Age: a decisive factor in thermal comfort

Six months after the start of the ConTerMa Multidisciplinary Coordinated Research Program, we are pleased to present some results and report on how we are approaching the study.

A part of ConTerMa's research aims to analyze the thermal comfort of older people in Residential Centers located in the Mediterranean continental climate and predict which thermal conditions are acceptable or preferred for this group of people.

Five centers located in Barcelona, ​​Valencia and Tarragona were selected to have a representative sample of buildings with different construction characteristics and air conditioning systems.

The experimental campaign began in February 2019. For each climatic season, it was planned to monitor around 15 rooms (common areas, gym, dining room, etc.) in each center. With a total of 45 monitored rooms and an average occupancy of 15 residents per room, it was proposed to obtain approximately 675 surveys for each climatic season.

To date, the experimental winter and spring campaign has been carried out, reaching a total of 1,516 surveys among residents and caregivers (872 in winter and 644 in spring).

To facilitate determining both Thermal Sensation, Acceptability and Thermal Preference, tabs with images such as those shown below were used.

Image 1. Evaluation of Thermal Sensation.

Image 2. Evaluation of the Preference.

Image 3. Acceptability Assessment.

For the characterization of the level of clothing of residents and caregivers and their activity, were used the reference values of UNE-EN-ISO-7730: 2005.

For the monitoring of the dry temperature (Ta) and relative humidity (HR) of the occupied spaces, average radiant temperature (Trm) and air velocity (va) was used the equipment Delta Ohm HD 32.3.

Image 4. Delta Ohm HD 32.3 device.

For the dry temperature (Taext) and relative humidity (HRext) outside the data of the meteorological stations closest to the buildings were used.

Until you have all the data monitored from the different climatic seasons, you cannot develop the comfort model or the comparison with the other models. However, in order to verify the reliability of the data collected, some correlation analyzes between variables have been performed with a sample of the data obtained.

In a first analysis of the data obtained in the experimental winter campaign in the center of Sagrada Familia we confirm that residents have a different level of Thermal Sensation than caregivers.

We also examined whether the residents' Thermal Sensation depended on the monitored room. In this case the monitored rooms were the library, the gym, the occupational therapy room and the television room. Although the spaces are very

different, some with large windows, others without solar radiation, some with a very high occupancy rate, others very low, etc. We check that the thermal sensation of the occupants does not depend on the room or its characteristics, but it does depend on the operating temperature (Top) and the outside temperature (Taext). The Top takes into account the Ambient temperature (Ta) and the heat absorbed or emitted by all the elements in the room, such as furniture, walls, windows and even the same people represented through the (Trm).

The dependence of Taext on Thermal Sensation guarantees the validity of adaptive thermal comfort models in heated buildings (winter campaign).

From this first analysis we also obtained a Neutral Temperature (Tn) (when residents express a sensation of thermal neutrality) of 23.2oC. In some cases the occupants prefer sensations of a little cold or a little heat and therefore the Comfort Temperature (Tc) may not coincide with the Tn. Anyway, with the data analyzed at the moment we obtained the following expression that relates the Tc with the average outdoor temperature (Tmext):

Tc = 0.086 TIMQ + 22.103

Given that during the experimental winter campaign the Tmext ranged between 11 and 20oC, it seems that the neutrality temperature of the residents surveyed coincides with the comfort temperature.

Finally, with the analyzed data sample we conclude that there is no relationship between the level of clothing of the residents and their Thermal Sensation. This indicates that residents do not apply adaptive measures to shelter or unwind when they are cold or hot. This does not happen with caregivers, as the results indicate that this group changes their level of clothing based on their Thermal Sensation.

These results suggest large differences between existing models and those that are really necessary for older people.

At the moment they are only a first approximation waiting to analyze all the grouped data.