The purpose of this system is to provide one improved ventilation system allowing significant good indoor air quality, heating (and cooling) energy savings and acceptable thermal comfort on summer, by using especially renewable energy.This concept is based on sensors measuring relative humidity in bathroom and kitchen, occupancy in bedrooms and toilet, and agitation (i.e.
Within the EU RESHYVENT project four demand controlled ventilation systems have been developed, each one for a specific application field. The scientific support work for the industries has been reported in a number of documents. A number of these reports will be published as AIVC Technotes after completion of the project.
The article describes the influence of the supply air devices that are part of hybrid ventilation system which is being developed within a EU funded project RESHYVENT as a part of this project, on thermal comfort in living-room of a three-bedroom apartment. The supply air radiator and the supply air convector are compared. The fresh air is sucked through a supply air convector and supply air radiator respectively and the air leakage through the facade is assumed too. 2 variants, which cover different outdoor temperature and supply air temperature for each device, have been solved.
This paper summarizes the work within the EU RESHYVENT project in regard to design parameters for the performance assessment of hybrid ventilation systems. A framework for performance assessment based on simulation was developed. Performance criteria were defined for air flows, indoor air quality, thermal comfort, acoustics, energy, and emissions.
An idea to build a demonstration house fitted with a hybrid ventilation system arose when Brno University of Technology joined the RESHYVENT project. There has not been much attention paid to the residential ventilation in the Czech Republic. Window airing and passive stack ventilation are still the most common ways of ventilation in residential buildings. In this context a decision was made to build a house equipped with a demand controlled hybrid ventilation system.
In this paper the effectiveness of retrofitting strategies in a sunspace attached to a one-storey building has been investigated. Natural and hybrid ventilation, air-tight glass partitions, awnings and increased thermal mass retrofitting scenarios were implemented, mainly for the Greek climate. Window openings and sensor-controlled fans were used to create a controllable and secure environment. Combined ventilation and thermal simulation were applied, taking into account all the related physical phenomena, such as ventilation, infiltration and solar radiation.
Part of the task in the design of ventilation systems involves selection and specification of system components - components sizes and expected performance characteristics or criteria to achieve specific ventilation objectives for anticipated environmental conditions. Careful selection of these components is required to ensure that they are able to react to changes in environmental conditions.
In Norway and Sweden's schools, hybrid or natural ventilation with ground-coupled fresh air intake ducts (or culverts) is the popular way of conditioning air.The ground-coupled ducts are normally made of concrete and easily accessible for inspection and cleaning; they can be divided into two parts: the air-intake culvert and the air-distribution culvert. Measurements show that the use of ground-coupled ducts along with a suitable airflow regulation is a guarantee that the supply air is colder than room air.
Almost all existing analysis methods for building ventilation airflows, such as the simpleanalytical methods, multi-zone methods and computational fluid dynamics (CFD), give onlyone unique solution for one set of identical input parameters when started with zeroinitialization or zero initial conditions. This can be shown to be incorrect in some situations.Multiple stable solutions are found in some very simple buildings, which indicate that thebuilding airflows are of a nonlinear dynamical system.
This paper is based on the results of Subtask B of the HybVent Project. It presents a critical review of the literature and recent developments in analysis methods for natural and hybrid ventilation in buildings. Ideally, analytical methods aimed at modelling hybrid ventilation systems should incorporate at least three key aspects i.e: the natural ventilation mode, the mechanical ventilation mode and the control strategy. Depending on the input parameters used within the control strategy, thermal comfort and indoor air quality related parameters may also need to be predicted.