The quality of living at home has become increasingly important in recent years, both for the general improvement of living conditions, which has greatly increased the needs, and for the time spent daily by people inside buildings, which in many cases exceeds 90% of the total. The combination of thermal, visual, acoustic and indoor air quality comfort is the discipline that guides the design, construction and evaluation of contemporary buildings: it is the concept known today as IEQ or Indoor Environmental Quality. The quality of indoor environments has important relationships and effects with the well-being experienced by end-users at the home, with productivity and health in the workplace and with the energy performance and sustainability of buildings. Among the four dimensions of IEQ, the climatic quality of the building - understood as the combination of thermo-hygrometric conditions and air quality - is taken over by the HVAC functions and is of fundamental importance for its energy implications.

Application examples of HVAC systems

Discover the solutions Ekinex has developed for climate control systems

Thermo-hygrometric comfort

Climatic comfort is a complex concept, since it depends on a large number of variables, both objective and subjective; moreover, the conditions within confined spaces are subject to transients and the occupants themselves, aware or not, can implement adaptive behaviours. In terms of thermo-hygrometric comfort, the two main parameters to be controlled are the temperature and relative humidity of the air; during the design of the HVAC system, desired values are defined, which are then taken as a setpoint values by the control and regulation devices.

Actually, there are several combinations of temperature and relative humidity resulting in a comfortable climate defining a “comfort zone” that may be represented in a diagram. Some home automation devices allow this zone to be defined by means of five parameters (minimum and maximum temperature, minimum and maximum relative humidity and absolute humidity), informing system supervision when the combination of measured values is outside the comfort zone.

The EN ISO 7730 standard offers the design tools to assess not only the overall comfort experienced by occupants of moderate thermal environments using the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indexes, but also any local discomfort using four indexes that consider respectively the air currents, the vertical air temperature gradient, the temperature, the floor temperature and the radiant asymmetry.

Application examples for controlling the thermoregulation functions