for Cardinal Newman Hall Randall Lessard ET 494 Spring 2014 Instructor Dr Cris Koutsougeras Advisors Dr Rana Mitra Mr Byron Patterson Originally The goal of the ID: 809594
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Slide1
A Design Analysis of Solar Thermal Systems
for Cardinal Newman Hall
Randall
Lessard
ET 494
Spring 2014
Instructor: Dr.
Cris
Koutsougeras
Advisors: Dr.
Rana
Mitra
Mr. Byron Patterson
Slide2Originally:The goal of the project was
to design and install 2 independent solar thermal systems that will tie into the existing boiler water heating system and domestic hot water system, thereby reducing the energy consumed and providing a cost-effective solution to obtaining heated water for Cardinal Newman Hall.
Project Description
Slide3To complete the design process for the solar thermal systems by determining the most efficient components and location of components.Using these component specifications to:Obtain varying fluid flow data.
Analyze changes in solar thermal system performance during varying weather conditions.
Updated Objective
Slide4Solar collector absorber plates harness solar radiation and convert it to thermal energy.
Thermal energy is transferred to a heat-transfer fluid flowing through the collector.
Solar Thermal System
Slide5This fluid, and water from a return line meet in a heat exchanger (often within the pumping station), and thermal energy is transferred to the water
.The heated water is pumped back to a boiler to be “heated”.
Solar Thermal System
Slide6If needed, the water will be pumped into the boiler to heat.
If not needed, the water will flow through a bypass pipe and continue circulating through the system.This process effectively keeps the boiler from turning on, saving nonrenewable energy, while maintaining hot water in the system to supply to the building.
Solar Thermal System
Slide7Calculate volume flow rate & head loss in existing boiler systems from outlet of pumps.Choose suitable pumping stations which meet criteria for the size of collector arrays.
Determine orientation, size, and type of piping which will connect the pumping stations to existing boiler systems.Calculate performance of systems to find most efficient combination of components.
Process for Designing Systems
Slide8Domestic Water Heater (Copperglass 40 CGA)Input – 400,000
btu/hrWorking pressure -125 psi
Pump
outlet
size – 1 ½”Existing Systems
Slide9Boiler (ThermoPak GW-1050)Input – 1,050,000
btu/hrWorking pressure – 75 psi
Pump
outlet
size – 1” Existing Systems
Slide10Recommended velocity of water through copper tubing:
1.6 ft/s – 3.3 ft/s
All flow calculations are completed using lowest recommended flow rate, average flow rate, and highest recommended flow rate.
Calculations
Slide11Calculated at outlet of pump
Volume Flow Rate
Volume Flow Rate (gallons per minute)
Velocity (
ft
/s)
Copperglass
ThermoPak
1.6
8.91
4.12
2.45
13.6
6.3
3.3
18.37
8.49
Slide12Moody’s
Diagram
Calculated at outlet of pump
Head Loss
Head Loss (
ft
)
Velocity (
ft
/s)
Copperglass
ThermoPak
1.6
0.138
0.0824
2.45
0.291
0.189
3.3
0.507
0.311
Slide13Lochinvar SPS0250SE Flowstar 221337
Solex DWHX 6094603US
Pump
Station Choices
Slide14Pump = Grundfos UPS 25-58UMax Pressure = 145 psiFlow Range = .26 – 3.17
gpmConnection size = ¾”Dimensions (H x W x D)
= (14” x 9.5” x 7.5
”)
Total Efficiency = 19.17%
Lochinvar
SPS0250
Slide15Grundfos UPS 25-58U
Slide16Pump = Wilo Star S-16 UMax Pressure = 145 psiFlow Range = 0.1 – 4
gpmConnection Size = ¾”Dimensions =
(
14.9” x 8.94” x 5.9
”) Total Efficiency = 18.96%SE Flowstar
221337
Slide17Wilo Star S16 U
Slide18Pump = Wilo Star S21 FMax Pressure = 87 psiFlow Range = 0.3 – 3.5
gpmConnection = ¾”Dimensions =
(25.6” x 15.6” x 9.8
”)
Total Efficiency = 10.11%Solex DWHX 6094603US
Slide19Wilo Star S21 F
Slide20Pump selection is based off the following principles:Motor input horsepower (EHp
) = power input*1.341Brake horsepower (BHp) = (2)motor efficiency*
EHp
Hydraulic horsepower (
WHp) = [Head*Capacity]/3960Then:Total efficiency = (WHp/
EHp
)*100%
Pump efficiency = (
WHp
/
BHp
)*100%
Information is obtained from data sheets and pump curves.
Comparing Pumps
Slide21Type L Copper tubingBest thermal conductivity of all engineering metalsHighly resistant to aqueous corrosion
Cost-effectiveConnection Piping
Slide22Lochinvar Brazed Plate Heat Exchanger HEX20025Made of 316L Stainless Steel
Sustain pressures up to 450psi @ 350° FThe exchangers shall be placed half the distance from pumping stations and supply line to boilers.
Heat Exchanger
Slide23COMSOL Model
Slide24Lochinvar SCH090Array of 4 collectors (6’7” x 13’2”)Thermal performance rating – 84,500
btu/dayAbsorber surface area - 79.76 ft^2Fluid capacity – 1.9 gallons
Recommended flow rate – 0.872
gpm
Chosen Collectors
Slide25To calculate, a set of heat flow equations are needed.Instantaneous thermal efficiency
SRCC (Solar Collector Certification and Rating) obtained the following efficiency equation for the SCH090 collectors:
0.708 = 0.714 – 0.698
Thermal Performance of Collectors
Slide26Created reasonable parameters to gather experimental data. ( & )
Obtained min, avg
, and max values for the summer and winter at
latitude 30
° N and also for clear, mildly cloudy, and cloudy weather.
Intensity of Solar Radiation (
I
)
Slide27Experimental Data
Slide28Results
Slide29Results
Slide30Results
Slide31Efficiency will be only slightly lower in winter.
However, significantly lower in cloudy weather.Efficiency drops linearly as temperature
gradient
increases.
Systems not very useful in cloudy, winter weather.
System Results