Buildings and Energy a systematic approach

Transcription

1 Buildings and Energy a systematic approach Enno Abel Elmroth Chalmers University University of Technology Technology Arne Lund of

2 Façades Windows Roof Floors Rooms Internal walls Room distribution Architecture Building structure Building physics- functions Thermal performance Moisture performance Air tightness Durability Concrete Visible Non tangible Invisible

3 Technical installations HVAC systems heating, ventilation, air conditioning, cooling, Electrical systems Control systems Technical installations Indoor climate Indoor temperature Air Quality Service functions light, power access, communication, data, water, sewerage Non tangible Invisible

4 HVAC systems Electrical systems Control systems All parts of the building have to function together and must as a whole be fit to use for its purpose

5 All of those taking part in the planning and construction of new buildings and reconstructions the proprietor-client the architect the building designer the technical consultants the contractor 1. Must have some understanding of each others professional fields 2. Must have a mutual respect for each others professions 3. Must be aware of what is cause and what is effect when a building is designed and when it is in operation

6 Cause and effect The Outdoor climate The architectural and structural building design The requirements for indoor climate The emissions from the activities in the building

7 Cause and effect The Outdoor climate The architectual and structural building design The requirements for indoor climate The emissions from the acivities in the buliding Decide The heat deficite and its variation in individual rooms The heat suplus and its variation in individual rooms The amount of air born pollutants to be removed

8 The Outdoor climate Cause and effect The architectual and structural building design The requirements for indoor climate The emissions from the acivities in the buliding Decide The heat deficite and its variation in individual rooms The heat suplus and its variation in individual rooms The amount of air born pollutants to be removed And by that The measures needed for ensuring the indoor climate Capacity, extent, complexity of the systems for Heating, Ventilation, Air-Conditioning, Cooling

9 System boundraries The building the Room Air Requirements on: Thermal climate Air Quality The interplay Building - Activity Outdoor climate results in Heat deficit Heat surplus Air born pollutants the Room The System boundrary layed around the Room Air The Architect The System boundrary layed around the Room The Architect The Building Designer

10 System boundraries The building The System boundrary layed around the Room Air the Room Air Thermal climate Air Quality Heat El The HVAC systems Supply heat Remove surplus heat Remove air born pollutants Building - Activity Outdoor climate Heat deficit Heat surplus Air born pollutants The Architect The System boundrary layed around the Room the Room The Architect The Building Designer

11 System boundraries The community Flowing water Flowing air Omvandlingsprocesser utanför huset Power Heating & cooling processes in house The house Technical service DHW, sewerage lighting, power access, communications, etc. Room air Fuels Heat Fuels HVAC systems Heat supply Heat removal Removal of air born pollutants Heat deficit Heat surplus Air born pollutants

12 The Building Envelope

13 Energy efficient buildings: Success aspects: Careful planning and design Use wellknown basic technology: Good thermal insulation in the building envelope Reduce thermal bridges Well insulated windows Very good air-tightness of the building envelope Well designed heating and ventilations systems inlc. heat recovery High quality of control systems in order to make use of internal gains and solar heat gains

14 Energy efficient buildings: Success aspects: Careful comissioning, continuing maintenance Measuring air-, water- and energy-flows Energy efficient white gods (A-Class at least) Use of solar heat gain: Limited glasing areas facing south Solar protecting during summer season Solar collectors for covering at least 50% of domestic hot water PV-cells for creating an image Qality control

15 Energy efficient buildings: Success aspects: Good thermal insulation: S-houses Apartments External walls >35 cm >30 cm Roofs >50 cm >40 cm Foundations >20 cm >20 cm Windows, U< 1,0 U< 1,0 W/(m 2 K)

16 Traditional External Walls Brick walls Lightweight Blocks

17 New Building Design: Each material has a special function

18 Example: Design of a Factory made house

19 Foof element 500 mm Mineral wool, U=0,116 W/m 2.K.

20 Advantages of improved windows Reduce heat losses Shorten heating season Improve thermal comfort Reduce risk for surface condensation Improve sound insulation More efficient use of floor area

21 Maximum window height if cold draught should be avoided 215 cm at 5 o C 175 cm at 10 o C 70 cm at 5 o C 60 cm at 10 o C 45 cm at 20 o C 110 cm at 5 o C 85 cm at 10 o C 65 cm at 20 o C 130 cm at 20 o C two glass window three glass window Energy efficient window

22 Some definitions: Airtightness Prevent air from penetrating through building envelope Wind protection Prevent air movement in insulation layers caused by wind Vapour barrier Prevent vapour from entering building element

23 Airtight Buildings Reduce infiltration of unwanted air from outside energy efficient Reduce the risk for draught Prevent moisture damages due to moisture convection Improve the performance of mechanical ventilation systems Reduce traffic noise from outside

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25 Make a pressurization test in all apartments. Combine with thermografy. Good airtightness is often good building quality

26 Build tight and ventilate right A building can never be too airtight!!

27 Different Wind Protections in External Walls

28 Good design of connections: air-tight and good edge insulation

29 The length of thermal bridges can be up to 2.5 km in ordinary building with 34 apartments! The extra heat losses corresponds to about 10 kwh/m 2 and cause cold floors

30 Kv Jöns Ols i Lund energy efficient, wellknown technology, cost-effective A Building with 34 apartments Traditional concrete structure, with lightweight external walls Measured, delivered energy 84 kwh/m 2 incl heating and ventilation, domestic hot water, household electricity and auxilary electricity (less than 50 % compared to other newly built apartment buildings in Sweden)

31 It is possible to build sustainable and very energy efficient houses and to achieve very good comfortable indoor climate to reasonable costs by using well aproven technologies.

32 Requirements

33 The initial planning process The Customer specifies The Performance demands The Quality demands The cost ceiling The planned activity Emission of Heat & Pollutants The architect The building designer The earliest lay out of the building Analysis Possible HVAC solutions Need of space Investment Operation and maintenance cost

34 The initial planning process Possible HVAC solutions Need of space Investment Operation and maintenance cost The customer (The architect) Accepts or Accepts not Accepts Accepts not The Customer scrutinizes the specification of demands analyses the planned acitivity requests a modified building lay-out An optimized basic solution of the building as a whole Start of technical design

35 Demands Performance requirements Floor areas Room distribution Etc Indoor climate Thermal climate Air Quality Air cleanness (laboratories etc) Barriers Lighting level and quality Restrictions on disturbances noise draught electric/magnetic fields glare vibrations Operation reliability Quality requirements Aesthetic design Efficient use of space God coordination of spaces Minimised Life Cycle Cost Energy efficiency Ecology and sustainability considered Generality and flexibility Technically and economically optimised solutions Durability and ease of maintenance

36 Demands Specification of demands The demands must be specified before starting the design The demands must be expressed by measurable quantities. The method of measuring should be defined. The responsibility for fulfilling the demands should be defined. Consequence analysis The client should be made aware of and accept the consequences of the demands on: o First cost o Space required o Operation costs o Service and management

37 Consequence analysis

38 The initial planning process The Customer specifies The Performance demands The Quality demands The cost ceiling Responsibility of the Customer The planned activity Emission of Heat & Pollutants The architect The building designer The earliest lay out of the building Responsibility of the Architect (in first hand) Analysis Possible HVAC solutions Need of space Investment Operation and maintenance cost Responsibility of the HVAC designer (in first hand)

39 Some Swedish nonresidential buildings constructed after 1995 Share of the total construction cost 100% Electrical installations BMS Air Conditioning Heating systems Cooling systems, 50% The Building Foundation, Structure, Building envelope, Floors, 0% 20-30% of total cost Offices Laboratories

40 Consequence analysis Temperature 30 o C 25 o C The room temperature has to be kept below the duration curve Lowest accepted temperature level 20 o C Working hours/year 80 working hours/year Solar protection factor g g = Solar radiation through the window Solar radiation towards the window

41 Consequence analysis Window size and solar protection Surplus heat removed with with chilled beams Design cooling load W/m g g 0.4 Reference case g 0.2 South-facing facade Relative glass area %

42 Consequence analysis Window size and solar protection Surplus heat removed with with chilled beams Design cooling load W/m g 0.7 Approximate additional investment cost compared to the standard case 100 /m 2 50 /m 2 50 g 0.4 Ref case g 0.2 South-facing facade 0 /m Relative glass area %

43 Consequence analysis Window size and solar protection Surplus heat removed with with chilled beams Design cooling load W/m Approximate additional investment cost compared to the standard case 100 /m 2 g /m 2 70 /m 2 50 g 0.4 Ref case g 0.2 South-facing facade 0 /m Relative glass area %

44 Consequence analysis Window size and solar protection Surplus heat removed with chilled air Air Change Rate 1/h 7 Approximate additional investment cost above the reference case 150 /m g 0,7 3 g 0,4 2 Reference case g 0,2 1 South-facing facade Relative glass area % 100 /m 2 50 /m 2 0 /m 2

45 Consequence analysis Air humidity η T = 0.5 MWh/m 3 sec year g/kg Lowest accepted RH at +22 o 30% 40% 50% C Increased need of supply air heating Supply air heating without humidification Furthermore, a special facade design may be needed

46 Consequence analysis 1/h 10 9 Liter/(m 2 s) 6 Sammanträdesrum Kontorsrum Liter/(m 2 s) CO 2 halt CO 2 halt

47 The ventilation and air-conditioning may have one of the following main purposes 1. To remove air borne pollutants in order to ensure Air Quality 2. To remove heat surplus in order to avoid too high room temperatures 3. To compensate safety ventilation exhaust ventilated hoods, safety cabinets 4. To establish a high cleanness level pharmaceutic industry, microelectronics, clean rooms

48 Type of premises The decisive task of the air system Air Change Rate Residential buildings There is`always one specific task that decides the system solution the air flow rate of the ventilation and air-conditioning system To remove air borne pollutants Purpose Air Quality > 0,5 1/h Offices All air systems Air-Conditioning Offices Chilled water systems Chilled beams Fan-coils, To remove surplus heat Purpose Room Temperature To remove air borne pollutants Purpose Air Quality >5 1/h 1-2 1/h Laboratories To support safety ventilation To enforce barriers To prevent hazardous exposure Purpose Staff protection /h

49 Energy efficiency

50 Energiy efficiency 1. The function of the building must not be jeopardized by the measures taken for energy saving. 2 There must be a balance between the resources sacrified for energy saving and the real total energy gain

51 Energy efficiency Very energy efficient new buildings with very low need of energy implies a limited increase in the total need of energy The extensiv need of energy in the building sector can only be decreased by energy saving measures in the existing stock

52 Measures for improved energi efficiency Existing buildings Existing residential buildnings decrease heat losses building envelope, heat rcovery make the heat supply and the heating system more efficient chose energy efficient domestic lighting and efficient domestic equipment Existing nonresidential and commercial buildings improve the operation of the HVAC systems replace HVAC components and systems replace lighting systems take every possible step for decreased heat surplus

53 From both global perspective and building sector perspective a decreased environmental impact from energy use in buildings is the main challenge for property owners, building designers building contractors

54 Implementation of EU-Directive on Energy perfomance of Buildings

55 EU Directive on Energy performance of Buildings The objective is to promote the improvement of the energy performance of buildings within the community, taking into account outdoor climatic and local conditions, as well as indoor climate requirements and cost-effectiveness

56 EU Energy Directive on Energy Performance of Buildings (a) general framework for a methodology of calculation of the integrated energy performance of buildings, (b)the application of minimum requirements on the energy performance of new buildings, (c)the application of minimum requirements on the energy performance of large existing buildings that are subject to major renovation, (d)energy certification of buildings, and (e)regular inspection of boilers and of air-conditioning systems in buildings and in addition an assessment of the heating installation in which the boilers are older than 15 years.

57 General framework for the calculation of EPB The methodology of calculation of EPB shall incl. at least following aspects: Thermal charactestics of the building envelop incl airtightness Heating installation and hot water supply, incl. their insulation Air-conditioning installation Ventilation Built-in lighting installation (mainly non-residential buildings) Positioning and orientation of buildings, incl. outdoor climate Passive solar systems and solar protection Natural ventilation Indoor claimate conditions, incl.designed indoor climate

58 General framework for the calculation of EPB cont. The positiv influence of the following aspects shall be taken into account: Active solar systems and other heating and elecricity systems based on renewable energy sources Electricity produced by CHP District or block heating and cooling systems Natural lighting

59 General framework for the calculation of EPB cont. Categories of buildings for calculation: Single-family houses of different types Apartment blocks Offices Education buildings Hospitals Hotels and resturants Sports facilities Wholesale and retail trade services buildings Other types of energy-consuming buildings

60 EPBD-standards: Presentation of Energy Performance Terminology and Definitions System Boundaries Calculation Methods: Heating, cooling, lighting etc Input Data: outdoor and indoor climate, default values (MS) Automation and Control Verification Methods: thermography, air changes, etc Inspections: Boilers, AC-systems

61 Main scheme CEN standards to support the EU s Energy Performance of Buildings Directive (EPBD) Minimum Energy Performance Requirement Energy Performance Certificate System inspections Energy performance Ways of expressing energy performance pren EP Certificate format and content Energy certification of buildings pren Overall energy use, primary energy, CO2 emissions Total delivered energy Procedures for calculated and measured energy rating pren Heating systems with boilers pren Air conditioning pren Ventilation systems pren System and building energy needs for heating, cooling, humidification, dehumidification, hot water, lighting and ventilation systems pren ISO 13790, pren , pren , pren 15243, pren , pren 15265, pren 15193, pren 15241, pren Definitions and terminology, external climate data, indoor conditions, overheating and solar protection, thermal performance of building components, ventilation and air infiltration,.. e.g.: pren ISO 6946, pren ISO 13370, pren ISO , pren 13947, pren ISO 10211, EN ISO , pren ISO 14683, pren ISO 10456, pren 15242, pren 13779, pren 15251, pren ISO 15927, EN ISO 7345, EN ISO 9288, EN ISO 9251, EN 12792

62 High level CEN standards EN number pren ISO (ISO/DIS 13790) pren pren pren pren Content Energy use for heating and cooling Overall energy use, for space heating, cooling, ventilation, domestic hot water and lighting, inclusive of system losses and auxiliary energy; and definition of energy ratings Ways of expressing energy performance (for energy certificates) and ways of expressing requirements (for regulations) Content and format of energy performance certificates Boiler inspections Air-conditioning inspections

63 Level 1: Energy performance of buildings - general Energy performance of buildings General procedures ~ EN 15603, ~ EN Overall energy use and/or CO2 emission Aggregation of energy needs, heating, cooling, lighting, ventilation, hot water, determined in Level 2 standards Conversion to primary energy and CO2 emission Definition of system boundaries (delivered and produced on site, renewable energy sources, district heating and cooling, ) Ways to express energy performance of buildings Classification, benchmarks Expression for energy performance requirements Building energy performance certificates

64 Level 2: Building energy needs and energy performance of technical buildings systems a) Assessment of energy needs of buildings Energy needs for space heating and cooling and for lighting, incl. interaction with thermal losses of technical building systems (heating, ventilation, cooling, hot water, and lighting) b) Calculation of energy performance of technical building systems Calculation of energy performance of heating, domestic hot water, ventilation, cooling and lighting systems, including interactions and including renewable energy systems. Including relevant terminology, definitions and symbols c) Energy performance of buildings on basis of measured energy use Energy performance of buildings including the technical building systems (heating, ventilation, cooling, hot water, and lighting) on the basis of measured energy use per energy carrier (gas, oil, electricity, etc.). d) Validation criteria for energy calculation methods General principles and procedures on test cases and validation criteria for dynamic calculation methods that include the building, the technical building systems and their control and the indoor environment.

65 Level 3: Supporting standards a) Energy performance of components Building thermal transmission properties and heat flows Building ventilation and air infiltration heat flows Solar and visual properties of components Daylighting availability in buildings b) External climate data c) Criteria for indoor environment including thermal, indoor air quality, light and noise d) Economy

66 Key-standards for Energy declaration pren 15217: Energy performance of buildings Methods of expressing energy performance and for energy certification of buildings psen 15603: Energy performance of buildings Assessment of energy use and definition of ratings Asset rating Operational rating Comparing measured data with calculated results Assessing energy saving retrofits pren-iso (draft): Energy performance of buildings Calculation of the energy use for space heating and cooling (EN ISO extended)

67 Energy performance of buildings - Calculation of energy use for space heating and cooling ISO/DIS Different types of calculation methods: Two basic types of methods: Dynamic methods, calculating the heat balance with short periods (typically one hour) Quasi-steady state methods, calculating the heat balance over a period long enough to ignore dynamic effects (typically, one month or whole heating season) Three different types of methods: A fully described monthly quasi-steady state calculation method A fully described simple hourly calculation method Calculation procedures for detailed simulation methods The choice between the three methods can be made at national level