Preheating time estimation in intermittent heating with hot-water radiators by considering model uncertainties

Intermittent heating refers to heating buildings only during occupied periods. Owing to the thermal inertia of buildings, a preheating time is necessary to bring the indoor temperature into a comfortable range at the start of occupied periods. This paper proposes a new method to estimate the preheating time in intermittent heating with hot-water radiators by considering model uncertainties. First, a dynamic physical model is established based on the thermal equilibrium of buildings, and is approximated as a first-order continuous-time model by ignoring the influence of ambient conditions on the indoor temperature. The ignored part is represented as model uncertainties. Second, the continuous-time model is identified from collected data of indoor temperature and supply water temperature, and the model uncertainty is obtained based on the identified model. Third, the preheating time is determined with a credible probability to ensure that the indoor temperature meet thermal comfortable requirements. The proposed method has two novel features: (i) it can be applied to buildings with unknown physical parameters and unmeasurable ambient conditions, and (ii) it can yield reliable estimates of preheating time based on the model uncertainties to ensure the success of preheating under a given probability. Experimental examples demonstrate the effectiveness of the proposed method. •A new method is proposed to estimate the preheating time in intermittent heating.•The preheating time is determined from a mathematical model identified from data.•Model uncertainties are considered to statistically ensure the success of preheating.•Physical parameters of room models and ambient conditions are not required.•The proposed method is validated at two experimental rooms with different sizes.