A critical review of displacement ventilation
Leon Glicksman1998
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Abstract
This paper reviews several aspects of the performance of displacement ventilation: temperature distribution, flow distribution, contaminant distribution, comfort, energy and cost analysis, and design guidelines. Ventilation rate, cooling load, heat source, wall characteristics, space height, and diffuser type have major impacts on the performance of displacement ventilation. Some of the impacts can be estimated by simple equations, but many are still unknown. Based on current findings, displacement ventilation systems without cooled ceiling panels can be used for space with a cooling load up to 13 Btu/(hfr) (40 W!m 2 ). Energy consumed by HVAC systems depends on control strategies. The first costs of the displacement ventilation system are similar to those of a mixing ventilation system. The displacement system with cooled ceiling panels can remove a higher cooling load, but the first costs are higher as well. The design guidelines of displacement ventilation developed in Scandinavian countries need to be clarified and extended so that they can be used for U.S. buildings. This paper outlines the research needed to develop design guidelines for U.S. buildings.
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Center for the Built Environment, 2006
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Energy and Buildings, 2002
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International Journal of Energy Research, 2007
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Energy and Buildings, 2010
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International Journal of Energy Research, 2010
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Displacement ventilation system Displacement ventilation system
a longer period for the use of free cooling
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EXPERIMENTAL STUDY TO THE PERFORMANCE OF THE DISPLACEMENT VENTILATION UNDER DIFFERENT OPERATION CONDITIONS.
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Title Chilled ceiling and displacement ventilation system : Laboratory study with high cooling load Permalink
2015
Radiant chilled ceilings with displacement ventilation represent a promising system that combines the energy efficiency of both subsystems with the opportunity for improved ventilation performance. Laboratory experiments were conducted for an interior zone office with a very high cooling load (91.0 W/m 2) and with two different heat source heights to investigate their influence on thermal stratification and air change effectiveness. The results showed that displacement ventilation with a chilled ceiling is able to provide a stable thermal stratification and improved ventilation effectiveness compared to mixing ventilation for a wide range of configurations. Stratification and air change effectiveness decreases when a larger portion of the cooling load is removed by the chilled ceiling. For every degree decrement of the surface temperature of the radiant ceiling, the stratification decreases by 0.13 K and the air change effectiveness by 0.13. Moving the computer processing units (representing 51% of the total room heat gain) from the floor level to 1.5 m height markedly increased the room median stratification and the median air change effectiveness (from 1.15 to 2.90). Therefore, increasing the height of heat sources has the potential to reduce energy use and improve indoor air quality.
Design of Chilled Ceiling Displacement Ventilation for Direct Expansion HVAC System
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Performance evaluation of the displacement ventilation combined with evaporative cooled ceiling for a typical office in Beirut
Energy Conversion and Management, 2015
The study investigates by modeling the performance of displacement ventilation (DV) aided with a Novel Evaporative Cooled Ceiling, Maisotsenko cycle (M-cycle). The proposed system will increase the load removal of the DV system beyond the 40 W/m 2 limit with no additional energy consumption. Predictive mathematical models of the conditioned space and the evaporative cooled ceiling will be developed to study the energy performance of the suggested combined system for typical offices of Beirut. The study identifies different values of supply air relative humidity at a certain supply flow rate and temperature while meeting space load, indoor air quality, and thermal comfort. The proposed system resulted in cooling load removal capacity enhancements of 18.65%, 44.3% and 72.25% at supply air relative humidity of 90%, 50% and 10⁰C respectively. The results indicated a better performance at lower supply air relative humidity.
Chilled ceiling and displacement ventilation aided with personalized evaporative cooler
Energy and Buildings, 2011
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Displacement ventilation system combined with a novel evaporative cooled ceiling for a typical office in the city of Beirut: performance evaluation
Renewable Energy and Power Quality Journal, 2015
Displacement ventilation (DV) system incorporated with a novel evaporative cooled ceiling, Maisotsenko cycle (Mcycle) is a passive technique used to enhance the load removal in spaces. This study examines the performance of the integrated system in increasing the load removal of the DV system beyond the 40 W/m 2 limit with no additional energy consumption for a typical office in Beirut. Mathematical models for the space and the evaporative cooled ceiling will be developed and then validated through experimentation. Simulations are performed under different supply air relative humidity values, were an improvement in sensible load removal of 18.65%, 44.3% and 72.25% at supply air relative humidity of 90%, 50% and 10% respectively. Results showed better cooling performance at lower supply air relative humidity.
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2015
The study investigates the performance of displacement ventilation (DV) aided by a novel evaporative cooled ceiling using Maisotsenko cycle (M-cycle). The integrated DV and evaporative cooled ceiling system is known to increase the load removal of the DV air conditioning system beyond the 40 W/m2 limit with no additional energy consumption. To increase the efficiency of the evaporative cooled ceiling, solid desiccant (SD) dehumidification system regenerated by parabolic solar concentrator thermal source is used. Predictive mathematical models of the conditioned space, the SD and the evaporative cooled ceiling are integrated to study the energy performance of the suggested combined system while utilizing an optimized control strategy for typical offices of moderate humid climate. The control strategy aims to determine optimal values of supply air flow rate and temperature and regeneration temperature while meeting space load, indoor air quality, and thermal comfort requirements. The integrated system performance is optimized to get the minimal energy cost and then compared to the cost when using a chilled ceiling displacement (CC/DV) air conditioning system.
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