Improving Indoor Arenas for the Equine Industry

Equine indoor arenas are a unique infrastructure investment found at equine farms and facilities. They are semi-indoor structures for exercising horses, exhibiting skills during competitive events, and other equine related activities. These spaces do not always include mechanical ventilation or stirring fans and occupancy by horses and humans can be sporadic and inconsistent, which creates a challenging space for understanding and predicting airflow. Typically, indoor arenas have a sand-based footing over which the horse travels. The impact of the hooves can cause dust to become a concern within the facilities. Environmental concerns within these facilities (temperature, respirable dust, moisture, and air movement) have been identified through surveys and small research studies. Three research areas were designed and completed to examine different aspects of indoor arenas. The first research area involved observational studies of the environment within indoor arenas around Lexington, KY. Second, computational fluid dynamic modeling evaluating the impact of different ventilation designs on air movement within indoor arenas. Lastly, an intensive lab study determining the differences environmental conditions and dragging maintenance schedules has on footing moisture content for 3 different footing types. The environmental studies were conducted in two parts. The first characterized 37 indoor arenas in a one-time site assessment and the second monitored 15 indoor arenas for a week in the winter and summer to examine seasonal differences. During the one-time site assessments spatial variability of roof, ambient air, and footing temperatures, air speeds, and light intensity was evaluated in relation to design features of the arena and facility usage information. The environmental monitoring demonstrated distinct diurnal patterns in the facilities regarding temperature, dew point temperature, and solar radiation. In addition, both studies showed that air speeds within the facilities were below recommended levels of 0.51 m/s (100ft/min). Overall, there is a need for more research on the environmental conditions within indoor arenas, the potential health impacts to the humans and horses in the spaces, and how design changes to the facility could improve this environment. Computational fluid dynamic (CFD) modeling provided visualization of the effect of different ventilation design aspects and the impact of orientation on air speeds within indoor arenas. Adding eave ventilation and ridge vents in combination with large windows allows for more air movement through the facilities with large openings at the tops of walls providing the highest amount of air movement within the arena. Orientating the arenas with the long side wall perpendicular to the predominant wind direction allowed for the more air flow through and within the facility. Finally, observing the change in footing moisture content of 3 different footing types (sand with fiber, sand, and sand with organic matter) determined that environmental conditions (winter, summer humid, and summer dry) are important for how quickly the moisture will be evaporated out of the footing. Summer dry conditions (30°C/40% RH) had the largest moisture content change in all 3 footing types, while winter (7°C/75% RH), and summer humid (30°C/80% RH) both demonstrated less water loss. Understanding the rate at which moisture is lost from footing can help facility managers decide when to add more water

Multiphysics simulations of fire inside the cavity of a facade

The facade system is highly complex and requires achieving multiple objectives to provide occupants with a safe and comfortable environment. Any attempt to improve these objectives, such as aesthetic, thermal or acoustic insulation, could potentially affect the fire safety of the facade system. This is especially true as novel materials were introduced over the last decades, resulting in an ongoing rise in facade fires. Researchers have observed that a narrow cavity in a facade system encourages rapid facade fire spread. Unfortunately, there is little knowledge of quantifying the impact of cavities on a facade fire. Computational Fluid Dynamics (CFD) fire simulation represents an excellent tool to complement experimental studies on fire inside a narrow cavity of a flammable facade. Cavity fire is a multiphysics phenomenon, and all physics, i.e. fluid flow, heat transfer, buoyancy, combustion and pyrolysis involved in the model must be coupled step-by-step for a narrow cavity fire scenario to ensure model reliability. This thesis provides a step-by-step development of a CFD simulation for a narrow cavity fire. We split the facade cavity fire into six different scenarios with increasing complexity and validated the model against experimental data in the literature to limit the compensation effect. The compensation effect is the concept where similar results could be obtained by varying two or more parameters. We studied how cavity barriers affect fire dynamics and performed parametric studies to quantify the impact of both material properties and cavity width on fire dynamics inside a cavity of a flammable facade. This work demonstrates that modelling represents a powerful tool to aid in understanding facade cavity fire to improve building fire safety.Open Acces

Exploration of passive cooling potential to improve indoor environment quality (thermal comfort, relative humidity and air movement) in thermally free-running multi-residential dwellings in Thailand urban areas

Multi-residential buildings in Thailand's urban areas have significant issues regarding indoor environmental quality (IEQ). These buildings, typically designed with singlesided ventilation, tend to suffer from inadequate ventilation, particularly in thermally free-running buildings. This leads to poor IEQ, especially for low-socioeconomic groups. Natural ventilation, as a passive cooling strategy, offers benefits in enhancing thermal comfort, sustainability, and cost-effectiveness. Three phases of the study were established for investigating the potential of passive design options by focussing on natural ventilation to improve IEQ. Phase 1 involved physical measurements to assess current indoor environmental conditions and occupant perception surveys to characterise typology and typical buildings. These measurements provided base case data for Phase 2, where Computational Fluid Dynamics (CFD) and building simulation models were developed to explore factors affecting natural ventilation and thermal behaviour, both outdoors and indoors. In Phase 3, potential design options for improving IEQ were evaluated, involving consultations with Thai building professionals. The study revealed that the optimal design scenario could improve thermal comfort by up to 21.9% compared to the original room configuration. This optimal case also maintained healthier relative humidity levels 5% longer. During the rainy season, these benefits were even more obvious, with a 42.3% increase in thermal comfort and a 56% increase in periods of healthy humidity levels. Additionally, the optimal design consistently achieved natural ventilation rates exceeding 0.2 m.s-1, occasionally reaching up to 0.4 m.s-1 at the occupant level, signifying a substantial improvement. The research proposes design options, focusing on passive cooling through natural ventilation for new multiresidential buildings in urban areas