English

We present a study of natural ventilation design during the early (conceptual) stage of a building's design, based on a field study in a naturally ventilated office in California where we collected data on occupants' window use, local weather conditions, indoor environmental conditions, and air change rates based on tracer-gas decay. We performed uncertainty and sensitivity analyses to determine which design parameters have most impact on the uncertainty associated with ventilation performance predictions.

Because of the customers’ need of best possible comfort condition and satisfaction, shopping centers are conditioned by means of basic HVAC systems, often without considering the potential of natural ventilation to reduce energy consumption related to cooling and ventilation. Within the European project CommONEnergy, EURAC researchers are dealing with ventilative cooling strategies as retrofit solutions for shopping centers.

Natural ventilation is widely applied to new building design as it is an effective passive measure to reach the Net Zero Energy target. However, the lack of modelling guidelines and integrated design procedures that include technology solutions using passive design strategies to exploit climate potential, frustrate building designers who prefer to rely on mechanical systems.

The aim of our study was to determine the effect of a cooling jet on performance and comfort in warm office environment. We compared cognitive performance, subjective workload, cognitive fatigue, thermal comfort, symptoms, perceived working conditions and perception of airflow in warm temperature (29.5 °C) in two conditions: with and without the jet. Twenty-nine students participated in the experiment in which a repeated measures design was employed. The jet improved the speed of response in a working memory task with increasing exposure time but did not affect other performance measures.

The experiments are carried out in a climate chamber located at the Department of Civil Engineering Aalborg University. The objective of the experiments is to evaluate the performance of the system combining diffuse ceiling ventilation and thermally activated building construction (TABS) in terms of thermal comfort and energy performance. 20 cases with different boundary conditions are conducted varying on climate condition heat load. TABS water temperature and flow rate with or without diffuse ceiling.

This work presents an energy assessment of the natural ventilation performance within buildings located on both hot-temperate and mild-temperate conditions such as the existing along the central region of Mexico. With the assistance of a coupled thermalairflow simulation program, simulations are run without and with natural ventilation, respectively. Thereby, the consumption of air-conditioning presented in this region is validated with data from literature when natural ventilation is not applied.

This paper presents and analyses the performance of an integrated system with diffuse ceiling ventilation and a thermally activated building construction. A full-scale experiment is carried out in a hot box with an office setup. The performance of the integrated system is evaluated under different boundary conditions, considering different weather conditions, internal heat loads, TABS activation modes and with/without diffuse ceiling. The measurement results indicate that the diffuse ceiling plays a beneficial role improving thermal comfort in the occupied zone.

As a response to new energy policies in the building sector, office buildings have become well-insulated and highly-airtight, resulting in an increasing cooling need both in summer and in winter. In order to effectively save energy, new interests in cooling concepts using passive cooling technologies and renewable energy sources have risen. Based on a literature review of natural ventilation, building thermal mass activation and diffuse ceiling ventilation, this paper proposes a new system solution combining these three technologies for cooling and ventilation in office buildings.

This paper investigates the dynamic cooling performance of a novel system combining natural ventilation with diffuse ceiling inlet and thermally activated building systems (TABS). This system is tested in the lab under three climatic conditions representing typical seasons in Denmark, including a typical winter day, a typical day in the transitional season and a typical summer day. The corresponding dynamic control strategies have been designed for these three cases in the measurements.

A novel HVAC system combining natural ventilation with diffuse ceiling inlet and thermally activated building systems (TABS) has the ability to fulfill the requirements of cooling and ventilation in future Danish office buildings. In order to study the cooling performance of this system, a test chamber is constructed in a way to represent the characteristics of an office room. Twenty cases are tested under steady-state conditions, including ten cases without ceiling panel and ten cases with ceiling panel.