English

Ventilation is essential for the health and comfort of building occupants. It is particularly required todilute and/or remove pollutants emitted by occupants' metabolism and activities. The concentration of metabolic CO2 is well correlated to metabolic odour intensity. Therefore CO2 concentration can beefficiently chosen as an indoor air quality index when occupants are the main source of pollution inside the buildings.

Energy used for building heating, ventilating and air conditioning contributes to a great share in thetotal energy consumption worldwide. Better understanding and management of energy distribution inthose processes is essential for the improvement of process quality and efficiency of energy use. This paper presents a data-based mechanistic modelling approach to model the dynamic indoortemperature distribution in an imperfectly mixed ventilated airspace based on energy input to thesystem.

For outsiders, a national energy performance (EP) requirement level is quite a black box. Within the EU Asiepi project (www.asiepi.eu) we are developing a methodology to make a comparison of EP requirement levels possible among member states of the EU.An unexpected finding has been that far from all EU countries consider all energy uses in their EP method required by the EPBD (Energy Performance of Buildings Directive). The energy use for fans, domestic hot water and cooling are among the energy uses which are not taken into account by various countries.

Due to the increase in CO2 emissions and the resulting climate change more and more efforts aremade to reduce energy consumption. As a result, the energy demand of buildings is to be reduced by specific measures, for example thermal insulation or intelligent ventilation systems. A demand-based (moisture-controlled) exhaust ventilation system is assessed in comparison to a supply and exhaust ventilation system with heat recovery by means of computational investigations.

The ventilation system in nursery buildings requires particular care to guarantee the safety of children[1,2]. When suitable outdoor conditions occur, natural ventilation can provide an appropriate indoorenvironment in terms of temperature, humidity and concentration of contaminants, if the designprocess is coherently developed taking into account the characteristics of the prevailing winds [3].This study investigates numerically the fluid dynamic behaviour occurring in a naturally ventilatedpreschool building designed for the municipality of Rome.

This study examines the potential for using passive ventilation systems to meet ASHRAE 62.2requirements as a step in the process for optimizing hybrid ventilation systems. A brief review of theliterature with reference to the passive and hybrid ventilation systems in residential building ispresented. The review focuses on key aspects of ventilation system performance, including indoor air quality, air distribution and ventilation rates.

The aim of this study is to analyse the physical characteristics of airborne virus, consider thepossibility of using coupled analysis model and tracer gas for analysing virus diffusion in buildingspace and, based on reports of how the infection spread in a hospital where patients were discovered, analyse infection risk using tracer gas density and also diffusion patterns according to the location, shape, and volume of supply diffusers and exhaust grilles.

Even when providing the same nominal rate of outdoor air (OA), different ventilation systems distribute air in different ways, affecting the occupants differently depending on the dwelling, on source disposition and strength, on occupants behavior, and on the cooling or heating system.

Tests were conducted on two instrumented air-cooled water chillers (15 kW and 30 kW cooling capacity). Refrigerants evaluated included R22 as the baseline fluid, R407C and R410B. When testing with R407C, the retrofit procedure did not involve any major hardware change. The results with the first chiller equipped with a counter-current plate evaporator showed that both capacity and EER are maintained within 5%. The second chiller, which was not equipped with a counter-current evaporator showed poorer results.

An approach to the steady-state simulation of heat pumps and refrigerating equipment is presented. Novel features of the proposed model are the strategy and formalism adopted in the programme development. Individual mathematical models for component design are linked to enable the simulation of a basic vapour compression cycle. This paper introduces some of the component modules, which can be used for pure as well as mixed refrigerants.