NEARLY ZERO ENERGY BUILDING DEFINITION NEARLY ZERO ENERGY BUILDING DEFINITION SHALL BE BASED ON DELIVERED AND EXPORTED ENERGY ACCORDING TO EPBD RECAST AND EN 15603:2008 ENERGY USE IN THE BUILDINGS INCLUDES ENERGY USED FOR HEATING, COOLING, VENTILATION, HOT WATER, Delivered energy LIGHTING AND APPLIANCES. Total energy use THIS IS NEEDED FOR of the building Exported energy CALCULATION OF EXPORTED ENERGY OR TO ANALYZE System boundary of building technical LOAD MATCHING AND GRID systems INTERACTION OF NZEB Building site = system boundary of delivered and exported energy
ON SITE RENEWABLE RE generators ENERGY W/O FUELS Heating en. Cooling en. Electricity DELIVERED ENERGY Electricity ENERGY USE District heat Solar gains/ ENERGY NEED loads BUILDING District cooling BUILDING Heating energy NEEDS Fuels TECHNICAL Heating (renewable and SYSTEMS Heat Cooling energy Cooling non-renewable) transmission Ventilation Electricity for Energy use EXPORTED DHW and production lighting ENERGY Lighting Electricity for Internal heat Appliances Electricity System losses gains/loads appliances Heating en. Energy need SB and conversions Cooling en. Energy use SB Building site boundary = system boundary of delivered and exported energy
DELIVERED ENERGY Electricity District heat District cooling Building n Fuels (renewable and non-renewable) Building 2 EXPORTED ENERGY Electricity Building 1 SITE ENERGY Heating en. CENTRE Cooling en. Building site boundary = system boundary of delivered and exported energy
EXPERIENCE WITH LOW ENERGY BUILDINGS Per Heiselberg
ENERGY USE HIGHER THAN EXPECTED Based on 230.000 single family houses with energy labelling. Preliminary results not yet validated or published Reference: Kirsten Gram-Hanssen, SBi 2015
HOME FOR LIFE, LYSTRUP, DENMARK
Home for life – Energy Concept
Home for life – Energy balance Energy need and production from solar [kwh/m 2 /year] Energy production solar thermal and solar cells 60 Electricity Electricity Hot water and technique household heating -8 -14 -33
EXPERIENCES RELATED TO ENERGY USE AND PRODUCTION THE MOST IMPORTANT DEVIATIONS: • Energy use for heating higher than expected • Electricity use for heat pump higher than expected • Electricity use for control system higher than expected • Energy use DHW lower than expected • Electricity use for appliances and plug loads lower than expected. • Production from solar thermal system as expected • Production from PV as expected Reference: Esbensen, 2012
7. As 6, corrected for less efficient heat recovery 1. Measured 8. As 7, corrected for use of solar shading 2. As 1, corrected for weather 3. As 2, corrected for indoor temperature 9. As 8, corrected for measuring equipment and screens 4. As 3, corrected for lower person load 10. As 9, corrected for DHW use 11. As 10, corrected for efficiency of heat pump 5. As 4, corrected for domestic electricity use 12. Predicted energy use 6. As 5, corrected for air tightness Reference: Esbensen, 2012
RELATIVE IMPORTANCE OF DIFFERENT ASPECTS Reference: Esbensen, 2012
Overheating – living room Reference: Esbensen
IMPACT OF IMPROVED CONTROL AND OPERATION Sleeping, year 1 Sleeping, year 2 1% 2% 1% 6% 13% 14% 18% 59% 20% 66% Living year 2 Living year 1 1% 2% 2% 10% 13% 32% 32% 26% 58% 24% Reference: VELUX og Esbensen
WHY DO WE FACE THESE CHALLENGES IN HIGH PERFORMANCE BUILDINGS? IT IS NOT POSSIBLE TO REACH GOALS THROUGH MORE • Envelope insulation, Building airtightness, Ventilation heat recovery, WHICH ARE ROBUST TECHNOLOGIES WITHOUT USER INTERACTION NEW MEASURES NEEDS TO BE INCLUDED • Demand controlled ventilation • Shading for solar energy control • Shading for daylighting control • Lighting control • Window opening ALL TECHNOLOGIES: Where performance is very sensitive to control • • Which involve different degree of user interaction Whose function and performance are difficult for users to understand •
WHY DO WE FACE THESE CHALLENGES IN HIGH PERFORMANCE BUILDINGS? THE PRIMARY OBJECTIVE OF USERS IS FULLFILLMENT OF THEIR NEEDS (INDOOR ENVIRONMENT) AND THEY WILL ALWAYS ADJUST CONTROLS ACCORDINGLY. THIS OFTEN LEADS TO HIGHER ENERGY USE AND POORER INDOOR ENVIRONMENT THAN EXPECTED. AUTOMATIC CONTROL SHOULD BE BETTER ADAPTED TO THE FULLFILMENT OF USER NEEDS
ENERGY EFFICIENT VENTILATION OF HIGH PERFORMANCE BUILDINGS PER HEISELBERG
ENERGY EFFICIENT VENTILATION OF HIGH PERFORMANCE BUILDINGS
ENERGY DEMAND IN TYPICAL OFFICE BUILDING Energy demand distribution Cooling Heating Lighting Ventilation Misc. Conditions U-value: 1,5 W/m²K, g-value: 0,60, Lt-value: 0,70 SFP: 2,1 kJ/m³ Light control: Manual Thermal mass: Light Total energy demand 96 kWh/m² 30 % window area in relation to floor area Infiltration 0,3 h -1
ADDITIONAL CHALLENGES IN HIGH PERFORMANCE BUILDINGS The current development towards nearly -zero energy buildings have lead to: an increased need for cooling – not only in summer but all year • Increased potential for using the cooling potential of outdoor air An reduction of Electricity use for air transport becomes increasingly important • Increased use of natural/hybrid ventilation • Distribution of cold air to rooms without creating discomfort Effective decentralized ventilation solutions •
SIX DIFFERENT AIR DISTRIBUTION SYSTEMS -Tested in the same geometry and with the same load
q o - ∆T o Design Chart pvn@civil.auc.dk
WIDEX/WESSBERG A/S
WIDEX/WESSBERG A/S
SOLBJERGSKOLEN SOUTHWEST OF ÅRHUS
SYSTEM PRINCIPLE
DRAUGHT RISK • Winter condition: supply air temperature -8 o C, ACH =4 DR <20% ISO 7730
VENTILATION SOLUTIONS Hybrid ventilation Air Natural Mechanical Conditioning ventilation ventilation Micro- Occupant Building Thermal climate Profile Design Comfort Building Outdoor Internal IAQ Use Climate loads
RATIONALE FOR HYBRID VENTILATION • HAS ACCESS TO BOTH VENTILATION MODES IN ONE SYSTEM, EXPLOITS THE BENEFITS OF EACH MODE AND CREATES NEW OPPORTUNITIES FOR FURTHER OPTIMISATION AND IMPROVEMENT OF THE OVERALL QUALITY OF VENTILATION. • FULFILS THE HIGH REQUIREMENTS ON INDOOR ENVIRONMENTAL PERFORMANCE AND THE INCREASING NEED FOR ENERGY SAVINGS AND SUSTAINABLE DEVELOPMENT. • RESULTS IN HIGH USER SATISFACTION BECAUSE OF THE HIGH DEGREE OF INDIVIDUAL CONTROL AS WELL AS A DIRECT AND VISIBLE RESPONSE TO USER INTERVENTIONS. • OFFERS AN INTELLIGENT AND ADVANCED VENTILATION SOLUTION FOR THE COMPLEX BUILDING DEVELOPMENTS OF TODAY, THAT IS USER TRANSPARENT AND SUSTAINABLE.
HYBRID VENTILATION STRATEGIES Alternating or combined natural and mechanical ventilation – This principle is based on a combination of two fully autonomous systems where the control strategy consists of switching between or combining both systems. – It covers fx systems with natural ventilation in the intermediate seasons and mechanical ventilation during midsummer and/or midwinter or it covers systems with mechanical ventilation for workstations during occupied hours and natural ventilation for building and night cooling.
INSTITUTE OF DEVELOPMENT ECONOMIES (JETRO), CHIBA, J Courtesy of: Dr. Tomoyki Chikamoto, Nikken Sekkei Ltd, Japan
HYBRID VENTILATION AND AIR CONDITIONING SYSTEM Effective exhaustion of High IAQ and heat and pollutant thermal comfort Fresh air EA (Exhaust Air) 30℃ Heat from OA (Outside Air) Task Zone Pollutant from Task Zone Ambient Zone CH CH 28℃ C C OA 20℃ 26℃ Higher temp. upply jet s Task Zone 26℃ 22℃ 22℃ Under-floor AC system for Ambient Zone Supply fan unit Personal supply outlet for Task Zone for Ambient Zone (D irect supply of fresh air to human body) Personal AC system for Task Zone
HYBRID VENTILATION AND AIR CONDITIONING SYSTEM Automatically controlled window - This opening is also used for smoke exhaust opening in case of fire Task supply unit Ambient - Air volume and direction are supply unit easily changed by each user
CONTROL OF HYBRID VENTILATION AND AIR CONDITIONING SYSTEM Fresh air EA (Exhaust Air) OA (Outside Air) Ambient Zone CH CH C C OA Task Zone Ambient zone is controlled mildly by Cool air central BA system for energy saving. Task zone is controlled by each one’s choice for human’s comfort. Warm air Air volume and direction are easily changed by each user. Task supply unit is detachable.
HYBRID VENTILATION STRATEGIES STACK AND WIND SUPPORTED MECHANICAL VENTILATION – This principle is based on a mechanical ventilation system, which makes optimal use of natural driving forces. – It covers mechanical ventilation systems with very small pressure losses where natural driving forces can account for a considerable part of the necessary pressure difference.
Mediå School, Grong, Norway N M Courtesy of: Professor Per Olaf Tjelflaat, Norwegian University for Science and Technology, Trondheim, Norway
AIR SUPPLY SYSTEM
AIR EXHAUST SYSTEM
Mediå School, Grong, Norway LOW PRESSURE LOSS IN SYSTEM • VENTILATION SUPPLY ABOUT 35 PA – Filter about 15 pa – Heat recovery about 10 pa – Heating about 5 pa • VENTILATION EXHAUST ABOUT 20 PA – Heat recovery about 12 pa TOTAL PRESSURE LOSS WINTER ABOUT 55 PA TOTAL PRESSURE LOSS SUMMER ABOUT 28 PA PRESSURE LOSS SUMMER (WITHOUT FILTER) ABOUT 13 PA
Energy efficient Heating and Cooling of buildings • Low temperature Heating-High Temperature Cooling • Water based systems • Radiant heating and cooling ceiling panels • Thermo Active Building Systems (TABS) • Chilled beams • Floor heating and cooling
Low-Temperature heating High-Temperature Cooling • Heat exchange through large surfaces (floor, ceiling, walls) • Supply water temperatures: – Heating: 25 – 40 ° C – Cooling: 16 – 23 ° C (temperature limited by dew-point to avoid condensation) • Wide range of systems, solutions both for residential and non-residential buildings 74
Sus ustain tainability ability • Higher efficiency of boilers and chillers • Lower distribution looses • Better use of renewable energy sources – Ground heat exchangers – Waste heat from processes – Dry coolers – Heat pumps • Low energy consumption for circulation • Low exergy 75
CONCEPTS OF RADIANT HEATING AND COOLING SYSTEMS • Minimum 50% heat exchange by radiation • Heating - cooling panels • Surface systems • Embedded systems • Most recent development is the increasing application world wide.
Suspended cooled ceilings
System stem type pes Water as the heat carrier Heat exchange is > 50% radiant Different installation concepts (thermally coupled or insulated form the building structure) 78
THERM RMO ACTIVE BUILD ILDIN ING G SYST STEM EMS S (TABS BS) Window Room Floor Concrete Room Pipes Reinforcement Trend started in nineties in Switzerland, typically used in Europe Suitable primarily for sensible cooling and for base heating Installed in the centre of concrete slab between the reinforcements Diameter of the pipes varies between 17 and 20 mm The distance between pipes is within the range 150 - 200 mm Installed during the main building construction with prefabricated slabs.
Concept of Thermo Active Building Systems
Concept of Thermo Active Building Systems (TABS) EXAMPLE OF INTERNAL CONDITIONS WITH THERMAL SLAB 30 1 29 PMV 28 0.5 27 PREDICTED MEAN VOTE TEMPERATURE [°C] T air T floor T mr 26 25 0 24 T ceiling 23 -0.5 22 21 T water return 20 -1 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00 18.00 19.00 20.00 21.00 22.00 23.00 0.00
COMBINAT ATION N WITH LOW ENERG RGY Y SOURC RCES ES Day Cooling method Heating supply temp. : 25 - 40 ° C heat pumps Ground water condensing boiler ground coupling waste heat Geothermal heat/coolth Night solar energy Cooling supply temp. : 16 - 23 ° C reversible heat pump Night air ground coupling free cooling Cooling unit air cooled chillers UPONOR Corporation (2010) 82
Add ddit ition ional al be bene nefi fits ts – la large ge atri riums ums and nd foyer ers The under-floor cooling system directly removes solar heat gains Minimum of such gains influences air temperature Comfortable floor surface temperature is maintained at the same time 83
Airport Bangkok
Airport Bangkok
Terminal building June 30 2008
Balanced Office Building Aachen, Germany • Gross floor area 2,151 m² • 4 storeys • Efficiently insulated external envelope • Ground-coupled heating and cooling with TABS • Ventilation system with heat recovery • Daylight-controlled lighting • Rainwater collection for use in toilet flushing
Energy concept
cooling period
Energy efficiency Yearly energie costs [ € /m²a] 35000 Bestand 60 % energy saving for lighting by daylight BOB.1 steering 30000 94 % energy saving compared with conventional cooling 25000 The need of energy for heating, cooling, air- ventilation lighting and warm water is 27,8 kWh/m² per year 20000 Energy costs per m², per year: 2,7 EUR, per month 22,5 Cent 15000 10000 5000 0 Heizung Kühlung Lüftung Beleuchtung Pumpen Warmwasser Summe
Office Building in Madrid, Spainain 16 000 m2 Natural & Mechanical ventilation External solar shading & green facade TABS combinned with free cooling (covers 40-50 kWh/m2) Energy use (kWh/m²y) Actual CTE - MADRID % Heating + DHW 27,35 77,00 -64,5 Cooling 12,58 85,00 -85,2 Lighting 11,37 34,00 -66,6 91 Total 51,30 196,00 -73,8
Office Building in Madrid, Spain 92
Chilled Beams Water based distribution
Chilled Beams
Chilled Beams Water based distribution
Low Exergy Hydronic Radiant Heating and Cooling Why? • Water based systems • Low temperature heating - High temperature cooling • More economical to move heat by water: – Greater heat capacity than air – Much smaller diameter pipes than air-ducts – Electrical consumption for circulation pump is lower than for fans • Lower noise level • Less risk for draught • Lower building height for TABS • Higher efficiency of energy plant • But – Reduced capacity? – Acoustic? – Latent load?
VENTILATIVE COOLING P E R H E I S E L B E R G D E P A R T M E N T O F C I V I L E N G I N E E R I N G
DEFINITION OF VENTILATIVE COOLING VENTILATIVE COOLING IS APPLICATION (DISTRIBUTION IN TIME AND SPACE) OF VENTILATION AIR FLOW TO REDUCE COOLING LOADS IN BUILDINGS VENTILATIVE COOLING UTILIZES THE COOLING AND THERMAL PERCEPTION POTENTIAL (HIGHER AIR VELOCITIES) OF OUTDOOR AIR IN VENTILATIVE COOLING THE AIR DRIVING FORCE CAN BE NATURAL, MECHANICAL OR A COMBINATION
VENTILATIVE COOLING IS A SOLUTION THE DEVELOPMENT TOWARDS ” NEAR ZERO ENERGY BUILDINGS ” HAS RESULTED IN AN INCREASED NEED FOR COOLING – NOT ONLY IN SUMMER BUT MOST OF THE YEAR! VENTILATIVE COOLING CAN BE AN ATTRACTIVE AND ENERGY EFFICIENT PASSIVE SOLUTION TO REDUCE COOLING AND AVOID OVERHEATING. • Ventilation is already present in most buildings through mechanical and/or natural systems using opening of windows • Ventilative cooling can both remove excess heat gains as well as increase air velocities and thereby widen the thermal comfort range. • The possibilities of utilizing the free cooling potential of low temperature outdoor air increases considerably as cooling becomes a need not only in the summer period.
POTENTIAL AND LIMITATIONS OUTDOOR CLIMATE POTENTIAL • Outdoor temperature lower than the thermal comfort limit in large part of the year in many locations • Especially night temperatures are below comfort limits • Natural systems can provide “zero” energy cooling in many buildings LIMITATIONS • Temperature increase due to climate change might reduce potential • Peak summer conditions and periods with high humidity reduce the potential • An urban location might reduce cooling potential (heat island) as well as natural driving forces (higher temperature and lower wind speed). Elevated noise and pollutions levels are also present in urban environments • Building design, fire regulations, security are issues that might decrease the use of natural systems • High energy use for air transport limit the potential for use of mechanical systems
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