Transcript Solar Powered Air Conditioning for Elderly, Low Income

Solar Powered Air Conditioning
for Elderly, Low Income
Houstonians
Robert L. Howard, Jr., Ph.D.
National Society of Black Engineers
Houston Space Chapter
Introduction
The Need
– Air conditioning can be as high as 25-40% of
a household’s 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
NSBE – Houston Space Chapter
August, 2003
Chapter Technology Seminar
Introduction
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
NSBE – Houston Space Chapter
August, 2003
Chapter Technology Seminar
Introduction
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 transportation
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August, 2003
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Introduction
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
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August, 2003
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Introduction
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
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August, 2003
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Introduction
 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 don’t do it, who will?
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Introduction
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
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August, 2003
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Brief Survey of Solar Electric
Power
More than just a set of solar panels
Variety of components required for proper
functioning
Photovoltaic Panel
– Three basic types: single crystal silicon,
polycrystal silicon, and thin film/amorphous
– Convert sunlight directly into DC electricity
NSBE – Houston Space Chapter
August, 2003
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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
NSBE – Houston Space Chapter
August, 2003
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Brief Survey of Solar Electric
Power
Charge Controller
– Used in any solar power system that includes
batteries
– 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
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August, 2003
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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
protection
Frame/Structure
– Hold solar panels in place; roof or pole
mounts; some pole mounts track sun
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Overview of Mars Testbed Solar
Recharge Station
Some in-house JSC experience with solar
power systems
– 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-theart technology can improve life on earth as
well as explore space
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Overview of Mars Testbed Solar
Recharge Station
NSBE – Houston Space Chapter
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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
NSBE – Houston Space Chapter
August, 2003
Chapter Technology Seminar
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
batteries)
• Provides constant temperature
• More expensive and complex
– Presentation will explore both options, but will
not choose between them
NSBE – Houston Space Chapter
August, 2003
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Solar Powered Air Conditioning
System
Daylight-only Configuration
NSBE – Houston Space Chapter
August, 2003
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Solar Powered Air Conditioning
System
Continuous Operation Configuration
NSBE – Houston Space Chapter
August, 2003
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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.
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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 inhouse rather than use commercial equipment
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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
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August, 2003
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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 Conditioner
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August, 2003
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Preliminary System Sizing –
Option 1 (Daytime-only)
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
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August, 2003
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Preliminary System Sizing –
Option 1 (Daytime-only)
Inverter
– Sized based on power generated
– Using Powerstar 1300 inverter, but requires
DC Converter
• Powerstar operates at 12 V, photovoltaic panels
operate at 24 V
• Powerstar costs $540, converter costs $285 for
total of $825.00
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Preliminary System Sizing –
Option 1 (Daytime-only)
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
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August, 2003
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Preliminary System Sizing –
Option 2 (Continuous Operation)
Batteries
– AGM batteries chosen - 12V Concorde PVX2120L 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
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August, 2003
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Preliminary System Sizing –
Option 2 (Continuous Operation)
Charge Controller
– Trace C35: three units used – one for every
two batteries
– Total cost: $337.05
Tracking Mounts
– Two UTRF64 tracking mounts used at cost of
$1,978
– Total cost for Option 2: $11,819.64
NSBE – Houston Space Chapter
August, 2003
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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
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August, 2003
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Fundraising
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 donations
Will pursue grants and contracts from
foundations, government agencies,
businesses, nonprofits, etc.
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Fundraising
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
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August, 2003
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Engineering Roadmap
This paper is only a first step, not a
complete analysis
Need for additional studies - engineering
work continues
– Deepen understanding of solar power systems
– Resolve outstanding technical issues
– Generate
• Finalized specifications
• Safety reviews
• Implementation procedures
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August, 2003
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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
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August, 2003
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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 devices)
– Side benefit: many of these may have outreach uses
 Goal: first operational unit completed in time for
summer 2004
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August, 2003
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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
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August, 2003
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Conclusion
 We can’t help everyone suffering in Houston
 We will make a difference
 We will pioneer a roadmap other organizations
can follow
 Enhance image of NASA, NSBE, contractors,
partners
 Gain sense of satisfaction – we will have used
our skills to change the lives of people
NSBE – Houston Space Chapter
August, 2003
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Questions?
NSBE – Houston Space Chapter
August, 2003
Chapter Technology Seminar