Building AdVentAdvanced ventilation technology to demonstrate good air quality and thermal comfort**TKKREHVA Supporters Seminar10.12.2009 BrusselsJarek KurnitskiD.Sc., Adjunct ProfessorSitra, the Finnish Innovation FundHelsinki University of Technology, HVAC-Technology

www.buildingadvent.com

Partners Buro Happold Consulting EngineersUK Brunel University UK National and Kapodistrian University of Athens Greece Helsinki University of TechnologyFinland Aalborg UniversityDenmark Faculdade de Engenharia da Universidade do PortoPortugal Dissemination focussed partners INIVE UIA REHVA

IntroductionThe Building AdVent project:made an attempt to find 18 excellent non-residential buildings with advanced ventilation technologies from all over Europethe objective was to disseminate information to designers on successfully implemented ventilation systems

How to measure an advanced ventilation technology?Three level assessment based on measurements and occupant questionnaires:Measured indoor environmental performance:room temperature, (air velocity) and ventilation rate or CO2 concentration during summer and winter seasonsQuestionnaire survey to assess occupant satisfaction and to identify major indoor climate complaintsEnergy performance data (from utility bills or measured):heating, cooling and other electrical energy use

Building AdVent project did this assessment for 18 non-residential buildings with advanced ventilation technologies from all over Europe

Examples of the buildingsGreek Office23 m2/persACFan-coils combined with ceiling fans Centralized mechanical vent.

Finnish Office25 m2/persACChilled beamsCentralized mechanical vent. CAV 3 l/(s m2)

English Office10 m2/persNatural vent. by automatically controlled high-level windowsNight ventilative cooling only

Long and short term measurements with the aim to end up with indoor climate foot-print

Indoor climate foot-print according to EN 15251:2007:Foot-print of thermal comfort based on measured temperatures Foot-print of IAQ based on ventilation rate

an example from EN 15251

Long and short term measurements for the foot-printIndoor air qualityEstimation based on CO2 concentrationIn CAV systems estimation based on ventilation rateGeneral thermal comfortTemperatures from selected rooms (measurements or from BMS)Local thermal discomfort (not used in the foot-print)Draft rate air velocity measurements measurement period of 3 minutes, i.e. has to be representativeMeasurements during representative summer and winter daysChallenging in naturally ventilated buildingsResults depend on measurement point and time

Examples of energy performance dataAnnual energy use in the buildings. Heating and cooling energy is not adjusted for climatic differences between the building locations.

Occupant questionnaire/ indoor climate complaintsSurvey response: satisfaction with environment based on occupants responses If there is something wrong, this can be easily seen from questionnaireMeasured performance of Category I (EN 15251) may be ranked as satisfaction below 80% (expected to be >80%)

102v, T124v146v, T149vSelection of rooms/measurement points for the foot-print an example of 6 storey building Ground floormeasurement points and parameters (red circles)

204v, T204v, T224v, T244v, TFirst floor

401v, T422v, T439v, T461v, TThird floor12 measured rooms/open plan offices in total in this case Measurements from ground, 1st and 3rd floors (6-storey building), selected together with building manager so that most critical locations were measuredVentilation rates from commissioning measurement protocols (CAV system)

Air velocity measurements draft rate (ISO 7726) local thermal discomfort

Air velocity, draft rate and PPD a summer day

Daily temperature fluctuationsDaily temperature fluctuations during one week: a room with highest, typical and smallest fluctuation (measured with small loggers in this case)

An example of foot-print of thermal comfort and IAQFoot-print of general thermal comfort based on measured temperatures (weighted with area) and and a foot-print of IAQ based on ventilation rate Room temperatures remained between 23.5 C and 25.5 C (category I, EN15251, CR 1752) for 97 % of occupied hours for cooling season.In heating season temperature was between 21.0 C and 23.5 C (category I) in occupied hours for the full measurement period. Daily temperature fluctuations were typically around 1.0 C to 1.5 C in the occupied hours during heating season.

Conclusions from the AdVent approach Performance assessment needs both measured and questionnaire dataResults from Building AdVent buildings show how difficult it is to achieve good occupant satisfaction with indoor climateQuestionnaire is sensitive to many confounders, but:If something is wrong, this can be easily seen from results powerful tool for screeningMeasured performance of Category I (EN 15251) still can lead to occupant satisfaction below 80% in such simple field surveys (expected to be >80%) indicating a need of further analysesExpectancy factor may cause deviation in comparison between buildings (Building AdVent experience)More or less measurements needed in any case:IAQ assessment based on ventilation rates or CO2 measurement straightforward in any building General thermal comfort/room temperatures also easily measurable/accessibleRepresentative results of draft rate/air velocity most challenging especially in naturally ventilated buildings

The best buildings?Many confounders in the measurements and energy dataTop 5 based on occupant satisfaction:Case Study No 11 CHH ChristophorusHaus, MIVA, Stadl-Paura, Austria (>77%, balanced)Case Study No 9, YIT Office Building, Turku, Finland (>73%, balanced)Case Study No 4 Edifcio Solar XXI, Lisbon, Portugal (>73%, hybrid)Case Study No 12 SFO Spirehuset, Hirtshals, Denmark (>67%, natural pulse)Case Study No 15 Rijkswaters taat Building, Terneuzen, Netherlands (>67%, natural)