An intermittent heating strategy by predicting warm-up time for office buildings in Beijing

• Published in: Energy and buildings 2017-11, Vol.155, p.35-42
• Main Authors: Xu, Baoping, Zhou, Shaoxiang, Hu, Wenju
• Format: Article
• Language: English
• Subjects: Bathrooms; Buildings; Coiling; Coils; Computer simulation; Energy conservation; Energy efficiency; Heating equipment; Heating systems; HVAC; Insulation; Intermittent heating; Mathematical models; Model predictive control; Office building; Office buildings; Predictive control; Radiators; State space models; Strategy; Studies; Temperature effects; Thermodynamic properties; Warm-up time; Working hours
• ISSN: 0378-7788; 1872-6178
• DOI: 10.1016/j.enbuild.2017.08.062

•A control strategy is proposed for the intermittent heating of office buildings.•A physical model for forecasting thermal behavior of the building is developed.•The required heating capacity can be limited by extending the warm-up time.•A system with lower thermal inertia has greater energy saving potential. In order to achieve building energy efficiency and keep the indoor temperature within a defined comfort range during working hours, a predictive control strategy is proposed for intermittent heating of office buildings by predicting the warm-up time on each working day. A physical model for simulating and forecasting thermal behavior of the building is developed using the state space method. Furthermore, a modeling analysis case is given based on a typical office building in Beijing with different types of building insulation and terminal forms. The increasing capacities of heating equipment, transition time, room temperature variation and energy saving rate are simulated and analyzed. Results indicate that when applying an intermittent heating strategy, the required heating capacity for each room is 1.1–1.3 times to that of a traditional continuous heating system. The warm-up time ranges from several minutes to several hours depending on conditions, while cooling down time is much shorter than warm-up time. In addition, we found that heating systems in ordinary buildings with fan coils as terminal devices have faster temperature responses than those in energy efficient buildings with radiators. It is necessary to consider standby heating for bathrooms to keep room temperate above antifreeze value. The heat saving rate for intermittent heating can reach about 20% in a typical week compared with continuous heating, and a system with lower thermal inertia has greater saving potential.