Sustainable Built Environment Chapter 12 Integrated Building System Analysis

1. Sustainable Built EnvironmentChapter 12 Integrated Building System Analysis A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

2. OBJECTIVE To provide students with a review of the analytical tools to assist with the design of buildings and their systems – and the assessment of building performance and costs. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

3. Topics • Buildings, building systems and their interaction • Tools for building performance assessment • Environmental impact assessment methods • Tools for sustainable design analysis • Building cost assessment A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

4. 1.Buildings, Building Systems and their Interaction A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

5. Design Considerations A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

6. Indoor Environment A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

7. Sustainability Minimise resources required in the construction, use and eventual demolition of building (i.e. lifetime costs). A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

8. Indoor environment Building characteristics Building services Heating Cooling Ventilation Lighting Location Orientation Layout Materials of construction Glazed area etc. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

9. Need for an integrated approach Design procedure in the past Final decisions Key decisions Services design Integrated approach(set out in EP 2) Key decisions Services design Final decisions A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

10. Interaction between building and services – Example 1 Increasing glazed area: • increases heat loss. • on facades orientated to sun increases heat gain. • reduces need for artificial lighting. • Increases possibility for ventilation in summer A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

11. Interaction between building and services – Example 2 • Fresh air supply controls indoor air quality but requires conditioning (heating, cooling) • Possibilities for reducing energy penalty include 1. Heat recovery 2. Flow controlled by sensor • These increase complexity of systems and may limit opportunities for natural ventilation A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

12. Design work in the past A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

13. Integrated building system analysis • Tool to enable decisions to be made during the design process. • Possible to simulate performance at the design stage. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

14. Building simulation simple mathematical representations for sizing systems simple ‘look-up’ methods for transient heat transfer computing power, understanding of building physics, numerical methods increased emphasis on making simulation software A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

15. Types of simulation A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

16. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

17. Objectives: • Achieving correct internal environment. • Approximate sizing of plant. • Approximate prediction of energy consumption. • Available data: • Outline form of the building, including main sub-divisions and their uses. • Limited information on building envelope. • Assumptions/default values for occupancy, internal heat gains etc. • Possible simulations: • Effect of building orientation on energy consumption. • Determination of peak heating and cooling loads. • Determination of plant size and space requirements. • Assessment of feasibility of natural ventilation. Conceptual design 17/62 A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

18. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

19. Possible simulations: • Calculation of cooling requirements for typical rooms • Analysis of daylighting and use of artificial lighting • Comparison of HVAC alternatives • Air infiltration • Indoor environment • Available data: • Preliminary architectural drawings • Method and materials of construction • Options for fenestration • Options for solar protection • Occupancy pattterns and system schedules • Internal heat loads (occupancy, equipment etc.) • HVAC system alternatives • Objectives: • Based on preliminary drawings compare alternative design options for building systems. Preliminary design A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

20. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

21. Detailed design Objectives Available data Possible simulations • Detailed drawings by the architect, structural engineer etc. • Performance of HVAC equipment • Manufacturers’ data on components • Detailed sizing of air handling and cooling equipment • Selection and sizing of ductwork, piping and air teminal devices • Simulation of control strategies • Detailed evaluation of air movement and comfort. • Architect’s drawing close to final form • Principal need – detailed specification of building systems, especially HVAC equipment. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

22. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

23. Tender evaluation, construction and commissioning Objectives: • Comparison of the energy performance of rival tenders • Sizing and selection of equipment (e.g. piping and ductwork) by contractors. Objectives: Available data: • Final building and system design data • Product information • Commissioning measurements ２ Possible simulations: • Energy consumption comparisons of alternative air-handling units • Energy performance of tenders for total system or sub-system proposals • Control and balancing calculations for pipingand ductwork • Effect of control strategies A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

24. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

25. Operation and maintenance Objectives: • To provide a comparison with monitored energy consumption and internal environment. Objectives: Available data: • Data from BMS systems etc. • Weather data ２ Possible simulations: • Expected annual & monthly energy consumption over real period • Identification of causes of problems with internal environment • Identification of system operating problems • Simulate effect of changes in control strategies A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

26. Idealised Building Design Process(from IEA Annex 30) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

27. Objectives: • To determine effects of system improvement or replacement • To determine effects of change of use or internal layout • Available data: • Actual performance data • Information on proposed changes • Possible simulations: • Internal environmental conditions • Investigation of changes in zoning or plant • Assessment of potential energy saving measures Renovation A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

28. Modelling underpins building simulation A Modelling of building performance • Principal areas of modelling: • Thermal analysis – building • Thermal analysis – building systems • Air flow Computer-based models (mainly) developed which range from simple correlations based on field data to dynamic numerical methods based on understanding of the physical processes - heat transfer and fluid flow B C A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

29. Thermal Analysis - Buildings Calculation of the effect of climate, construction features and internal heat. construction features internal heat (a) Internal environment (b) Heating and cooling loads built form, materials, fenestation, orientation etc. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

30. Simple models which ignore transient effects (solar gain, diurnal changes in temperature etc.) • Mainly used for plant sizing Steady state heat transfer • Deal with specific building elements Elemental Thermal Analysis - Buildings • Allow thermal inertia to be included. • Simple treatment of forcing functions (such as solar gain) Quasi-dynamic analysis • No restriction on forcing functions • Fully time-varying output Dynamic analysis A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

31. Thermal Analysis – Building Systems Models systems and controls Pre-configured system Quasi-dynamic Dynamic • Components and controls represented by idealised mathematical equations – gives closer representation • Similar to above system but includes detailed modelling of components and control systems (e.g. thermal inertia of heating or cooling coils). • ‘Black box’ approach – mathematical relationship from curve-fitting actual performance data or manufacturers’ data A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

32. 1.Single cell ventilation models 3.Room air movement (CFD) 2.Multi-cell ventilation models Modles 1 1 1 1 • Ventilation and air movement A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

33. Single – cell model A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

34. Multi-cell model A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

35. Multi-celled models - software • Developed by Lawrence Berkeley Laboratory • Maintained as a commercial product by CSTB, France COMIS • Developed and maintained by NIST, Building & Fire Research Laboratory – USA • Freeware – can be downloaded from:http://www.bfrl.nist.gov/info/software.html CONTAMW A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

36. 2. Tools for Building Performance Assessment A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

37. Simulation tools • Pre-design tools • Relatively simple (e.g. look-up charts) • Useful for making early decisions • Detailed simulation software • More precise prediction of performance • May be whole building or specific aspect (e.g. CFD for Indoor air flow) • Integrated data exchange • Provision of improved user interfaces • Links to other types of softwares (e.g. CAD) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

38. Example Pre-design Tools LT-method (Lighting & Thermal) • Developed by Cambridge University, UK • Simplified design tool to provide initial guidance on built form and glazed area for non-domestic buildings. • Defines passive and non-passive zones. • Uses simple set of graphs for four orientations and two climate zones (based on monthly average temp.) • Graphs enable heating and cooling loads to be calculated. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

39. Example Pre-design Tools HEED • Developed by UCLA. • Designed for houses and simple single zone buildings. • Calculates hourly heat balance over a full weather year • If internal temperature falls outside a given ‘comfort’ band it calculates heating or cooling load. • Heating and cooling loads, together with energy use calculated over whole year. • Can use worldwide climate files designed for EnergyPlus A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

40. Energy-10 Developed by NREL and now marketed by Sustainable Buildings Industry Council, USA. Intended for houses or small commercial buildings with one or two thermal zones. Calculates savings resulting from energy-saving strategies (passive solar heating, high performance windows etc.) BREDEM BRE Domestic Energy Model. Simple model for calculating energy consumption (and CO2 emissions) for houses. Based on monthly degree-day calculations, takes into account physical characteristics of house, location, heating system, control and lifestyle of occupants. Used in UK as basis of national Standard Assessment Procedure for energy rating of dwellings. Example Pre-design Tools A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

41. BLAST Building Loads Analysis and System Thermodynamics – also conceived in 1979 – by US Army CERL and University of Illinois. Estimates peak load (design day) calculations and annual energy performance. Computes hourly design loads, demands on systems and fuel and power consumption. Prediction based on an hourly room heat balance (conduction loads, solar gain, internal heat gains, infiltration and temperature control strategy to maintain comfort. No longer maintained. DOE-2 Conceived in 1979 and continuously developed and maintained by Lawrence Berkeley Laboratory. USA. Designed to allow users to choose building parameters to improve efficiency while maintaining thermal comfort and cost-effectiveness. Detailed Simulation Software A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

42. DOE-2 BDL Processor: Reads and transforms input data LOADS: Calculates sensible and latent heat component of hourlyheating/cooling load for each space taking into account weather, solar gain, occupancy, lighting, infiltration etc. HVAC: Two sub-programs - PLANT and SYSTEMS. PLANT calculates performance of boilers, chillers, cooling towers etc. Calculates fuel and electrical demands. SYSTEMS calculates performance of air-side equipment (fans, coils etc) ECON: Calculates cost of energy used Weather Data: Hourly annual data from US National Weather Service. Library: Source of input data for building elements (walls, windows etc.) A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

43. TRNSYS • TRNSYS (TRaNsient Systems Simulation) is designed to simulate transient performance of thermal energy systems. Designed and maintained by National Renewable Energy Laboratory, USA. • It has a modular structure – the user selects components from an extensive Library of ‘TRNSYS types’ and defines the way that they are connected. • The Library includes a wide range of components of thermal and electrical systems as well as routines to handle weather data and time-dependent forcing functions and output data. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

44. EnergyPlus EnergyPlus is based upon both BLAST and DOE-2 and is an energy analysis and thermal load program. It contains a number of improvements, including the user defined sub-hourly time-steps for interactions between thermal zones and HVAC systems. It is a simulation engine and does not have its own user-interface. This allows software designers to provide interfaces designed for particular professional users. ESP-r Under continuous development by the Energy Systems Research Unit, Strathclyde University, UK, since 1974. The system has mathematical models for heat and moisture transfer, air flow, lighting, electrical power flow, control systems and a range of conventional and renewable technologies. These models are controlled by a central ‘Project Manager’. It is based upon a finite volume conservation approach in which a problem is transformed into a set of conservation equations which are integrated at successive time-steps. It has a facility for defining building geometry or can be linked to CAD software. Detailed Simulation Software A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

45. Integrated Data Exchange • COMBINE • EU-funded research programme to develop methods for facilitating data transfer between different design and analysis program. • VisualDOE • Commercial program with user-friendly interface with DOE-2. Extensive database of templates for HVAC systems and central plant. • e-quest • Freeware developed by California energy utilities to provide user-interface with DOE-2; • DesignBuilder • Commercial program providing user-friendly interface for EnergyPlus. Building information can be imported from CAD software. • Virtual Environment • Maintained by IES Ltd, UK uses APACHE software as core. A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

46. Mary Seacole Building - Brunel University A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

47. Virtual Environment – building definition A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

48. Brunel Building – View 1 A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

49. Brunel Building – View 2 A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment

50. Brunel Building – View 3 A Multidisciplinary Approach to Curriculum Development in Sustainable Built Environment