ASHRAE Journal- September 2008

with large windows where you can expect a significant influence of sun radiation either directly or due to a warm ceiling or wall surface (atria, airports, shopping malls, etc.). Floor cooling absorbs the sun radiation before it heats the space. The world’s largest construction with floor cooling is the new airport in Bangkok, Thailand.3 Some 150,000 m2 (1.6 million ft2) of floor cooling is installed in the concourses and main terminal buildings. The roof over the concourses (Figures 4 and 5) consists of glass and a plastic membrane construction. Due to the high outside temperatures and sun radiation, this results in a high cooling load. A combination of displacement ventilation and floor cooling has been installed (Figure 4). The floor cooling was dimensioned to remove 70 W/m2 to 80 W/m2 (22 Btu/h · ft2 to 25 Btu/h · ft2) with a supply water temperature of 13°C (55°F), return water 19°C (66°F) and a floor surface temperature of 21°C (70°F). The manifolds for the floor system were installed inside the displacement air diffusers (Figure 5). As the dew point in the supply air is 10°C (50°F) and lower than the supply water temperature, there is no risk for condensation on the pipes. The design dew point in the space was 16°C (61°F) due to evaporation from the occupants. This is still 5°C (9°F) lower than the surface temperature of the chilled floor. Compared to a full air system a 30% reduction of energy consumption was predicted during the design.3 Figure 5: Installation of floor cooling with manifolds in the displacement diffusers at the new Bangkok airport. Conclusions FLOWHOOD ELECTRONIC FLOWHOOD DIRECT DIGITAL READOUT 25-2500 CFM • A hydronic floor cooling system provides sensible cooling without noise, draft, obstacles, or the need for cleaning. • The maximum cooling capacity for most spaces is less than 50 W/m2 (16 Btu/h · ft2). In spaces where the sun shines directly on the floor (atrium, entrance hall, showroom), the cooling capacity is significantly higher—up to 100 W/m2 (32 Btu/h · ft2). • A floor cooling system must be controlled to avoid condensation. This may be done by a supply water temperature that is controlled by the dew-point temperature. References 1. Borresen, B. 1994. “Floor heating and cooling of an atrium.” Internationaler Velta-Kongreß. Arlberg/St. Christoph. 2. Olesen, B.W. 1997. “Possibilities and limitations of radiant floor cooling.” ASHRAE Transactions 103(1):42 – 48. 3. Simmonds, P., W. Gaw, S. Holst, S. Reuss. 2000. “Using radiant cooled floors to condition large spaces and maintain comfort conditions.” ASHRAE Transactions 106(1):695 – 701. 4. ANSI/ASHRAE Standard 55-1992, Thermal Environmental Conditions for Human Occupancy. 5. ISO Standard 7730. 1994. “Moderate thermal environments— determination of the PMV and PPD indices and specification of the conditions for thermal comfort.” Geneva: International Organization for Standardization. 6. Michel, E. and J-P. Isoardi. 1993. “Cooling floor.” Proceedings of Clima 2000. 7. Deli, I. 1995. “Het gebruik van vloerverwarmingssystemen voor keeling.” Diplomarbeit, TU, Eindhoven. 8. Olesen, B.W., E. Michel, F. Bonnefoi, M. De Carli. 2000. “Heat exchange coefficient between floor surface and space by floor cooling: theory or a question of definition.” ASHRAE Transactions 106(1):684 – 694. 9. EN15377-1. 2007. Design of Embedded Water Based Surface Heating and Cooling Systems: Determination of the Design Heating and Cooling Capacity. 10. REHVA. 2007. REHVA Guide 7. “Low temperature heating-high temperature cooling.” AUTOMATICALLY CORRECTS FOR AIR DENSITY & BACKPRESSURE CHOICE OF METERS - AIR FLOW ONLY, OR AIR FLOW, VELOCITY, PRESSURE & TEMPERATURE OPTIONS INCLUDE: MEMORY, AVERAGE & SUM TO 2000 READINGS, SEQUENTIAL RECALL, AUTO-READ REPAIR POLICY - TWO WEEK TURNAROUND OR LESS CUSTOM TOPS MADE TO ORDER Shortridge Instruments, Inc. 7855 East Redfield Road • Scottsdale, Arizona 85260 (480) 991-6744 FAX (480) 443-1267 www.info.hotims.com/19354-53 22 ASHRAE Journal September 2008 http://www.info.hotims.com/19354-53

Table of Contents Feed for the Digital Edition of ASHRAE Journal- September 2008

ASHRAE Journal- September 2008 Section: Contents Contents Section: Commentary Options for Sustainability Section: Industry News The Silk Route for Energy Solar Thermal Is Unrealized Opportunity Industry Groups Sue City of Albuquerque Section: Letters Letters Section: Meetings and Shows Meetings and Shows Section: Feature Articles Article-Radiant Floor Cooling Systems Article-HVAC Design for Sustainable Lab Article-Mixed Mode Ventilation Article-Single- Design Considerations For Active Chilled Beams Article-Acoustic Design In Green Buildings Article-Teams, Contracts & BIM Section: Building Sciences Some Old Lessons Distilled Section: Washington Report Energy in Federal Buildings Section: Products HVAC&R Product Showplace Section: Emerging Technologies Toplighting & Lighting Controls For Commercial Buildings Section: Special Products Fans & Blowers Section: Classified Ads Classified Ads Section: Advertising Index Advertising Index

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