Post on 28-Jul-2018
• Make sure to proof read report multiple times
• All appendices should be referenced in the text – i.e. “Detailed calculations are included in Appendix A”
•Show your final values in a table but include detailed calculations in an appendix, list all assumptions, show units, reference assumed values for material properties and radiation data.
General Comments on Report Writing
• ALL values, concepts, equations, and costs need to be cited in the body of the text with references listed at the end of the report.
• ALL references appearing in the list should have a citation within the report
• Format according to one of the formal bibliography formats and be consistent
A Note on REFERENCES
• In Text Citations:
In a direct gain system energy passes through the window and is directly absorbed in the building materials (Duffie and Beckman, 2006).
• End Notes
In a direct gain system energy passes through the window and is directly absorbed in the building materials [1].
A Note on REFERENCES
Introduction /2
•We were looking for a short description of the project, including task, rules, performance criteria and end goal
Background Research /5
• Wanted key concepts of passive solar building design
• Orientation
• Glazing area
• Thermal mass
• Solar collection (indirect, direct, sunspace)
• Insulation, air leakage
• Trombe wall, passive ventilation strategies, overhang
• Information on active solar systems was also appreciated
Background Research /5
• Also wanted discussion on heat transfer properties
• Convection (Forced and Natural)
• Radiation (Solar gain and losses)
• Conduction
• Thermal Storage
Design Drawings /5
• Needed clear, neat, dimensioned drawings that adhered to rules
• Labels are very helpful at allowing the marker to understand design
• Drawings should be stand alone
Preliminary Engineering Analysis /10
• Looking for calculations that justified your design
•Heat Loss Calculation
•Cannot ignore heat loss from window, conduction or convection
•Heat Gain Calculation
• Needed to include the transmission of the Plexiglas
•Needed to have peak solar gains as well as average
•Storage Calculation
Materials and Cost Estimates /2.5
• ALL materials except the provided VIP panels and batteries and Plexiglas must have been included in total cost
• A standardized price for Plexiglas per square cm will be provided at a later date
• Recycled materials must have been included in cost (i.e. If you didn’t pay for something an estimate on the retail price must be included in total cost)
Work Breakdown /2.5
• Complete list of tasks
•Don’t forget you will need to schedule time to prepare the presentation and final report
• Needed distribution of who is doing what – even distribution among team members
• Neatly displayed and easy to read – tables or a Gantt chart
• VIP panels are rigid but may not hold large amounts of mass, consider using a frame or plywood to increase robustness, especially if heavy thermal mass is being used
• When attaching items inside your unit, make sure not to use screws or nails on the VIP panels
• Design has to be able to open so we can insert thermocouple and do the block test to ensure the minimum internal volume rule has not been broken
Design Issues – Structural
• If using electronics, ensure they are protected from the elements
• If using water as a thermal mass, ensure it is freeze protected (i.e. salt water, glycol, other anti freeze chemicals)
• If using any chemicals, make sure to include a MSDS in the next report and inform us of any hazards during the set up
Design Issues – Safety
• Don’t underestimate the importance of having a lot of thermal mass
• Equally as important is getting heat into and out of thermal mass
• Radiation incident on mass?
• Increased convection?
• Watch internal space requirements
• If system has some form of active control, make sure to tune it to optimize performance
Design Issues – Thermal Mass
Closing Remarks
• Proofread
• Follow instructions and make sure to not break any rules
• Keep performance criteria in mind
• Show your work
• References
• Remember your group number and put it on future deliverables
• Stay posted on rules and rule updates
• Submit a dynamic and transient model of your design’s performance (can be Excel, Matlab, EES)
• Submit final construction drawings of your device, must be neat, labeled, dimensioned and clearly show the features of your design
• Submit a report containing
– Model Summary discussing the development and reasoning behind the model
– The results predicted by your model
– Plot of Temperature VS. time for at least 7 days
– Submit a final design description and justification for design based on model results
– Updated cost estimation (include all materials except VIP panels, costs of Plexiglas and battery will be provided)
– Performance criteria (Comfort Zone, Affordability, Temperature Swings)
• Due October 31st
• Remember we want to get these set up on the roof on Nov. 9 and Nov. 10 so you will have to have your unit assembled by then
• You will be submitting a model summary, final design concept and design drawings (.pdf/doc) andyour model (.xls, .ees, .m)
• Weather data has been posted to the web
• If you want any other weather data let me know and I can get it for you (different incidence angles, sun positions etc.)
• We are giving you an excel file with a dynamic and transient model for a very simple design.
• Your job is to modify this file to represent your design as accurately as possible
Modeling
Simple Example Model
Polystyrene Insulation
Double Pane Vertical Window
Concrete Patio Stone Floor (painted black)
Simple Example Model
Excel Sheet has four tabs
• Model
• Contains design specifications, material properties and
calculations
• References
• Shows sources for information used in model
• Equations
• Shows equations used and assumptions
• Performance
• Evaluates the design using the three performance criteria
Simple Example Model
The model requires you to enable circular referencing,
this may already be enabled depending on your
version of excel
How to enable:
File, Options, Formulas, Check the box beside “Enable
Iterative Calculations"
Tint Ts,int Ts,ext Tamb
Eq. 8:Window Thermal Resistance
Assuming: No
convection in window
cavity, fully mixed
interior air, 1d
conduction through
the window, lumped
convective/radiative
heat transfer
coefficient
Eq. 9:Wall Thermal Resistance
Assuming: Fully mixed interior
air, 1D conduction through
walls, all walls are same
thickness and conductivity, no
heat loss through the floor,
lumped convective/radiative
coefficient
Tint Ts,int Ts,ext Tamb
Qloss, walls
Eq. 10: Total Thermal Resistance
Tint
Rwind
Tamb
Qloss, tot
Rwall
Ignores edge effects
and assumes heat loss
is uniform on all walls
Assuming: window transmittance τ, floor absorbance α,
all radiation transmitted by the window is absorbed in
the floor (with absorptivity α) (i.e. no shortwave radiation
escapes back through the window)
Time step
Assuming: lumped capacitance, floor all one temp, finite
difference, lumped radiation and convection coefficient hn
natural convection from floor, air has no heat capacity
Time step
1
. 3( )( )(T T )t t t
floor loss n r floor roomQ h h IA
Delta T is
timestep
Trm TambTfloor
Qloss 1/hA Rtot
Time step
Assuming: air
has no heat
capacity, natural
convection from
floor to air,
lumped radiation
and convection
coefficient from
interior surfaces,
all assumptions
related to R total
• Model is modified and improved to reflect team’s design
• Make sure you use the updated weather data from the course web site
• Design is simplified appropriately, model is accurate, equations are valid
• Heat loss, heat gain, heat storage calculations
• Model outputs dynamic, transient performance of the device based on weather data
• Incorporates dynamic referencing (allows design variables to change and performance prediction is updated)
Expectations
Model/Performance Prediction Expectations
• All design factors are accounted for or addressed
• Assumptions are clearly listed and limitations of assumptions are explained
• Report shows understanding of assumptions and their effect on the accuracy of the model
• Final design incorporates model analysis—model is used to justify final design decisions
Detailed Design Expectations • Design drawings are clear and dimensioned
• Drawings include material labels
• Design concept is clearly explained and justified using the dynamic model
• Design shows critical thinking and creativity