Thermal Comfort Analysis in Residential Structures for the Elderly in Atlantic Climate

The average life expectancy of the world population has been increasing, increasing the age group above 65 years. In this sense, support services for the elderly population experience a greater demand in response to growing needs, as is the case of long-term care services, such as day centers (CDs) and structures. residential services for the elderly (ERPI). In this context of services for the elderly, the parameters of quality and comfort are presented as crucial factors for the well-being of the users / residents, and thermal comfort (TC) is a key factor in the monitoring of the quality and well-being of this population.

In order to achieve and maintain the optimum CT values ​​in buildings with this type of service, high energy costs are spent to rectify the structural conditions of the buildings. To structure a viable mathematical model that allows defining the optimized structural characteristics in the construction and rehabilitation phase of buildings for CD or ERPI, it is necessary to analyze the TC of the users and predict which thermal conditions are acceptable or preferred for this population. This study, still in progress and part of the ConTerMa Program, analyzes the TC variables (air temperature, average radiant temperature, air velocity and air humidity) in the Atlantic continental climate zone, monitoring 8 ERPI and CD located in 5 municipalities of the Metropolitan Area of ​​Porto.

The objective of this project is to analyze the TC of older people in ERPI and CD located in the Atlantic climate zone and predict what thermal conditions are acceptable or preferable for this group of people, considering their physical activity, clothing and thermal sensation. With these data the influential factors in the TC of the elderly will be analyzed and analytical models will be developed to determine the characteristics of the CT for this population group within the different climatic zones. The development of CT adaptive analytical models will model the structural specifications of the buildings needed to optimize the CT, both for the construction of new buildings and for the adaptation of pre-existing structures.

CT can be described as the environmental characteristics that affect the heat exchange between the human body and the environment. CT depends both on physical parameters and physiological aspects, affected by lifestyle, activity, age, health status, gender and adaptation to the individual's climate and local environment and space [1 ]

Both international standards ISO 7730: 2005 [2], ASHRAE 55: 2013 [3] and EN 15251: 2007 are intended to specify the recommended environmental conditions for an elderly population. Field studies show that existing regulations may not be applicable to people over 65 years of age because their thermal responses are different from those of the active population. This segment of the population has very specific characteristics, such as low levels of metabolism, not being able to easily change their level of activity or clothing, as well as the lack of vasoconstriction that can decrease the thermal sensation or a greater tolerance to heat that can cause Dehydration during the summer. When the evaluation of the TC is discussed, there are two main models that can be used: the predicted mean vote (PMV) model [4] and the adaptive model. The model most commonly used to evaluate general or body CT is the Fanger model (1973) of predicted mean vote (PMV) [4]. According to this model, for a given situation to be considered thermally comfortable, it must be satisfied as a basic condition that allows the physiological mechanisms responsible for thermoregulation to reach thermal equilibrium, that is, that the body is able to balance the heat gained ( of metabolic origin or of the environment) and the heat eliminated by different procedures.

The Fanger PMV model is widely used and accepted in the field of CT evaluation. However, it is a stationary model (static model), therefore, it does not take into account the temperature variations throughout the day, it is the result of investigations in thermal cameras, it is only applicable to humans exposed to a long period of time in constant conditions and with a constant metabolic rate and a thermal insulation of stable clothing and does not consider the adaptation of the occupants to achieve comfort conditions [4].

As for the questionnaires on thermal sensation, users and residents of the buildings under study, several questions were proposed, assigning a scoring system. For the attribution of values ​​and the use of scales, known scales were selected, as shown in Table 1.

The application of environmental comfort models for older people offers the possibility of improving the quality of life and, at the same time, offers great potential for energy savings. Therefore, based on the analytical model obtained, the historical environmental data of the participating institutions will be compared to, on the one hand, form and create good practices that improve the quality of life of the users / residents and, on the other, point to energy efficiency This energy saving translates into approximately 30% of the cooling load, compared to that of a fixed temperature set point, as indicated by conventional comfort theory.

The adaptive method is the result of real-time monitoring in the participating institutions in which the real acceptability of the thermal environments is analyzed, which depends to a large extent on the context, the behavior of the occupants and their expectations.

Unlike the static CT model, in the adaptive model people play an instrumental role in the creation of their own thermal preferences by the way they interact with the environment, modify their own behavior or gradually adapt their expectations depending on the thermal environment in which they are found [5].

At the end of this project an analytical model of interpretation of environmental parameters and structuring of adaptation measures of buildings for the purpose studied will be created. Of the studies carried out in the CT area, the need for specific models of comfort for the elderly stands out. In general, comfort standards do not currently apply to the elderly population, only determining higher restricted limits of the Percentage of expected dissatisfaction (PPD), instead of determining the environmental and physical conditions that affect the TC.

With the calculation of the indexes related to thermal comfort, comparative analyzes will be carried out, comparing the values ​​obtained in the Atlantic climate and the Mediterranean climate, which will allow a more consistent study and with a broader view of the subject given the climatic differences found in the two climates studied. The data collected and the results obtained will also be communicated to the participating institutions, serving as a study base for the improvement of environmental conditions and quality, in residential institutions and for the support of the elderly.

Keywords: Thermal Comfort, Atlantic Climate, Analytical Model, Estimated Average Vote, Population Aging.

Financing

Project financed within the framework of the Announcement of the Selection of Multidisciplinary Research Works on Ageing 'European Regional Development Fund in the framework of the Interreg V-A Spain - Portugal Cooperation Programme, (POCTEP) 2014-2020, File: 6/2018_CIE_6', within the Coordinated Programme 'ConTerMa- Análisisis del confort térmico en residencias de ancianos en el espacio de cooperación transfronterizo de España-Portugal'.

Bibliographic references

1. Vandentorren, S., et al., August 2003 heat wave in France: risk factors for death of elderly people living at home. Eur J Public Health, 2006. 16(6): p. 583-91.

2. Standardization, I.O.f., ISO 7730 2005-11-15 Ergonomics of the Thermal Environment: Analytical Determination and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria. 2005: ISO.

3. Ashrae, Standard 55-2013 User's Manual: ANSI/ASHRAE Standard 55-2013, Thermal Environmental Conditions for Human Occupancy. 2016: ASHRAE Research.

4. Fanger, P.O., Assessment of man's thermal comfort in practice. British journal of industrial medicine, 1973. 30(4): p. 313-324.

5. Brager, G.S. and R.J. de Dear, Thermal adaptation in the built environment: a literature review. Energy and Buildings, 1998. 27(1): p. 83-96.