Thermal Comfort

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An overview of the conditions that produce the

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Thermal Comfort

  1. 1. BUILDINGS & THERMAL COMFORT What are the qualities that assure we are comfortable in our homes? Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  2. 2. BUILDINGS & THERMAL COMFORT The ability to provide thermal comfort is one of the most important functions of a building not too hot, not too cold… Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  3. 3. BUILDINGS & THERMAL COMFORT …which we might think of as our third “skin”. Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  4. 4. BUILDINGS & THERMAL COMFORT Optimal thermal comfort requires the heat loss of the human body to be in BALANCE with its heat production. This is similar to the relationship between an activity (exercising, skiing...) and clothes - our second skin. Heat Production Heat Loss Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  5. 5. BUILDINGS & THERMAL COMFORT The conditions that maintain this thermal balance in a building are: o  air temperature o  the temperature of the surrounding surfaces ( the ”mean radiant temperature") o  air speed and turbulence o  humidity of the air Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  6. 6. BUILDINGS & THERMAL COMFORT When we adjust a thermostat we are setting a goal for a comfortable air temperature Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  7. 7. BUILDINGS & THERMAL COMFORT How that temperature actually feels depends on drafts and air currents in the room Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  8. 8. BUILDINGS & THERMAL COMFORT and the temperatures* of the wall, window, ceiling, and floor surfaces in the room * this condition is called the “mean radiant temperature” Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  9. 9. BUILDINGS & THERMAL COMFORT and the level of humidity at that temperature Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  10. 10. BUILDINGS & THERMAL COMFORT This chart illustrates the summer and winter comfort zones relative to temperature and humidity In cold weather we are more comfortable “wetter” In hot weather we prefer it “drier” Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  11. 11. BUILDINGS & THERMAL COMFORT To feel good, a range of combinations create a comfort field in which: •  the air is not too humid •  air speeds remain within established limits •  the difference between radiant and air temperature remains small •  the difference of the radiant temperature in different directions (between your body and adjacent surfaces) remains small •  room air temperature between head and feet is small •  the perceived temperature varies less than 1.5°F within the living area •  the air is clean Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  12. 12. BUILDINGS & THERMAL COMFORT Maintaining this comfort field is the domain of these two important building systems: o  BUILDING ENVELOPE which includes the walls, floors, and roof or ceilings that enclose the building, and any penetrations of that enclosure for doors, windows, chimneys, vents, etc. plus the accumulated air leakage created by gaps in the structure o  MECHANICAL SYSTEMS that provide supplemental heating, sometimes cooling, and any controlled ventilation. Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  13. 13. BUILDINGS & THERMAL COMFORT Shortcomings in the building envelope often require us to tolerate conditions outside the comfort field. Buildings that are leaky, drafty, and minimally insulated, with average windows, variation in temperature between ceiling and floor, and cold surrounding surfaces are likely to be experienced as uncomfortable … this is typical of MOST buildings! Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  14. 14. BUILDINGS & THERMAL COMFORT We seek control over these conditions thru the use of mechanical systems like boilers and furnaces. … that stuff in the basement that keeps us warm Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  15. 15. BUILDINGS & THERMAL COMFORT … with the turn of a dial though fuel costs may prompt other strategies Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  16. 16. BUILDINGS & THERMAL COMFORT To overcome our discomfort we may rely (at a cost) on additional fans, heaters, humidifiers, etc. to establish a local comfort zone … or just wear more clothes Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  17. 17. BUILDINGS & THERMAL COMFORT By making integrated improvements to the building envelope and mechanical systems we can provide a more dependable comfort field. This is an illustration of Passive House strategies Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  18. 18. BUILDINGS & THERMAL COMFORT These are the strategies and effects that we rely on to create the conditions that assure thermal comfort STRATEGIES EFFECT Maximize insulation levels Retard the transfer of heat (including losses to ground) Eliminate thermal bridges Retard the transfer of heat (thru solid materials) Dramatically reduce air leaks Retard the transfer of heat and moisture (thru air leakage) Install Net Gain Windows Gain more energy than is lost thru glass Orient the building to capture solar Maximize ability to gain energy without energy and shade to prevent the risk of overheating overheating Use natural ventilation to cool Reduce the need for mechanical cooling Use heat recovery ventilation Assure a constant and controlled rate of fresh air while recovering energy Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  19. 19. BUILDINGS & THERMAL COMFORT NET GAIN WINDOWS These improvements allow us to acquire greater control over each of the factors that determine comfort. Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  20. 20. BUILDINGS & THERMAL COMFORT The effect, while scientifically quantifiable, is ultimately valued for its quality: We can be considerably and consistently more comfortable in our homes. Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants
  21. 21. BUILDINGS & THERMAL COMFORT MAKE SENSE Designers & Builders of FUTURE FRIENDLY HOMES • Certified Passive House Consultants

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