Effects of return air vent height on energy consumption, thermal comfort conditions and indoor air quality in an under floor air distribution system

Heidarinejad, Ghassem; Fathollahzadeh, Mohammad Hassan; Pasdarshahri, Hadi

doi:10.1016/j.enbuild.2015.04.004

Cited by 43 publications

(26 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They recommended that the return vents should be located at the upper boundary of the occupied zone for seating occupants (1.3 m). Likewise, the study by Heidarinejad et al [15] also revealed that positioning a return air vent at a lower level was beneficial to saving energy, but negative for the thermal comfort and IAQ in a small office. Apparently, most of the studies demonstrated that the optimum height of return vent in a small space was around 1.3 m in order to maintain a balance between the thermal comfort and energy saving [14,15].…”

Section: Introductionmentioning

confidence: 91%

“…Likewise, the study by Heidarinejad et al [15] also revealed that positioning a return air vent at a lower level was beneficial to saving energy, but negative for the thermal comfort and IAQ in a small office. Apparently, most of the studies demonstrated that the optimum height of return vent in a small space was around 1.3 m in order to maintain a balance between the thermal comfort and energy saving [14,15]. Furthermore, in our previous research [16], a series of numerical computations with various height positions (Z = 0.8 m-2.6 m) of the return vents were conducted in order to comprehensively evaluate the effects of the height of return vents on thermal comfort, contaminant removal, and energy efficiency.…”

Section: Introductionmentioning

confidence: 91%

See 1 more Smart Citation

Numerical Study on Effects of Air Return Height on Performance of an Underfloor Air Distribution System for Heating and Cooling

Fan

Zheng

et al. 2020

Energies

View full text Add to dashboard Cite

The exhaust/return-split configuration is regarded as an important upgrade of traditional under-floor-air-distribution (UFAD) systems due to its higher energy efficiency. Moreover, existing studies are mostly focused on the effect of the return vent height on the performance of an UFAD system under cooling conditions. Knowledge of the performance under heating conditions is sorely lacking. This paper presents a numerical evaluation of the performance characteristics of an UFAD system with six different heights of the return vents in heating operation by comprehensively considering thermal comfort, air quality, and energy consumption. The results show that, in the heating mode, the general thermal comfort (predicted mean vote-predicted percentage dissatisfied (PMV-PPD) values) and indoor air quality indices (mean age of air and volatile organic compounds (VOCs) concentration) were greatly improved and energy consumption was slightly reduced with a lower return vent height. Although these were opposite to the findings of our previous study regarding the performance in cooling mode, an optimal return vent height in terms of the comprehensive all-year performance can be recommended. This method provides insight into the design and optimization of the return vent height of UFAD for space heating and cooling.

show abstract

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 91%

Numerical Study on Effects of Air Return Height on Performance of an Underfloor Air Distribution System for Heating and Cooling

Fan

Zheng

et al. 2020

Energies

View full text Add to dashboard Cite

show abstract

“…Mijakowski and Sowa 21 proposed humidity-sensitive air inlets in a kindergarten building to improve the performance of passive stack ventilation, but the effect was not sufficient to meet current recommendations of Polish and European standards for indoor environments in newly designed kindergarten buildings. Ghassem et al 22 found that the height of return air vent from ceiling to floor could influence temperature gradient at the vertical direction, and thermal discomfort could be increased by reducing the height of the return air vent location. Kuo and Chung 23 investigated the effects of air vent location on occupants' thermal comfort in the occupied zone and suggested that the inlet diffuser should be located at the half-upper wall, if a wall-mounted diffuser is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…Ghassem et al. 22 found that the height of return air vent from ceiling to floor could influence temperature gradient at the vertical direction, and thermal discomfort could be increased by reducing the height of the return air vent location. Kuo and Chung 23 investigated the effects of air vent location on occupants’ thermal comfort in the occupied zone and suggested that the inlet diffuser should be located at the half-upper wall, if a wall-mounted diffuser is necessary.…”

Section: Introductionmentioning

confidence: 99%

A parametric study of the combined effects of window property and air vent placement

Duan

Wang

2018

Indoor and Built Environment

View full text Add to dashboard Cite

The creation of energy-efficient buildings that maintain thermal comfort is a major goal of architectural design. The study on the interrelation of vent location and window properties on indoor thermal conditions and energy performance is still needed. With the rapid development of building window technologies, such combined effects have become more complex. This work using computational fluid dynamics examines airflow patterns, temperature distributions, thermal comfort indices and corresponding heat transfers through exterior windows in an office unit during summer and winter seasons. Our results indicate that, buildings with low-insulated windows, above-the-window air register and under-the-window air register, have obvious advantages in forming comfortable conditions in summer and winter, respectively. Building with highly insulated windows, the central-ceiling placement of air supply vents is capable of merging airflows for the entire room, providing appropriate indoor thermal conditions and significant savings in energy use. The percentage of occupants dissatisfied with the thermal conditions achieved is slightly higher than best performances achieved in other reference models but still within recommended limits. The findings from this research provide an improved understanding of how thermal comfort and energy issues could change in response to different vent locations and types of building windows.

show abstract

“…Many researchers employed parametric studies [4][5][6] to achieve better performance of enclosed environments. In the parametric studies, one usually fixes all but one variable, and tries to optimize a cost function with respect to the non-fixed variable.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Environment/Energy Pareto Optimal Front of an Office Room Using Computational Fluid Dynamics-Based Interactive Optimization Method

Xue

2017

Energies

View full text Add to dashboard Cite

This paper is concerned with the development of a high-resolution and control-friendly optimization framework in enclosed environments that helps improve thermal comfort, indoor air quality (IAQ), and energy costs of heating, ventilation and air conditioning (HVAC) system simultaneously. A computational fluid dynamics (CFD)-based optimization method which couples algorithms implemented in Matlab with CFD simulation is proposed. The key part of this method is a data interactive mechanism which efficiently passes parameters between CFD simulations and optimization functions. A two-person office room is modeled for the numerical optimization. The multi-objective evolutionary algorithm-non-dominated-and-crowding Sorting Genetic Algorithm II (NSGA-II)-is realized to explore the environment/energy Pareto front of the enclosed space. Performance analysis will demonstrate the effectiveness of the presented optimization method.

show abstract

Effects of return air vent height on energy consumption, thermal comfort conditions and indoor air quality in an under floor air distribution system

Cited by 43 publications

References 14 publications

Numerical Study on Effects of Air Return Height on Performance of an Underfloor Air Distribution System for Heating and Cooling

Numerical Study on Effects of Air Return Height on Performance of an Underfloor Air Distribution System for Heating and Cooling

A parametric study of the combined effects of window property and air vent placement

Exploring the Environment/Energy Pareto Optimal Front of an Office Room Using Computational Fluid Dynamics-Based Interactive Optimization Method

Contact Info

Product

Resources

About