night cooling

The present study aims at assessing the geo-climatic potential applicability of controlled natural ventilation (CNV) as a natural ventilative cooling (NVC) technique in the Mediterranean area. This assessment was carried following two approaches: (1) a climate-dependent evaluation of the NVC potential of different locations considering a “virtual space”; (2) a calculation of the NVC potential of different locations considering a “real” building through dynamic energy simulations.

The present study describes the potential improvement of summer comfort and reduction of energy consumption that can be achieved by adopting passive cooling solutions, such as daytime comfort ventilation with increased air velocities and night cooling, in domestic buildings. By means of the IDA ICE based software EIC Visualizer, the performances of ten ventilation and cooling strategies have been tested in four different climatic zones across Europe (Athens, Rome, Berlin and Copenhagen).

In many locations mechanical ventilation has been the most widely used principle of ventilation over the last 50 years but the conventional system design must be revised to comply with future energy requirements. This paper examines the options and describes a concept for the design of mechanical ventilation systems with minimal pressure loss and minimal energy use.  This can provide comfort ventilation and avoid overheating through increased ventilation and night cooling.

Application of night cooling to educational buildings looks very promising in mild climates. Night coolingstrategy performance in a school building to be realised in Italy during 2008 has been studied by meansof a commercial CFD code.Due to the symmetry of the building, first a 2D numerical model consisting of a vertical section throughthe three-storey building has been developed. The CFD model includes the solid zone describing theconcrete structure.

Describes a new multicriteria analysis of ventilation during summertime in Europe. These theories are used to determine the best ventilation strategy on a university building, aiming to ensure optimum indoor air quality, occupant thermal comfort, and lower energy consumption when using accelerated diurnal or nocturnal ventilation and/or air conditioning. The article defines the possible actions, then the quality criteria for thermal comfort, indoor air quality and energy consumption.

Night-time cooling of buildings is a recognized way of reducing the use of air conditioning, and hence energy consumption. The paper describes the construction and testing of a latent heat storage system, which uses a novel combination of night cooling, heat pipes and phase change materials (PCMs) and has the distinct advantage that it is suitable for fitting to existing buildings. The design of the heal pipe/PCM heat storage unit is briefly discussed.

A number of new techniques have been developed in recent years, by various researchers, to assist in the sizing and positioning of natural ventilation openings. These may be of considerable assistance in the natural ventilation design process, while still allowing architectural freedom. This paper reviews some of the available techniques. The complexity of the configurations accounted for by the procedures ranges from two openings with the indoor air at a uniform temperature to a technique that allows for multiple openings throughout a multi-zone structure.

Adequate ventilation and good air quality are essential for the comfort of occupants and productivity. Excessive ventilation however, may result in discomfort and high energy loss. A study was carried out to examine the influence of ventilation on indoor thermal conditions. The results show that ventilation has profound effect on lowering the indoor temperature, particularly the night time ventilation. Derived PMV is compared with actual votes (thermal sensation) and found that PMV is lower than actual votes.

In the recent past new concepts for the building envelope have been developed with theunderlying wish to improve the energy performance of a building as well as comfortconditions in the inner spaces. Examples are: solar walls, high-tech window systems, doublefacades and integration of daylighting systems and of PV-panels. In this paper the doublefacade concept is discussed.This kind of facade is considered as a device to be used for pre-heating the ventilation airduring winter as well as for nocturnal cooling of the building during summer.