Zmr heating load calculation
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This document provides information on calculating heating loads for buildings. It discusses key factors that influence heating loads such as outdoor and indoor temperatures, heat transfer methods, thermal properties of building materials, window properties, thermal bridges, and adjacent unheated areas. The document also provides example calculations and tables of correction factors to account for the influence of unheated neighboring spaces.
![HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019
Global heat transmission coefficient U
Internal surface
transfer
Conduction
through the wall
External surface
transfer
=
1
U
R
= +s si se
R R R
Global Heat
Transmission
Coefficient
[W/m²°C]
Thermal Resistance
= si i se
R R R R](https://image.slidesharecdn.com/zmrheatingloadcalculation-190508135852/85/Zmr-heating-load-calculation-25-320.jpg)
Zmr heating load calculation
- 1. HEATING LOAD CALCULATION T = 0°Cext T = 20°Cint 20kW 20kW 70°C
- 2. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Heating through the stove pipe Historical Scene from the 3rd century BC Fumes through the chimney 500 000 BC : Direct Evacuation Scene from the 3rd century BC Modern Heating
- 3. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 System Parameters
- 4. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 HEAT T ↑ T ↓ Conduction Convection Radiation Heat Transfer
- 5. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Conduction
- 6. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Convection
- 7. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Radiation
- 8. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 2 - Conduction 3 - Convection 1 - Radiation Da Vinci simulation
- 9. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Thermal Balance Comfort = Balance between the man and environment Thermal Balance Thermal imbalance Heating Balance
- 10. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Human Behavior
- 11. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Human Behavior 24% 35% 35% 6% HEAT EXCHANGE Evaporation Convection Radiation Ingestion of food 0 - 1% Conduction
- 12. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Comfort parameters Air velocity Ambient air Temperature Walls Temperature Relative Humidity Metabolism Clothes
- 13. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Metabolism “MET”
- 14. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Clothes “CLO”
- 15. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Relative humidity
- 16. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Air Velocity 0.2 /aV m s
- 17. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Confort temperature Radiant temperature of Walls Tp Temperature of the ambient air Ta + = 2 air parois rs T T T
- 18. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Global Comfort Calculation
- 19. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Room Temperature Indoor Temperature To Tday Tnight Dwellings Living, Bed room, Kitchen, Dining, Dressing room 21 °C 17 °C Bath, Shower 23 °C 17 °C Entrance, Release, Corridor, Stairway, laundry, Store 18 °C 15 °C Schools, Universities Classroom, Library, Permanence 19 to 21 °C 15 °C Access, Halls, Releases, Circulations, Stairway 15 °C 12 °C Gymnasium, Workshops 18 °C 15 °C Light workshops 21 °C 17 °C Shower 23 °C 17 °C Polyvalent rooms, Restaurants 18 °C 15 °C Dorms, chambers, Cloakroom 21 °C 17 °C Administration, Ganitor 21 °C 17 °C Indoor Temperature To Tday Tnight Offices Offices 21 °C 17 °C Hospital, Private clinic Patients rooms 20 - 22 °C 17 °C Operating rooms 26 °C Rooms of radio 22 °C Rooms of consultation 22 °C Rooms of breeding of the premature ones 25 - 30 °C Infants 22 °C Rooms of spectacle Removed external clothing 18 °C Preserved external clothing 14 °C
- 20. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Building Enhancement for more comfort
- 21. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Thermal Conductivity Wood Homogeneous Isotropic v e Transmission by vibrations of atoms or molecules Transmission by the free electrons Thermal conductivity of the material (W/m.°C) “ = constant” Brick Copper Air Material Glass FiberIron 0.21 85386 0.024 0.046 (W/m.°C) 0.52 Glass 0.74
- 22. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Insulator Conductor Void = o Liquids< Solids Gas < Liquids in (W/m.°C) METALS AND ALLOYS (at the ambient temperature) Copper 99,9% 386 Tin 61 Aluminum 99,9% 228 Nickel 61 Aluminum 99% 203 Mild steel (1% of C) 46 Zinc 111 Lead 35 Alloy (Al 92% - Mg 8%) 104 Titanium 21 Brass (Cu 70% - Zn 30%) 99 Stainless steel (Cr 18% - Nor 8%) 16 Iron 85 NONMETAL SOLIDS (at the ambient temperature) Electro graphite 116 Wood 0.21 Concrete 1.75 Polyester 0.209 Glass pyrex 1.16 Polyvinyls 0.162 Porcelain 0.928 Asbestos (sheets) 0.162 Glass 0.74 Phenoplasts 0.046 Asbestos cement 0.70 Glass Fiber 0.046 Bricks 0.52 Rock Wool 0.043 LIQUIDS GAS (at 0°C and under the normal pressure) Sodium at 200°C 81,20 Hydrogen 0.174 Mercury at 20°C 8,47 Air 0.024 Water at 100°C 0.67 Nitrogen 0.024 Water at 20°C 0.59 Oxygen 0.024 Benzene at 30°C 0.162 Acetylene 0.019 Dowtherm A at 20°C 0.139 Carbon dioxide 0.014 Thermal Conductivity
- 23. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 d A A . T R d R : Flux Thermique (W) Parois Homogène Simple Flux Thermique A : Surface de la parois (m2) : Différence de température(°C) R : Résistance Thermique (m2°C/W) T d : Epaisseur de la parois (m) : Conductivité Thermique (W/m°C)T1 T2 Conduction through a homogeneous wall
- 24. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Transmission through multi-layer walls d1 1 2 3 d2 d3 A Homogeneous walls Non-Homogeneous walls Wall in series Wall in Parallel 1 2 3 1 2 3 di A3 A2 A1 31 2 1 2 3 + dd d R iR R i i i A A R R 3 31 1 2 2 1 2 3 + AA A A R d d d
- 25. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Global heat transmission coefficient U Internal surface transfer Conduction through the wall External surface transfer = 1 U R = +s si se R R R Global Heat Transmission Coefficient [W/m²°C] Thermal Resistance = si i se R R R R
- 26. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 WALL Flow Rsi Rse Rs Vertical 0,13 0,04 0,17 Horizontal 0,10 0,04 0,14 0,17 0,04 0,21 Periferal Resistances Circulation d’air Rsi = 0.13 m²°C/WRse = 0.04 m²°C/W Rse = 0 m²°C/W Rsi = 0.17 m²°C/WRsi = 0.10 m²°C/W
- 27. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Air Layer Thickness of the air layer (mm) Thermal resistance Rg m²°C/W 4 0.10 0.10 0.10 6 0.12 0.12 0.12 8 0.14 0.14 0.14 10 0.15 0.15 0.15 12 0.16 0.16 0.16 15 0.16 0.17 0.17 20 0.16 0.18 0.18 25 0.16 0.18 0.19 50 0.16 0.18 0.21 100 0.16 0.18 0.22 300 0.16 0.18 0.23
- 28. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Rsi Rse = Rsi Indoor Clading Ventilated Air Layer Outoor Air Layer
- 29. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 U Value 4 4 5 5 Rsi Rse Indoor Outoor 1 si 2 se 1 1 = + ... ... n n dd R R R Rg R U Internal Plaster Brick terra cotta Thermal insulation Brick terra cotta External Plaster Rsi Rse + + + + + + = 0.015 0.15 0.16 0.12 0.02 = 0.13 0.04 5.26 0.7 0.44 0.36 0.44 0.87 R
- 30. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Example of calculation of U value Construction de l’élément Désignation de l’élément Mur extérieur . No Matériaux de construction d (m) l (W/m°C) R , d/l (m2°C/W) - Résistance surfacique intérieur Rsi 0.13 1 Enduit béton avec sable - intérieur 0.015 0.7 0.02 2 Block Béton creux 15cm 0,09 3 Isolation thermique - XPS 0.05 0.03 1.66 4 Block Béton creux 10cm 0.12 5 Enduit béton avec sable - extérieur 0.02 0. 7 0.03 - Résistance surfacique extérieur Rse 0.04 Rtotal = 2.00 U = 0.5 W/m2°C = 1 U R
- 31. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Glazing + + Y g . . .l = f f g g g W W U A U A U A Af = Ag = + Lg = AW = U Value of the Frames Uf In practice, the Uf values are very wide. If it misses controlled data, the following values will be taken: Wooden/Uf wood-metal = 1.9 (W/m2°C) Synthetic material Uf = 2.5 (W/m2°C) Insulated metal frame Uf = 3.3 (W/m2°C) Non insulated metal frame Uf = 5.0 (W/m2°C) U Value of glass Ug • Simple glazing All thicknesses. vertical glazing Ug = 5,8 (W/m2°C) horizontal glazing Ug = 6,9 (W/m2°C) • Double glazing or triple, makes the calculation of Ug. Guides ψg The values ψg depend on the U values of glasses : • Simple glazing: ψg = 0.00 (W/m°C) • Doubles or triple Glazing with frame in: Wood/wood-metal ψg = 0.05 (W/m°C) Synthetic material ψg = 0.05 (W/m°C) Insulated metal frame ψg = 0.07 (W/m°C) Non insulated metal frame ψg = 0.00 (W/m°C)
- 32. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Thermal bridges Indoor Cold bridge ψ Oudoor IndoorOutdoor Cold bridgeψ ψ1 ψ2 Insulator
- 33. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Ubat calculation
- 34. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Type of Heating Losses Openings ~13% Roofs ~30% Renewed air ~20% Grounds ~7% Thermal Bridges ~5% Walls ~25% ~ 80% Transmission ~ 20% air Renewal HLt = U x A x b x ΔT1 HLr = 0.34 x N x V x ΔT1 HL = ( HLt + HLr ) x 1.1 ΔT1 = Ti - To
- 35. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Walls Plancher bas Plancher haut Plancher basPlancher bas Plancher bas Plancher haut Plancher haut Plancher haut Plancher bas Plancher intermédiaire Plancher intermédiaire Plancher intermédiaire Plancher intermédiaire Plancher intermédiaire Plancher haut Angle < 60°
- 36. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Adjacent non-heated areas – Correction Factor « b » Roof Garage Underfloor space Full ground Type of air tightness of the room not heated Situation A No carries nor window, jointed well, not of opening of ventilation Non-ventilated B All well jointed components, small openings of ventilation Slightly ventilated C Little seals, some open joints or presence of openings of ventilation Ventilated D Little seals, many opened joints, or large openings of ventilation Strongly ventilated Type of Room A B C D Underfloor space 0.35 0.6 0.75 0.9 Technical shaft 0.5 0.7 0.8 1 Stairway 0.3 0.5 0.7 Attic 0.25 0.5 0.75 0.9 Insulated tiled roof 0.2 0.4 0.6 0.8 Non insulated tiled roof 0.4 0.6 0.8 0.9 Parking 0.4 0.6 0.8 0.9 Under ground (Horizontal) 0.4 0.6 0.8 0.9 Under ground (Vertical) 0.6 0.75 0.9 1 Cellar 0.25 0.5 Extension buildings 0.25 0.5 0.75 0.9 Full ground (Horiz.) 0.3 Full ground (Vert.) 0.6 Heated neighbor 0.2 Non heated neighbor 0.35 Table for Correction factor “b” HLt = U x A x b x ΔT1
- 37. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Air Renewal Air Change rate N (h-1) Dwellings Living, Bed room, Dining. 0.5 Kitchen, Entrance, Hallway, Stairway 1.5 Bathroom, Shower 2 Schools, Universities Classroom, Permanence 1.5 Halls, Releases, Circulations, Stairway 1.5 Library, Auditorium 4 Teachers Rooms, Administration 1 Polyvalent rooms, Restaurants, Gymnasium 2 Hospital, Private clinic patients rooms, operation rooms 0.5 consultation Rooms, Operating rooms 1 Theater 4 Store 2 Offices 0.5 Natural ventilation:Forced ventilation:To heat Why? Consequences? Thermal comfort Technical Equipment Energy Consumption To ventilate Why? Consequences? Indoor Air Quality Technical Equipment Energy Consumption HLr = 0.34 x N x V x ΔT1HLr = 0.34 x Q x ΔT1
- 38. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Heat Loss Calculation Room: ............................ Ti: ..................... (°C) Te: .................. (°C) Length: ..................... (m) Width: .................... (m) Height: ........... (m) Surface: ..................... (m²) Volume: ..................... (m³) Walls Length Width Height Area Net Area U Coeff. b ΔT1 Results (U.A.ΔT1.b) Ext. Wall (1) Opening Ext. Wall (2) Opening Int. Wall (1) Int. Wall (2) Ceiling Floor H.L.t= Air Renewal N = V = m³ Flow Q= m³/H H.L.r= (0.34xNxVx ΔT1) Sommation Increases (%) Total Heat Losses H.L.(W)
- 39. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 • Type of building • Type of walls & insulation. • Single or Double glass • Ceiling and floor • Place of project • Which floor Heat Loss Calculation
- 40. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Heat Losses from Buildings T = 0°Cext T = 20°Cint Déperdition 20m 0m
- 41. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 20m 0m 20m /h 3 T = 0°Cext T = 20°Cint 20kW 10m 0m 10m /h 3 T = 0°Cext T = 10°Cint 10kW 5m 0m 5m /h3 T = 0°Cext T = 5°Cint 5kW Heat Losses Evolution
- 42. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 T = 0°Cext T = 20°Cint 20kW 20kW 70°C 20m 0m 20m /h 3 20m /h3 How to maintain the indoor temperature
- 43. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 T = 0°Cext T = 20°Cint 20kW 20kW 70°C 20m 0m 20m /h 3 20m /h3 T = 5°Cext T = 20°Cint 15kW 15kW 57.5°C 20m 0m 15m /h3 15m /h3 5m T = 10°Cext T = 20°Cint 10kW 10kW 45°C 20m 0m 10m /h3 10m /h3 10m Outdoor temperature variation Effect
- 44. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 20m 0m 25m /h 3 20m /h 3 T = 0°Cext T = 20°Cint 20kW 25kW 20m 0m 25m /h3 25m /h 3 25m T = 0°Cext T = 25°Cint 25kW 25kW Excess of Heat
- 45. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 T = 0°Cext T = 15°Cint 15kW 15kW 20m 0m 15m /h3 20m /h3 T = 0°Cext T = 20°Cint 20kW 15kW 20m 0m 15m /h3 15m /h3 15m Unsufficient Heat
- 46. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 T = 0°Cext T = 20°Cint 20kW 20kW 70°C 75°C 65°C Radiator Temperature
- 47. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 Radiator Selection Ts Tr Tm Ta Tm=70ºC ΔT2=50ºCTs: Supply temperature Tr: Return temperature Ta: Ambient temperature Tm: Mean radiator temperature ΔT2: Temperature difference between radiator and ambiance ΔT2=Tm-Ta Small radiators with high temperature 90ºC 70ºC Old standard 75ºC 65ºC EN standard The new Low temperature standard 55ºC 45ºC Tm= Ts+Tr 2
- 48. HEATING LOAD CALCULATIONZMERLY ACADEMY - 2019 T = 0°Cext T = 20°Cint 20kW 20kW 70°C T = 0°Cext T = 20°Cint 20kW 20kW 50°C T = 0°Cext T = 20°Cint 20kW 20kW 90°C Radiator Sizing
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