English

The wind shadow model has been developed to calculate the wind sheltering effects of upwind obstacles for air infiltration calculations. This effect must be determined for infiltration calculations because, in almost all situations, only the unobstructed mean wind speed is known for a building site. This model has adapted the theoretical calculation procedures developed for far wake centreline velocity deficit calculations to near field flows, where shelter has a significant effect.

Forced air distribution systems can have a significant impact on the energy consumed in residences. It is common practice in U.S. residential buildings to place such duct systems outside the conditioned space. This results in the loss of energy by leakage and conduction to the surroundings. In order to estimate the magnitudes of these losses, 24 houses in the Sacramento, California, area were tested before and after duct retrofitting. The systems in these houses included conventional air conditioning, gas furnaces, electric furnaces and heat pumps.

The European Energy Performance in Building Directive (EPBD) requires methods for the calculation of the energy performance for use in the context of building regulations.The European Commission has supplied a Mandate (M343,2004) to CEN to develop a series of standards, each covering a part of the calculation of the energy performance of buildings and procedures for the inspection of heating and airco systems.The paper introduces briefly the methods for the calculation of the energy needs for heating and cooling of buildings and the relation with the higher level standards.

An energy performance regulation has to consider not only energy, but -either explicitly or implicitly- also the relevant comfort aspects: indoor air quality (IAQ), lighting level, humidity level, temperatures (summer, winter) and hot tap water availability.
After all, the easiest way to minimize energy consumption is to switch off heating, ventilation, lighting, hot tap water, ...
What is the relation with the EPBD requirements on energy performance? Is there a potential conflict? Is there a need for additional minimum comfort requirements?

There is increasing evidence that indoor environmental conditions substantially influence health and performance. Macro-economic estimates show that the potential benefits from indoor environmental improvements for the society are high. Some calculations show that the estimated cost of poor indoor environment is higher than energy costs of heating and ventilation of the same buildings.

This paper gives an overview of a few quality assessment methods used for ventilation systems. They cover two categories of approaches: regulatory compliance checks, that are external to the building project actors; voluntary contract-based quality assessment procedures, e.g., embedded in a certification scheme. The examples are briefly described and analysed. Quantitative results are given where possible.

The ventilation of an attic is critical in estimating heating and cooling loads for buildings because the air temperature in the attic is highly sensitive to ventilation rate. In addition, attic ventilation is an important parameter for determining moisture accumulation in attic spaces that can lead to structural damage and reduced insulation effectiveness. Historically, attic venting has been a common method for controlling attic temperature and moisture, but there have been no calculation techniques available to determine attic ventilation rates.

Field tests were carried out in two flat ceiling, residential attics at a dedicated test site over a two year period. The scope of this paper is to present measurements of ventilation rates, indoor-attic exchange rates, temperatures and wood moisture contents at various locations in the attics. Attic ventilation rates are correlated with wind speed, wind direction, and attic-outdoor temperature difference. Wind speed is shown to be the dominant driving force for ventilation; however, wind direction is important particularly when the attic is sheltered.

The paper is devoted to the trial implementation of two different types of hybrid ventilation systems in dwelling buildings done in the scope of the EU LIFE Programme supported project ECOVENT.Recent changes in Latvian Building Codes require higher thermal resistance of buildingstructures, air tight windows and mandatory ventilation systems. Use of mechanical ventilationsystems may reduce the positive effect of improvements of thermal performance of buildingstructures by 30-40% of the achieved economy.

The objective of the project was to design an HVAC system for a lithium battery manufacturing facility in Minnesota, USA. The system was to be designed for a 7544 sq. ft. space with a 9 ft high ceiling, to be maintained at 25 F dew point temperature (1.3% relative humidity @ 70 F dry bulb temperature). The facility had to be designed and constructed inside an existing warehouse style, 14 ft high roof building, absolutely vapor tight, such that no moisture can migrate to the indoors from any interior walls, floor or roof.