Thermal comfort and ventilation effectiveness in an office room with radiant floor cooling and displacement ventilation

2015 ◽  
Vol 22 (3) ◽  
pp. 317-327 ◽  
Author(s):  
Michal Krajčík ◽  
Roberta Tomasi ◽  
Angela Simone ◽  
Bjarne W. Olesen
Keyword(s):  
Thermal Comfort ◽  
Displacement Ventilation ◽  
Ventilation Effectiveness

scholarly journals FIELD STUDY ON THE THERMAL COMFORT AND VENTILATION EFFECTIVENESS IN A CONCERT HALL WITH DISPLACEMENT VENTILATION SYSTEM

2002 ◽  
Vol 67 (559) ◽  
pp. 37-44
Author(s):  
Sueng-jae LEE ◽  
Shin-ichi TANABE ◽  
Ken-ichi KIMURA ◽  
Kazuhiro OTAKA ◽  
Makoto KOYAMA ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Field Study ◽  
Ventilation System ◽  
Displacement Ventilation ◽  
Concert Hall ◽  
Ventilation Effectiveness

scholarly journals Incorporating cooling and ventilation effects into a single IEQ indicator

2019 ◽  
Vol 111 ◽  
pp. 02011
Author(s):  
Matjaž Prek ◽  
Gorazd Krese ◽  
Žiga Lampret
Keyword(s):  
Thermal Comfort ◽  
Indoor Environment ◽  
Cooling System ◽  
Ventilation System ◽  
Whole Body ◽  
Indoor Environmental Quality ◽  
Displacement Ventilation ◽  
Wall Displacement ◽  
Flat Wall ◽  
Ventilation Effectiveness

The influence of dissimilar cooling and ventilation system combinations on indoor environmental quality (IEQ) has been studied. A comparison of chilled ceiling cooling in combination with displacement ventilation, cooling with fan coil unit, and cooling with flat wall displacement inlets was performed. All observed variations were evaluated based on whole-body and local thermal comfort criteria as well as with regard to ventilation effectiveness. The analysis was made based on results of numerical simulations carried out in two steps. First, DesignBuilder was applied to model the buildings’ thermal performance and to evaluate its interaction with the environment. The latter included the calculation of heat gains as well as the heat loss on the boundary surfaces of the observed air-conditioned room. In the second step, ANSYS Fluent was used to simulate the response of indoor environment by utilizing the simulation results obtained in the first step, in order to evaluate the interaction between building and human. Afterwards, the observed thermal comfort and ventilation criteria were merged into a novel indoor environment indicator, which enables to describe the indoor environment quality with a single value. Among the analysed systems, the ceiling cooling system in combination with displacement ventilation was found to be the most suitable as it offers a high level of thermal comfort with adequate ventilation efficiency. Fan coil cooling was the least favourable option in terms of thermal comfort, while flat wall displacement inlets exhibited the lowest ventilation effectiveness. The performed investigation demonstrated the necessity to assess indoor environment with regard to IEQ in addition to energy consumption.

scholarly journals Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment—Heating Mode

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1835 ◽  
Author(s):  
Arman Ameen ◽  
Mathias Cehlin ◽  
Ulf Larsson ◽  
Taghi Karimipanah
Keyword(s):  
Thermal Comfort ◽  
Distribution Systems ◽  
Cold Climate ◽  
Air Distribution ◽  
Temperature Pattern ◽  
Office Environment ◽  
Ventilation Effectiveness ◽  
Local Thermal Comfort ◽  
Heating Mode ◽  
Occupied Zone

A vital requirement for all-air ventilation systems are their functionality to operate both in cooling and heating mode. This article experimentally investigates two newly designed air distribution systems, corner impinging jet (CIJV) and hybrid displacement ventilation (HDV) in comparison against a mixing type air distribution system. These three different systems are examined and compared to one another to evaluate their performance based on local thermal comfort and ventilation effectiveness when operating in heating mode. The evaluated test room is an office environment with two workstations. One of the office walls, which has three windows, faces a cold climate chamber. The results show that CIJV and HDV perform similar to a mixing ventilation in terms of ventilation effectiveness close to the workstations. As for local thermal comfort evaluation, the results show a small advantage for CIJV in the occupied zone. Comparing C2-CIJV to C2-CMV the average draught rate (DR) in the occupied zone is 0.3% for C2-CIJV and 5.3% for C2-CMV with the highest difference reaching as high as 10% at the height of 1.7 m. The results indicate that these systems can perform as well as mixing ventilation when used in offices that require moderate heating. The results also show that downdraught from the windows greatly impacts on the overall airflow and temperature pattern in the room.

Effect of Air Supply Temperature on the Performance of Displacement Ventilation (Part I) - Thermal Comfort

2005 ◽  
Vol 14 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Zhang Lin ◽  
T. T. Chow ◽  
C. F. Tsang ◽  
L. S. Chan ◽  
K. F. Fong
Keyword(s):  
Thermal Comfort ◽  
Displacement Ventilation ◽  
Air Supply

Thermal comfort of different displacement ventilation systems in an aircraft passenger cabin

2017 ◽  
Vol 111 ◽  
pp. 256-264 ◽  
Author(s):  
Julia Maier ◽  
Claudia Marggraf-Micheel ◽  
Tobias Dehne ◽  
Johannes Bosbach
Keyword(s):  
Thermal Comfort ◽  
Displacement Ventilation ◽  
Passenger Cabin ◽  
Ventilation Systems

Increasing Energy Efficiency of HVAC Systems of Buildings Using Phase Change Material

2011 ◽  
Author(s):  
Lee Chusak ◽  
Jared Daiber ◽  
Ramesh Agarwal
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Energy Requirements ◽  
Exterior Wall ◽  
Displacement Ventilation ◽  
Cooling Systems ◽  
Comfort Levels ◽  
Chilled Ceiling ◽  
Change Material

Using Computational Fluid Dynamics (CFD), four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) a combined air and hydronic radiant system (overhead system with a chilled ceiling), (c) an all-air raised floor system (displacement ventilation), and (d) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall to compare the four cooling systems. The second set of computations consider a glass window, a phase change material layer and the plastic shade configuration for the exterior wall to examine the effect of the phase change material (PCM) layer on the cooling energy requirements. Both sets of simulations assumed an external wall that changed temperature as a function of time simulating the temperature changes on the exterior wall of the room during a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.

Reducing Energy Demand in Commercial Buildings: Balancing Convection and Radiant Cooling

2010 ◽  
Author(s):  
Lee Chusak ◽  
Andrew Harris ◽  
Ramesh Agarwal
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Savings ◽  
Ventilation System ◽  
Computational Domain ◽  
Exterior Wall ◽  
Displacement Ventilation ◽  
Comfort Levels ◽  
Isothermal Wall ◽  
Chilled Ceiling

Using Computational Fluid Dynamics (CFD) software, three different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) an all-air raised floor system (displacement ventilation), and (c) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one isothermal wall (simulating an exterior wall of the room) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations were conducted. The first set of computations utilized a constant temperature isothermal exterior wall, while the second set utilized an isothermal wall that changed temperatures as a function of time simulating the temperature changes on the exterior wall of a building throughout a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation, especially the displacement ventilation with a chilled ceiling over the conventional mixing ventilation system.

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