Downdraft Assessment of Glass Curtain Wall Buildings with a Radiant Floor Heating System

Abstract

Abstract:The present study aims to evaluate whether downdraft can be prevented by applying a radiant floor heating system in glass curtain wall buildings. A radiant floor heating system does not directly supply heat to cold air, but does so via heat exchange with a cold airflow. Assessing whether a downdraft is prevented is, thus, necessary. For this assessment, a radiant floor heating system was applied to perimeter zones with different window types modeled using a computational fluid dynamics (CFD) simulation. The relationship between the radiant floor heating system and the windows was examined via an assessment of the resulting downdraft by considering the radiant heat exchange effect between the window and the floor. The assessment was conducted by utilizing a CFD simulation. The simulation results show that the temperature difference between the air supplied through the radiant floor heating system and the air descending along the cold surface of the window increased when the radiant floor heating system was applied to a narrow area with a high temperature. Furthermore, the airflow velocity increased with the heat exchange. The airflow re-entered the window side, and the downdraft in the occupied area exceeded the strict value specified by the standards. Conversely, if heat were applied according to the indoor thermal output by widening the radiant heat area of the radiant floor heating system, a downdraft could occur as a result of a blocking failure prior to the influx of the cold air into the occupied area caused by low surface temperatures. Therefore, applying a radiant floor heating system is advantageous in a perimeter zone without causing airflow inducement at the window side with acceptable surface temperatures.

Determination of Solar Energy for the Bioclimatic Design of Housing in the City of Juliaca Peru

“…A work entitled "Building integrated solar thermal systems presentation and zoom on the solar potential" [9], carried out in BIST (Barcelona Institute of Science and Technology) in a bioclimatic building with solar energy demonstrates that The peak Solar Irradiation in the month of August is 955 w/m 2 with a symmetrical variation during the day, but in the month of December there is an increase to 1098 w/m 2 peak with an average of 1047 w/m 2 in a range of very short time of 30 min of (HSP) shown in figure 10, which is very little to have a good performance with equipment that work with solar energy; what we mentioned above from the city of Juliaca has a peak average of 1110.04 w/m 2 and a time interval of 6.5 hours (HSP). In the scientific article entitled "Evaluation of downward currents of glass curtain wall buildings with a radiant floor heating system" [29], for this evaluation, a floor heating system was applied to the perimeter zones with different window types modeled using a Computational Fluid Dynamics (CFD) simulation with an initial temperature between (10-16)°C for 24 hours. The results of the simulation show that the temperature difference between the air supplied through the underfloor heating system and the air descending along the cold surface of the window increased between (18)(19)(20)°C shown in the Figure 11, comparing with the research carried out in the experimental room, an average temperature of 20.93°C is reached, demonstrating the increase in temperature thanks to the use of renewable solar energy.…”

A Study on Establishing Thermal Output Conditions of Radiant Ceiling Heating Panels for Improving Thermal Comfort of Perimeter Zone in Buildings

“…In order to replace convective heating systems with radiant ceiling heating panels, it is essential to rapidly respond to external load fluctuations, prevent discomfort such as downdraft, and maintain adequate thermal output to handle the heating load in the perimeter zone [6]. However, despite the application of panel forms to address external load fluctuations, there is a scarcity of data regarding the necessary thermal output, corresponding heating surface area, and surface temperature for perimeter zone applications.…”

Comparative Economic and Experimental Assessment of Air Source Heat Pump and Gas-fired boiler: A Case Study from Turkey

“…Despite the fact that their COP values are unrelated to the cost-effectiveness of heat pumps and geothermal energy, the use of these energy sources is likely more efficient due to their COP values [18]. The detailed computational fluid dynamics simulation model of offices with radiant ceiling panels for heating and cooling was examined by Joe et al [19]. The model was developed using real case studies and verified using 1-year observations.…”