Transcript Proposal for a Domestic Hot Water System

Proposal for a Domestic Hot
Water System
Researched by David Luong, Mark
Piper, Colton Bangs, Aloysius
Obodoako, Disha Katharani
Advantages of a Solar DHW
System
• Off-grid capability
– Ideal for isolated areas where connection to
grid power is difficult to impossible
• Renewable energy source
– System completely powered by solar radiation
– Savings in long term investment
System Requirements
• Family Size of 3-4 needing 80 gallons of
hot water per day
• Maximum storage tank temperature of 120
degrees F
• Average of .63 kW-hrs per day
– Assume 9 hours at 70 W peak in operation
Location Resources
• For Philadelphia region,
– Air temperature varies between 40-80
degrees Fahrenheit [4-27 degrees C]
– Freezing conditions necessitate antifreeze in
thermal circulation system (Propylene glycol
typically used)
Solar Availability in Philadelphia
Region
Monthly Average Radiation on Tilted Collectors in Philadelphia
70
H_bar_t (kW-hr/m^2)
60
50
40
Tilt Angle of 40 degrees
Tilt Angle of 55 Degrees
30
20
10
0
0
2
4
6
8
10
12
14
Month
K-T model of collector facing true south and ignoring local
shading. Ground reflectivity is .2 for all months except .5
for January, .7 for February, and .4 for March.
Schematic of DWH System
System Overview
PV Collectors
Thermal
Collector
Controller
Storage Tank
(with heat
exchanger)
Pump
Hot Water Out
Cold Water In
Solar Collector Certification and Rating (June 10, 2005)
The SRCC is an independent third-party organization working out of Cocoa, FL
composed of a twelve-member board of directors.
They select a collector at random from participating manufacturers, test it for
performance and durability, and release an annual report. In return, the
manufacturer gets to stamp the SRCC certification and rating on its product.
A Sample SRCC Rating
continued
Decoding the Rating
• Energy per day is given in the lower table as dependent
on weather and temperature differential (Tin – Tamb)
• The SRCC rates Philadelphia as about 14 MJ/m^2/day.
• A typical clear day is said to receive 23 MJ/m^2/day,
mildly cloudy is 17 MJ/m^2/day and cloudy is 11
MJ/m^2/day.
• Thus, to analyze collector performance in Philadelphia,
we used an average of the mildly cloudy and cloudy day
ratings.
Collector Type
The SRCC defines category C as a DHW in a warm climate, and category D
as a DHW in a cool climate. We used category C to approximate the losses
during summer and D in the winter.
Comparing Collectors
Company
Location
Model
C (Summer)
D (Winter)
pg. #
Net Aperature Area
(sq. ft)
24.5
18.5
131
36.39
Thermo Technologies
Columbia, MD
Mazdon TMA-600-30
Synergy Solar
Austin, TX
Synergy T26.68
14
5
129
24.46
Heliodyne, Inc.
Richmond, CA
Gobi 410
26
11
66
38.3
Focus Technology Co
Nanjing, China
Apricus AP-30
22
17
59
40.85
SunEarth
Fontana, CA
Empire EP-40
22.5
9.5
104
37.08
Alternate Energy Technologies
Jacksonville, FL
Morning Star MSC-40E
28.5
?
49
36.9
ACR Solar International
Carmichael, CA
Fireball 2001
9
3.5
24
18.51
Efficiency Rating Per Collector Area
MJ/m^2
Model
C (Summer)
D (Winter)
Mazdon TMA-600-30
7.2
5.5
Synergy T26.68
6.2
2.2
Gobi 410
7.3
3.1
Apricus AP-30
5.8
4.5
Empire EP-40
6.5
2.8
Morning Star MSC-40E
8.3
Fireball 2001
5.2
2.0
For our climate and purpose, the Mazdon TMA-600-30 panel
manufactured by Thermo Technologies in Maryland is the most efficient.
Project Load
Energy Needed
(MJ/day):
Gallons/day
Summer
Winter
80
5.6
33.8
160
11.1
67.7
Obviously, the winter load will determine the number of panels needed to
achieve a desired level of DHW. The family will probably desire three of
the Mazdon collectors in order to generate the majority of the winter DHW
load needed.
Solar Thermal Collector
•
Fireball 2001 Solar Collector
– Available in exciting architectural
colors
– Weights 38 lbs, easy installation
– Copper Solar absorber plate
• Coated with premium black crystal
– Low emissivity and high absorptivity
• Serpentine Design to increase fluid
exposure to collector
– Rigid Foam Installation for heat
retention in the collector box
• Coated with special heat reflecting
white paint called Enerchron
– Reflects heat back onto underside of
the absorber
– Lightweight Polycarbonate glazing
• High insulation value and UV
protection
• Greenhouse effect
Solar Thermal Collector
• Fireball 2001 Solar
Collector from
SolarRoofs.com
• Critical Efficiency
– 88% on Clear Day
– 82% on Mildly Cloudy
– 69% on Cloudy Day
• Loss Coefficient
(kW/m2/˚C
– .0264 on Clear Day
– .0233 on Mildly Cloudy
– .0255 on Cloudy Day
Instantaneous Efficiency
Thermal Performance of Fireball 2001 Solar Collector
1.4
Clear Day
Mildlly Cloudy
Cloudy Day
1.2
1
0.8
0.6
0.4
0.2
0
-40
-20
0
20
40
60
80
Ti-Ta (deg C)
Features
Heat Transfer Fluid can be potable
water or Propylene glycol
Maximum stagnation temperature of
250 degree F
Hot Water Storage Tank
• ASHRAE recommends 20 gallons of hot water
consumption per day per person
• 120 gallon storage tanks in a 3 person
household are typically used in the United States
given its higher hot water consumption
• Need to include heat exchanger to extract heat
from glycol thermal fluid
Solar Storage Tank
Rheem - Solaraide TC
•
•
•
•
•
•
Features
80 Gallon tank w/ heat
exchanger
Tank Lining resist corrosion
Anode rod equalizes
turbulent water action
Automatic temperature
control
Collector feed located at
front of tank
Has temp. and press.
release valve
Solar Circulating Pump
• Desire low power pump to transfer thermal
energy from solar collector to storage tank
through a heat transfer liquid.
– Choose Propylene glycol to avoid freezing in
system
– Must operate in recommended flow rate range
prescribed by solar thermal collector
El-SID Pump from Thermo
Technologies
•Highly conducive to PV panels because of
its adjustable flow rate
•Flow rate changes depending on sun
brightness
•Power Requirements and Performance
•12-17 VDC, Current range of .6-.85
Amps, Power of 10 watts
•Maximum flow rate of 3.3 GPM
•Optimal flow rate is 1.2 GPM for
Mazdon Thermal Collector
•Features
•Long lasting
•Absence of moving parts,
brushes, or bearings
•Magnetic coupled drive
Solar Controller
• Needed to monitor system to avoid overheating
the storage tank and to set efficient operating
conditions
– Ensures efficient heat collection
• Desire low cost, low power consumption, and
simple user-interface
Low Voltage Solar Energy
Differential Controller
•
The USDT 2001 can be powered by a 24
volts DC or AC source to monitor supply and
return temperatures.
– Need to use two 12 volt PV panel in
series to operate via VDC.
– Microprocessor temperature controller to
regular solar heating. LED to indicate
supply temperature exceeding return
temperature by programmable
temperature difference.
– Frost or cooling protection is regulated
through return temperature monitoring.
– Max. Adjustable deltaT of 50 F
– BP protection range of 32-200 F
– Anti-front cycling for system freeze
protection (adjustable up to 50F)
www.thermotechs.com
Photovoltaic Module
• Needed to power solar circulation pump
and controller.
– Power requirements
• 12 watts needed
– Solar pump needs 12-17 VDC and controller
needs 24 VDC
PV Panel from Solar Electric
Supply-10
• 10 Watts,12V Nominal,17V Peak
– Open Circuit Voltage: 21.6 V
– Short Circuit Current: .7 A
• Peak Voltage/Current: 17V/.59A
• Polycrystalline Type
• Frame
– Anodized aluminum with tempered glass - Omni-mount
frame
• Need to have two placed in series to generate adequate
voltage to power components
System Cost
•
•
•
•
•
•
Solar Thermal Collector
$2500-3000
PV Collector
$89.95x2
Storage Tank
$1160
Circulating Pump
$229
Solar Controller
$159
TOTAL
~$4500