Download presentation
Presentation is loading. Please wait.
Published byRoger Coupland Modified over 10 years ago
1
10 June 2014©Uponor1 Snow Melting Systems
2
10 June 2014©Uponor2 Why Snow Melting ? Safety Garage ramps, driveways Sidewalks, bldg. entrances Emergency exits Reduced maintenance cost No shoveling, no plowing No salting Extended surface life Carpets and tiles in the buildings Concrete, interlock stones Surrounding landscaping NO LITIGATIONS
3
10 June 2014©Uponor3 Snow-Melt Design/Performance CL1 Residential (Ar = 0) 120 Btu/sqft/hr load Semi-auto / manual controls 9 o.c. CL2 Type Commercial/Public (Ar=.5) 150 Btu/sqft/hr load 9 o.c. Automatic controls CL3 High safety areas (Ar = 1) upper range of 200 Btu/sqft/hr 6o.c. Automatic controls /idling option
4
10 June 2014©Uponor4 Variables Affecting Load Design? Environmental Factors Snow fall rate Wet or fluffy/dense snow Snow temperature Outside temperature Wind conditions Per ASHRAE Applications Heat Flux for City To 95% of heat flux Snow free area ratio 1, 0.5, 0.0(0=snow cover=no wind effect)
5
10 June 2014©Uponor5 Snow Melt Heat Balance q= q s +q m +A r (q h +q e ) q heat flux required at surface q s sensible heat flux q m latent heat flux (melting snow) A r snowfree area ratio q h convective and radiative heat flux, after snow has melted q e evaporative heat flux
6
10 June 2014©Uponor6 Snowmelt Design p.41 Step 1- Identify the outside air temp. and wind speed Step 2- Identify Delta T for system design Step 3- Select design surface temp. Step 4- Determine btu/sqft Step 5- Determine supply water temp. Step 6- Identify the installation area Step 7- Determine btu/h requirements (boiler sizing) Step 8- Determine type and size of tubing Step 9- Determine the amount of tubing Step 10- Determine active loop lengths and # of loops Step 11- Determine total loop length with leader Step 12- Select percentage of glycol Step 13- Determine gpm Step 14- Determine system gpm Step 15- Determine system pressure drop
7
10 June 2014©Uponor7 Design parameters Design temp. = 5F Wind speed = 10 mph Surface temp. = 38F 1700sqft driveway 5/8 MultiCor Appendix A – worksheet p. 61
8
10 June 2014©Uponor8 Snowmelt design Step 1- Identify the outside air temp. and wind speed Step 2- Identify Delta T for system design Step 3- Select design surface temp.
9
10 June 2014©Uponor9 Snowmelt design Step 4- Determine btu/sqft/hr Step 5- Determine supply water temp. Appendix C – Page 66
10
10 June 2014©Uponor10 Snowmelt design Step 6- Identify the installation area -Ex. Sidewalk 17ft x 100ft = 1,700 sqft
11
10 June 2014©Uponor11 Snowmelt design Step 7- Determine btu/h requirements (boiler sizing) Ex. Sidewalk -126 btu/sqft x 1,700 sqft = 214,200 btu/h Step 8 - Determine type a size of tubing
12
10 June 2014©Uponor12 Snowmelt design Step 9- Determine the amount of tubing 1.33 x 1,700 = 2,261 Step 10- Determine active loop lengths and # of loops 2,261 / 200 = 11.3 loops ( ~12 loops) or 2,261 / 11 = 206 ft per loop
13
10 June 2014©Uponor13 Snowmelt design Step 12- Select percentage of glycol Ex. Sidewalk we selected 40% glycol mixture
14
10 June 2014©Uponor14 Snowmelt design Step 13- Determine gpm Appendix C, p70 206 ft x 0.0081 = 1.67 gpm per loop
15
10 June 2014©Uponor15 Snowmelt design Step 14- Determine system gpm 1.67 gmp/loop x 11 loops = 18.37 gpm Step 15- Determine system pressure drop 0.03090 x 226 = 7.0 ft of head Appendix E, p85
16
10 June 2014©Uponor16 System Design TYP. SYSTEM Outdoor Air Temp - 0 °F Wind Speed - 10 mph Fluid Temp Drop 25 °F, (25-30 °F) Tube Spacing 6-9 o.c. Surf Temp 38 °F, (36-45 °F) Fluid Max 150 °F 200 Btu/sqft/hr
17
10 June 2014©Uponor17 Mechanical Components
18
10 June 2014©Uponor18 Snowmelt typical loop layout
19
10 June 2014©Uponor19 Architectural Considerations
20
10 June 2014©Uponor20 Installation Methods
21
10 June 2014©Uponor21
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.