The paper presents the evaluation of the current HVAC components and indoor climate of a high tech Naval Depot in case of failure events. The methodology of the research was: First, implementation of the heat, air & moisture models of the building and HVAC components in SimuLink. Second, validation of the models using measured data from the present building control system. Third, simulation of the current and new HVAC systems designs. Fourth, discussion of the usability of the approach.
We are developing a model that is able to predict the most adapted venetian blinds position (slat angle) for a VDU office worker, considering visual comfort matters. This algorithm, which takes into account room parameters as well as visual comfort criterions, is being validated by an in-situ measurement campaign. During 8 months, two field studies are lead to understand the way that office-workers actually use their blinds.
The main goal of this work is the modeling of the flow field and temperature distribution in thekitchen of a house where natural ventilation techniques were implemented. The Fluent 6.1 commercial CFD software was used. The k- e turbulence model and the Boussinesq approximation for buoyancy were employed. The heat released from a water heater in continuous operation dictates the temperature distribution in the kitchen. Several simulations were performed by varying the boundary conditions and seeking agreement with the available experimental data.
The analytical model described in the first part of the paper is partially validated here by comparing the theoretical results to experimental data collected in a series of model test experiments in an open-jet anechoic wind tunnel. The emphasis is on the validation of the trailing-edge noise model. A comparison is made with existing numerical computations in the literature. The transfer function is found to be roughly invariant with respect to flow conditions encountered on an isolated airfoil. Furthermore, a first application of the model to a cooling fan is presented.
This paper, the first of 2 parts, is dedicated to the analytical modeling of the broadband noise radiated by subsonic fans, such as encountered in HVAC or engine cooling applications. A fan noise prediction scheme is proposed on the basis of single-airfoil linearised unsteady aerodynamics theories. Spanwise distributed sources only are investigated, corresponding to three basic mechanisms, namely the noise from impingement of upstream turbulence, the trailing edge noise associated with turbulent boundary layer scattering, and vortex shedding noise.
Design process of buildings currently addresses indoor air quality through ventilation flow rates requirements. In some circumstances, this approach may be not sufficient and an alternative is to determine ventilation rates through contaminant-based design methods. The authors present several examples of such approach, especially using multizone modeling (CONTAMW model) in a two-story classroom/office building equipped with a CO2 demand-controlled ventilation.
Cooling ceiling systems are controlling only the sensible heat balance of the rooms; they are always combined with a ventilation system foreseen to control indoor humidity and to cover air renewal requirements. Between the types of cooling ceiling in use, the passive chilled beams seem to be the most sensitive to ventilation air influence. Jn most of the cases, the ventilation outlets are located in the ceiling void, and consequently this generates a penalty on the beam cooling power. The work presented aims at estimating this influence, through results issued from experimental studies.
Gas cooking in the home can release high levels of nitrogen dioxide (N02) and carbon monoxide (CO). This study investigated the effect of various ventilation strategies to reduce personal exposure to these pollutants. It considered the effectiveness of windows, a kitchen extract fan and trickle ventilators for different dwellings, occupant behaviour, environmental conditions etc. Strategy selection was based on the need to minimise both personal exposure and energy loss. These strategies were simulated using BRE's BREEZE multi-zonal computer code.
Zonal models have been proposed to bridge the gap between the whole-building macroscopic modeling methods of programs like CONTAM or COMIS and the more detailed microscopic modeling metho.ds based on solutions of the time-smoothed Navier-Stokes equations for room airflows. This paper identifies a critical shortcoming of conventional approaches to zonal modeling by introducing alternative approaches a) to formulate the key cell-to-cell flow relations upon which zonal models are based and b) to assemble the zonal system equations.