Radiant 101 Casey Swanson Him Ly

Radiant 101 Casey Swanson & Him Ly

Terms and Definitions • AUST Average Uncontrolled Surface Temp. ― Area weighted of all interior surfaces ― Excluding cooled panel • MRT Mean Radiant Temp. ― (AUST+cooled panel)/2 • Operative Temp. ― ― Temp. an occupant feels (MRT + room temp)/2 Winter (68 F – 75 F) Summer (73 F – 79 F) 16 March 2018 ©Uponor 2

Calculating AUST MRT OT Room Temp. = 77 F Room Temp. = 68 F AUST = 78. 2 F AUST = 66. 4 F MRT = 72. 1 F MRT = 75. 7 F Operative Temp. = 74. 6 F Operative Temp. = 71. 9 F 16 March 2018 ©Uponor 3

National Building Code Requirements Refers to ASHRAE 55 on thermal comfort: “produce thermal environmental conditions acceptable to a majority /80% of the occupants within the space. ” Factors: • Metabolic rate / activity Clothing • Air Temperature • Air Speed Humidity Radiant Temperature • • • 16 March 2018 ©Uponor 4

Thermal Comfort…ASHRAE Standard 55 Floor Surface Temperature, °F Predicted Percent Dissatisfied 80 60 40 30 66 °F 10 6 4 41 84 °F Design Range 50 59 68 77 86 95 104 Ref. : ASHRAE Standard 55 -2004 16 March 2018 ©Uponor 5

Thermal Comfort…. ASHRAE Standard 55 Predicted Percent Dissatisfied Radiant Temperature Asymmetry, °F ng 80 all Ce ili 60 ar m l. W o Ce l oo Co W 40 20 ing il C 10 6 all W Warm 4 Design Range 0 9 18 27 36 45 54 63 Ref. : ASHRAE Standard 55 -2004 16 March 2018 ©Uponor 6

Thermal Comfort…ASHRAE Standard 55 10 10 8 Design 6 6 Range 4 2 0 4 0 Ref. : ASHRAE Standard 55 -2004 4 16 March 2018 7 11 ©Uponor Predicted Percent Dissatisfied Air Temperature Difference Between Head and Feet, °F 80 60 60 40 40 20 20 14 14 18 7

Common HVAC concerns that a radiant system can solve • • • 16 March 2018 Inconsistent temperatures Circulation of dust and allergens High (O&M) operating and maintenance costs Aesthetics Space considerations Building heights Large glazing areas Dry air Noise Window condensation Odor circulation Damp lower levels ©Uponor 8

Radiant Overview • A hydronic system consists of an installation of embedded tubes or surface mounted panels • Radiant heating and cooling systems use the structure and surfaces of an area to transfer energy ― In radiant heating systems, the energy moves away from the heated surface towards the cooler area ― In radiant cooling systems, the energy moves towards the cooled surface from the warmer area 16 March 2018 ©Uponor 9

Convection Radiation Convection Tsc & Dp Toc Tih Toh Ref. : ASHRAE Standard 55 -2004 16 March 2018 ©Uponor 10

Radiant –Efficiencies § Water has roughly 3, 500 times the energy transport capacity of air § With radiant space conditioning systems, the ventilation function is separate – – § The volume of air moved and component size can be up to 5 times less Fan power and duct size is much smaller The cost of a radiant system is comparable to traditional variable-air-volume (VAV) system *Analysis and statistics provided by the Lawrence Berkeley National Laboratory (LBNL) 16 March 2018 ©Uponor 11

Radiant System Economics • LBNL modeled office buildings in 9 US cities comparing radiant with ventilation and all other forced air VAV systems § Findings: – Radiant cooling, on average, saves 30% overall energy for cooling and 27% on demand – Energy savings of • • 17% in cold, moist climates 42% in warmer, dry climates The Hearst Tower, New York City 16 March 2018 ©Uponor 12

System Types, Strategies and Design Considerations

Types of Systems • There are two primary types of radiant systems ― High Mass: incorporates the mass of the building with tubing embedded within the structure ― Low Mass: uses surface mounted ceiling/wall panels 16 March 2018 ©Uponor 14

High Mass Systems (cooling) • Draws the energy from the surface toward the embedded tubing in the slab or wall ― Chilled water is circulated through the tubing • Similar installation to radiant floor heating systems ― Very common to incorporate a hybrid system that cools and heats based on demand ― Slower response times and more residual energy Low Mass Systems • Low mass radiant cooling systems are based on the Fanger Concept ― They react fairly quickly to temperature change ― Have little or no residual energy ― Must be used as an active system • Work well for retrofit applications 16 March 2018 ©Uponor 15

Types of Loads • Sensible load ― Direct solar load • Latent load ― Can not address ― Mechanical system is required The Akron Art Museum, Ohio 16 March 2018 ©Uponor 16

Sensible Load • The external loads account for only 42% of thermal cooling peak ― ― • • • A typical office building in Los Angeles as modeled by LBNL 16 March 2018 28% of the internal gains were produced by lighting 13% by air transport 12% by people 5% by equipment This is the dry bulb heat or heat gain in the space Radiant cooled systems can handle a significant portion of this load Absorption is dependant upon a decreased surface temperature ©Uponor 17

Latent Load • This is the energy that is contained in the moisture in the air, the wet bulb load or gain • A phase change is required to address this load • Radiant cooling systems can not address this load ― The ventilation system must: ― Address the latent load ― Balance of the sensible load if any exists ― Control the level of humidity within the air system § Meet the requirements of the Indoor Air Quality Standards for fresh air • Dew point is determined by the relative humidity and temperature within the space • In most cases an Rh of 50% or lower will be sufficient to prevent condensation on the cooling surface • Humidity level in the building must be controlled through the ventilation system 16 March 2018 ©Uponor 18

Direct Solar Load • Short wave radiation (sun, electrical lights) ― Energy transferred independent of room temperature and surrounding surfaces • Amount of energy absorbed depends on absorbtivity of material • In spaces with high solar gain 25 – 32 Btu/h/ft 2 • If Solar load exceeds cooling capacity ― Increases the floor surface temperature ― Emits long wave radiation back into space The Los Angels Federal Building, California ` 16 March 2018 ©Uponor 19

Direct Solar Load Absorptance for Solar Radiation Surfaces Carpet dark ______ Black metallic surfaces (asphalt, carbon, slate, paper. . ) 0. 85 . 98 Tile or plaster, white or light cream 0. 30 ─ 0. 50 Red tile, stone or concrete, dark paints (red, brown, green, etc. ) 0. 65 ─ 0. 80 White painted surfaces 0. 23 ─ 0. 49 Table: Absorptances for Solar Radiation, Source ASHRAE Fundamentals, 1996 16 March 2018 ©Uponor 20

Total Heat Exchange Coefficient Mode Heating Cooling Surface Btu/h ·ft 2 ·°F W/m 2 · ºK Floor 1. 9 11 1. 2 7 Wall 1. 4 8 Ceiling 1. 2 7 1. 9 11 16 March 2018 ©Uponor 21

q(tot) = q(con) + ql, (rad) + qs, (rad) q(tot) = h(tot) x (to – ts) + qs, (rad) q(tot) – total space heat flux (Btu/sq ft) q(con) – convective heat flux (Btu/sq ft) ql(rad) – long wave radiative heat flux (Btu/sq ft) qs(rad) – short wave radiative heat flux (Btu/sq ft) h(tot) – heat exchange coefficient to – operative temperature ts – floor surface temperature 16 March 2018 ©Uponor 22

Design Considerations • Radiant energy to condition a space is only a few degrees different from the temperature of the conditioned space • The supply water temperature to the floor needs to be 2 degrees above the dew point • In highly humid areas ― Buildings need to be moderately well air sealed ― Ventilation air would need some dehumidification • Cross section of the cooling surface needs to be big enough to deliver the cooling at a small water temperature differential 16 March 2018 ©Uponor 24

Design Considerations • Keep the total loop lengths within standard coil lengths of 300 or 1, 000 feet ― Two or three loops per 1, 000 foot coil ― One loop per 300 foot coil ― Work out a straight forward, standardized basis of design ― Keep things consistent and repeatable ― 5/8” he. PEX™ plus tubing at 6 or 9 inches on center • Always design for the best possible system performance • Remember, radiant cooling enhances, it is not a stand alone system • Allows the downsizing of HVAC equipment and ductwork • Design differential temperatures ― 5 8 o. F for cooling ― 10 20 o. F for heating 16 March 2018 ©Uponor 25

System Strategies • Active systems are systems that run during the occupied time ― They provide a nearly steady set point ― Typically cost more to operate • Passive systems also called activated core or activated concrete systems They operate most often during the unoccupied time ― Occupants may experience a slight drift in set point temperature across the day ― Take advantage of off peak energy rates to lower operating costs 16 March 2018 ©Uponor 26

The Water + Life Building, Southern California Common Design Results • Most radiant cooling designs fall within the following parameters § § § 16 March 2018 ©Uponor 12 to 14 Btu/h/ft 2 of sensible cooling Up to 32 Btu/h/ft 2 of solar absorption 66 o. F minimum floor surface temperature 76 o. F to 78 o. F room set point temperature 55 o. F thru 58 o. F supply fluid temperature 27

Common Radiant Applications • • • The Copenhagen Opera House 16 March 2018 ©Uponor Museums Institutional, educational and recreational facilities High-rise hotels / offices Manufacturing & retail spaces Hospitals/health care and assisted living facilities Dormitories, barracks & prisons Churches Wineries Airports Residential 28

Featured Project

Bangkok International Airport • Outdoor Temperature at 77 95°F and year round high RH relative humidity • The annual horizontal solar radiation total is more than 1, 500 k. Wh/m²a, results in a solar radiation of 1, 000 W/m² • 45, 708 m 2 (492, 000 ft 2) radiant cooling • Humidity is conditioned in the airport to 50 60% • Ventilation is four air changes/hour 16 March 2018 ©Uponor 30

Bangkok International Airport • Radiant Cooling Supply Water Temp is 13°C (55°F) • Return Water Temperature of 19°C (66°F) • Cooling capacity of 80 W/m² (25. 5 btu/ft²) • 40% of the total load Airport Load is handled by the radiant cooling • Total cooling load energy savings = 30. 5 % 16 March 2018 ©Uponor 31

Bangkok International Airport 16 March 2018 ©Uponor 32

Bangkok International Airport Temperature Distribution 55 o. C (131 o. F) 21 o. C (70 o. F) 16 March 2018 ©Uponor 33

Bangkok International Airport Comparison of cooling loads for the entire airport Optimized Concept Original Concept 44% DE CR EA Total Load: 191 GWH/a 513 k. Wh/m 2 a Total Load: 275 GWH/a 739 k. Wh/m 2 a 16 March 2018 ©Uponor 34 SE

Design Services • Assist in radiant systems design ― Design Parameters ―Heating/cooling sensible loads ―Solar gain ―Space setpoint and relative humidity ―Construction details • Radiant schedule • CAD loop layout • Bill of materials 16 March 2018 ©Uponor 35

Questions? Thank you