Solar Collecting Water Heating System

1
Solar Collecting Water Heating System

• Victor Salinas
• Josh Wilkins
• Christian Cantu

2
Overview of the situation being addressed

• The demand of Energy is on the Rise
• Energy demand is increasing as third world
  countries industrialize
• Alternative methods of energy are being sought to
  minimize consumption of natural resources
• Several systems in the past have been developed
  to harness solar energy as a means to heat water

3
General Overview

• Sub-Functions
• Concept Variants
• Objectives/Design Criteria
• Comparison of Design Criteria and Objectives
• Design Criteria Weighting Factors
• Variant Ranking with respect to Criteria
• Decision Matrix
• Winning Variant

• Overview of Problem Formulation
• Need Statement
• Problem Definition
• Goal/Objective
• Constraints
• Benchmarks
• Conceptual Design
• Overview
• Methodology
• System Concept
• Function Structure

4
Cliental

• Residential Areas
• Advisors
• Dr. Jones (solar collector advisor)
• Dr. Mahdi (water system advisor)

5
Need statement

• Previous systems using renewable energy to heat
  water have been found to be bulky and have a high
  initial and maintenance cost. Our client requires
  a system that is lightweight and cheap, but
  strong enough for various operating conditions.

6
Goal/Objectives

• Goal
• Create direct solar powered water heating system
• Solar collector (parabolic dish and frame)
• Water circulation system
• Objectives
• Build a collector that uses the optimal materials
  available
• Make a strong and lightweight frame for collector
• Must allow for optimal heating of water
• Design for future mass production with low cost

7
Constraints

• Strong and durable
• Withstand up to hurricane winds (75 mph)
• Withstand sunlight degradation (UV resistance for
  10 years)
• Capacity of the System
• Storage tank can hold (40 gallons)
• High efficiency
• Have an Output over input efficiency of at least
  90
• Affordable
• Mass Production cost must be under 500
• Adjustable
• Allow for optimization due to sun position
  (entire planet)
• Can be mounted on roof tops
• Inclinations up to 45o

8
Market Assessment (Benchmark)

• Conventional Water Heater (W.H.)
• Storage tank capacity 20-80 gal
• Fuel options Electric, natural gas, oil,
  propane
• 30-45 efficiency
• Initial cost 150-450
• Draw Back standby losses energy needed to
  keep hot
• Professional Solar Water Heating Systems
• Suns energy harnessed to reduce operating cost up
  to 90
• Last 15-40 years
• Uses energy to directly heat water, various means
• Initial cost 1500-3500
• 4-8 years payback with savings in gas/electricity
• Draw Back initial price too high (requires
  backup water heating source)

Energy star
9
Concept design overview

• Trial and error approach
• Building and designing as we move along
• Research and modify existing concepts
• Senior Design Teams ( 05, 01, 98)
• Market

• Identified the problem
• Defined main function
• Gathered information about previous designs and
  about applicable standards
• Design (strength and bulkiness)
• Materials (Cost, Properties and Weight)

10
Concept design Methodology

• Identify Sub Functions
• Parabolic Collector
• Frame
• Water Flow System
• Developed Concepts for each subsystem
• Compare
• Concept Variants
• Design Criteria
• Objectives

11
Function structure

• Solar Collector
• Collector Frame
• Holds the solar collector and the water system
• Parabolic Collector
• Focuses energy to be used to heat water
• Water circulation system
• Water Flow System
• Uses energy focused from the collector to
  ultimately heat water

12
Function Structure
13
Design Criteria/objectives (Frame)

• Design Criteria
• Frame
• Life expectancy
• Re-Assembly Process
• Quantity of Parts
• Stiffness
• Re-Alignment
• Size
• Wind Tolerance
• Earthquakes
• Sun Degradation
• Creep
• Load Changes

• Objectives
• COST UNDER 500
• LIGHT WEIGHT
• THERMO EFFICEINCY gt 90
• WITHSTAND HURRICANE WINDS (75 MPH)
• WITH STAND UV DEGRADATION (5YRS)
• WITH STAND VIBRATIONS
• OPTIMIZATION DUE TO SUN POSITION
• MOUNT UP TO 45 DEGRESS ON INCLINE

• Concept Variants
• Single Post
• Box
• X frame

14
Frame Concept variants

• X Frame
• Advantages
• Can change shape as necessary
• Allows for varying size of dishes
• Disadvantages
• Very Unstable

• Box Frame
• Advantages
• High stiffness
• Disadvantages
• More material required
• Doesnt allow for future changes in dish position

• Single Frame
• Advantages
• Light
• Allows for Pivoting
• Disadvantages
• Poor Specific Strength

15
Effect of Frame variants on dish variants

• Single Stand
• Provides no support for the solar collector
• Requires a very high stiffness solar collector

• X Frame
• Provides support on the solar collector
• Allows for a lower stiffness solar collector

• Box Frame
• Provides support along the entire edge of the
  solar collector
• Allows for a very low stiffness solar collector

16
Frame weighting factors
17
frame Objectives/design criteria (D.C.)
18
Frame Variant ranking wrt criteria

• Design Criteria
• Frame
• Life expectancy
• Re-Assembly Process
• Quantity of Parts
• Stiffness
• Re-Alignment
• Size
• Wind Tolerance
• Earthquakes
• Sun Degradation
• Creep
• Load Changes

19
Frame Decision matrix
20
Dish/stand Interface

• Main support for dish will come from suspension
• Mounted on either side of dish with adjustable
  angles mounted to frame
• Key for optimization during the year

21
Design Criteria/objectives (dish)

• Design Criteria
• Dish
• Life expectancy
• Re-Assembly Process
• Stiffness
• Alignment with Sun
• Size
• Wind Tolerance
• Earthquakes
• Reflectivity
• Availability of Sun
• Sun Degradation
• Rain Degradation

• Concept Variants
• Fixed
• Flexible

• Objectives
• COST UNDER 500
• LIGHT WEIGHT
• THERMO EFFICEINCY gt 90
• WITHSTAND HURRICANE WINDS (75 MPH)
• WITH STAND UV DEGRADATION (5YRS)
• WITH STAND VIBRATIONS
• OPTIMIZATION DUE TO SUN POSITION
• MOUNT UP TO 45 DEGRESS ON INCLINE

22
Dish Concept variants

• Flexible
• Advantages
• Variable focal line
• Very light
• Allows for maximum optimization
• Disadvantages
• More likely to be disfigured in high winds
• Much more effort required for consumer to operate

• Fixed
• Advantages
• High stiffness
• Less susceptible to strong winds
• Constant assumed focal line
• Disadvantages
• Higher weight

23
Dish Decision matrix
24
Initial Dish Scrimp
25
Design Criteria/objectives (water Sys)

• Objectives
• COST UNDER 500
• LIGHT WEIGHT
• THERMO EFFICEINCY gt 90
• WITHSTAND HURRICANE WINDS (75 MPH)
• WITH STAND UV DEGRADATION (5YRS)
• WITH STAND VIBRATIONS
• OPTIMIZATION DUE TO SUN POSITION
• MOUNT UP TO 45 DEGRESS ON INCLINE

• Concept Variants
• Direct Flow
• (w/ pump)
• Heat Exchanger (w/ pump)
• Convective Flow

• Design Criteria
• Water System
• Life expectancy
• Re-Assembly Process
• Quantity of Parts
• Stability
• Leaks
• Control Temperature
• Control Flow Rate

26
Concept variants Water system

• Closed system
• Advantages
• System becomes like a heat exchanger
• High efficiency
• Much higher temperatures attainable
• Continuous processing
• Disadvantages
• More parts, more complex

27
Concept variants Water system

• Open system
• Advantages
• Most direct way to heat water
• Minimal optimization needed
• Disadvantages
• Inefficient
• Might require reprocessing for water to get
  noticeable hotter

28
Water Circulation System Requirements

• Convective flow
• Advantages
• Allows high temperatures
• No Electricity
• Used in both systems
• Disadvantages
• Requires tank to be above level of dish
• Flow stops if there is no change in temperature
  (i.e. lack of sunlight)

• Electric Pump
• Advantages
• Stable water flow
• Disadvantages
• Requires Electricity

29
Water circulation sys Decision matrix
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Final Concept Selection

• FRAME Single Post
• DISH Fixed
• WATER CIRCULATION Direct Heating w/ Convective
  flow

31
Pr0-e Model
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Determining the Focal length
33
Focal length overview

• in order to assume a reasonable answer for c
  verify that the ratio f/d is between
• 0.35ltf/dlt0.5
• If the ratio f/d is 0.25 the focal point will be
  located at the same distance as c

34
Solving for focal length
35
Dish dimensions
36
Drag Coefficient

• Latter Case
• Cd is essentially independent of Reynolds number
  for Regt1000.(pg438)
• Drag coefficient for all objects with sharp edges
  is essentially independent of Reynolds number
  (for Regt1000)because the separation points and
  the size of the wake are fixed by the geometry of
  the object.(pg 438)

37
Drag coefficient

• Found on Table 9.3 pg 439

38
Solving for Drag Force
39
Results of drag force
40
frame Verification (Dimensions)
41
Solving force analysis
42
Force Results
43
Road Map

• Finish baseline testing on old dish
• SCRIMP new dish
• Complete stand for testing
• Air flow analysis, stress analysis on new dish
  and stand

44
Angle optimization

• Developing program that will tell position of the
  sun as a function of time, day, latitude and
  longitude
• Current program dictates position of sun for
  Edinburg, TX

45
Questions?
46
Quality Deployment Function (QFD)

• It is a technique for product/service
  developments, brand marketing, and product
  management.
• This technique focuses on the characteristics of
  a new or existing product/service from the
  viewpoints of market segments, companies, and
  technology-development needs.

47
Qfd

• First three steps
• Who, What, and Who vs. What
• Here it is clear that Cost, Efficiency, and
  Structural Stability are the three top
  requirements

48
QFD
Contd

• Step four Nows vs. Whats
• From this comparison the Heat Pump is the closest
  to what our costumer desires but it is still not
  satisfactory

49
QFD
Contd

• Step five is the Hows
• Step six is the comparison to the Whats

50
Dish weighting factors
51
Dish Objectives/design criteria (D.C.)
52
Dish Variant ranking wrt criteria

• Design Criteria
• Dish
• Life expectancy
• Re-Assembly Process
• Stiffness
• Alignment with Sun
• Size
• Wind Tolerance
• Earthquakes
• Reflectivity
• Availability of Sun
• Sun Degradation
• Rain Degradation

53
Water System Weighting Factor
54
Water System Objectives/design criteria (D.C.)
55
Water system variant ranking wrt criteria

• Design Criteria
• Water System
• Life expectancy
• Re-Assembly Process
• Quantity of Parts
• Stability
• Leaks
• Control Temperature
• Control Flow Rate