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Space-Conditioning Systems for Low-Carbon Buildings 4.421 Department of Architecture Spring 2019

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Instructor: Les Norford lnorford@mit.edu Teaching Assistant: Awino awino@mit.edu Monday and Wednesday, 2:00-3:30, Room 5-415; Lab Friday 9:30-11, Room 5-415 Units: 3-2-7; 3-2-4 available. Class is open to students in all degree programs Consensus understanding of climate change identifies a need to drastically reduce anthropogenic emissions of greenhouse gases in coming decades, including those associated with buildings. In this course, we seek a thermofluids understanding of the basics of natural and mechanical systems for conditioning high-performance buildings and will develop and assess systems based on this understanding. We will focus on options for the Metropolitan Warehouse, future home of the School of Architecture and Planning. Can this and other buildings, large or small, be ventilated without use of ducts and fans? Can they be maintained at a comfortable temperature with little or no use of mechanical systems? We will investigate natural ventilation in detail. Topics include the thermal and fluid dynamics of airflow in buildings, application to multi-zone wind- and buoyancy-driven airflows, and adjustments in urban areas to account for reduced wind speeds. Performance assessments will be based on first-principles analyses and simulations that couple airflow and energy analysis programs. Building cooling strategies will be motivated by mapping conventional and innovative cooling systems on the psychrometric chart. First-principles analysis and simulations with an equation-based language, Modelica, and with EnergyPlus will be used to quantify the performance of energy recovery systems, membrane- and desiccant-based dehumidification, evaporative cooling, thermal storage at diurnal (building materials) and annual (ground-coupled heat pumps) scales and radiant cooling and heat-rejection systems. System design in leading commercial practice will be presented and critiqued. Working in groups and making use of design workflows under development at MIT and Harvard, we will assess climate- and building-specific systems on the basis of thermal comfort, energy consumption, carbon emissions and resilience to climate change.

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Learning objectives The objectives of the course are to help students: • Understand the societal and environmental context of building energy consumption; • Understand and apply the scientific principles underlying the thermal and fluid dynamic

characteristics of buildings and building conditioning systems, and apply these fundamentals to practical design problems;

• Recognize design opportunities to use natural ventilation; • Develop an ability to use contemporary component and whole-building simulation programs

to analyze building performance; • Learn to evaluate a range of technologies for creating comfortable indoor environments and • Demonstrate an ability to critically discuss and present the environmental concept of low-

energy and low-carbon building systems integrated into a building. Requirements This course requires the following: • Attendance of bi-weekly lectures; • Timely completion of assignments that involve analytic and computational assessment of

system performance; • Completion of a group course project; • Active participation in class discussions. Course Grading 40% homework assignments 20% interim design project presentation 30% design project final presentation and report 10% class participation

Please familiarize yourself with MIT’s Academic Integrity Expectations at http://web.mit.edu/academicintegrity/. We will largely work in groups; information shared from other groups should be acknowledged. Required text None. Readings will be assigned from multiple sources. Software (we’ll use much but not all of following) • Rhino 6 (http://Rhino3d.com ) is the 3D modeler we will use to represent buildings in a

form that can be linked to performance analysis tools through the Grasshopper visual scripting program, which comes with the Rhino download.

• Ladybug and Honeybee (https://www.ladybug.tools) are two of the four insects developed by MIT Department of Architecture alumnus Chris Mackey (M.Arch and SMBT 2015) for building performance analysis in Grasshoppper. Both are freely downloadable and installed as a set of set of functions (not exe files) that can be dragged onto the Grasshopper canvas.

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Ladybug can perform user-defined climate analyses, such as 3-D plots of temperature as a function of date and time and wind roses limited to specific outdoor temperatures. Honeybee links to EnergyPlus for energy analysis and to Radiance and Daysim for daylighting analysis, OpenStudio for HVAC system templates for EnergyPlus and THERM for thermal analysis of walls and windows. The installation instructions with the download provides the necessary URLs.

• DIVA for Rhino (http://diva4rhino.com/) includes daylighting and the Archsim interface to the EnergyPlus building energy analysis program.

• Archsim (http://archsim.com ) will be used to define building templates and create first-cut EnergyPlus input data files (IDFs) that we will modify with provided Python scripts to represent internal loads (peak values and schedules) appropriate for energy-efficient buildings.

• EnergyPlus (https://energyplus.net ) is the whole-building energy simulation program we will use to generate heating and cooling loads that must be met by space-conditioning equipment we will define and represent by seasonal efficiency metrics.

• Dymola is an interface for the Modelica equation-based system analysis program. Download and installation instructions have been established by the SA+P IT service, cron, and will be provided at the appropriate time. We will use this to analyze advanced systems for cooling and drying air brought into buildings.

• CC WorldWeatherGen (http://www.energy.soton.ac.uk/ccworldweathergen/) morphs weather files to account for projected regional climate change.

• CONTAM (https://www.nist.gov/services-resources/software/contam) is a freely available program developed by the National Institute of Standards and Technology (NIST) to simulate multi-zone airflows and contaminant transport. It treats each zone as well mixed but can also perform a computational fluid dynamics simulation in a single targeted zone.

• CoolVent (http://coolvent.mit.edu) is a freely downloadable tool developed at MIT for analyzing airflows and indoor temperatures associated with naturally ventilated buildings.

• scSTREAM computational fluid dynamics program. Download and installation instructions have been established by cron and will be provided at the appropriate time.

• CBE Thermal Comfort Tool (http://comfort.cbe.berkeley.edu) is an interactive psychrometric chart that will identify regions of temperature and humidity that are thermally comfortable for humans.

• Climate Consultant (http://www.energy-design-tools.aud.ucla.edu) is a freely downloadable tool that runs under Windows or Mac OS and provides a relatively comprehensive set of non-customizable graphical presentations of data from standard weather files. We prefer Ladybug and the CBE thermal comfort tool but acknowledge that Climate Consultant is easy to use for standard climate information.

• ASHRAE or other psychrometric chart software (HDPsyChart or comparable) that will plot condition lines and cooling paths

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Schedule as of 20190206– subject to (hopefully) minor revision W1 2/6 L1 Climate change, urban heat island, buildings 2/8 Lab Overview of MIT’s plans for the Metropolitan Warehouse; Met tour and

formation of teams; installation of Rhino, Grasshopper, Ladybug and climate-morphing software

R Carbon and climate change reports A1 National carbon emissions, with end-use disaggregation W2 2/11 L2 Low-energy building standards, practices and examples: Passive House,

LEED, Living Building Challenge, etc.; energy and carbon emissions 2/13 L3 Thermal comfort and energy balance, the heart of all passive and active

design considerations 2/15 Lab climate analysis using Ladybug with current and morphed climate files;

overview of EnergyPlus, its interfaces, and low-carbon building templates R morphing of climate files A none: project work to assess present and future Cambridge climate for

analysis of the Met; define building, schedules and loads for EnergyPlus W3 2/19 L4 Note President’s Day shift! Natural ventilation toolkit 2/20 L5 Buoyancy- and wind-driven airflow; two-way airflows through single

openings; steady-state mass and energy balances 2/22 Lab Climate analysis with Alpha Arsano’s CLIMA+; continued use of

EnergyPlus and interfaces to define building loads; R none A2 Multizone airflow calculations and application to solar chimneys W4 2/25 L6 Mass and energy balances for multiple zones in series, for wind and

buoyancy flows; advanced analytic flows 2/27 L7 Urban airflows, with quantitative emphasis on reduced airspeed and

wind-pressure coefficients 3/1 Lab analytic solutions for mass and energy balances; CoolVent for multizone

flow and temperature calculations, with emphasis on chimneys R wind-pressure coefficient literature A3 Assessment of UCL School of East European and Slavic Studies (SEESS)

building W5 3/4 L8 CONTAM math, templates, wind-pressure coefficient libraries, demo and

tutorial 3/6 L9 Heat storage at diurnal and longer time scales: thermal mass, PCM, earth

tubes. Ground-temperature plots. 3/8 Lab CONTAM models for Met Warehouse R CONTAM manual and tutorials A4 CONTAM, with and without CFD, for natural ventilation assessment W6 3/11 L10 Building thermal dynamics

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3/13 L11 Early design assessment of natural ventilation (Nari Yoon, GSD) 3/15 Lab Assessment of building thermal mass and night flush (simulation and

analytics in spreadsheet) and NV assessment with Ms. Yoon’s grasshopper workflow

R Strand’s earth tube model for E+; source of ground temperature models, Carrilho de Graca’s summary of night flush

A5 thermal dynamics for reducing peak loads and for night flush, using Yoon workflow

W7 3/18 L12 Critique of naturally ventilated buildings in practice 3/20 Preparation for first project presentation: loads, opportunities for specific

approaches to natural ventilation 3/22 Lab First project presentation R none A none Spring break!! W8 4/1 L13 Moist-air processes, static and interactive psychrometric chart: condition

line, mixing, sensible load factor; vapor compression system, direct and indirect evaporative cooling, argument for splitting sensible and latent heat removal: eliminated reheat, warmer water, opportunities for free sensible cooling, including radiation

4/3 L14 heat pump fundamentals 4/5 Lab psychrometric chart calculations and visualizations R McQPS chapters 3 and 14; Gordon-Ng (available online through MIT

libraries); Jaffe and Taylor’s Physics of Energy A none W9 4/8 L15 Ground-coupled heat pumps 4/10 L16 Radiant cooling systems; active and passive chilled beams, TABS 4/12 Lab Modelica modeling: guest lecture by Chris Laughman, MERL

Dymola/Modelica set up and examples R ASHRAE GCHP manual A6 Ground-coupled heat pumps: sizing and performance W10 4/15 Patriots Day! 4/17 L17 All-air system (VAV), DOAS, heat and enthalpy recovery; membranes and

desiccants for dehumidification; desiccant wheels and desiccant regeneration

4/19 Lab Modelica for system evaluation and building performance (Tianyi Chen) R Modelica-based Buildings Library A7 Modeling a DOAS cooling coil in Modelica and building energy use

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W11 4/22 L18 Gordon-Ng and Zakula models, efficiency metrics (EER, COP, IPLV). Goals: part-load performance as function of understandable parameters. Low-lift options

4/24 L19 Honeybee for HVAC system modeling 4/26 Lab LN away; application of models for chilled beams R Models of chilled beams and TABS (from Zakula and Blum), A8 connecting a radiant cooling system to ground-coupled water W12 4/29 L20 Radiant heat rejection (Stanford, UC Boulder, PNNL) 5/1 L21 Water use for cooling and production of electricity: direct and indirect

evaporative cooling and Maitsosenko dew-point indirect evaporative cooler; desiccant or membrane front ends; absorption and adsorption cooling

5/3 Lab Modeling DEC, IEC, and dew-point IEC using the psychrometric chart, combining IEC with dehumidification front end (Chua)

R M-cycle and papers by Chua and Palmer A none W13 5/6 L22 Systems and sustainability boundary; low-carbon system design; critique

of built and student projects (A10 or other input) 5/8 L23 Heat and water recovery at building and district scale. Stanford vs. MIT:

heat recovery, co- and tri-generation. 5/10 Lab MIT campus central plant tour R none A preparation for project presentations W14 5/13 L24 project preparation 5/15 project presentations (no final exam)