Towards Sustainable and Intelligent Built Environment

Transcription

1 Towards Sustainable and Intelligent Built Environment Moncef Krarti, PhD, PE, LEED AP Professor and Coordinator Building Systems Program University of Colorado

2 OUTLINE Energy Use Trends and Statistics for Buildings Sustainable and Intelligent Buildings Technologies for Sustainable Built Environment Vision and Strategic Future for AE at Penn State Summary and Conclusions

3 Basic Statistics Most people spend 80% of their time indoors Early 1900 s, 20% of people live in cities In 2010, 80% of people lives in US cities; Worldwide, 50% of people in urban area By 2030, 60% of all world population will live in urban areas. Most of the growth will be in cities of developing countries

4 Basic Statistics Energy Consumption in the Built Environment

5 Future Trends Energy Consumption Projections for the Buildings (Source: EIA, 2017)

6 Future Trends Several standards codes in various countries are mandating design and operation of: Sustainable Buildings (LEED, BREEAM, Living Building Challenge) Intelligent Buildings (ICT/Data, Control Systems) Resilient Buildings (Climate change and Severe Weather Events) In particular EU has a mandate that all new buildings need to be nearly net-zero energy by 2020 (Source: EPBD, 2013)

7 Impacts of Built Environment Buildings can affect: Quality of ecosystem and environment Availability of material and utility resources Energy consumption and carbon emissions Indoor and outdoor quality and occupant productivity

8 Examples of Sustainable/Intelligent Buildings Building: The Edge, Deloitte, Amsterdam Features: Received one of the highest BREEAM score ever of 98.4%. Behaves depending on employees needs and preferences (Employees are allocated a parking space when they arrive). The energy generated by users of the building gym is harvested to run the building.

9 Examples of Sustainable/Intelligent Buildings Building: Siemens City: Vienna, Austria Features: Rests on 120 concrete thermal piles that extend 100 feet into the ground to provide heating and cooling (thermos-active foundations). Is equipped with a building management system that can access over 10,000 sensors to control desired levels of lighting, room temperature and ventilation to improve productivity of occupants.

10 Benefits of Sustainable/Intelligent Buildings Improve operating costs (energy use, operation and controls, preventive maintenance) Add value to the property (sale value, tenant retention, rent value) Enhance life safety and security (fire alarms, earthquake notifications) Integrate within smart cities and smart grids (distributed generation, share information with centralized user interface)

11 Sustainable/Intelligent Buildings Design/Retrofit Approach An integrated Design/Retrofit Approach is needed with all the building stakeholders involved throughout the project phases

12 Sustainable/Intelligent Buildings Design/Retrofit Approach The main ingredients of Sustainable/Intelligent Buildings include: Integrated analysis tools and methodologies Dynamic systems and technologies Sensors and data flow Control systems and data management Collaboration and coordination between various disciplines is required

13 Sustainable Buildings Design/Retrofit Analysis Tools The ideal design and analysis tool should optimize energy use, thermal comfort, indoor quality, grid interaction, and economic impact for integrating several building energy systems Weather file Building model DOE2 inp file with predefined EEMs EEMs 1) EEMs' options 2) Options' costs for EEMs DOE2 simulation engine inp file simulation output Optimization engine Optimization results 1) Suboptimal path 2) Optimal design solution for ZNE building

14 Design/Retrofit Analysis Tools Automated Energy Auditor Features: Automatically Develop and Calibrate Energy Model of Audited Building Determine Optimal Energy Retrofit Measures (based on a specific Investment Level) Use Bayesian Optimization

15 Net-Zero Energy Building Design Commercial Buildings in Shanghai LCC ($) Millions Identify the potential reductions in energy use and carbon emissions for new commercial buildings in the Changning District in Shanghai. Detailed Modeling and Optimization Techniques were used. LCC-12%d 0% 20% 40% 60% 80% 100% % Energy Cost Savings Source: Huang and Krarti (2015)

16 Net-Zero Energy Building Design Office Buildings in Italy Source: Luddeni and Krarti (2018)

17 Net-Zero Energy Building Design Office Buildings in France Source: Deneuville and Krarti (2018)

18 Net-Zero Energy Building Design Residential Buildings in Nigeria Source: Kwag and Krarti (2017)

19 Sustainable Building Retrofit Residential Buildings in Mexico Identify energy efficiency measures for existing residential buildings in Salamanca, Mexico Source: Griego and Krarti (2012)

20 Benefits of Buildings Microclimate Impact of Vegetation on Heating and Cooling Microclimate depends on: Density and type of vegetation (grass and trees) Presence of water (lake, ponds) Presence of other buildings Source: Chen and Krarti (2011)

21 Buildings and Microclimate Impact on Heating and Cooling Increasing the vegetation density from 35% to 55% can save 20% of summer cooling energy use Source: Chen and Krarti (2011)

22 RC LOW ENERGY BUILDINGS Impact of Building Form and Shape Building Relative Compactness (RC) is one indicator of the form: = ( V / SA) ( V / SA) cube building

23 LOW ENERGY BUILDINGS Impact of Building Form and Shape Et/Eref Ratio of Cooling Energy Use with 0% Glazing RC L T + H Cut Rc U

24 Integrated Heating and Cooling 1- Earth Tubes 2- Evaporative Cooling Ventilated Wall Cavities 3- Natural Ventilation 4- Ventilated Slabs 5- Thermo-active Foundations 6- Ground Source Variable Refrigerant Flow Zone 2 Cold supply air Ventilated Slab Supply air to the zone leaving the slab Supply air to the zone leaving the slab Zone 1 Hot supply air

25 Integrated Heating and Cooling Thermo-Active Piles and Foundations Save digging costs associated with vertical GSHP loops Installation of GSHP Piping inside the Foundation Piles of Buildings

26 Integrated Heating and Cooling Energy Performance of Thermal Piles Percent reduction of cooling and heating energy end-uses associated with a TAF system relative to a VAV system for a prototypical office building in five US climates Source: Menyard and Krarti (2017)

27 Integrated Heating and Cooling Energy Performance of Ventilated Slabs Advantages of the ventilated slab systems 8 m Better thermal comfort 0.02 m - Ceiling slab (Cooling) - Floor slab (Heating) 0.25 m 3 m 3 m Ventilated Slab Zone 2 Zone 1 Cooling Cooling Mortar Concrete Mortar Energy savings compared to conventional air system - Heating energy savings up to 50 kwh/m 2 /year - Cooling energy savings of 13-30% and peak demand savings of 28% 0.25 m - The reduction in fans can be up to 50% Source: Park and Krarti (2017)

28 Low-energy Materials and Envelope Systems Coupled with Proper Controls Breathing Materials and Walls Double-Skin Façades Hybrid Systems Phase Change Materials Dynamic Insulation Dynamic Cool Roofs Double Skin Façade Technology

29 Low-energy Materials and Envelope Systems Dynamic Insulation Systems Change thermal properties based on heat flow direction Gas Vertical Wall

30 Low-energy Materials and Envelope Systems Dynamic Insulation Systems Potential Cooling Energy Use Savings for US Homes

31 Intelligent Controls For both individual and group of buildings Use of (wireless) sensors: occupancy, temperature, lighting, CO2, etc. Use of thermal mass of buildings to store energy and preheat and pre-cooling Use of optimal controls for operating dynamic building shell and HVAC equipment Use of renewable energy systems to meet buildings needs

32 Lighting Controls Types Standard on/off switches and relays Occupancy sensors Manual dimming Light-level sensors or photosensors (daylighting controls including stepping and dimming) Clock switches Centralized controls

33 Lighting Controls Occupancy Sensors Two types are available: 1. Infrared sensors: use the infrared radiation emitted by surfaces (human body) and operate when in direct line-of-sight of occupants (no partitions) 2. Ultarsound sensors: use the sonar principle (emit a high frequency sound and sense reflected frequencies. Can operate even with partitions but only in small spaces (large spaces produce weak signals)

34 Lighting Controls Daylighting Controls Daylighting, properly controlled, has the potential to significantly reduce the amount of energy used by electrical lighting Proper selection of windows is important to both daylighting and natural ventilation since windows have a significant impact on both of these areas

35 Daylighting Controls Dimming Controls 1.0 Fractional light output Increasing daylight illuminance Zero daylight illuminance Minimum light output fraction Fractional input power Minimum input power fraction

36 Daylighting Controls Stepped Controls 1.0 Step 1 Step 2 Fractional input power Step Daylight illuminance Illuminance set point

37 Daylighting Controls Glazing Characteristics 1. U-value 2. Solar Heat Gain Coefficient (SHGC) 3. Visible Transmittance (VT) 4. Air Leakage (AL)

38 Daylighting Design Daylighting Depth H 2.5 H workplane

39 Daylighting Design Daylighting Model

40 Energy Savings from Daylighting Controls Regression Analysis Lighting Reduction Relationship for Phoenix % Energy Reduction/(Ap/Af) y = 75(1-e -7.6x ) 40 R 2 = Transmittance * Aw/Ap

41 Optimal Daylighting Controller Basic Concept Solar Radiation Model Luminance Efficacy Model Alternatively Processor /Controller Indoor luminance Models i.e. EnergyPlus Measured Outdoor GH and DF illuminance Fluorescents Lamp Performance Data If solar data is credible, NO need to use outdoor photosensors Solar/LE Models Indoor surfaces and openings conditions could be predefined to calculate required indoor illuminance level for any time step EnergyPlus With pre-calculated lamp performance data, NO need to use indoor photosensors AGI32 Depending on the lighting design, circuiting of lighting fixtures or groups of lamps can be optimize GenOpt Source: Seo and Krarti (2015) 41/44

42 Optimal Daylighting Controller Lighting Circuiting Layout Circuit Layout Option 1~5 Lighting Output Fraction Layout1 Layout3 Layout5 Layout2 Layout4 Lighting Energy Savings Relative to No Daylight Control South: 46.5~67.2% East: 18.6 ~ 45.2% Lighting Output Fraction Dec 21 (Hour) South facing case Layout1 Layout2 Layout3 Layout4 Layout Dec 21 (Hour) East facing case Lighting Energy Savings Relative to Layout 1 South/East: Layout2: 6.3% / 1.4% Layout3: 20.5% / 13.6% Layout4: 28.2% / 30.1% Layout5: 38.7% / 32.6% Designers can verify the energy efficiency of their lighting design Source: Seo and Krarti (2015) 42/44

43 Smart Grids Distributed Generation Systems

44 CONCLUDING NOTES There is significant opportunities in retrofitting existing building stocks including urban centers and large communities Suitable design and retrofit analysis tools and integrated systems and controls have to be developed for sustainable urban centers and large communities

45 Advances in three areas are needed: 1. Bldg. Matls. and Envelopes 2. Efficiency and Renewables 3. Optimal Bldg.-Grid Integration Economics Policy Culture Integrated thermal envelope Zero net energy CEM Emissions CFM Reliability Life-Cycle Assessment HVAC CFM Vision for Buildings Integrated Design, Construction, and Operation Solar - PV Day lighting Photovoltaics Fenestration CFM: Computational Fluid Mechanics CSM: Computational Solid Mechanics OCS: Optimal Control Strategies CEM: Computational Energy Modeling Smart Grid / Distributed Energy Wind Intelligent materials (PCM) Energy conservation CEM Fuel cell storage Temperature Control CEM Recycled materials Tree OCS Soilstructure interaction CSM CFM CSM Geothermal Heat Exchange

46 REFERENCES

47 THANK YOU CU Solar Decathlon Houses