infrastructure components can be stirred. As a result, instead of rudimentary functionality, home automation today can deliver capabilities that have a real impact on comfort, security, and energy conservation of residential and industrial buildings.
Of similar significance as the new possibilities of home automation have been its advances in the user interface. The smartphone and tablet revolution has finally brought the personal, universal remote control device to the home. Proprietary, stationary panels and control devices are phasing out, being replaced by apps, which are easy to operate, to maintain, and to upgrade. With smart phone voice assistants becoming ready for usage by the masses, Star Trek style, reliable voice control for smart homes has finally arrived.
2.1 Smart Buildings and the Internet of Things (IoT)
With improved usability and new capabilities, the motivations for installing smart home technologies have become broader as well. The vision of green buildings, capable of significantly reducing energy and water consumption, is finally becoming real. Other use cases are safety management, home automation for the elderly and disabled (assistive domotics) and remote building control. Beyond providing powerful point solutions, smart buildings in addition have become a central component of larger Internet of Things concepts such as smart cities, smart industry and smart grids.
2.2 The Potential for Energy Conservation
Looking at the distribution of total energy consumption, the share of the private sector is significant. In the 28 European Union countries (EU-28), in 2014, 25% of the total energy was consumed by the residential sector, in the US 22%. (Figures 2.1 and 2.2). Thus, energy conservation in homes does move the needle even from a global perspective. And the savings potential for all energy forms used in the private sector is large. Space heating and cooling takes the largest share with between 50% and 70% of the total residential energy usage. Water heating takes second place, followed by electric appliances and lighting.
In US households over the past 20 years the share of energy used for space heating has steadily declined, while the share for space cooling has increased. Main factors for this trend are increased adoption of more efficient equipment, better insulation, more efficient windows, and population shifts to warmer climates. (Figures 2.3 and 2.4).
Figure 2.1 2014 EU-28 energy consumption per sector
Figure 2.2 2014 US energy consumption per sector.
Figure 2.3 2014 Residential end-use energy split EU-27
Figure 2.4 2014 Residential end-use energy split US
Still the potential for energy conservation in the industrialized world is enormous. There are four main approaches for reducing residential energy consumption, all of which should be noted:
- building insulation
- usage of state of the art appliances
- installation of efficient water heating and space heating systems
- installation of smart building automation and control
With the advances in home automation as described above, the last one in the list, building automation, has become an increasingly attractive choice, providing the opportunity for significant savings with relatively low upfront investment. Smart appliances coordinate their operation with smart meters (home gateways), reducing overall energy consumption and avoiding load peaks. Monitoring current and past power consumption and identifying load profiles provide the basis for intelligent power management with capabilities such as:
- Intelligent heating control by automatically managing room temperature based on time, outside temperature, and presence
- Smart lighting system, managing illumination based on presence detection, sunrise, or sunset timing and room function
- Intelligent, proactive blinds, keeping the interior of the building cool or warm
- Monitoring and management of electricity consumption
- Reducing water consumption through sensor faucets and intelligent plant watering management
2.2.1 Calculating Actual Building Automation Energy Savings
Studies report electricity savings of up to 30% using automated lighting as well as heating energy savings of 15%-20% using automated heating in residential buildings. But how much is it that you can really conserve by implementing a smart home? Answering this question was the task of a major standardization effort in Europe, which has come up with a comprehensive specification on how to measure and calculate building automation based energy savings: The European standard EN15232:“Energy performance of buildings – Impact of Building Automation, Control and Building Management”. For the first time, EN15232 specifies standardized methods to assess the impact of Building Automation and Control Systems (BACS) on the energy performance of these different building types:
- lecture halls
- wholesale & retail
The performance of building automation is categorized in four classes (A-D), A representing the highest performance building automation, D the lowest.
For each building type and each BACS Class, so called BACS Factors are given, with which the thermal and electrical energy savings can be calculated. Table 2.2 shows the description of the four BACS classes and the BACS factors for the different building types. Table 2.1 displays the percentage of thermal savings by installing building automation of efficiency classes A and B in reference to the standard class C.
Table 2.1 Thermal and electrical savings for various building types using BACS classifications
Table 2.2 BACS class definition
2.2.2 Smart Grids need Smart Buildings
Smart homes also allow for integration with smart power grids, which are in build out around the world, driven by renewable energy generation on the rise. Smart meters and smart gateways can only work, if a home control and automation infrastructure is in place. This infrastructure then can interact with the supply and demand driven electricity cost in smart power grids. Wind and sun based renewable energy generation introduces significant energy level fluctuations in the utilities’ power grids. Thus, for example, it can make sense to cool down the freezer two or three degrees below normal operation during times of high wind, so it can stay off longer in times of the day with lower energy supply.
By being able to continuously monitor energy levels and prices in a smart power grid, and by scheduling (delay or early start) high energy processes such as
- heating up the hot water tank
- operating the dish washer and washing machine
- cooling the freezer and refrigerator
smart meters can contribute significant energy savings without impacting the comfort level of residents.
2.3 Safety Management and Assistive Domotics
Another application for state of the art home automation is remote building control and safety management with features such as
- controlling the vacant home (temperature, energy, gas, water, smoke, wind)
- feeding and watching pets
- watering plants indoors and outdoors
- presence simulation to keep out intruders
- assistive living systems (assistive domotics), allowing elderly and handicapped people to stay home safe through reminder systems, medication dispensing, blood pressure and pulse monitoring as well as emergency notification
2.4 Changing the World (a bit) to the Better
Home automation standardization based on open Internet technologies, omnipresent smartphones and sensor equipped devices have been the catalyst for manufacturers to start integrating control functionality in their products as a default. The broad wave of Internet of Things technologies has embraced smart homes and smart buildings, making it an integral part of its concepts. This has further accelerated the acceptance and deployment of smart home technologies, which have arrived in the mainstream. So (finally) everything is there, that is needed for a truly intelligent home. Following the instructions in this book, you will be able to test this claim by translating the described concepts into real world solutions for your home.
Smart home technologies have come a long way. Technological advances, climate change and demographic transitions have redefined what they are and why they are being deployed. Rather than being a futuristic niche for geeks and luxury home owners, smart homes have become an integral part of the life of millions. Capable of helping to solve pressing problems such as global warming or demographic transitions, they are changing the world (a bit) to the better. 2.5 Bibliography
US Department of Energy. (2016): Total Energy Interactive Table Browser. www.eia.gov/beta/MER/index.cfm?tbl=T02.01#/?f=A&start=2013&end=2014&charted=3-6-9-12
Eurostat European Commission (2016): Final energy consumption, by sector. ec.europa.eu/eurostat/data/database?node_code=tsdpc320
Enerdata. (2015) Energy Efficiency Trends in Residential in the EU. www.odyssee-mure.eu/publications/efficiency-by-sector/household/
US Department of Energy. (2016) Annual Energy Outlook 2015. https://www.eia.gov/beta/aeo/#/?id=4-AEO2015&cases=ref2015&sourcekey=0
Baggini, Angelo and Lyn Meany. (2012) Application Note Building Automation and Energy Efficiency: The EN 15232 Standard. http://www.leonardo-energy.org/sites/leonardo-energy/files/Cu0163_AN_Building%20automation_v1_bis.pdf