Slide 1

PASSIVE HOUSE VENTILATION SYSTEMS Patricia Alonso Alonso LECTURER Patricia.alonso.alonso@udc.es Department of Building Constructions

Slide 2

Why do buildings need to be ventilated?

Slide 3

..keep people healthy and comfortable..reduce moisture and condensation in winter .......reduce heat gain in summer Because we..

Slide 4

PASSIVE HOUSE VENTILATION SYSTEMS FOR DESIGN... EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 5

PASSIVE HOUSE VENTILATION SYSTEMS EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS FOR DESIGN...

Slide 6

Thermal comfort sensation Temperature EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS SeasonTemperature (C) Summer23.25 Winter21.23 Data table: temperature and thermal comfort

Slide 7

Thermal comfort sensation Data table: Relative humidity and thermal comfort EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 8

Thermal comfort sensation Warmth feeling is reduced using air movement 1C less for 0,2 m/s velocity increased. Limit: 5C Velocity (m/s) Sensation Until 0,2inappreciable 0,2 to 0,5 Nice, but air movement is perceved 0,5 to 1Mild discomfort to severe discomfort 1 to 1,5Unfit for human comfort >1,5Corrective action is required Data table: Air velocity and comfort sensation. Source: EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 9

Comfort sensation Air quality Sick building Symdrome EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Araujo, 2009)

Slide 10

PASSIVE HOUSE VENTILATION SYSTEMS EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 11

CONCEPTS Natural ventilation without any mechanical device 1.Difference between two points Chimmey or Stack effect The higher temperature difference, the better natural ventilation EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 12

2. Decrease in pressure over extraction point Venturi effect The higher wind velocity and little extraction gap size, the better natural ventilation. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 13

3. Dynamic pressure generated by the wind over a hole Wind effect The higher wind velocity, the pressure generated and difference of pressure with respect of other hole, the better of the ventilation. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 14

TECHNIQUES IN BUILDINGS A.Pure natural ventilation The simplest form of ventilation is window opening (shape, side and position in relation to each other) -Direct (Effectiveness: The depth of the room should not exceed 2,5 times the room height) -Cross-ventilation (Effectiveness: The depth of the room should not exceed 5 times the room height) H 2,5 or 5 H Cross-ventilation Direct EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 15

B. Naturally forced ventilation (utilising updraught systems) (Effectiveness: air pressures decreases with increasing height. Warm air has a lower density than cold air) Reheating faade Reheating roof Heat chimmey extraction Wind chimmey induction Elevated atria Reheating faade Reheating roof EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Neila,2009)

Slide 16

Updraught systems Extraction at wet areas. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Heat chimmey extraction Source: (Neila,2009) Source: (Araujo,2009)

Slide 17

Elevated atria EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Araujo, 2009)

Slide 18

PASSIVE HOUSE VENTILATION SYSTEMS EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 19

PASSIVE COOLING SYSTEMS FOR BUILDINGS Evaporative cooling Vegetation and water Air and water Radiant cooling Wet roofs Courtyards Conductive cooling Cold surfaces Underground ducts Underground constructions Convective cooling Night ventilation EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 20

Water: To a good evaporation it is necessary to achieve a high spraying level The best: a water jet Worse: a water pond EVAPORATIVE COOLING It is a adiabatic process The overall energy is not altered EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006) Source: (Neila, 2009)

Slide 21

Vegetation: A tree is capable of evaporating 500 Kg of water/year every m 2 of exterior surface. That means 1212MJ/m 2 a year that is equivalent to a cooling power of 40W/m 2 of vegetal surface EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)Source: (Neila, 2009)

Slide 22

Water and vegetation: To evaporate 1 gram/s of water (it is necesary 2424 Julius/s or 2,42kW cooling power) it is reduced 2,2C the temperature of a m 3 air Example: Alhambra de Granada EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006) Source: (Neila, 2009)

Slide 23

Air: Popular architecture of Middle East: Wind towers Malqaf or windcatchers EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 24

Water and air: Windcatchers with evaporative cooling effect Sample of Malqaf using Salsabil (fountain), (Hassan Fathy 1986) Section of Malqaf using Pottery Jars to cool Air at Maziara Egypt by Hassan Fathy (Rosa Schiano 2007) EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 25

Water and air: Windcatchers with evaporative cooling effect Bahadori (1985) developed the Downdraught Evaporative Cool Towers as an upgrade to the traditional Malqaf & Badgir EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 26

Source: (Rosa Schiano 2007) Water and air: Mashrabiya. Muscatese Evaporative cooling window system. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 27

Water and air: Recent example: Spanish Pavilium. Zaragoza 2008 (Spain) Patxi Mangado Architect Based on Botijo effect (Porous water pot) EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: Mercadel, 2014

Slide 28

Spanish Pavilium. Zaragoza 2008 (Spain) Patxi Mangado Architect EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Mangado, 2009)

Slide 29

RADIANT COOLING When the cooling system is reducing the quantity of energy of an environment it is named sensitive cooling. Two things we need: A bit of cold and mass enough to dump the heat and maintaining the temperature. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 30

Types of heat sinks to radiate: Celestial dome that covers us The ground that supports us The air that surrounds us The water Types of radiant mass at buildings Radiant slabs and ceilings Wet roofs Faade Courtyards EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 31

Radiant slab and ceiling EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Wet roofs Water confined in black bags and set on the roof Roof pond Source: (Helena Granados, 2006)

Slide 32

Faade: Trombe-Michel walls, (Northwest of Spain) Typical galera of A Corua (Spain) Constructive detail of a galera EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 33

Courtyards: Cooling effect over night radiation Outside air temperature should be 5K below the inside room temperature for at least 5 to 6 hours EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 34

CONDUCTIVE COOLING Underground buildings. Cave dwelling About nine meters underground the temperature is steady. Plan of a cave dweling at Guadix, Granada (Spain) EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 35

Cave dwelling Guadix, Granada (Spain) Ventilation chimmey of cavesTypical plan of a cave EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 36

Underground ducts Duct under the ground passing an airstream and then pushing up to the building interior. Earth pipes Example: Canadian well EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Helena Granados, 2006)

Slide 37

CANADIAN WELL Geothermal system where the stability of the temperatures of underground are used to improve the air temperature before entering in buildings (underground in winter the temperature is higher and in summer is less than in outside), providing freshness in summer and warmth in winter. Ducts are buried between 1.5 and 3 m the long of ducts are between 10 and 100 m. Airstream pass through this ducts therefore it is heated or cooled before pushing up to building interior. Typical diameter of an earth pipe is 20cm Ducts are buried between 1.5 and 3 m Ducts length are between 10 and 100 m EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 38

The distance between them should not be less than one metre A low velocity of 2m/s should be ensured Between temperatures 12-18C the earth-pipe is not usually used A Canadian well can reduce the temperature by 5 to 8C in your house during a heat wave using virtually no electricity EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Eco-house system website, 2014)

Slide 39

EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Typical ventilation installation of Standard Passive house Source: (Wikipedia, 2014)

Slide 40

Passive house standards with heat recovery ventilation system (HVR) EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Source: (Araujo, 2009)

Slide 41

Spanish Building Code C.T.E. DB-HS-3 Interior Air Quality Proposed solution (Comunidad de Madrid) Night cooling is very efficient Minimum maintenance Very interesting in refubishing EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS Centralized ventilation Humidity sensor Individual ventilation unit Intelligent CO 2 sensor Source: (Fenercom, 2014)

Slide 42

EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS CONVECTIVE COOLING Using cold mass of air. Night ventilation Example: Villa Costozza in Italy, Andrea Palladio Source: (Helena Granados, 2006)

Slide 43

PASSIVE HOUSE VENTILATION SYSTEMS EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 44

HOW TO PROCEED?.. EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 45

1. We should analize very vell the environment and socio- economical and local aspects 2. We could select different VENTILATION strategies to apply at Corte, Corsica 3. We could try to develop a diagram of how it would work 4. We could develop the solutions selected EVAPORATIVE COOLING RADIANT COOLING CONDUCTIVE COOLING CONVECTIVE COOLING CONCEPTS & TECHNIQUES SYSTEMS INTRODUCTION CONCLUSIONS

Slide 46

For example.. Steps to analize building constructions Source: (Neila, 2004) 1. Location 2. Climate 3. Environmental conditions 4. Socioeconomic conditions 5. Formal description 6. Constructive description 7. Environmental use and bioclimatic strategies

Slide 47

the next step is your decision

Slide 48

PASSIVE HOUSE VENTILATION SYSTEMS Thank you for your attention Patricia Alonso Alonso LECTURER Patricia.alonso.alonso@udc.es Department of Building Constructions *All this information and images exposed are been used only for educational purposes