passive cooling

For zero and low energy buildings, high-energy efficiency ventilation is very often confused with a complex mechanical ventilation system with heat recovery. In school gymnasiums, where large volumes have to be ventilated, and where intermittent occupation is very usual, demand controlled natural ventilation has several advantages, making this technique very attractive. High stack height makes natural ventilation very efficient, limiting the necessary number and dimensions of windows.

Aim of this work has been to determine the effectiveness of evaporative cooling and ventilation control strategies on a case study to ensure an adequate combination between energy efficiency and high levels of indoor comfort.
The case study has been a kindergarten, situated in the context of the climate continental Mediterranean area (Cerignola, Italy, 41°16'00"N, 15°54'00"E, 120 m asl), oriented on an east/west axis, classrooms south faced, and the services zone to north.

Natural ventilation is increasingly considered one of the most efficient passive solutions to improve thermal comfort in buildings. However in order to support its planning and implementation, quantitative analysis on airflow paths and heat-airflow building interactions are needed. This requires an adequate accounting of both internal effects, from building layout and structure, and external forcings from atmospheric factors.
This paper has dealt to analyze the potential of building automation systems for ventilative cooling of residential buildings.

This article compares the thermal performance and comfort levels produced by dry and wet roofponds monitored during the summer of 2011 in Las Vegas, NV.  The measured data shows that under typical summer conditions, a dry roofpond with a depth of 15.24 cm. installed over typical U.S. residential construction is able to keep the maximum indoor operative temperature approximately 5.1 C° below the maximum outdoor air temperature, with the minimum indoor operative temperature remaining approximately 1.8 C° above the minimum outdoor air temperature.

Objective of this study is to evaluate the cooling potential of buried pipes and a derivative thereof, for buildings situated in Brazilian climate. In a first step, the cooling potential of these techniques is characterized independently of any building dynamic, in terms of the available temperature differential relatively to a specified comfort set point, with simulation performed by way of a specific model.

Cool roof is a well-documented passive cooling strategy for buildings in several climate conditions. The mechanism consists of the reduction of the heat load entering the roof, which is characterized by high solar reflectance and high thermal emittance. The purpose of this paper is to study the coupled effect produced by such a technology. First, the passive cooling contribution is quantified, then, the “active” contribution is investigated.

Few studies focus on commercial low-rise buildings which are often characterized by low-cost constructions materials and weak energy performances. For these large volumes, the heat transfers with the roof and the ground are prevalent. In this article, we show how the analysis of heat transfers through both the roof and the ground can achieve their thermal performance. The roof design and its opening systems is a key factor of the thermal and lighting performance.

A lightweight aluminium nocturnal radiator, painted with an appropriate paint, was established on the roof of the Department of Environmental & Natural Resources Management in Agrinio, in Western Greece. The dynamic thermal performance of the system during summer months was calculated using an accurate mathematical model, based on the heat transferred from the air circulating inside the radiator to the ambient air. Furthermore, an extensive validation process was carried out.

Passive cooling in the built environment is now reaching is phase of maturity.  Passive cooling is achieved by the use of techniques for solar and heat control, heat amortization and heat dissipation. Modulation of heat gain deals with the thermal storage capacity of the building structure, while heat dissipation techniques deal with the potential for disposal of excess heat of the building to an environmental sink of lower temperature, like the ground, water, and ambient air or sky.

Natural ventilation is increasingly considered a promising solution to improve thermal comfort in buildings, including schools. However in order to support its planning and implementation, quantitative analysis on airflow paths and heat-airflow building interactions are needed. This requires an adequate accounting of both internal effects, from building layout and structure, and external forcings from atmospheric factors.