Adaptive thermal comfort

Many post-occupancy comfort studies of energy renovated residential buildings have documented elevated temperatures above comfort levels, not only during the summer period but also during the shoulder months. The main focus in renovation projects is on heat savings while the risk of overheating is not considered.

It is estimated that HVAC systems represent the highest energy consumption (approximately half of the total energy consumed) and one of the highest cost, especially in non-residential buildings. Therefore, that energy consumption in related to the cost of the building, the energy consumption and the thermal comfort.
Although the comfort of the users should be a factor to be aware of, it may not be the only one. It is advisable to have a balance between this variable and energy consumption, because of its impact on the environment and climate change.

Zero Energy Buildings require airtightness and mechanical ventilation systems to provide air changes and energy saving. These requirements contrast with the principles of natural ventilation. Through a case study located in Modena, Italy, a design strategy is proposed as a solution to integrate natural and mechanical ventilation systems at different times of the year to reduce the energy consumption in a newly designed high-density ZEB. The internal comfort evaluation for the warm season is then verified with a multizone dynamic simulation and a CFD analysis.

Rehva Guide No 6 – Indoor Climate and Productivity in Offices - states as its main purpose to establish quantitative relationships of indoor environmental aspects with performance and sickness absenteeism. The following relationships were established: temperature with performance, ventilation with performance, perceived indoor air quality with performance and ventilation with sickness absenteeism.

In this paper, a global map of maximum indoor operational temperatures of buildings is presented. Maximum indoor operational temperatures were evaluated around the world using both PMV and ATC.

Although the adaptive comfort model has gained unprecedented popularization during the past few decades, the mechanism behind the model, especially with regard to certain key hypotheses, still requires further clarification. To validate whether people with greater individual control tend to attain comfort state in wider ranges of indoor thermal environments, we designed an investigational study in Beijing apartments with different degrees of individual control over space heating systems.

In achieving low-energy operation, occupant-controlled mixed mode buildings rely as much on the judicious use of active climate control by occupants as they do on the efficiency of the building services. The extent to which occupants choose to use natural ventilation for creating a thermally comfortable environment is informed in part by the human heat balance, and by the availability and effectiveness of adaptive comfort devices, but is also a function of social, cultural, and local context. Qualitative study is suited to exploring these factors in more detail.

This paper presents a method for predicting occupants’ indoor thermal sensation in naturally-ventilated environments, based on real thermal sensation samples, using a GA-BP neural network model. This method improves the traditional back propagation neural network by incorporating an integrated genetic algorithm into the BP neutral network which aims to optimise the connection weight or threshold of the parameters in the input layer of the GA-BP neutral network model, which represent the factors affecting adaptive thermal comfort.

In this paper, a review is made of the adaptive thermal comfort model. This is then applied and compared with the performance of the conventional thermal comfort model for a school located in a Mediterranean weather environment. Measurement data, combined with a building thermal response numerical model, are used to define the comfort performance under ambient natural ventilation and passive conditions for various classrooms. These results can then be used to identify the locations that require further measures to improve comfort, such as extra passive heat load and shading measures.

Analytic models and static approaches as the case of Fanger, Deval, Sherman, Gagge, and Stolwijkmodels cannot completely predict indoor thermal comfort. Building designers could take advantage of adaptive approach of thermal comfort which can account for the complex interaction betweenoccupants and their environment that could affect their comfort.We had carried a field study in two office buildings on March 2005. It has included physicalmeasurements and questionnaires on thermal perception and appreciation.