Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 12:56
This study analyses the climate-dependent passive ventilative cooling (PVC) potential in central and southern Europe. This analysis was carried out in two phases: (1) evaluation of PVC potential as a climate-dependent variable, in different locations representative of European climate zones for both wind-drive airflow (comfort ventilation) and temperature gradient (environmental and structural cooling); (2) verification of the above PVC potential through dynamic energy simulations on a reference-building model located in selected cities.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 12:37
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.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 12:29
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.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 12:03
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.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 12:01
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.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 11:57
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.
Submitted by Maria.Kapsalaki on Wed, 02/12/2020 - 11:38
In the PSO project 345-061, a novel system solution combining natural ventilation with diffuse ceiling inlet and thermally activated building systems (TABS) has been proposed for cooling and ventilation in Danish office buildings. Due to the application of diffuse ceiling inlet, cold outdoor air can be supplied into the room without any risk of draught even in the extreme winter. This means that natural ventilation is available even in winter and it is beneficial to reduce the energy consumption for buildings with cooling demand in cold seasons.
Submitted by Maria.Kapsalaki on Thu, 02/06/2020 - 15:06
Ventilation systems play an important role in providing a good indoor air quality in dwellings. Mechanical exhaust ventilation systems implement natural vents, also called trickle vents, to supply outdoor air to the dwelling. The airflow through these natural supply vents depends on the natural driving forces, i.e. wind and the stack effect, which vary in time.
Submitted by Maria.Kapsalaki on Tue, 02/04/2020 - 13:03
Installing Natural Ventilation (NV) system in office buildings leads to the reduction of energy consumption of heating, ventilation and air conditioning (HVAC), which accounts for approximately 50% of total in an office building in Japan. However, it is difficult to estimate the NV performance before its completion, because the NV system is easily affected by the outdoor environment. Thus, its design method is not yet established.
Submitted by Maria.Kapsalaki on Tue, 02/04/2020 - 13:00
Building energy simulation (BES) and Airflow network (AFN) programs generally incorporate wind pressure coefficients (Cp) estimated from secondary sources, namely data bases or analytical models. As these coefficients are influenced by a wide range of parameters, it is difficult to obtain reliable Cp data. This leads to uncertainties in BES-AFN models results, especially for naturally ventilated building studies, where air change rate which strongly depends on Cp, is a key value for thermal comfort and energy consumption results.