General Work

Meeting Minutes

September 13
Sept 13 Unofficial Minutes
September 20
Video: September 20 meeting part 1
Video: September 20 meeting part 2
Video: September 20 meeting part 3
September 27
Video: September 27 meeting part 1
Video: September 27 meeting part 2
Video: September 27 meeting part 3
October 4
Video: October 4 meeting
October 9: Presentation Meeting
October 18
Video: October 18 meeting
November 1
November 8
November 15

Interesting Links

Jeremy

Video: Aluminum Hinge Concept
http://sci-toys.com/scitoys/scitoys/thermo/thermo3.html
http://www.kanthal.com/Global/Downloads/Materials%20in%20wire%20and%20strip%20form/Thermostatic%20bimetal/Bimetal%20handbook%20ENG.pdf
http://brassgoggles.co.uk/forum/index.php?topic=22480.0
http://landscapegardeningplants.com/landscapenews/nov10/itstoohot.html (Important bit: How hot do common landscape surfaces get in summer? The metal play ground equipment was 144.23°F(like 62°C))
For Jiggy: http://rredc.nrel.gov/solar/new_data/confrrm/au/ Looks like they only have data for 1997-1999. So when you click on the month it'll download a .csv document. The first column of the document (A) is the year. Column B is the month, C is day, D is hour, E is minute, and F is the solar irradiance (on a horizontal surface). The rest of the columns are (probably) unimportant for us.

Ted

Shape training of SMA http://www-personal.umich.edu/~btrease/share/SMA-Shape-Training-Tutorial.pdf
Bidirectional shape memory actuator http://micro.seas.harvard.edu/papers/SMS12_Paik.pdf
Technical specs of Flexinol SMA http://www.dynalloy.com/TechDataWire.php

Gantt Chart

Gantt Chart V4

Initial Background Research

Bimetallic Material Actuators - Jeremy

Bimetallic Materials<- Googledocs for now so I can keep adding to it

Previous Attempts at Adaptive Blinds - Ted

Previous Attempts at Adaptive Blinds

Project Definition

Adaptive Architecture Project Summary|

Jeremy

Develop automatically actuated window blinds that close when the room is hot and open when the room is cool. The mechanism must follow Chad’s design of square unit blinds. The actuators will be located in the corners of the square. These actuators will either be made of shape-memory material or bi-materials such that a temperature change will cause them to open or close the window blinds accordingly.
During summer months, the blinds should close in the middle of the day, when the sun is hottest, and open in the mornings and evenings. The squares will have some kind of covering to block sunlight when they are lowered and can fold up nicely to let light through as well.
The goals are to create a simple design that would save energy in cooling costs. The product should generate some kind of monetary savings during its lifecycle such that it can be expected to pay for its initial cost after a set number of years. The carbon footprint of the product should be minimal to enhance the environmental aspect of the design.

Lauren

Goal: Design an autonomous set of blinds using either a bi-material or a shape memory material as actuating hinges. The blinds must consist of connected square frames that collapse vertically (upwards or downwards) within a low (relatively) temperature range and that expand vertically within a higher (relatively) temperature range. When expanded the blinds should cover the window to prevent heat from entering the building. A suitable material should cover the frames. The actuating hinge material should be sensitive to heat (the hinge opens or closes depending on the outside temperature) and would be location at the corners of the frames. The blinds should be able to completely open or completely close. (ie not half open all the time). The lowest possible environmental footprint should be attempted.

Variables: Materials for hinges, frame and covering

Ted

With the use of large windows in modern architecture, an increasing amount of energy is required to cool the resulting temperature rise from direct sunlight. As a result, there is need for a technology that can autonomously allow natural sunlight but block direct sunlight from entering a building in order to reduce or eliminate the energy required to cool the interior space.

Objectives

• Evaluate and define problems in the basic concept that need to be addressed and any potential solutions

• Define the specifications (mechanical, temperature, electrical) required for the bi-material strip or shape memory material, as well as the frame and shades

• Choose materials that meet the required specifications

• Carry out a thermal analysis and obtain cost of using conventional hvac

• Carry out a life cycle analysis on the chosen materials to compare with conventional hvac

• Calculate cost of solution compared to conventional hvac

Constraints

• Location (Austin, Texas) and building design (single story ranch house)

• Room orientations

• Basic concept design of the modular blinds

• Ambient temperature and sunlight direction and intensity

Free Variables

• Materials

• Dimensions

• Placement of actuators

• Mounting points

Juan

The goal of our design project is to create an automatic system of blinds. With these blinds, we ideally want to remove the dependence of an air conditioning system to cool a room in Austin, Texas, but overall, reduce the cost of air conditioning long term to offset the cost of the blinds. The mechanism used to open and close the blinds would be either bi-materials, or shape memory materials. The materials should leave a smaller environmental impact when being processed, as well as have minimal effects on the structures surround the building that the blinds will be installed in.

Kush

The objective governing the project at hand is the drive to create, as well as determine the feasibility of, technologies that can behave autonomously. In this case the objective is to create blinds that behave autonomously to allow temperature control in a room to be attained. From the design project description given to us by Chad, it was described that glass is used as a medium to allow natural light to permeate into a building however one of the things associated with it is the rise in temperature due to heat accumulation. In order to combat this problem a conceptual idea of self-operational blinds has been created. This would allow for natural sunlight to permeate into the building at lower temperatures and would shut themselves during periods of high temperatures in order to stop intense sunlight raising the temperature of the building. The concept of the autonomously operating blinds is only a concept. The feasibility and design needs to be done. Such an application could only be used in certain conditions, where sunlight and heat are plentiful. As a result the assumption for this design is that the application would be in a place like Austin, Texas where the temperatures are quite high during the day time. The main concept behind the blind is a series of collapsing squares. In order to provide structural support for the squares either bimetallic strips or shape memory alloys will be used. One of the design objectives is keep the system as simple as possible. This is, for example, the use of a single strip of metal to act as a hinge. This would allow for the entire system to be autonomous and void of human contact as it would act as naturally as possible.

Issues, Challenges, and Solutions

Force exerted by actuator

The strength of the motion of the hinges must be enough so that it may collapse or unfurl the window blinds within a reasonable range of temperature. If the units are attached in a vertical series, the top box needs also to lift the weights of the blinds below it.
Solution: ??? counterweights?
Find a material that can lift the weight of the blinds. Make blinds as light as possible.

Operating temperature of actuator

What will the temperature of our blinds operate at? When should it open? when should it close? Air conditioning cools the room to about 23-25°C. Summertime highs outdoors in Austin are around 35°C and nighttime lows of around 26°C. How hot will the hinges get?
Solution: The boxes can serve to limit convection and increase local heat concentration, sort of like a mini greenhouse. This will give us a larger temperature range to work with.
Will the "mini greenhouse" effect allow the hinges to cool down enough to work?
How will direction of sunlight affect how the actuators work? What if a tree blocks half the window?

Bimaterial Temperature Calculator for 304 Steel and Low Density PolyEthylene: File:Austin Bimaterial Temperature Updated November 6.xlsx
SMA Temperature Calculator: File:Austin Shape Memory Alloy Temperature.xlsx

Price

How expensive will the hinges be?
Solution: Depends on bimaterial or shape-memory use. Alloy/Invar more expensive than steel/copper or brass.

-Figure out what will make the actuation work. Cost will be part of determining feasability

Customization

People have different temperature preference. Won't be able to customize at what temperature the blinds would open and close (beyond initial purchase).

Control

~~Do we want the blinds to also be manually controlled? Close or open the blinds regardless of temperature.~~

-Blinds will be on the outside

Response Time

How/can we control how quickly the actuators respond/move?

Questions for Blair

~~Quick questions off the top of my head to demonstrate formatting...:~~
~~Will this be used in conjunction with air conditioning or will it be stand-alone?~~

It will be outdoors.

~~Floor to ceiling? If the blinds are only near ceiling, temperature changes will be higher. Also if the rest of the window uses regular blinds there's no worry about privacy (manual control).~~

It will be outdoors. (Maybe curtains on the inside, location doesn't matter)

~~Will we want the columns of connected squares to also be connected? Ie. Do we want to make sure it all lifts at the same time or is it okay if they lift at different rates (cool pattern?)~~

Sure. Cool pattern would be great.

The expanding of the frames in the horizontal direction presents a problem if they aren't connected and aren't all moving up at the same time. If shade on one side prevents actuators from working the blinds may get stuck

~~Maybe rounded corners which would mean gaps, would that work?~~

More details. Size of gaps, benefits, etc.

What is the motivation for this connected square shape? Autonomous actuators could be used with Accordian blinds.
~~Can we play with color of material (ie black draws heat)~~

Yes. Do what we need to to make it work.

~~How large do we want the squares? Is that a variable for us to work with or is there a specific range?~~

6" ideally? Some multiple of 6" most likely so that it can fit over a standard window.

Questions for Chad

Which corners will the actuators be on? All four? If it's all four, two will have to bend in heat, two will have to straighten.

Objectives

Minimize overall environmental impact (cooling interior without use of HVAC, eco materials/production, etc)
Minimize complexity (lo-fi)
Minimize cost To be considered when given options where all other goals are equal

List of Constraints

Major constraints are in Bold. Minor constraints are in Italics.

Blinds must work autonomously
System is located in Austin, Texas
Blinds are installed on the outward face of the window
Unit box should be close to 6"
Folding unit must be square or "equiaxed"
Must be able to close all the way and cover entire window(block all light)
Should open all the way (completely collapse)
Should reduce cooling costs noticeably
Should be recyclable/made with recycled materials
Must lift a t.b.d. minimun weight (which should be more than it actually needs to, factor of 'safety')
Should work within a set temperature range(20-25C?) (I have this as minor because we may eventually want to play with customization)
Must operate for a long time without needing maintenance or hinge replacement
Should be visually appealing
Must be able to block the sunlight when closed
Material could let light through, but reflect infra-red
Blinds could be manually changeable
Fabric should not require much force to deform or close
Hinges must not exceed 90 degrees to close
Should be safe for people outside (not blinding or no hotspots)
Shouldn't harm environment or wildlife
Should withstand elements or wildlife
Must not be a fire hazard
Should be UV resistant

Bimaterial Actuators

Some ballpark calculations into what size bimetal strips (and ΔT) would be required and what force they are capable of. Material properties taken from IMPHY pdf catalogue sent out by email.
Force/length/curvature calculator (Version 5)
The actuation curves for each month with one curve for an average day of the month, one for the darkest day of the month, and one for the coldest day of the month.
Monthly averaged actuation curves (Version 2)