How much ventilation and how to ventilate in the future? The EU policy by 2020

Transcription

1 How much ventilation and how to ventilate in the future? Professor Bjarne W. Olesen, Ph.D. Department of Civil Engineering Technical University of Denmark The EU policy by 2020 By 2020 all new building must bee near zero energy buildings, nzeb 100% -20% -20% 20% 8,5% Greenhouse gas levels Energy consumption Renewables in energy mix

2 COMFORT-PRODUCTIVITY Building costs People 100 Maintenance 10 Financing 10 Energy 1 INTAKE FOR A PERSON PER DAY 1 kg FOOD 2 kg LIQUID 15 kg AIR

3 Global impact on people In developing regions 5000 persons die per day due to poor IAQ Hans Christian Andersen: The Princess on the Pea

4 CRITERIA FOR INDOOR AIR QUALITY ~VENTILATION RATES COMFORT (Perceived Air Quality) HEALTH PRODUCTIVITY ENERGY ASHRAE Ventilation Rate History Office spaces... Ventilation Rate (cfm/person) Smoking Areas Use of mechanical ventilation begins ASHRAE VAV becomes popular ASHRAE ASHRAE

5 Standard 62.1 Definition: What is Acceptable Indoor Air Quality? Air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction EN15251 Indoor environmental input parameters for design and assessment of energy performance of buildingsaddressing indoor air quality, thermal environment, lighting and acoustics Up for 5 year review at CEN (TC156 TC371 Together with JWG ISO TC

6 HEALTH Asthma and Allergy In several industrial countries 50% of school children is suffering from Asthma or Allergy. This number has doubled within the last 20 years International Centre for Indoor Environment And Energy

7 Odds Rstio for "cases" Odds ratio for being a case, i.e. children with at least two symptoms of possible three (wheezing, rhinitis, eczema) as a function of ventilation rates, in single family houses. (Bornehag et al., 2003). 0 n= 0.17 n= 0.29 n= 0.38 n= 0.62 Mean values for ventilation rates Plasticizers from polyvinyl chloride in dwellings increase the risk of asthma among children. Each column represents about 90 dwellings. DEHP: di(2-ethylhexyl) phthalate.

8 PVC=Modern Western Lifestyle Furnitures Food package Cleaning products Cosmetics Toys Floor and walls Cables Paitings Figure 1. Adjusted odds ratio of SBS for low outdoor air flow rate in commercial buildings [3]

9 STANDARDS EN Indoor environmental input parameters for design and assessment of energy performance of buildings- addressing indoor air quality, thermal environment, lighting and acoustics ASHRAE Thermal environment conditions for human occupancy ASHRAE 62.1 and Ventilation and indoor air quality CR 1752 Ventilation of buildings-design criteria for the indoor environment EN Ventilation for non-residential buildings - performance requirements for ventilation and room-conditioning systems Energy Efficient Technologies Indoor air quality Reduce loads (pollution sources) Natural ventilation Heat recovery Air distribution (contaminant removal) effectiveness» Personal ventilation Air cleaning Thermal comfort Reduce loads (building shell, solar screen, internal loads) Low Temperature Heating- and High Temperature Cooling Systems Use of building mass (Thermo-Active-Building-Systems (TABS)) Drifting temperatures

10 Office spaces... ASHRAE Ventilation Rate History Ventilation Rate (cfm/person) Smoking Areas Use of mechanical ventilation begins ASHRAE VAV becomes popular ASHRAE ASHRAE Standard 62.1 Definition: What is Acceptable Indoor Air Quality? Air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction

11 Analytical procedure Ventilation Rate Health Indoor pollution sources Human bioeffluents Building materials Furnishing HVAC system Equipment Tobacco smoking Building

12 CEN CR 1752 EN15251 ASHRAE 62.1 Diagram based on studies with Danish subjects (Fanger et.al). Similar results obtained by North-American subjects (Cain et.al.) Similar results obtained with Japanese subjects (Tanabe)

13 Existing standards prescribe mediocrity. DISSATISFIED 20% CEN CR 1752 EN ASHRAE 62.1 The Princess on the Pea v 1 7 VENTILATION 140 L/s p Basic required ventilation rates for diluting emissions (bio effluents) from people for different categories Category Expected Percentage Dissatisfied Airflow per person l/s/pers I 15 1O II 20 7 III 30 4 IV > 30 < 4 Adapted persons 2,5 l/s person (Cat. II )

14 Indoor pollution sources Human bioeffluents Building materials Furnishing HVAC system Equipment Tobacco smoking Building European Audit Project to Optimise Indoor Air Quality and Energy consumption in Office Buildings Sensory pollution load- perceived air quality Materials and activities Outdoor air Occupants Ventilation system

15 Adapted or Un-adapted? Bioeffluents (body odor) Adapted need only one third of outside air (~7 l/s to 2.5 L/s) Tobacco smoke (ETS) Only limited adaptation (odor, irritation) Building materials and HVAC systems No adaptation International Centre for Indoor Environment And Energy Concept for calculation of design ventilation rate People Component Building Component Breathing Zone Outdoor Airflow V bz = R p P z + R s S d + R a A z Minimum l/s/person Number of People Ventilation per Smoker Number of Smokers Building Area Minimum l/s/m²

16 7 independent studies have measured sensory pollution loads in 120 buildings (olf/m2floor) 97 office buildings & assembly halls (previous ETS) 6 office buildings (no ETS) 10 kindergartens 6 schools 1 department store 0.23± ± ± ± European standard (EN15251): Very Low-polluting building Low-polluting building Non-low-polluting building

17 Basic Ventilation Airflow for building emissions pollutions (l/s/m²) Category Airflow per person l/s/pers. Very low polluting building Low polluting building Non low polluting building I 1O 0,5 1 2 II 7 0,35 0,7 1,4 III 4 0,2 0,4 0,8 Recommended ventilation rates for non-residential buildings for three categories (EN15251) Type of building or space Category Per person l/s,person Per floor area l/s,m 2 Per person l/s,person Per floor area l/s,m 2 Per person l/s,person Per floor area l/s,m 2 Very low polluted building, revision Low polluted building, revision Non-low polluted building, revision Single office I 5,0 1,5 10,0 2,0 20,0 3,0 Landscaped office Conference room II 3,0 1,0 7,0 1,4 14,0 2,1 III 2,0 0,6 4,0 0,8 8,0 1,2 I 7,5 1,5 15,0 1,7 30,0 2,7 II 4,5 1,0 10,5 1,2 21,0 1,9 III 3,0 0,6 6,0 0,7 12,0 1,1 I 1,0 1,5 2,0 6,0 4,0 7,0 II 0,6 1,0 1,4 4,2 2,8 4,9 III 0,4 0,6 0,8 2,4 1,6 2,8

18 Low Polluting Building The majority of the materials are low polluting. Low polluting materials are natural traditional materials, such as stone and glass, which are known to be safe with respect to emissions, and materials which fulfil the following requirements: The emission of total volatile organic compounds (TVOC) is below 0.2 mg/m²h. The emission of formaldehyde is below 0.05 mg/m²h. The emission of ammonia is below 0.03 mg/m²h. The emission of carcinogenic compounds (IARC) is below mg/m²h. The material is not odorous (dissatisfaction with the odour is below 15 %). Type of building/ space Single office (cellular office) Landscaped office Conference room Occupancy person/m 2 0,1 0,07 0,5 Category CEN Occupants only l/s person ASH- CEN RAE Rp Additional ventilation for building (add only one) l/s m 2 CEN lowpolluting building CEN Non-lowpolluting building ASH- RAE Ra Total l/s m 2 CEN Low Pol. A 10 1,0 2,0 2 B 2,5 7 0,7 1,4 0,3 1,4 C 4 0,4 0,8 A 10 1,0 2,0 1,7 B 2,5 7 0,7 1,4 0,3 1,2 C 4 0,4 0,8 A 10 1,0 2,0 6 B 2,5 7 0,7 1,4 0,3 4,2 C 4 0,4 0,8 0,8 0,7 2,4 ASH- RAE 0,55 0,48 1,55 1 l/s m 2 = 0.2 cfm/ft 2 International Centre for Indoor Environment And Energy

19 Examples of recommended CO2 concentrations above outdoor concentration for energy calculations and demand control Category Corresponding CO2 above outdoors in PPM for energy calculations I 350 II 500 III 800 IV < 800 Recommended CO 2 concentrations for non-residential buildings for three categories VERY LOW POLLUTED LOW POLLUTED NON LOW POLLUTED TYPE OF BUILDING CATEGORY CO2 CO2 CO2 ppm ppm ppm SINGLE OFFICE LANDSCAPED OFFICE CONFERENCE ROOM AUDITORIUM

20 Residential buildings Criteria: comfort and humidity Category Air change rate 1) Living room and bedrooms, mainly outdoor air flow Exhaust air flow, l/s l/s,m 2 (1) ach l/s, pers 2) (2) l/s/m 2 (3) Kitchen (4a) Bathrooms (4b) Toilets (4) I 0,49 0,7 10 1, II 0,42 0,6 7 1, III 0,35 0,5 4 0, Adapted or Un-adapted? Conference rooms. Adapted? Classrooms. Adapted? Restaurants. Un-adapted? Department stores. Un-adapted But will health criteria still be met????? International Centre for Indoor Environment And Energy

21 Residential buildings Criteria: comfort and humidity Category Air change rate 1) Living room and bedrooms, mainly outdoor air flow Exhaust air flow, l/s l/s,m 2 (1) ach l/s, pers 2) (2) l/s/m 2 (3) Kitchen (4a) Bathrooms (4b) Toilets (4) I 0,49 0,7 10 1, II 0,42 0,6 7 1, III 0,35 0,5 4 0, ε v Required ventilation rate The total required system ventilation rate is calculated by taking into acount the ventilation effectiveness: Total system ventilation rate = V/ε v

22 Ventilation effectiveness Inhaled Air Quality V eff 1 V eff 1.4 (6)

23 Ventilation effectiveness Studies on ventilation effectiveness

24 WARM AIR HEATING Contaminant Removal Effectiveness System 11 Supply Supply air air Exhaust air air Window window heating floor floor System 2 System 5 CRE as a function of air flow rate for a combination of mixing ventilation and warm air heating, with internal gains of 90 W (cases 3, 4 and 7). The curves represent average in the occupied zone Only 0.1 % is inhaled International Centre for Indoor Environment And Energy

25 International Centre for Indoor Environment And Energy Round Movable Panel Headset International Centre for Indoor Environment And Energy

26 Performance of Air Supply Devices Personalised Air in Inhalation [%] New Outlet Old Outlet 0 2,5 5 7, ,5 15 V e = (10-20) V e = ( ) Supply Flow Rate [l/s] International Centre for Indoor Environment And Energy Ventilation Effectiveness ε V C = C CEN Report CR 1752 (1998) E I C C S S Concentrations: C E exhaust air C S supply air C I breathing zone Mixing ventilation Mixing ventilation Displacement ventilation Personalized ventilation T supply - Vent. effect. T supply - Vent. effect. T supply - Vent. effect. T supply - Vent. effect. T inhal T inhal T inhal T room C - C - C - C - < 0 0,9-1,0 < -5 0,9 <0 1,2-1,4-6 1,2-2, , ,9-1, ,7-0,9-3 1,3-2, ,8 > 0 1 >2 0,2-0,7 0 1,6-3,5 > 5 0,4-0,7 International Centre for Indoor Environment And Energy

27 Personalized systems Personalized systems There is a need to establish design and performance criteria for personalized systems. These performance requirements must be specified for the zone near the occupant. For the general environment the requirements must be relaxed compared to existing standards. There is a need for a testing procedure to verify the resulting ventilation effectiveness.

28 Demand Controlled Ventilation Commercial buildings Level of occupancy Residential buildings Time of day (at home, outside) Occupied room (living room, bedroom) Need for more representative sensors Control concepts AIR CLEANING Filters Photo catalytic Oxidation (PCO) Electrostatic Desiccant air cleaners Others International Centre for Indoor Environment And Energy

29 Why do filters pollute? Particle concentration Percentage Dissatisfied International Centre for Indoor Environment And Energy

30 Hypotheses SVOCs sorbed on particles SVOCs in gas phase Oxidized SVOCs Unreacted SVOCs Photo catalytic Oxidation (PCO) Catalyst:TiO 2 UV H 2 O CO 2 Adsorption of contaminants Photocatalytical reaction Desorption of final products

31 Results: Bldg mat, PCs, filters Perceived air quality (decipol) P<0.017 Purifier Off Purifier On P<0.03 low (35 L/s) intermediate (59 L/s) Outdoor air supply rate Results: Human bio effluents Perceived air quality (decipol) P<<0.001 Purifier Off Purifier On P<<0.001 low (12 L/s) intermediate (25 L/s) Outdoor air supply rate

32 AIR CLEANING The criteria for the ventilation rates are mainly based on perceived air quality PAQ, which is measured by a human test panel. It is therefore also important to be able to test the air cleaning efficiency in relation to the perceived air quality. The air cleaning efficiency can be expressed as: ε PAQ =Q o /Q AP (PAQ/PAQ AP -1) 100 % where ε PAQ air cleaning efficiency for perceived air quality Q o ventilations rate in l/s Q AP PAQ perceived air quality without the air cleaner, decipol PAQ AP perceived air quality without the air cleaner, decipol The Clean Air Delivery Rate is calculated as: CADR = ε PAQ Q AP (3,6/V) h -1 where Q AP air flow through the air cleaner l/s V volume of the room m 3. International Centre for Indoor Environment And Energy Other air cleaning technologies Desiccant air cleaners

33 Destilled water Natural mineral water

34 Ventilation vs performance % 100 Performance (R 2 =0.777; P=0.009) Ventilation rate (L/s per olf) The effect of the indoor environment on student performance

35 Performance of schoolwork as a function of classroom ventilation 1,4 Performance 1,2 1 0,8 0,6 R 2 = Ventilation (L/sp) Doubling ventilation rate ~14.5% higher performance 30 Summertime classroom T in C (NB: Different classes with natural/mechanical ventilation) No AC AC 15 pw1 Off Low High Mechanical ventilation

36 Slide 70 pw1 David, perhaps instead of using Off, Low, High, you should better use the actual ventilation rates; I think that to say mechanical ventilation off is a bit misleading. It was actually off but the audience may think that there were no ventilation et all. These ventilation rates were: Off=1/2( )=3.2 L/sp Low=1/2( )=5.2 L/sp High=1/2( )=9.6 L/sp Pawel Wargocki; 13/06/2007

37 Hours/week with windows open (NB: Different classes with natural/mechanical ventilation) No AC AC 0 Off Low High Mechanical ventilation 10 Hours/week with windows open (NB: different classes in winter & summer) Summer Winter 2 0 Low High Ventilation (with no cooling)

38 Indoor Environment in Schools Indoor Environment in Schools

39 Indoor Environment in Schools Indoor Environment in Schools

40 Analytical calculation of required ventilation Comparable to analytical calculation of cooling loads. No table with cooling loads (W/m 2 ) depending on room type. Ventilation rate Cooling load Parameter Ventilation rate Cooling load Comfort requirement % dissatisfied-odor(paq) Health- TLV % dissatisfied Max. t o, 26 o C Analytical Mass balance Heat balance Outside environment Particles, odors, gases Temperature, solar load, humidity Air cleaning Heat recovery Building materials Emissions/adsorption Heat resistance/heat capacity People Bioeffluents Heat emission Evaporation Internal sources Emissions Heat emission Computers Odors, gases Watts HVAC system Outside air, emissions from components Outside air, Cooled air, heat exchange

41 CONCLUSIONS There is no standard which directly specifies requirements for the indoor air quality. Instead it is indirectly achieved by specifying a required minimum ventilation rate There is a general agreement between ASHRAE and EN standards that both contributions from people and contributions from buildings (materials, furnishing, HVAC systems) must be taken into account when specifying the required ventilation rate. The standards for specifying ventilation rates should distinguish between buildings with low-emitting materials and buildings with high-emitting materials. This should increase the interest in establishing better test methods and better labelling of building materials. CONCLUSIONS Whether the required ventilation rate should be based on adapted or un-adapted persons should be evaluated on a case-by-case basis between rooms and the activities they serve; but at the same time, the health must be taken into account. For better evaluation of the health risk there is a need for threshold limit values that safeguard health in non-industrial environments In the future the goal must be a full analytical calculation of the minimum required ventilation rate (taking into account material emissions, air cleaning, etc)

42 CONCLUSIONS Heat recovery is essential for reducing energy consumption by ventilation There is a need to develop low pressure heat recovery methods for natural ventilation. The results of research indicate that : improved ventilation effectiveness demand control ventilation the use of air cleaning will be future technologies that reduce energy consumption for ventilation and improve indoor air quality. Recent research has resulted in improved personalized ventilation and conditioning systems, which can improve the indoor environment at a work place in an energy efficient way. There is a need to set-up comfort criteria and testing methods for personalized systems. Occupant behaviour is a major factor for the energy performance of a building, therefore we must increase our knowledge on human behaviour in buildings in relation to indoor environment and energy use.