Nocturnal Cooling of Water as Free Cooling Source for Building Indoor Radiant Cooling in Malaysian Climate

2016 ◽  
Vol 833 ◽  
pp. 94-101
Author(s):  
Muhammad Syukri Imran ◽  
Azhaili Baharun ◽  
Siti Halipah Ibrahim ◽  
Wan Azlan bin Wan Zainal Abidin
Keyword(s):  
Cooling System ◽  
Operating Temperature ◽  
Dew Point ◽  
Wave Radiation ◽  
Cooling Power ◽  
Test Model ◽  
Dew Point Temperature ◽  
Long Wave ◽  
Radiant Cooling ◽  
Free Cooling

Normally mechanical chiller supplies chill water temperature at a higher operating temperature to charge a radiant cooling system in building. Other source of cooling is possible since the operating temperature for radiant cooling is limited by the air dew point temperature. This study investigates cooling of water through long wave radiation to the night sky in Kuching Sarawak, Malaysia and utilise this water for radiant cooling purpose. Mathematical model were developed to predict the cooling power of the nocturnal cooling over typical metal roof and was compared to an experimental data. The measurement from the test model verified the predicted data and a yearly potential from nocturnal cooling in this region was established. The amount of cooled water generated from this night cooling system was also calculated. Results showed that an average of 73 W/m2 nocturnal cooling power is possible in this region.

scholarly journals Laboratory tests of a prototypical user-centric radiant cooling solution

2021 ◽  
Vol 2069 (1) ◽  
pp. 012122
Author(s):  
H Teufl ◽  
M Schuss ◽  
A Mahdavi
Keyword(s):  
Surface Temperature ◽  
Cooling System ◽  
Dew Point ◽  
Cooling Systems ◽  
Efficient Operation ◽  
Radiant Cooling ◽  
Close Proximity ◽  
Free Cooling ◽  
Condensed Water ◽  
Vapour Condensation

Abstract Radiant cooling systems are being increasingly promoted because of their energy efficient operation as well as their potential to improve occupants’ thermal comfort due to a draft-free cooling process. This paper focuses on a specific radiant cooling approach, which was introduced in previous contributions. This approach involves the positioning of relatively small-sized vertical radiant panels in the close proximity to occupants. Furthermore, the panels incorporate drainage systems or collection elements to accommodate, if needed, water vapour condensation. Consequently, the surface temperature of the radiant panels does not need to stay above the dew point temperature. We present the outcome of a preliminary experimental investigation of such a personal radiant cooling system. In this context, prototypical radiant panels were installed in a laboratory and multiple experiments were conducted. The uniformity level of the panels’ surface temperature distribution was documented. Moreover, near-panel air flow velocities were measured at several positions. Likewise, the formation of condensed water on panels was observed for different panel surface temperatures, room temperatures, and room humidity levels. The results of the preliminary laboratory investigation do not point to any risk of draft or turbulence discomfort.

scholarly journals Numerical Analysis on the Performance of a Radiant Cooling Panel with Serpentine-Based Design

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4744
Author(s):  
Mohammad Hakim Mohd Radzai ◽  
Chong Tak Yaw ◽  
Chin Wai Lim ◽  
Siaw Paw Koh ◽  
Nur Amirani Ahmad
Keyword(s):  
Pressure Drop ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Dew Point ◽  
Cooling Power ◽  
Full Potential ◽  
Ansys Fluent ◽  
Cooling Performance ◽  
Flow Configuration ◽  
Radiant Cooling

Radiant cooling systems (RCS) are gaining acceptance as a heating, ventilation, and air conditioning (HVAC) solution for achieving adequate thermal comfort and maintaining acceptable indoor air quality inside buildings. RCS are well known for their energy-saving potential; however, serious condensation problem hinders the growth of this technology. In order to prevent the risk of condensation, the supply water temperature is kept higher than the dew point temperature of the air inside the room. The full potential of the cooling power of a radiant cooling panel is limited. Therefore, this article is on maximizing the cooling capacity of a radiant cooling panel, in terms of flow configuration. Radiant cooling panels (RCP) with different chilled water pipe configurations are designed and compared, side by side with the conventional serpentine flow configuration. The cooling performance of the radiant cooling panels is evaluated by using computational fluid dynamics (CFD) with Ansys Fluent software (Ansys 2020 R2, PA, USA). Under similar flow and operating conditions, the common serpentine flow configuration exhibits the least effective cooling performance, with the highest pressure drop across the pipe. It is concluded that the proposed designs have the potential of improving the overall efficiency of RCP in terms of temperature distribution, cooling capacity, and pressure drop.

scholarly journals Membrane-assisted radiant cooling for expanding thermal comfort zones globally without air conditioning

2020 ◽  
Vol 117 (35) ◽  
pp. 21162-21169 ◽  
Author(s):  
Eric Teitelbaum ◽  
Kian Wee Chen ◽  
Dorit Aviv ◽  
Kipp Bradford ◽  
Lea Ruefenacht ◽  
...  
Keyword(s):  
Water Supply ◽  
Thermal Comfort ◽  
Cooling System ◽  
Thermal Sensation ◽  
Dew Point ◽  
Mean Radiant Temperature ◽  
Radiation Exchange ◽  
Radiant Cooling ◽  
Chilled Water ◽  
Radiant Temperature

We present results of a radiant cooling system that made the hot and humid tropical climate of Singapore feel cool and comfortable. Thermal radiation exchange between occupants and surfaces in the built environment can augment thermal comfort. The lack of widespread commercial adoption of radiant-cooling technologies is due to two widely held views: 1) The low temperature required for radiant cooling in humid environments will form condensation; and 2) cold surfaces will still cool adjacent air via convection, limiting overall radiant-cooling effectiveness. This work directly challenges these views and provides proof-of-concept solutions examined for a transient thermal-comfort scenario. We constructed a demonstrative outdoor radiant-cooling pavilion in Singapore that used an infrared-transparent, low-density polyethylene membrane to provide radiant cooling at temperatures below the dew point. Test subjects who experienced the pavilion (n= 37) reported a “satisfactory” thermal sensation 79% of the time, despite experiencing 29.6 ± 0.9 °C air at 66.5 ± 5% relative humidity and with low air movement of 0.26 ± 0.18 m⋅s−1. Comfort was achieved with a coincident mean radiant temperature of 23.9 ± 0.8 °C, requiring a chilled water-supply temperature of 17.0 ± 1.8 °C. The pavilion operated successfully without any observed condensation on exposed surfaces, despite an observed dew-point temperature of 23.7 ± 0.7 °C. The coldest conditions observed without condensation used a chilled water-supply temperature 12.7 °C below the dew point, which resulted in a mean radiant temperature 3.6 °C below the dew point.

Analytical modeling of a radiant cooling system for thermal performance analysis

2021 ◽  
Author(s):  
Arup Chandra Saha ◽  
Vikas Verma ◽  
Rahul Tarodiya ◽  
M.R. Mahboob ◽  
Rajesh Kumar
Keyword(s):  
Performance Analysis ◽  
Thermal Performance ◽  
Analytical Modeling ◽  
Cooling System ◽  
Radiant Cooling

scholarly journals Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Britta Jänicke ◽  
Fred Meier ◽  
Marie-Therese Hoelscher ◽  
Dieter Scherer
Keyword(s):  
Heat Stress ◽  
Short Wave ◽  
Wave Radiation ◽  
Short Wave Radiation ◽  
Long Wave ◽  
Building Facades ◽  
Urban Heat ◽  
The Mean ◽  
Human Bioclimate ◽  
Radiant Temperature

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as façade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature(Tmrt)are necessary to assess outdoor human bioclimate. We observedTmrtin front of a building façade in Berlin, Germany, which is half-greened while the other part is bare.Tmrtwas reduced (mean 2 K) in front of the greened compared to the bare façade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show thatTmrt(MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction ofTmrtwith the observed one in front of the façade greening, showing that the models were not able to simulate the effects of façade greening with the applied settings. Our results reveal that façade greening contributes only slightly to a reduction of heat stress in front of building façades.

scholarly journals A Typical Meteorological Year Generation Based on NASA Satellite Imagery (GEOS-I) for Sokoto, Nigeria

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Olayinka S. Ohunakin ◽  
Muyiwa S. Adaramola ◽  
Olanrewaju M. Oyewola ◽  
Richard L. Fagbenle ◽  
Fidelis I. Abam
Keyword(s):  
Energy Systems ◽  
Building Energy ◽  
Global Solar Radiation ◽  
Dew Point ◽  
Weather Data ◽  
Maximum Temperature ◽  
Building Energy Simulation ◽  
Dew Point Temperature ◽  
Northwest Region

Computer simulation of buildings and solar energy systems are being used increasingly in energy assessments and design. This paper evaluates the typical meteorological year (TMY) for Sokoto, northwest region, Nigeria, using 23-year hourly weather data including global solar radiation, dew point temperature, mean temperature, maximum temperature, minimum temperature, relative humidity, and wind speed. Filkenstein-Schafer statistical method was utilized for the creation of a TMY for the site. The persistence of mean dry bulb temperature and daily global horizontal radiation on the five candidate months were evaluated. TMY predictions were compared with the 23-year long-term average values and are found to have close agreement and can be used in building energy simulation for comparative energy efficiency study.

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