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Solar Powered Air Conditioning for Elderly, Low Income Houstonians


Air conditioning can be as high as 25-40% of a household's annual energy costs ... Voltage, wattage, amperage, BTU cooling capacity, price, vendor, etc. August, 2003 ... – PowerPoint PPT presentation

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Title: Solar Powered Air Conditioning for Elderly, Low Income Houstonians

Solar Powered Air Conditioning for Elderly, Low
Income Houstonians
  • Robert L. Howard, Jr., Ph.D.
  • National Society of Black Engineers
  • Houston Space Chapter

  • The Need
  • Air conditioning can be as high as 25-40 of a
    households annual energy costs
  • Many low-income residents cannot afford this and
    go without air conditioning
  • 60,000 homes in Houston without power in 2001
    only 14,443 in all of Texas received assistance
  • Senior citizens accounted for 14 out of 20
    heat-related deaths in Houston in 2001

  • The Need
  • CDC reports fans are useless at temperatures
    above 90 deg F with humidity above 35
  • Spur movement of hot, humid air
  • Causes increased heat stress accelerates body
    hearting and raises internal body temperature
  • Essentially turns room into convection oven
  • Should not be used for preventing heat-related
    illness in areas of high humidity

  • Problem persists despite local efforts to help
  • Window air conditioners donated, but wiring in
    many homes cannot handle added load
  • 1998 fatality widower had turned off air
    conditioner to save money
  • Houston libraries and multipurpose centers open
    as cooling centers, but inaccessible to some
    elderly less mobile, afraid to leave home, lack

  • Excellent opportunity for NSBE and NASA to come
    together in mutual fulfillment of charters
  • NSBE-Houston Space Chapter can make a positive
    impact by installing solar powered air
    conditioners in as many elderly, low income
    households as possible

  • Provides a cool zone within home elderly do not
    have to leave homes to be safe
  • Does not interfere with limited house wiring
  • Will not increase household electric bill
  • Technology available off the shelf, but not
    accessible to these communities cost and
    unfamiliarity we will bring it to them

  • Harmony of NSBE and NASA objectives
  • NASA vision is to improve life here, to extend
    life there, to find life beyond.
  • NSBE mission is to increase the number of
    culturally responsible Black engineers who excel
    academically, succeed professionally, and
    positively impact the community
  • Solar power system improves life here in a
    culturally responsible way that positively
    impacts the community
  • If we dont do it, who will?

  • Service project may well save lives at minimum
    it will increase the comfort of our elderly
  • Also benefits chapter members by providing
    hands-on technical experience many will not
    encounter in day-to-day job responsibilities

Brief Survey of Solar Electric Power
  • More than just a set of solar panels
  • Variety of components required for proper
  • Photovoltaic Panel
  • Three basic types single crystal silicon,
    polycrystal silicon, and thin film/amorphous
  • Convert sunlight directly into DC electricity

Brief Survey of Solar Electric Power
  • Inverter
  • Converts DC electricity into AC electricity
  • Most home appliances require AC power
  • Battery
  • Provide energy storage for use when solar panels
    cannot receive sunlight
  • Also supplement panels to smooth power level
  • Most are Lead-acid (30 sulfuric acid)
  • Absorbed Glass Mat (AGM) type recommended
    requires no maintenance and cannot leak

Brief Survey of Solar Electric Power
  • Charge Controller
  • Used in any solar power system that includes
  • Blocks reverse current (solar panels draining
    batteries) and prevents battery overcharge
  • May also prevent battery overdischarge, protect
    from electrical overload, and display battery
    status and flow of power

Brief Survey of Solar Electric Power
  • Power Outlets and Wiring
  • Proper gauge wiring essential to avoid poor
    performance of appliances and possible fire risks
  • Power outlets sometimes include circuit
  • Frame/Structure
  • Hold solar panels in place roof or pole mounts
    some pole mounts track sun

Overview of Mars Testbed Solar Recharge Station
  • Some in-house JSC experience with solar power
  • Environmental Office (COD) and Advanced EVA Group
    built a solar recharge station as part of a Mars
    testbed activity
  • Used commercially available components from
    Solarcraft (Stafford, TX)
  • Purpose was to demonstrate how state-of-the-art
    technology can improve life on earth as well as
    explore space

Overview of Mars Testbed Solar Recharge Station
Overview of Mars Testbed Solar Recharge Station
  • Reads like a prelude to this project
  • HSC will seek to tap into their expertise and
    possibly their relationship with Solarcraft
  • Will also seek to coordinate with MOD and
    Engineering Directorate organizations involved
    with solar power

Solar Powered Air Conditioning System
  • Two main options exist
  • Daylight-only system (no batteries)
  • Simpler, significantly less expensive
  • Offers no cooling between sunset and dawn
  • Continuously operating system (requires
  • Provides constant temperature
  • More expensive and complex
  • Presentation will explore both options, but will
    not choose between them

Solar Powered Air Conditioning System
  • Daylight-only Configuration

Solar Powered Air Conditioning System
  • Continuous Operation Configuration

Subsystem Data
  • In order to conduct a preliminary sizing, data
    was compiled on commercially available solar
    power subsystems and air conditioning units
  • Voltage, wattage, amperage, BTU cooling capacity,
    price, vendor, etc.

Preliminary System Sizing
  • Complete solar-powered air conditioning system
    sized based on current vendor prices
  • Should not be construed as an exact specification
    of what the system will look like or cost
  • Prices, component availability subject to change
  • Chapter may decide to construct items in-house
    rather than use commercial equipment

Preliminary System Sizing
  • Should be viewed as a ballpark estimate
  • Both options (daytime vs. continuous) sized
  • For simplicity, continuous system assumes
  • 12 hours charge time 10 hours discharge time
  • Overcast conditions not modeled in this analysis

Preliminary System Sizing
  • Both options assume cooling for a 300 to 350
    square foot area, which includes a kitchen
  • Rule of thumb suggests 8,000 BTU air conditioner
    for this square footage, with additional 4,000
    BTU to account for kitchen heat
  • Selected 1140 W Kenmore 12,300 BTU Multi-Room Air

Preliminary System Sizing Option 1
  • Photovoltaic Panel
  • SAPC-165 multicrystalline module
  • 156 W per module, 612
  • Total of seven required, for cost of 4284
  • Panel Mounting
  • UTRF64 Passive Tracking Mount
  • Tracks sun passively (no electric power)
  • Holds all seven SAPC-165, costs 989

Preliminary System Sizing Option 1
  • Inverter
  • Sized based on power generated
  • Using Powerstar 1300 inverter, but requires DC
  • Powerstar operates at 12 V, photovoltaic panels
    operate at 24 V
  • Powerstar costs 540, converter costs 285 for
    total of 825.00

Preliminary System Sizing Option 1
  • Wiring and Receptacle
  • Length will vary with each house impossible to
    specify in advance
  • Assuming generic value of 200
  • Total cost for Option 1 6,698
  • One unresolved concern uneven power supply
    levels may damage air conditioner
  • Chapter will need to resolve concern

Preliminary System Sizing Option 2 (Continuous
  • Batteries
  • AGM batteries chosen - 12V Concorde PVX-2120L
    offers the best value (2520 W-hrs)
  • Six batteries required to meet power goal
  • Cost 304.95 each, for a total of 1,829.70
  • Photovoltaic Panels
  • 15 SAPC-165 providing 2400W at 5,999.85
  • Inverters
  • Two Powerstar 1300 Inverters at 1,080

Preliminary System Sizing Option 2 (Continuous
  • Charge Controller
  • Trace C35 three units used one for every two
  • Total cost 337.05
  • Tracking Mounts
  • Two UTRF64 tracking mounts used at cost of 1,978
  • Total cost for Option 2 11,819.64

Preliminary System Sizing
  • Difference in price visually shows why Option 1
    remains a preferred choice
  • 6,698 vs. 11,819.64
  • Limitations in Option 1 must be solved before it
    can be considered valid, however

  • Chapter cannot pay for this project from dues,
    shirt sales, and dinners
  • Will seek to partner with JSC, contractors, and
    solar power companies in hopes of equipment
  • Will pursue grants and contracts from
    foundations, government agencies, businesses,
    nonprofits, etc.

  • Need chapter members to join Finance Zone to help
    Marlo in this area
  • Need new members from business directorates
    within JSC and contractors, especially B, H, and
    L mail codes

Engineering Roadmap
  • This paper is only a first step, not a complete
  • Need for additional studies - engineering work
  • Deepen understanding of solar power systems
  • Resolve outstanding technical issues
  • Generate
  • Finalized specifications
  • Safety reviews
  • Implementation procedures

Engineering Roadmap
  • Need for electrical engineers in the chapter to
    step up and get involved
  • New members especially needed from DF7, DT4, EC,
    EP, and JA13
  • Room for other chapter members engineers and
    non-engineers to contribute

Engineering Roadmap
  • Paper studies likely to continue through fall and
    into early spring
  • Build hardware experience prior to assembling air
    conditioner units
  • Conduct series of smaller, less expensive solar
    projects (e.g. solar fans, other low wattage
  • Side benefit many of these may have outreach
  • Goal first operational unit completed in time
    for summer 2004

Candidate Selection
  • No mechanism in place yet to select recipients
    must be accomplished prior to first delivery
  • Churches, United Way, etc. work routinely with
    the types of elderly we wish to serve
  • Coordinating with such organizations will help us
    to identify responsible elderly with genuine need

  • We cant help everyone suffering in Houston
  • We will make a difference
  • We will pioneer a roadmap other organizations can
  • Enhance image of NASA, NSBE, contractors,
  • Gain sense of satisfaction we will have used
    our skills to change the lives of people