Automation in the building industry

Commercial buildings consume almost 20% of the total primary energy used in the United States, and 30% of this energy is devoted to inadequate sensing, control, and the inability to properly use the capabilities of the existing building automation systems (BASs). Automated fault detection and diagnostics (AFDD) has been a topic of research interest for some time. Although AFDDs offer huge potential in the world of building automation for energy savings and thermal comfort, their deployment in the in-field “real world” systems is rather low.

Some reasons for this low penetration, as highlighted by Kim and Katipamula in their review, suggest the high initial cost of additional sensors and the need for customization of software solutions for specific applications. One of the goals of the Building Technologies Office (BTO) of the Department of Energy (USA) is to target to achieve 20% savings in energy use in commercial buildings by the year 2020 (Office of Energy Efficiency & Renewable Energy n.d.). It may be noted that properly tuned controls alone offer the potential to reduce commercial building energy consumption by about 29% (Office of Energy Efficiency & Renewable Energy 2017). Some of the technologies that may assist BTO in achieving this goal are highlighted in this issue of Science and Technology for the Built Environment (STBE), including AFDD, Wi-Fi direct technology, prototypical building energy modeling, thermostat set-points, and personal cooling systems (PCSs).

This particular issue of STBE presents 10 interesting articles covering a broad range of topics, including a review of AFDD by Kim and Katipamula, a novel wireless environment monitoring system by Yu and Zhang, a prototypical energy model by Yang et al., thermostat learning algorithms by Gunay et al., observations from a PCS by Verhaart et al., seasonal variation of carbon monoxide in a naturally ventilated underground residential car park by Zhao et al., activated carbon filter performance prediction model by Kuo et al., phase change materials from salt hydrate as secondary refrigerants by Irsyad et al., effect of temperature and pressure on ignition and quenching behavior of R32 and R717 by Takizawa et al., and the development of a new subcritical heat pump prototype to provide sanitary hot water by Pitarch et al.

Yu and Zhang applied a novel wireless environment monitoring system in buildings based on the Wi-Fi Direct technology. The proposed system can be used as the feedback of the HVAC systems which can effectively handle the unnecessary frequently moderating of the devices caused by outliers or frequent disturbance in temperature and humidity. Yang et al. presented a unique modeling approach called the “Prototypical building energy model” that represent the “typical” energy consumption behavior of a group of buildings with similar functions, and serve the purpose of energy performance evaluation and urban energy planning, for a building stock rather than a single building. The model was validated with the data from 34 office buildings in Qingdao City, China. The results were able to mimic the “typical” energy consumption behavior with reasonable accuracy.

Gunay et al. presented the results of an interesting study where occupants observed were to interact with their thermostats once every 56 h of occupancy; and to change the temperature set-point, on average, by 1°C. This suggests that the fixed temperature set-points not only waste energy, but also frustrate some occupants. Verhaart et al. studied the user interaction pattern of a PCS in individual offices that related to level of comfort level and perceived air quality. The results showed that women required less cooling, while the office indoor temperature can be maintained at several degrees higher than is customary with personal cooling, resulting in significant energy savings.

Zhao et al. experimentally evaluated the seasonal variation of carbon monoxide in a naturally ventilated underground residential parking lot during 1 year in China. The daily mean carbon monoxide concentration in the parking garage was below the long-term (8 h) carbon monoxide exposure limit in parking lots from the World Health Organization (25 ppm) in summer, autumn, and spring; while more than 90% of the measurements exceeded the World Health Organization long-term (8 h) exposure limit of 15 ppm in winter. An air-exchange rate of 0.12 or 1 h–1 would ensure for the carbon monoxide concentration to remain below the allowable limits.

Kuo et al. developed an activated carbon filter performance prediction model that uses the ASHRAE standard accelerated test. Filters are widely used to create an airborne molecular contamination (AMC)-free environment in industrial buildings. Irsyad et al. developed PCM from salt hydrate Na₂HPO₄ with 5.04% concentration (Na₂HPO₄.12H₂O) and CaCl₂ with 40% concentration (CaCl₂.6H₂O) as secondary refrigerant. These hydrates showed small pressure drops and high heat transfer characteristics. Takizawa et al. studied the effects of temperature and pressure on ignition and quenching behaviors of mildly flammable refrigerants, R32 and R717. The quenching distance decreased slowly with increasing temperature and decreased steeply with increasing pressure.

Pitarch et al. proposed a new subcritical heat pump cycle to provide sanitary hot water, where subcooling affects the coefficient of performance strongly. In nominal condition (inlet/outlet water temperature in the evaporator being 20°C/15°C and in the heat sink being 10°C/60°C), the optimal subcooling is 42 K with a heating coefficient of performance of 5.35, which is about 25% higher than the same cycle working without subcooling.

Please read on to learn more about the new technologies that may lead to advanced building automation.