Buildings and Their. Carbon Footprints. 12 September San Jose, Costa Rica

Transcription

1 Buildings and Their Carbon Footprints 12 September 2017 San Jose, Costa Rica Friedrich Hohnerlein, Dipl.-Ing., Principal Vikki Poitra, Masters of Architecture m-g-h ingenieure + architekten GmbH Karlsruhe, Germany 1

2 Overview Part 1: Our planet is a greenhouse Part 2: Calculating a building s carbon footprint Part 3: International building certifications 2

3 Our Planet; Our Greenhouse 3

4 Greenhouse Gases (GHGs) that form the atmospheric blanket" around the planet Chlorofluorocarbons (CFCs) 4

5 Carbon Cycle 5

6 A Carbon footprint is All of the carbon dioxide emissions including the other GHGs, created by the building s operation. NOTE: The other GHGs are converted into the amount of CO 2 that would cause the same effects on global warming. This is called the equivalent CO 2 amount. A subset of the more comprehensive Life Cycle Assessment (LCA). Once the size of the carbon footprint is known, a strategy can be devised to reduce a building s carbon footprint through technological or consumption strategies. NOTE: The mitigation of carbon footprints through the development of alternative projects, such as solar or wind energy, represents a way of reducing a carbon footprint and is often known as carbon offsetting. Source: Carbon footprint. Wikipedia the Free Encyclopedia. 14 May

7 Step 1: Create a Building Information Model (BIM) First step in evaluating carbon footprint, is creating a virtual model of the building. The more detailed the model, the more accurate the results will be. Model the building s envelope with all of its openings as well as any major internal structures providing mass for significant heat storage. Identify the internal conditioned areas of the building. Delineate these into zones based on their the occupancy and use. 7

8 Building Envelope in BIM 8

9 Conditioned Zones in BIM 9

10 Step 2: Create a Building Energy Model (BEM) Using BIM as the Base Input data sourced directly from BIM, e.g., building orientation, building area, construction assemblies, conditioned internal zones, renovation status, etc. Input additional data including specific material information such as U-values, infiltration, solar absorptance, etc. 10

11 Step 3: Create Thermal Zones Database Group like zones together into "thermal blocks which are collections of one or more rooms or spaces with similar heating/cooling requirements. Input this information into the provided spreadsheet. 11

12 Step 4: Create a Daily Use Profile for the Building 12

13 Step 5: Input Project Location 13

14 Step 6: Input Climate Data 14

15 Step 7: Calculate U-Values The U-value is the average heat transmission coefficient for the building materials and their assemblies. 15

16 Step 8: Create the Construction Material Database For each significant assembly, input relevant data into the provided spreadsheet, e.g., material, area, thickness, u-value, etc. 16

17 Step 9: Evaluate Thermal Bridging Potential Evaluate the thermal performance of construction details at the building connections. Assign the resulting performance values to thermal blocks to factor in their effect on the building s overall energy balance. 17

18 Thermal Bridge Simulation 18

19 Step10: Perform Solar Modelling Using the Model-Based Solar Irradiation Study, model the solar gain associated with each transparent element of the building envelope. This advanced tool enables building designers to strategically place each window opening with respect to the building s geometry and its surroundings. The intended end result here is to identify and utilise the benefits of solar gain throughout the year while avoiding its unwanted effects. 19

20 What a Building Solar Analysis Looks Like 20

21 Step 11: Input Energy Source Factors Input primary energy sources. The output will be CO2 emissions based on data specific to the project location as well as based on DIN V-18599, a German standard. 21

22 Step 12: Input Local Energy Costs 22

23 Step 13: Input HVAC Information 23

24 Step 14: Baseline Building Energy Simulation for Comparison The software program automatically models a baseline building for the energy simulation comparison. The baseline building is based on ASHRAE The program automatically rotates the comparative baseline building by 90 degrees three different times, reanalyzing the project after each rotation. Eventually, the energy performance of the four baseline building variations is averaged with the resultant data set being used for the performance rating of the designed building. 24

25 Step 15: Output - Energy Performance Evaluation Report With the dynamic energy simulation completed, an Evaluation Report summarising energy consumption by targets and sources as well as the project s environmental impact is generated. 25

26 Energy Consumption by Targets Heating Cooling Service hot water Ventilation Lighting 26

27 Energy Consumption by Sources Source type Renewable Fossil Secondary Name Solar External air Natural gas Electricity 27

28 Environmental Impact Finally, this chart summarizes the environmental impact of the building's operation, by displaying the building s Carbon Footprint and Primary Energy usage. 28

29 Still an Art; Not Yet a Science Carbon evaluation varies amongst the many tools available. There are many existing and evolving standards for carbon calculation, and no footprint is precise. 29

30 A final note on a building s carbon footprint In addition to a building emitting GHGs once it is operational, also be aware of the embedded carbon and GHGs associated with building materials. And carbon issues associated with site selection. While it can be difficult to calculate the carbon footprint of a building material due to various manufacturing processes, transport to the site, etc., do your best to know something about the origin and production of a material before specifying it. Is the timber sustainably harvested from a nearby forest? Did the power used in the manufacturing process, come from a renewable source? Rule of thumb - buy locally and use your best judgment. 30

31 GHGs and Certification Programs All three leading certification programs DGNB, BREEAM and LEED require a Life Cycle Analysis in which a building s carbon footprint can be calculated 31

32 Building certifications are tools designed to promote sustainable building planning and construction They identify key factors that determine sustainable building practices, and make those practices measurable. They also help create incentives within the building industry, calling for more sustainability in the way that buildings are planned, constructed and operated. 32

33 Worldwide: A Variety of Certification Systems BREEAM, LEED and DGNB are the three largest using a third party verification check. BREEAM (Building Research Establishment Environmental Assessment Method), Great Britain. Established criteria. Good, Very Good, Excellent, Outstanding. LEED (Leadership in Energy and Environmental Design), USA. Established in 1998, based on BREEAM. 52 criteria. Silver, Gold, Platinum. DGNB (Deutsche Gesellschaft für Nachhaltiges Bauen), Germany criteria. Bronze, Silver, Gold. Other countries have also developed their own certification systems. France - HQE (Haute Qualité Environnementale) Switzerland - Minergie China - Three Star System Japan - CASBEE (Comprehensive Assessment System for Built Environment Efficiency) Australia - Green Star Unique to DGNB is that it is a system designed to be adaptable to local conditions in a way that makes building in different countries directly comparable. As a result, DGNB has developed a number of partnerships with other countries. 33

34 Overall Comparison of DGNB, LEED & BREEAM 34

35 The Beginnings of Germany s Building Certification: DGNB Because Germany s strong and well-developed construction culture with its high degree of technological expertise and corresponding approach to quality were not adequately reflected in other established building certifications, the German Sustainable Building Council (DGNB) was founded in 2007 by 40 organisations representing Germany s construction and real estate sectors to design and implement their own certification program. In 2009, it was implemented. 35

36 DGNB: A Public, Not-for- Profit NGO Mission is to develop and promote methods and solutions for sustainable design, construction and management of buildings. 1,200 member organisations DGNB System content based on the long-term, voluntary commitment of leading experts Ongoing adaptation 36

37 DGNB Promotes Sustainability over Being Green 37

38 DGNB Incorporates Life Cycle Assessment 38

39 DGNB Summary It is a program that addresses all of the key aspects of sustainable building: environmental, economic, sociocultural and functional aspects, technology, processes and site. The first four quality sections are equally weighted Uniquely the DGNB System is the only tool giving as much importance to the economic aspect of sustainable building as it does to the ecological criteria. The assessment is always based on the entire life cycle of the building. Additionally, it focuses on the well-being and experience of the end-user. DGNB is a comprehensive tool that does not merely focus on individual measures but instead, measures the overall performance of a building or urban district. 39

40 Any Questions? Thank you. 40