State-of-the-art, challenges and new perspectives of thermal comfort demand law for on-demand intelligent control of heating, ventilation, and air conditioning systems

The indoor thermal environment in buildings, industry, and other fields greatly affects human thermal comfort, productivity, energy consumption, and even health. The heating, ventilation, and air conditioning (HVAC) system is the primary way to regulate the indoor thermal environment. However, the local thermal discomfort phenomenon is widespread nowadays. With the increasing demand for intelligent control of the indoor thermal environment on demand, it is necessary to clarify the thermal comfort demand law of the human body. Note that, existing related studies mainly focus on the thermal comfort model, the thermal sensation model, and the thermophysiological model. And researchers tend to consider physiological parameters in these models rather than directly considering psychological factors. But the objective physiological parameters and psychological factors are precursors of thermal comfort, which directly determine the human thermal comfort level. In addition, the human factors relationship between objective physiological parameters, psychological parameters, behavioral parameters, and environmental parameters has not been fully elucidated. Therefore, it is difficult to achieve truly intelligent regulation. This investigation provides new insights for future research directions on human factors engineering for on-demand intelligent control of HVAC systems, which helps to build a healthy, comfortable, productive, low carbon, and energy-saving indoor environments in closed/semi-closed spaces.