IBPSA2007

This study assesses the extent of the cooling effects of waterways on the thermal environment of urban districts of Osaka by measurement and simulation. The thermal environments of districts with and without waterways were measured in summer. The effects of the change of configuration of the district near waterway were calculated using computer fluid dynamics simulation. Results show the following. 1) Measured daily mean air temperatures were 0.5–0.8 K lower and SET* was 1.4–2.9 K lower in the district with the waterway than those in the district without waterways in peak summer.

Bases on the concept of task/ambient ventilation, fresh air can be decoupled from re-circulated air so as to improving ventilation effectiveness in breathing zone. Ceiling mounted high velocity circular jet diffusers, which are regarded as remote personalized ventilation air terminal devices (PV ATDs) without affecting room aesthetic effects, can be utilized to supply fresh air without causing draft rating because tropically acclimatized occupants prefer slightly higher air movement. Under-floor air diffusers are used to supply re-circulated air.

This study developed a drift-flux model for particle movements in turbulent indoor airflows. To account for the process of particle deposition at solid boundaries in the numerical model, a semi-empirical deposition model was adopted in which the sizedependent deposition characteristics were well resolved. After validation against the experimental data, the drift-flux model was used to investigate human exposures to particles in three normally-used ventilation types: mixing ventilation (MV), displacement ventilation (DV), and under-floor air distribution (UFAD).

While the scientific literature is full of studies looking at the impact of climate change driven by human activity, there is very little research on the impact of climate change or urban heat island on building operation and performance across the world. For this study, typical and extreme meteorological weather data were created for 25 locations (20 climate regions) to represent a range of predicted climate change and heat island scenarios for building simulation. Then a set of prototypical buildings were created to represent typical, good, and low-energy practices around the world.

The daylight coefficient method has been introduced in computer simulation as an efficient approach to compute indoor daylight illuminances through building static fenestration systems. A set of coefficients are calculated only once prior to simulation start for a given number of elemental patches making up to sky vault and ground.

Over the past 15 years, much scientific work has been published on the potential human impacts on climates. For the Third Assessment Report published by the United Nations International Program on Climate Change in 2001, a series of economic development scenarios were created and four major general circulation models (GCM) were used to estimate the anthropogenesis-forced climate change. These GCMs produce worldwide grids of predicted monthly temperature, cloud, and precipitation deviations from the period of 1961-1990.

According to the Czech legislative act the operative temperature is the evaluation criterion for thermal comfort in air-conditioned or heated spaces. The operative temperature respects the air temperature; mean radiant temperature and air velocity. For mean radiant temperature calculation the surface temperature of the surrounding walls must be known. Manual calculation of the mean radiant temperature is very complicated and not suitable for practical usage since the surface temperatures are difficult to determine.

District energy systems provide commercial and residential space heating, air conditioning, domestic hot water, steam, and industrial process energy, as well as sometimes co-generating electricity in systems. Though the district energy system is usually more economical and energy-efficient than individual heating and cooling systems, it is also much more complicated system.

The directionality of light is defined as the balance between the diffuse and directional components of light within an environment. It is an indicator about the spatial distribution of light flow onto an element or into a space. This paper presents a new luminance based metric that quantifies the directionality of light. The diffuse and directional components of the luminous environment are isolated as a unique feature of simulation-based approach. The rationale and methodology of the directional-to-diffuse ratio is discussed through visual demonstrations and quantified metrics.

The airflow network model in EnergyPlus provides the ability to simulate multizone wind-driven airflows. The model is also able to simulate the impacts of forced air distribution systems, including supply and return air leaks. The air distribution system portion of the model is currently applicable for constant-air-volume systems.