The paper describes the numerical simulation of a novel ventilation cooling system. The ultimate aimof the mathematical model is to facilitate the design of the system for specific buildings and climates.The model directly takes account of time dependency in that the diffusion equation for the heat flow inthe fabric of the room is solved. This approach means that important parameters (e.g. ventilationrates and internal heat gains) can be arbitrarily specified as functions of time.
The buildings sector offers the greatest potential for cost-effective reductions in greenhouse gasemissions out of all the sectors examined by the Intergovernmental Panel on Climate Change.However that potential was based purely on technical measures applied to existing buildings and newconstruction. It is becoming increasingly clear that non-technical options involving building occupantcomfort, culture and behaviour will also need to be implemented in order to stabilise atmosphericconcentrations of CO2 within a useful timeframe.
When a building is used only for intermittent occupancy, continuous operation of ventilation system isnot necessary for achieving good indoor air quality during the occupation periods. Such buildings havea great energy saving potential which is not harnessed enough yet. Indeed, energy loss can be avoidedby promoting natural means and managing mechanical ones.
The selection of design solar irradiance in the current ASHRAE and CIBSE design handbooks isindependent on design dry-bulb and wet-bulb temperatures. The probability that the load would notexceed the system capacity determined on this basis may not match the reliability level that the designweather data were meant to safeguard. Hence, a statistic method was developed for the rationalselection of coincident solar irradiance, dry-bulb and wet-bulb temperatures.
The aim of the study is to quantify the traffic generated particle number concentration levels (PM2.5; PMwith diameter ? 2.5?m) at various heights of a typical high-rise building in close proximity to a majorexpressway in Singapore. A 22-storey naturally-ventilated high-rise residential building located about15m away from a major expressway was selected for the study.
As highly insulated and airtight houses have built popularly, the problem which indoor air becomes lowhumidity in winter, is paid attention. The problem is caused by rise of heating level and increase ofventilation amount by mechanical ventilating equipments, etc.1)Then, to clarify the actual condition of indoor low humidity in winter, we monitored the actual humidityenvironment in 29 occupied houses in the Tohoku region and Niigata, Japan, from 2001 to 2006. As theresult, it is found that the indoor low humidity in winter is a common problem regardless of the housecondition.
In this present study, annual exceedance probability (AEP) analysis was applied as the method forassessing wind-driven natural ventilation in a street canyon, in which the effects of wind approachingfrom each direction were comprehensively taken into account. In order to evaluate the overallventilation performance in specific domain spaces within the street canyon, local air change rate andaverage kinetic energy were employed to calculate the AEP, instead of using the commonly adoptedvelocity ratio.
Until the end of 90-ties all dwelling buildings in Latvia were equipped with mandatory natural ventilationsystems with stack effect. Nowadays in many cases in dwellings there are only exhaust mechanicalventilation but air tight windows prevent natural air intake. Such systems result in bad IAQ.
High local concentrations of a pollutant can be the result of high local emission rates of the pollutant orinsufficient ventilation. Using tracer gases to map the ventilation in multi-zone buildings combined withmeasurements of the local pollutant concentration provide the means to discriminate between thesecauses.
The present paper is a review on methods and technologies for air cleaning from micro organisms andviruses, which are applicable with the present HVAC practices. The advantages and the drawbacks ofair dilution, filtration (HEPA, ULPA), ultraviolet germicidal irradiation (UVGI), photocatalytic oxidation(PCO), plasmacluster ions and other technologies for air disinfection and purification is criticallyanalyzed with respect to the used today air distribution principles.
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