A nodal model for displacement ventilation and chilled ceiling systems in office spaces.

Describes how a nodal model was developed intended to represent room heat transfer in displacement ventilation and chilled ceiling systems. Precalculated air flow rates were used to predict the air temperature distribution and the division of the cooling load between the ventilation air and the chilled ceiling. A network of ten air nodes is used to separately represent the air movements in the plumes and the rest of the room. Calculation of the capacity rate parameters is done by solving the heat and mass balance equations for each node using measured temperatures.

FTIR spectroscopy measurements and CFD simulations of the pollutants arising from unflued combustion in a room.

Simulates a kitchen for a study of indoor air quality. An extractive FTIR technique was used to measure combustion products from unflued combustion from a gas cooker in a ventilated room. On a comparison of the results with those from conventional instruments, the FTIR technique showed good agreement. The study incorporated the obscuring of the spectrum due to the effects of H2O and carbon dioxide and detection limits. The conditions in the room were investigated using CFD.

Behaviour of inclined jet on room cooling.

States that when used with ice storage systems, cold air distribution systems are popular since they require less operating and capital costs. Stresses the importance of a consideration of occupant comfort. The study looked at air circulation and temperature distribution in a room, considering different orientation, velocities and sizes of jet for a given vertical location of air inlet and outlet on opposing walls. A control volume method was used to solve the Navier-Stokes equations and an energy equation in two dimensional rectangular Cartesian coordinates.

A design procedure for displacement ventilation. Part 2 of a two-part how-to series on passive thermal displacement ventilation.

This article concentrates on displacement ventilation design procedures appropriate for rooms with heat- and contaminant-removal requirements. With passive thermal displacement ventilation, supply air is discharged directly into the occupied zone at a low velocity near the floor level and at a slightly cooler temperature than the design room temperature. The air from the diffusers spreads along the floor, creating a relatively cool layer of fresh air near the floor.

Shattering the energy barrier.

Describes how methods used in widespread energy efficient residential buildings in Germany are now being applied to larger buildings. Germany's Passiv Haus Institut has become a leading centre in developing a specification for the next generation of energy efficient buildings - the Passive House Standard. In 400 residential building the standard has reduced total energy consumption to 12% of the UK norm. Describes how this approach has been applied to a 2,200 m2 office and factory in Colbe, Marburg. The three-storey structure was completed in autumn 1998.

Birchensale school 2.

Reports on the detailed design of Birchensale Middle School, and how the design team has incorporated PROBE lessons into the specification. The school is over 30 years old, naturally ventilated and lightweight in construction. The PROBE team's role has been to help fine-tune the design based on the findings from PROBE post-occupancy studies. Perimeter classrooms are naturally ventilated with cross-ventilation via openable fanlights above the classroom doors.

Car park ventilation systems.

States that car park ventilation systems not only have to control the exhaust gases emitted by vehicles but take into account possible fuel spillages and the venting of smoke in the event of a fire. Explores ways of checking for compliance.

Effect of 2D modelling of thermal bridges on the energy performance of buildings. Numerical application on the Matisse apartment.

Discusses the accurate evaluation of the effect of thermal bridges on building energy performance using a modelling approach. Sisley software was used first of all to model the heat transfers in the intersections of walls. CLIM 2000 was used to reduce and integrate the models. A comparison was done between these results and the models obtained from thermal regulation values. It appeared that detailed modelling of heat transfers would provide an increased accuracy of around 5% when evaluating the building heat loss.

The influence of street canyons on the cooling loads of buildings and the performance of air conditioning systems.

Gives an overview of a computational approach to the so-called street canyon phenomenon, whereby microclimate influence on thermal loads of buildings and local contribution to temperature rise from air conditioning unit heat emission can affect the heating balance of buildings. Also discusses the influence of flow and temperature fields on the dynamic thermal balance of the building.

A two-layer turbulence model for simulating indoor airflow. Part II. Applications.

Describes the use of a two-layer model to predict mixed convection. It uses a one-equation model for near-wall region and the standard k-e model for the outer-wall region. In six cases its validation shows good agreement between computed and measured data. The model also reduces computing costs.

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