Experimental study of wind-opposed buoyancy-driven natural ventilation.

This paper presents an experimental study of natural ventilation induced by combined forces of thermal buoyancy and opposing wind in a single-zone building. Experiments demonstrated that for a certain range of buoyancy strength and wind speed, two different stable ventilation modes and thus flow rates exist for a fixed building geometry at given buoyancy and wind strength. In these situations, the final ventilation mode and the ventilation flow rate are dependent on the ventilation history of the building.

Evaporative cooling and sorption assisted dehumidification with liquid salt solutions.

The traditional way to dehumidify the outdoor air in an A/C-system is by cooling the air downbelow the dew point temperature. For this process a refrigeration system is necessary torealise these low temperatures. Nowadays the disadvantages of refrigeration systems fordehumidification are widely known. An alternative method to dehumidify the air is byseparating the process of dehumidification and cooling.The paper will present a testing plant of 1200 m air/h which is installed in the University ofEssen. This A/C-systems works with liquid desiccants.

Environmental comfort models for individual occupants.

Conventional models of building occupants' environmental preferences such as thermal comfort are used to give guidelines for the average environmental conditions that will satisfy large groups of people. The research described in this paper investigates how the preferences of an individual occupant can be modeled to predict their preferred thermal and environmental conditions. A novel, Internet based questionnaire was developed to gather thermal sensation votes.

Energy impact of ventilation in buildings.

The relative importance of ventilation in the energy balance of buildings has been increasing,as a consequence of control of heat exchanges through the envelope and internalgains. It is therefore very important to clearly understand the main factors that affect energyconsumption due to ventilation and potential ways to decrease the energy demand withoutaffecting IAQ.This study was developed within the European project TIP-VENT (JOULE).

Energy efficiency of ventilation systems.

The paper presents a short description of the measurement program and the data collected for the “SynergieHaus”-project initiated by PreussenElektra and partners (now merged to E.ON). Results of airtightness measurements (ACH 50-values) are shown for a to

Effect of control strategies on ventilation system performance.

Dynamic computer simulations were used to compare residential ventilation methods to identifyan approach that would improve indoor air quality with minimum energy penalty while maintainingcomfort.

Determination of the dimensioning value of the airflow when designing ventilation systems.

Before starting to design an HVAC installation for treatment, supply and exhaust of air to and from a building the needs should be listed, transformed to requirements and their consequences analysed. Requirements lead to different amounts of airflow for their fulfilment. These needs for airflow should be calculated. The demand leading to the highest call for airflow will decide the airflow for which the equipment should be dimensioned - the dimensioning airflow.

Design pressure difference for self adjusting air inlets.

At present the design pressure difference for air inlets in The Netherlands is 1 Pascal. This paperinvestigates the question whether or not this value is still appropriate.In recent years the airtightness of dwellings has improved remarkably. Self adjusting air inletshave been introduced on the market. What is the effect of these changing building features onthe pressure difference over the building envelope?

Design of ventilation systems in industrial buildings. A computational approach of displacement ventilation in paper industry.

In this paper, the ventilation of a “crêpe” paper-processing workshop containing dryers, which generate a high thermal load, is considered. Displacement ventilation has been used for many years in industries with high thermal load. The main ventilation de

Derivation of simple ventilation and thermal models for a naturally ventilated auditorium with high internal heat gains.

Measurements of ventilation rates and internal temperatures have been recorded in a naturallyventilated auditorium with high intermittent heat gains for a wide range of weather conditionsat a UK site. Satisfactory internal temperatures and high ventilation rates have been found forwinter, mid-season and summer external conditions.Simple ventilation and thermal models have been derived from experimental data whichallow the prediction of ventilation rates and internal temperatures within the auditoriumdespite the complex natures of the flow regimes and heat transfer mechanisms present.