In this paper the potential of night ventilation techniques is investigated. Extended real scalemeasurements have been performed, in three buildings, under free floating and airconditioned operation. Two of the buildings have been studied by using a theoretical modeldeveloped in TRNSYS [1] software. Simulation results have been validated by using themeasured data. Specific studies concerning the indoor air temperature and the cooling load ofthe buildings have been carried out in order to identifj the influence of night ventilationtechniques on the buildings thermal performance.
Although several investigations on how to design airtight buildings have been performedand the results furthermore have been published, many designers and contractors are stillunaware of this knowledge. Therefore, the aim of this work is to collect existing knowledgeand put it together to a practical guide. The target groups are architects, designers, contractorsand building services engineers.This paper is a summary of the report "Good Airtightness - guidelines to architects, buildingdesigners and contractors "published in Sweden during the autumn of 1997 [1].
This paper deals with the interzonal air movement in a building, throughhorizontal openings, under natural convective conditions. These airflow phenomena areinvestigated experimentally, through a series of experiments in the stairwell of a full-scalebuilding, using tracer gas technique. The resulting time-dependent concentration evolutionoffers a means of analyzing the flow field. These cases are also simulated by a CFD code, thatuses the finite-volume method and incorporates a low-Reynolds k-E two equation turbulencemodel.
A passive tracer gas technique - the homogenous emission technique was utilised formeasuring the air distribution in a part of an office building with displacement ventilation.Measurements were made during one winter period and one summer period. During thewinter period the ventilation was run continuously, while on/off regulation was used duringthe summer period.
The planning parameters of a cooling system for ventilation, for example the vaporization andcondensing temperatures, heat capacity flow rates, design temperatures and designtemperature differences have a strong influence on the investment and operating costs.The target of this research is to find economically optimized design parameters byminimizing the present value of investment and the operating costs of the cooling system.
A difficulty when designing natural ventilation in office buildings is the lack of simple designtools.In order to be able to predict natural ventilation air flow rates and indoor air temperatures atthe design stage, a computer model has been developed within the EU-JOULE projectNatvent (TM). The program is an integrated model with a thermal and an air flow modelcoupled together.
Due to the lack of proper sensors for odours, the odour concept, involving the unitsolf and decipol, is of very little practical use with respect to automatic control of VAVsystems. However, the decipol level in a room may be predicted from the concentration ofCO2 and the amount of fresh air supplied. By using the CO2 level as a decisive variable ofthe occupant load within the room, the actual air quality (decipol level) can be predicted.Once the decipol level is known, it is compared to a given set point, thus enabling thecontroller to alter the air flow rate accordingly.
The paper deals with energy consumption and heat recovery in office buildings with natural ventilation. Net energy consumption for ventilation is calculated for 7 European countries. The calculations are done with various air flow rates and occupancy. The calculations shows differences between the seven countries, but the net ventilation heat loss is substantial for all. Norway and Sweden will benefit most from heat recovery. Several heat recovery concepts for natural ventilation are presented.
The multiple spaces equation of ASHRAE Standard 62-1989 makes it possible to bring in a smaller fraction of outdoor air than that dictated by the critical space. This paper develops an analytical proof that increasing the primary airflow rate to t e critical space reduces the outdoor airflow rate required to meet ventilation requirements. For systems employing fan-powered boxes, where more than one box is critical, a systematic procedure for incrementally increasing the primary air is currently required.
This paper traces the evolution of the concept for the Memorial Tunnel Fire Ventilation Test Program conducted in West Virginia during the period 1989-1995. It clearly identifies the objectives set forth for the program by the technical evaluation committee (TEC) representing ASHRAE Technical Committee 5.9
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