Towards measuring real-time occupant levels to reduce ventilation fan energy consumption in existing institutional gathering spaces - a field study using thermal sensors.

Ventilation systems in buildings have been traditionally designed for the maximum projected number of occupants; while buildings often have fewer occupants than the maximum and in some cases can be unoccupied for extended periods. Changing the rate of outdoor air to reflect changes in the number of occupants in a space is referred to as demand control ventilation (DCV). A field study was performed using thermal sensors to determine the number of occupants using lecture rooms of an institutional building. The occupant data was used to calculate minimum ventilation for the lecture rooms using current ventilation standards from ASHRAE Standard 62.1. It was found that by current standards, the required ventilation is considerably less than the original design ventilation. Based on occupant data and variables specific to the lecture rooms, it was found that the ventilation can be reduced by at least 40% creating a potential for significant energy savings.

Towards measuring real-time occupant levels to reduce ventilation fan energy consumption in existing institutional gathering spaces - a field study using thermal sensors.

Ventilation systems in buildings have been traditionally designed for the maximum projected number of occupants; while buildings often have fewer occupants than the maximum and in some cases can be unoccupied for extended periods. Changing the rate of outdoor air to reflect changes in the number of occupants in a space is referred to as demand control ventilation (DCV). A field study was performed using thermal sensors to determine the number of occupants using lecture rooms of an institutional building. The occupant data was used to calculate minimum ventilation for the lecture rooms using current ventilation standards from ASHRAE Standard 62.1. It was found that by current standards, the required ventilation is considerably less than the original design ventilation. Based on occupant data and variables specific to the lecture rooms, it was found that the ventilation can be reduced by at least 40% creating a potential for significant energy savings.

Development the tool for demand control ventilation systems elements design and their impact to building life-cycle assessment: a review

The paper describes possible methodology for DCV – demand control ventilation design process which will lead to solving the most important problems of more accurate ventilation system design, the efficiency: time and costs of design while improving its effectivity (level of design confidence, degree of uncertainty, financial parameters). For this purpose it has been started developing the tool implementing the methodology. Furthermore, it describes steps of testing and validation design process by implementation state-of-the-art algorithms for measuring the occupancy or CO2 detection for DCV system control testing sites and their comparison with computation design results. It describes also the reasons and necessity of decomposition of whole ventilation system to specific elements for the design and assessment procedure.

Energy Saving Potential of Personalized Ventilation Applied in an Open Space Office under Winter Conditions

Mixing and displacement air distribution are the main ventilation principles applied in both residential and non-residential buildings. Recently, personalized ventilation when the fresh air is delivered directly to the occupants at a high ventilation effectiveness has become an alternative. Despite of this fact, little research has been carried out to quantify the energy saving potential of personalized ventilation. This study aimed to quantify the effect of ventilation effectiveness and control strategy on the energy performance and thermal comfort for an open plan office equipped by different types of ventilation systems, including mixing ventilation with constant air volume, demand control ventilation and personalized ventilation. A model was created in a program for dynamic energy simulations TRNSYS, representing one floor of a typical office building divided into four zones with different orientations and a core. Space heating and cooling were provided by ceiling fancoil units recirculating the room air, thus the tasks of ventilation and air conditioning were provided by two separate systems. The potential of personalized ventilation to save energy for fans and for the heating coil of the ventilation system presented about 70% compared to constant air volume mixing ventilation, however, the overall saving was only 20% when also the energy demand for space heating was considered. The energy benefit of demand control ventilation and personalized ventilation depends on the energy need for space heating and cooling, system configuration and operation, and occupancy.