English

Cross-ventilation flows (CV) are characterized by significant inflow momentum conservation as fluid flows across an enclosed rectangular volume as a confined jet. When the inflow area is smaller than the volume cross-sectional area the CV flow has distinct jet and recirculation flow regions. The simplified model presented in this paper characterizes the CV flow as the result of a confined axisymmetric jet driving one or two recirculation regions, each of which is a lid-driven cavity flow.

Throughout history, natural ventilation has remained the preferred choice for the majority of residential buildings, while, in commercial buildings, natural ventilation went from being the single option to somewhat of a lost art as mechanical ventilation systems and air conditioning became the standard during the second half of the twentieth century. Recently, as a result of environmental concerns, in particular the greenhouse gas emissions from buildings, interest in natural ventilation in commercial buildings has seen a resurgence.

Overheating in buildings is expected to increase as global warming continues. This could lead to heatrelated problems ranging from thermal-discomfort and productivity-reduction to illness as well as death. From the indoor-overheating point of view, the sensitivity of 9,216 Dutch dwelling-case to the climate change is quantified and ranked using detailed simulation and post-processing calculations. The results show that the sensitivity depends significantly on the dwelling’s design/operation characteristics. Minimally-ventilated dwellings are the most sensitive ones.

Overheating in buildings has been identified as an essential cause of several problems ranging from thermal discomfort and productivity reduction to illness and death. Overheating in buildings is expected to increase as global warming continues. The risk of overheating in existing and new buildings can be reduced if policy makers take decisions about adaptation interventions quickly. This paper introduces a methodology for supporting such decisions on a national level.

Research indicates that low-energy dwellings are more sensitive to overheating than regular dwellings. In this research the ventilative cooling potential of low-energy dwellings is considered. A low-energy dwelling based on the Active House concept, “House of Tomorrow Today” (HoTT), has been investigated as representative for low-energy dwellings in general. A computational model of the house was created with the software TRNSYS (in combination with CONTAM) and this model has been calibrated with actual (intervention) measurements in the HoTT.

The increasing number of highly insulated and air tight buildings leads to the concern of indoor environment overheating and related comfort and health issues. This can already happen in a temperate climate as found in the Netherlands. This work studies the ventilative cooling process as a possibility to avoid overheated dwellings. A monitored dutch passive house was modelled in Trnsys and the impact of increasing air flow rates on indoor temperatures was simulated. The most overheated zone was chosen to be analysed.

Reducing primary energy consumption is an essential issue for the sector of building construction. This paper refers to building ventilation systems and focuses on low pressure flat plate heat exchangers, designed for low pressure drops and low air velocity, minimizing the electrical consumption of fans. The device is conceived for working within passive ventilation systems, as a ventilation heat recovery stage during winter and sensible heat dissipation during summer.

This paper presents the general concept of the NAC (Natural Air Conditioning)-wall system and some experimental results on a first prototype. The originality of the system is to perform a solar DEC (Desiccant, Evaporative Cooling) open cycle by exploiting natural buoyancy driven ventilation, thus avoiding the use of fans.

The supply air is dehumidified by a zeolite based adsorption bed and is cooled indirectly by an evaporative cooler, through a low pressure heat exchanger.

The study proposes and compares low-cost strategies to improve the quality of existing building stocks, with special regard to a widespread Indian residential typology. A dynamic energy model of this particular local building typology was simulated with Energy Plus software and validated by comparing it with some original in situ measures, recorded by hourly step. The validated model was used to simulate a selection of low-cost and technically simple interventions, whose effects on the energy performance and indoor comfort were compared to the baseline case study.

The present study reports the results of a 12-month-long monitoring campaign of an earth-to-air horizontal heat exchanger (EAHX) system in a school complex in Imola, Italy. With more than 2 km of buried pipes, it represents one of the biggest Italian applications of this technology. Considerable differences between inlet and outlet air temperature have been noticed both in winter and in summer. Air temperature and relative humidity have been represented over a psychrometric chart while the energy performance of the system was analysed based on data of sensible heat exchange.