Tradicni & adaptivni model tepelne pohody

Translated title of the contribution: Traditional & adaptive thermal comfort

Research output: ThesisPhd Thesis 4 Research NOT TU/e / Graduation NOT TU/e)

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Abstract

One of the most common purposes of heating, ventilating and air conditioning systems is to provide conditions for human thermal comfort. A widely accepted definition formulates this as: Thermal comfort is that condition of mind which expresses satisfaction with the thermal environment (ISO 7730). From earlier research it is known that thermal comfort is strongly related to the heat balance of the human body. The heat balance equation for the human body is obtained by equating the rate of heat production in the body by metabolism and performance of external work to the heat loss from the body to the environment by the processes of evaporation, respiration, radiation, convection and conduction from the body surface. This balance is influenced by environmental parameters – air temperature, mean radiant temperature, air velocity and relative humidity and by individual parameters – metabolic rate and thermal insulation of clothing. The currently used standards for specifying indoor conditions for thermal comfort (most importantly CSN EN ISO 7730 and ANSI/ASHRAE 55-92) are based on this heat balance equation. These standards recommend thermal comfort requirements for moderate thermal environments. However, from thermal comfort field experiments conducted during recent years it was concluded that contextual factors and the thermal history modify the thermal expectations and preferences of the occupants of a building. This resulted in the introduction of an adaptive model of thermal comfort in which comfortable indoor temperatures are linked to the climate context of the building; i.e. indoor comfort is linked to outdoor temperatures. This thesis starts with summarizing the basic principles of thermal comfort in relation to optimal (comfort) indoor temperatures. The next two chapters introduce the concepts of traditional and adaptive thermal comfort models. Adaptive thermal comfort is discussed in more detail because this theory has not been published or applied until now in the Czech Republic. The experimental part of this thesis describes field experiments which were carried out during the 2000/2001 heating season in an office building in Prague. The main part of the experiments consisted of a survey using a questionnaire. The results are statistically analysed in order to assess the main variables of the adaptive thermal comfort model when applied in the Czech climate. Based on the experimental results, an equation was generated which relates the optimal indoor temperature to the outdoor temperature for the Czech Republic. The analytical part of this thesis quantifies the implications for energy demand of indoor temperature requirements based on a proposed adaptive thermal comfort standard relative to a more traditional thermal comfort approach. The main technique for this part of the research was computer modelling and simulation. The main conclusion of this thesis is that the theory of adaptive thermal comfort (as it has been published until now) is little relevant for countries with a moderate climate such as the Czech Republic. However, the theoretical, experimental and analytical research results reported in this thesis have increased our knowledge and understanding of building design Tradicní & adaptivní model tepelné pohody requirements especially related to indoor thermal comfort during the summer months. Since it is widely expected that in the near future in many buildings energy for cooling (and the associated impact this will have on the environment) will become an important issue, it is felt that the work and results reported in this thesis are very timely.
Translated title of the contributionTraditional & adaptive thermal comfort
Original languageCzech
QualificationDoctor of Philosophy
Awarding Institution
  • Czech Technical University
Supervisors/Advisors
  • Jokl, M., Promotor, External person
  • Hensen, Jan L.M., Promotor
Award date12 Dec 2001
Place of PublicationPrague
Publisher
Publication statusPublished - 2001
Externally publishedYes

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