The Effects of Solar Water Heating on Winter Peak Electrical Demand

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Title:
The Effects of Solar Water Heating on Winter Peak Electrical Demand
Physical Description:
1 online resource (72 p.)
Language:
english
Creator:
Swanson, Benjamin Spencer
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
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Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Mechanical Engineering, Mechanical and Aerospace Engineering
Committee Chair:
LEAR,WILLIAM E,JR
Committee Co-Chair:
INGLEY,HERBERT A,III
Committee Members:
FLETCHER,JAMES H

Subjects

Subjects / Keywords:
belt -- capacitance -- collector -- demand -- efficiency -- energy -- heater -- heating -- hot -- ics -- load -- loading -- morning -- panel -- peak -- power -- reduction -- solar -- south -- sun -- trnsys -- utility -- water -- winter
Mechanical and Aerospace Engineering -- Dissertations, Academic -- UF
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Mechanical Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Solar water heaters have demonstrated the ability to use the sun’s energy to produce hot water, thus displacing the need to use electricity and the resulting fuel usage, cost, emissions, etc. Many utilities have begun to investigate whether other benefits can be gained from solar water heaters. Most utilities in the Southeast of the United States experience peak demand for electricity during the winter months due to high electrical demand on cold mornings for space heating and hot water usage. This investigation,funded and supported by APPA, JEA, and Beaches Energy, studies the potential for solar water heaters to reduce winter electrical peaks. An integrated ICS solar/electric water heating system was installed at Beaches Energy Services in Jacksonville Beach, FL. The system was fully-instrumented and controlled to mimic typical hot water usage for a family of two. Data was collected over a two-year period, with focus on winter months.Testing showed that on the coldest winter mornings, the hot water demand averaged 14.4 kWh, with the solar hot water contributing 6.4 kWh or 44%. Comparison of experimental data to NREL’s solar heating model built on a TRNSYS platform showed similar trends with the major difference being lower transmissivity of the experimental solar collector as compared to the model default values due to dirt and salt associated with the beaches environment.The experimental data showed that a properly installed and maintained integrated solar/electric hot water system has the potential, on cold winter mornings, to reduce electricity usage by more than 40%.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
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Description based on online resource; title from PDF title page.
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This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Benjamin Spencer Swanson.
Thesis:
Thesis (M.S.)--University of Florida, 2013.
Local:
Adviser: LEAR,WILLIAM E,JR.
Local:
Co-adviser: INGLEY,HERBERT A,III.

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UFRGP
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Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0046424:00001


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1 THE EFFECTS OF SOLAR WATER HEATING ON WINTER PEAK ELECTRICAL DEMAND By BENJAMIN SPENCER SWANSON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DE GREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013

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2 2013 Benjamin Spencer Swanson

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3 To my mom. You have no idea.

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4 ACKNOWLEDGMENTS I would like to take this opportunity to express my gratitude to my committee Dr. William Lear and Dr. Herbert Ingley for their guidance, support, and patience during this season of life and the thesis that has come of it. I owe my deepest thank s to Dr. James Fletcher for his relentless encouragement to finish strong and for the many hours of support during the research and writing. I would also like to thank Dr. Neal Coulter and Dr. Joseph Campbell for their wisdom and encouragement. I thank Beaches Energy, APPA, and JEA for funding, cost share, and oversight. Finally, I thank Jason Harrington for long hours of help and friendship during classes, homework, research, thesis and the distracting conversations that make up life.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF FIGURES ................................ ................................ ................................ .......... 7 LIST OF ABBREVIATIONS ................................ ................................ ............................. 9 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 12 Solar Water Heating ................................ ................................ ................................ 12 Water Heating ................................ ................................ ................................ .. 12 Solar Water Heating Design ................................ ................................ ............. 13 ICS Background ................................ ................................ ............................... 14 Solar Water Heating Incentives and Rebates ................................ ................... 16 Peak Electrical Demand ................................ ................................ .......................... 16 Peak Demand Risks ................................ ................................ ......................... 16 Winter Peaking ................................ ................................ ................................ 17 Solar Water Heating as a Redu ction Method ................................ ................... 17 This Study ................................ ................................ ................................ ............... 18 2 LITERATURE REVIEW ................................ ................................ .......................... 20 Solar Collecto r Performance ................................ ................................ ................... 20 Solar Collector Modeling ................................ ................................ ......................... 21 Solar Collector Experimental Setup ................................ ................................ ........ 2 2 Hot Water Use ................................ ................................ ................................ ........ 23 Electrical Use ................................ ................................ ................................ .......... 24 Peak Reduction ................................ ................................ ................................ ...... 26 Knowledge Gaps ................................ ................................ ................................ .... 27 3 EXPERIMENTAL METHODOLOGY ................................ ................................ ....... 28 Experimental Details ................................ ................................ ............................... 28 Solar Collector ................................ ................................ ................................ ........ 28 Apparatus ................................ ................................ ................................ ............... 29 Infrastructure ................................ ................................ ................................ ........... 30 Data Acqui sition ................................ ................................ ................................ ...... 30 Controls ................................ ................................ ................................ .................. 31

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6 4 EXPERIMENTAL RESULTS ................................ ................................ ................... 41 Ambient Conditions ................................ ................................ ................................ 41 Temperature Data ................................ ................................ ................................ ... 41 Flow Data ................................ ................................ ................................ ................ 42 Energy Data ................................ ................................ ................................ ............ 43 5 MODELING ................................ ................................ ................................ ............. 54 Weather, Hot Water Draw and Simulation Model ................................ ................... 54 System Model ................................ ................................ ................................ ......... 55 Anchoring the Model ................................ ................................ ............................... 56 Auxiliary Heat ................................ ................................ ................................ .......... 59 6 CONCLUSIONS ................................ ................................ ................................ ..... 67 Conclusions from Experiment ................................ ................................ ................. 67 Further Work ................................ ................................ ................................ ........... 68 LIST OF REFERENCES ................................ ................................ ............................... 69 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 72

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7 LIST OF FIGURES Figure page 1 1 ICS solar collection basic principles. ................................ ................................ .. 19 3 1 PROGRESSIVTUBE ICS system cutaway. ................................ ........................ 33 3 2 Integral Collector Storage solar water heating system mounted on the lower wooden platform support structure. ................................ ................................ .... 34 3 3 Pipework connecting the ICS system.. ................................ ............................... 35 3 4 Water supply infrastructure. ................................ ................................ ................ 36 3 5 Piping and instrumentation diagram (P&ID) of the ICS solar system with infrastructure and data acquisition. ................................ ................................ ..... 37 3 6 Campbell Scientific CR5000 data logger and relay with AC/DC rec tifier for water draw controls. ................................ ................................ ........................... 38 3 7 ASHRAE 90.2 hot water draw profile versus the projected draw profile. ............ 39 3 8 Sprinkler time rs for water draw control strategy. ................................ ................. 40 4 1 for January 14 to January 17. ................................ ................................ ............. 45 4 2 January 14 to January 17. ................................ ................................ .................. 46 4 3 Measured temperatures at inlet and outlet of ICS for January 14 to January 17. ................................ ................................ ................................ ...................... 47 4 4 Measured temperatures of water supply and inlet to ICS for January 14 to January 17. ................................ ................................ ................................ ......... 48 4 5 Temperature measure ment comparison between the outlet of the collector and the inlet of the electric water heater from January 14 to January 17. .......... 49 4 6 Comparison of the inlet and outlet temperature of the electr ic water heater from January 14 to January 17. ................................ ................................ .......... 50 4 7 Flow meter data compared to ASHRAE 90.2 draw profile from January 14 to January 17. ................................ ................................ ................................ ......... 51 4 8 Electricity consumed by the auxillary water heater as measured by the power transducer. ................................ ................................ ................................ .......... 52

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8 4 9 Energy rate calculations based on the flow rate and temperature differential on the morning of January 15. ................................ ................................ ............ 53 5 1 Selective Surface ICS Model Temperatures. ................................ ...................... 60 5 2 User Input ICS Model Temperatures. ................................ ................................ 61 5 3 User Input ICS Model Temperatures with reduced absorption and lengthened return pipe. ................................ ................................ ................................ ......... 62 5 4 User Input ICS Temperatures for January 14. ................................ .................... 63 5 5 Experimental Data Temperatures January 15. ................................ ................... 64 5 6 Electric Water Heater Model for January 15. ................................ ...................... 65 5 7 Consumed energy for an average January day. ................................ ................. 66

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9 LIST OF ABBREVIATION S APPA American Public Power Association ASES American Solar Energy Society ASHRAE American Society of Heating, Refrigeration and Air Conditioning Engineers BA Building America DEED Demonstration of Energy & Efficiency Development EPDM Ethylene Propylene Diene Monomer FPL Florida Power and Light FSEC Florida Solar Energy Center ICS Integral Collector Storage KAU Ki ssimmee Utility Authority LOLP Loss of Load Probability NREL National Renewable Energy Lab OPEC Organization of Petroleum Exporting Countries P&ID Piping and Instrumentation Diagram SRCC Solar Rating Certification Corporation TMY2 Typical Meteorological Ye ar data set 2 TRNSYS Transient System Simulation Tool USA United States of America USD United States Dollar VAC Voltage Alternating Current VDC Voltage Direct Current

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science THE EFFECTS OF SOLAR WATER HEATING ON WINTER PEAK ELECTRICAL DEMAND By Benjamin Spencer Swanson December 2013 Chair: William E. Lear, Jr. Major: Mechanical Engin eering produce hot water, thus displacing the need to use electricity and the resulting fuel usage, cost, emissions, etc. Many utilities have begun to investigate whether other b enefits can be gained from solar water heaters. Most utilities in the Southeast of the United States experience peak demand for electricity during the winter months due to high electrical demand on cold mornings for space heating and hot water usage. This investigation, funded and supported by APPA, JEA, and Beaches Energy, studies the potential for solar water heaters to reduce winter electrical peaks. An integrated ICS solar/electric water heating system was installed at Beaches Energy Services in Jackso nville Beach, FL. The system was fully instrumented and controlled to mimic typical hot water usage for a family of two. Data was collected over a two year period, with focus on winter months. Testing showed that on the coldest winter mornings, the hot wat er demand averaged 14.4 kWh, with the solar hot water model built on a TRNSYS platform showed similar trends with the major difference being lower transmissivity of the ex perimental solar collector as compared to the model

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11 default values due to dirt and salt associated with the beaches environment. The experimental data showed that a properly installed and maintained integrated solar/electric hot water system has the potent ial, on cold winter mornings, to reduce electricity usage by more than 40%.

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12 CHAPTER 1 INTRODUCTION Solar Water Heating Solar water heaters produce hot water, thus displacing the need to use electricity and the resulting fuel usage, cost, emissions, etc. Many utilities, especially those in the Southeast of the United States, have recognized the advantages of solar thermal technology and established incentive programs to facilitate wide spread use. Despite the many benefits of solar water heating the utilities are in a sense subsidizing the customer to not use the utilit product, i.e. electricity. As a result, the utilities have begun to investigate whether other benefits can be gained from solar wa ter heaters. Many utilities in the Southeast of the United States, such as JEA in Jacksonville, Florida, experience peak demand for electricity during the winter months [1] This is due to many customers using el ectricity for space heating and hot water usage, both of which undergo high demand during cold winter mornings [2] Minimizing peak electrical demand, given that electricity is generated with regard to demand because it does not lend well to storage, is critical for utilities to avoid brown outs as well as to avoid the requirement to build new power plants, a costly endeavor [3] There exists the possibility that solar water heating technology, properly designed and implemented, could provide thermal hot water capacitance /storage and thus reduce the need for electricity during this critical period and provide a quantifiable benefit to the utility [4] Water Heating Domestic water heating accounts for a significant fraction of electrical consumption with studies showing rang es from 13% to 21% [5] During the

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13 winter peak demand, the fra ction of electrical consumption increases to 25% [6] Currently, e lectric resistance water heaters are responsible for 99% of the electricity consumed heating water for residential dwellings in Florida [6] thus there exists a large opportunity to reduce the winter peak load by implementing solar water heating technology [6] The benefits also extend to the customer, given that research has s hown that s olar water heating has the potential to meet 90% of the residential hot water needs [4] The solar water heating systems installed in the United States as of 2010 provide enough hot water for 1.5 million homes [7] In 2010 alone, over 35,000 solar water heating systems were installed which represents a 6% increase from 2009 [8] Solar Water Heating Design Solar water heating sys tems consist of a solar collector a storage tank and depending on the technology, a pump that runs on electricity [9] A solar collector is a heat exchanger that absorbs the incoming solar irradiation and transfer s that heat to water flowing inside the tubes. Unlike typical heat exchangers that transfer heat from one fluid to another, solar collectors depend on radiation from the sun for input energy The incident radiation varies with sun position and cloud cover but can provide flux levels up to 1100 W/m 2 [10] or if sustained for an hour up to 66 kWh /m 2 Systems typically fall into either an active or passive design category. The active designs use pumps and controllers to ci rculate fluid between the collector and a heat exchanger or collection tank Due to the ability to circulate water even during times of low or no hot water usage, heat can be transferred to the water storage tanks more efficiently. Active systems provide t he advantages of higher efficiency and better

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14 protection from freezing, but suffer the disadvantages of higher initial cost s and the loss of functionality during power outages. Passive systems, which have no moving parts or electrical demand, circulate wat er through a collector by relying on the pressure from the water supply. The system is typically plumbed in series with a standard water heating tank. Passive systems have no electrical components to fail which can provide greater reliability, but are more susceptible to freezing if located in regions with extreme weather [9] A common passive system that is often part of utility incentive programs is the integral collector storage system (ICS). An ICS system is mad e up of interconnected tanks coated with high absorption paint enclosed in an insulated structure The top of the structure has a transparent cover to admit radiation from the sun. Throughout the day, the water inside the tanks absorb s the solar energy rai sing the temperature of th e water [10] Figure 1 1 [11] illustrates the basic principles of ICS solar collection. An ICS system serves to preheat the water going into a conventional domestic water heater and provide supplemental storage. ICS systems are very popular due to their simplicity and historically lower costs. Because the supplemental storage is located inside the unit, ICS systems are not as well pr otected from freezing as some of the other systems. Fortunately, in more mild climate regions such as the southeast, long and frequent freezes are rare and typically do not last long enough to freeze the large volume of heated water within the integrated c ollector ICS Background The first ICS systems were constructed in the late 1800s. The water storage took place in four galvanized iron cylinders contained in a five sided wooden box. The cylinders were painted with a dull black paint to maximize heat abso rption and the box

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15 was lined with felt paper for insulation Instead of an open top, a single glazed aperture was installed to insulate the box and increase efficiency. In 1892 the units marketed under the name Climax Solar Water Heater were sold for 15 U SD and over a 5 year period 1600 units were sold in the state of California. The early inventors and entrepreneurs did very little systematic studies to increase performance, but in 1936 the first detailed study was conducted at the University of Californi a Agricultural Experimental Station T he performance differences between exposed and closed boxes were investigated as well as using single ICS tanks versus multiple tanks. Just as interest in optimization began to gain traction, the discovery of oil fiel ds and natural gas coupled with promotion and subsidies for these fuels brought solar research to a halt in the United States until the early 1970s [11] In Japan, however, development was stimulated due to a lack of fo ssil fuels and the resulting high energy costs. Commercial units in Japan came to market in 1947 and ICS system constructed of stainless steel was released. During the same time period an ICS system using a polyvinylchlo ride bag was closed membrane. With a peak of 240,000 units sold in the production year 1963 1964, EC embargoed Arabian oil in the early 1970s there was resurgence in solar energy as a viable source for water heating in the USA, South Africa, Australia and Japan. With this renewed interest, universities, research institutions and solar enthusiasts began putting effort and resources into furthering ICS systems as an alternative to the conventional domestic water heaters of the era [11]

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16 The popularity of ICS systems from inception has always been closely tied to the av ailability and cost of energy. In principle, the ICS design has not changed a great deal since the first units produced over a century ago. The early systems lost a great deal of heat to the ambient during long periods of little to no collection and during the night This is still a concern today. Solar Water Heating Incentives and Rebates Many utility companies, including JEA and Beaches Energy in Jacksonville, Florida, have long running program s of financial incentives to encourage the installation and u se of domestic solar water heating JEA provides $800 per residential installation and gives 30% of the total up to $5000 toward commercial systems [12] Beaches Energy of Jacksonville Beach has a $500 rebate for residential solar water heating installations [13] Of the solar water heaters installed a significant fraction have been ICS systems [5] Peak Electric al Demand Peak Demand Risks Peak electrical demand i s an important issue for utility companies During times of low demand, utility companies are able to maximize efficiency by operating the lowest marginal cost plants. During periods of near peak demand, the utility companies bring online all of their available electricity producing units to prevent outages. Loss of load probability (LOLP) is a way of quantifying risk for utility groups and is greatest at peak times Economic e fficiency, environmental quality, fuel security and facility siting are all factors that are detrimentally impacted by operating near the margins of maximum output. Typical load shifting strategies require smart controls to shift a percentage of the energy use to off peak times or to attempt to store energy during low demand for times

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17 of higher demand [14] Solar water heating du e to its energy capacitance, has the potential to store surplus energy collected the afterno on before for use during the peak and act as a load shifting option. Winter Peaking The southeast with much milder winters than the majority of the United States seems like an unlikely region for winter peaking. During the hot summers the overall elect rical loading is high, but the loading is not as concentrated as on cold winter mornings. This is in part, a result of heavy dependence on electrical resistance space heating versus dependence on wood heating oil, and natural gas fuels that are used in m any of the colder winter regions. O n January 11, 2010 at 7:10 AM, JEA set a new record for peak electrical demand [1] ; similarly at 7:04 AM the same day, Kissimmee Utility Authority (KAU) experienced a new record [15] Even in Atlanta, Georgia during the same day b etween 7 AM and 8 AM t he Southern Company set a new record [16] Florida Power and Light (FPL) had 14,000 homes lose power by midmorning on January 11 which FPL attributes to the added power consumption related to space heaters and inefficient home heating systems [2] Solar Water Heating as a Reduction Method The potential for sola r hot water heaters to provide peak demand reduction for winter peak utilities has not been extensively researched in the published literature. One publication published by t he American Solar Energy Societ y (ASES) detailed that Lakeland Electric saw a reduc tion of 0.7 kW per system during their winter peak when used in conjunction with a 7 AM 7 PM timer that interrupted the electric supply [4] The type of system s and installation requirements however, were not detailed. Most of the published literature in this area

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18 does not provide detailed accounts of how peak savings were achieved. For solar water heating to effectively reduce winter peaking, the heat energy g ained during the day must be maintained through the cold night and available for use during the morning activities of the residential customers, namely showering and kitchen needs. The concern is whether the heat energy gained by solar radiation during the day would be lost via radiation and convection during the cold winter nights, potentially requiring the electric hot water heaters to consume the same if not more electrical energy. This Study In this thesis, the potential for solar water heaters, specifi cally of the ICS design, to reduce winter electrical peaks is studied. The study includes an ICS system integrated with an electric water heater with appropriate controls and instrumentation to simulate typical residential water usage and monitor the effec ts The collected data was compared to an NREL [17] model built off of a TRNSYS platform to project monthly performance and the effects on energy use The experimental data and the modeled results were used to ev aluate the potential peak load reduction on winter mornings through implementation of a solar water heating ICS system.

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19 Figure 1 1 ICS solar collection basic principles [11] ( Source: M. Smyth, P.C. Eames, B. Norton, Renewable and Sustainable Energy Reviews, (2004) )

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20 CHAPTER 2 LITERATURE REVIEW This chapter presents a review of literature on solar collector performance residential electric ity and hot water consumption, so lar modeling solar experiments and peak reduction Solar Collector Performance Published literature includes studies that indicate implementation of solar water heating technology can reduce the overall energy use in typical households. Kettles and Merrig an [18] found over 2500 publications related to solar water heating performance. A selection of representative studies were reviewed and summarized. The studies were grouped into two time frames; late 19 70s and early 1 9 80s. The reporting shows an average savings of 1830 kWh/year from the early time frame. Specific to Florida, studies done by the Florida Solar Energy Center between 1978 and 1980 revealed an energy savings of 2232 kWh/year. The findings from the later tim e frame were a n average of 2502 kWh/year savings nationally and the Florida Public Service Commission finding s were 2044 kWh/year of savings between 1982 and 1984 locally The average electric water heater in Florida u ses approximately 3000 kWh/year. Thi s reporting suggests that solar energy has the potential to displace between 68% and 74% of the electrical energy required to meet the water heating needs of the average household. Masiello et al. [19] published a s tudy based on 171 residences in central Florida revealing domestic hot water used 2240 kWh of the 17,130 kWh total for the average annual electrical load of a household approximately 13% of the total F our residences that included solar water heating exhi bited a 61% reduction.

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21 Moore [5] estimates that s olar water heating decreases the typical household energy use by 8% 10% based on a correspondence with Danny Parker from the Florida Solar Energy Center Merrigan and Par ker [6] monitored eighty single family residences for two years in Florida Twenty of the homes used solar hot water systems and averaged 2.7 kWh per day versus the 8.3 kWh used by the electrical resistance water heat ers Parker [20] found solar to provide a 61% reduction against conventional electric water heating in a study of 204 residences in central Florida. Of the 204 residences, 150 were electric resistance and 4 were solar Progress Energy Florida (formerly Florida Power Corporation) estimates that incorporating a solar hot water heater reduces the daily energy use associated with hot water from 7.69 kWh to 3.11 kWh [5] Solar Collector M odeling TRNSYS was originally developed in 197 3 at the University of Wisconsin Solar Energy Laboratory From conception the purpose of TRNSYS was to simulat e thermal energy systems mak ing it an invaluable resource for solar an d other renewable energy sour ce modeling [10] Commercially TRNSYS is used by the Solar Rating Certification Corporation (SRCC). The SRCC is designated by the U.S. Government to validate the performance of solar energy sources for the purpose of fe deral tax credit eligibility [21] Haberl and Cho [22] reviewed a collection of publications to determine the uncertainty of different approaches to solar modeling. The findings re vealed TRNSYS simulat ions often agreed within 5% of the experimental results

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22 Solar Collecto r Experimental Setup This section reviews the different experimental arrangements used in the published literature to evaluate the performance of typical solar hot water systems. Colon and Parker [23] conducted a solar water heating performance study for the U.S. Department of Energy on site at the Hot Water System Laboratory at the Florida Solar Energy Center in Cocoa, FL. To mode l a typical household, a 32 square feet ICS system was installed facing due south with a pitch of 22 from horizontal The solar panel was installed preheating the water inlet to a standard 50 gallon water heater. The ICS system used in the test is a PT40 CN (Thermal Conversion Technologies) Progressive Tube Collector with 32 square feet of surface area and 40 gallons of internal storage. Temperatures were measured and collected at the tank inlet and outlet, mixing valve outlet and the mains inlet F low mea surements we re taken to quantify the total number of gallons going through the collector and used for mixing. E lectrical energy wa s measured to quantify the frequency and usage of the resistive tank elements. The water was drawn at 1.5 gallons per minute a ccording to the water draw profile. The water draw profile is further explained in the Hot Water Use section. The Solar Rating & Certification Corporation (SRCC) [24] has done extensive performance and durability testing on solar collectors and systems. The collectors are positioned and fixed at 0 azimuth (due south) and normal to the sun at solar noon +/ 4 , Instru mentation is instal led to measure inlet and outlet temperatures, ambient and environmental temperatures, fluid flow rate, wind velocity, auxiliary energy use when applicable, and radiation data. Other information necessary for the performance testing

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23 and reporting is the flu id heat capacity, particularly in cases where potable water is not the heat transfer fluid the local and solar time, and date and year of the testing. Hot Water Use This section reviews the published literature concerning modeling the quantity of hot wat er use and typical hot water draw throughout the day. Many of the papers reviewed are focused on the Southeast region, Florida in particular. Parker et al. [25] published a study on the energy use patterns and determine d the average dwelling to have 4.6 occupants. On average 63.6 gallons of domestic water heating were required to meet the needs of the average household. The lowest hot water consumption falls between the hours of 11:01 PM and 6:00 AM. The highest usage i s between 6:01 AM and 8:00 AM and is about 4.5 gallons per hour. Lutz et al. [26] determined that t he average household in Florida is made up of 4 occupants and uses between 64.7 and 74.6 gallons of hot water. The study showed that households with electric water heaters use less hot water than households with gas water heaters This is a result of the behavior patterns of the occupants shifting to avoid running out of hot water because of the slower recovery rates of the electric water heater. Parker [20] electrical demand peaks as a result of the severe but infrequent cold snaps. Combatting the peak loading is difficult due to the electrical demand for the majority of the year does no t requiring add itional generation capacitance. As a result of this observation, the study monitored 150 conventional electric resistance water heating units with storage tanks and four solar water heating systems. Of those monitored, 80% of the water heaters were located in unconditioned space. The average number of

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24 occupants was 2.81 with the most common being 2. The temperature of the water from the tap ranged from 19.4C in February to 27.2 C in September. The average mains temp was 24C. A 15 20% increase in hot water use during the winter season as compared to the summer was observed T he conclusions drawn from this increase are that more hot water is needed for mixing as a result of the l ower mains temperature and residents take longer showers when the aver age air temperatures are lower In a study by Colon and Parker [23] t he water draw profiles used to mimic family use were alternated between the ASH RAE 90.2 with a set draw of 64.3 gallons per day and a dynamic draw profile based on a study of water usage conducted by Building America (BA) and the National Renewable Energy Lab (NREL) with an av erage of 54.8 gallons per day. Though the dynamic draw pat terns of NREL/BA vary from month to month, the January pull is 67.2 and the February and March pulls are 66.4 gallons per day which are very similar to the ASHRAE 90.2 draw profile. The Solar Rating & Certification Corporation [27] has an approximate volume draw of 64.3 gallons per day at a water temperature of 14.4 C. The water is drawn at three gallons per minute at six different consecutive hours starting at 9:30 AM Electrical Use Moore [5] claims the greatest domestic energy use after HVAC is attributed to water heating, ranging from 13% to 21%. Parker et al. [25] published test results from FSEC show ing that hot water heating requirem ent accounts for 8.0 kWh of the total 42.8 kWh consumed for the day which calculates to 18. 7%. Lutz et al. [26] determined residential water heaters make up 11% of electricity consumed in the average household.

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25 Parker [20] included monitoring 204 residences in Central Florida. The total average annual electricity load was 17,130 kWh of which 2,240 kWh was from water heating. This calculates approximately 13% of the total for domestic w ater heating. Merrigan and Parker [6] monitored eight single family residences for two years in Florida. Electric water heaters averaged 8.3 kWh per day of electrical consumption and had an average system efficiency o f 82%. The residences that implemented solar water heating systems averaged only 2.7 kWh per day a reduction of 5.6 kWh. Colon and Parker [23] research revealed t he inlet feed from the water mains varied by close to 1 9 C from the coldest to the warmest months of the test. The low was 10.6C and was experienced in December. This number has a great effect on the performance of the solar water heating system and also on the amount of hot water used for mixing to get the a ppropriate temperature for usage. During the warmest month about 4.15 kWh is required to bring 50 gallons of water at mains temperature up to the 49C set by the mixing valve. During the coldest month about 8.4 kWh is required to do the same. This transl ates to twice the energy required to get the same volume of 49C water delivered to the consumer. The testing of an ICS system shows an average temperature outlet of about 27C during the c oldest winter months. B ased on the average outlet temperature, the test suggests the ICS system is capable of compensating for the difference in the mains temperature. T here is a 63% variance in daily energy use for water heating from January to July. A closer look at the monthly performance in the winter resulted in 7.96 kWh/day for the ICS feeding a 50 gallon electric heater compared to 8.51 for a standard electric tank in December 2009, 9.29 vs. 10.52 in January 2010 and 9.39 vs. 10.41 in February 2010 respectively. The annual

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26 difference resulted in 1703 kWh vs. 2692 kW h. The difference in the winter month savings appear to be small, but when summed on an annual basis become substantial. Peak Reduction Lutz et al. [26] concluded that due to the thermal storage capacity of water heaters they are ideal for load management strategies. The load management Merrigan and Parker [ 6] published literature states that a pproximately 50% of all electricity consumed of the total annual use in Florida is residential and 21% of that is water heating. Only 1% of the water heating technologies in use in Florida are from alternative sources. Consumption of hot water in the winter increased from summer on average by 27% and the electricity demand increased by 47% to make up the difference for the increased demand and the extra electricity required to heat the water as a result of lower inlet w ater temperatures. This translates to e lectric resistance water heaters being responsibly for approximately 1.1 kW of the 4.2 kW that each residential customer contributes to the winter peak. Of that, customers using solar water heating experienced a 0.7 k W reduction. This reduction has the potential for a substantial shift in the demand profile relative to coincident peaks experienced in Florida. [20] residential monitoring study included four houses with sola r water heaters. The houses with solar water heating systems saw a 61% annual energy reduction compared to the houses with conventional electric units or 1,420 kWh/year. The peak reduction was 0.31 kW for the winter and 0.14 kW for the summer Colon and Parker [23] data reveals the ICS system saved close to 2.5 kWh/day. Looking at the potential for morning peak demand reduction, the data at 8:00

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27 AM was analyzed and the ICS 50 system provided a 14% reduction on average A 35% reduction was experienced on average during the entire morning peak time window. A 50% evening peak reduction was experienced using the ICS. A closer look at the effects on winter peak demand show conflicting evidence. The paragraph states that a 3 0% reduction was experienced during the highest average peak demand which occurred at 8:00 AM in February 2010, but the graph in the literature demonstrates the ICS coupled to the 50 gallon electric tank used greater than 10% more electricity than the 50 g allon benchmark system. The daily percent reduction for the ICS using the ASHRAE 90.2 draw profile was 39%. Knowledge Gaps The average day electrical consumption based on the research of Colon [23] shows that not all so lar water heating systems are created equal. The ICS system on average does not perform as well as the flat plate systems, yet are promoted using the incentives programs. According to Moore [5] 22% of the known units ins talled under systems and there could be potentially more due to 16% of the total are classified as unknown. All of the literature shows promising results from solar water heating and in some cases even a positive effect on el ectrical peaks but the question is left as to whether ICS systems reduce winter electrical peak loading.

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28 CHAPTER 3 EXPERIMENTAL METHODOLOGY To quantify the effects of an Integral Collector Storage solar water heater on peak electrical demand, a PROGRESSIVTUBE Sy stems PT 40 CN by TCT Solar was instrumented with a data acquisition and control system. The system was controlled to mimic typical household usage and sensors were extensively placed to acquire performance data The experiment was s ite d at Beaches Energy Services in Jacksonville Beach, FL from the fall of 2010 through the spring of 2012. T h e effort was Efficiency Developments (DEED) program and JEA Experimental Details Beaches Energy Services provided space and infrastructure at their vehicle maintenance facility namely an unshaded plot of land, electrical power, water and protected space for tanks and data acquisition equipment. A solar collector was installed using the suppli ed water and electrical power for the system and subsystems. performance. A controls strategy was implemented to mimic household usage and create a repeatable test. Solar Collect or The PROGRESSIVTUBE PT 40 welded to interconnecting end pipes creating a continual series flow pattern. The smaller diameter interconnecting pipes connect the top of the lower pipe to the bottom of the next. The outer surfaces of the pipes are coated with a solar selective material to optimize solar radiation absorption and reduce losses. The case sides and back are

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29 made of aluminum. Rigid closed cell polyisocyanurate insulation lines the sides and back, and i s placed between the collector tubes. The glass surface is double walled with and the inner glass at 96%. The PT 40 CN has a collector face of four feet by eight feet providing 32 square feet of surface area total and has 40 gallons of internal storage. Figure 3 1 shows a cutaway of the PROGRESSIVTUBE ICS system [28] Apparatus The Depar [29] guidelines for system sizing in the southern United States recommends 20 square feet of collector surface area for each of the first two residents and 8 square feet for each additional resid ent with 1.5 2 gallons of storage for each square foot of collector area The average residential dwelling is occupied by 2.8 people [19] thus requiring approximately 50 square feet of collector space ICS solar sy stems are typically mated to a conventional domestic water heater and for this experiment the system was plumbed in series with a dual element electric resistance 40 gallon unit manufactured by General Electric Based on the collector surface area and the combined storage, the system mimicked a half scale test. The ICS was installed using aluminum struts with mounting brackets from the manufacturer and feet by eight feet was constructed from two by six inch lumber and four by eight feet sheet of plywood. This platform mimicked a flat roof. The ICS and support structure can be seen in Figure 3 2 Solar collectors installed in the Northern Hemisphere r eceive maximum sun exposure when installed facing south and year round performance is optimal when angled equal to the latitude of the location installed. To increase winter performance

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30 and protect from overheating in the summer, collectors are frequently installed up to 20 degrees greater than latitude [30] For this experiment, the collector was installed facing due south and pitched at latitude +10 degrees which corresponds to a 40 degree ab ove the horizontal or 10:12 equivalent roof pitch. Typical roof angles range in pitch from 4:12 to 9:12 or 18 to 37 degree angles [31] Three quarter inch diameter copper tubing runs from the ICS for approximatel y four feet and is mated to half inch diameter rubber hose. The tubing and hose are wrapped in pipe insulation to minimize heat loss and provide an added level of freeze protection. The copper, hose and insulation are shown in Figure 3 3 The hose volume was calculated to be approximately 0.5 gallons which would be equivalent to approximately 20 feet of inch diameter copper tubing. Infrastructure As part of the in kind financial contributions by Beaches Energy for the APPA DEED grant, an electrical meter was installed to provide electrical power consumption to the resistive elements of the water heater. A typical residential install would have 240VAC run to the unit, but the power available in this case was 208VAC. The vehicle ma intenance shop has a carwash bay with a water filtration and recirculation system. By utilizing the water filtration system for the water supply, all water for the experiment was reclaimed and re circulated minimizing water waste. For added water capacity and to aid in reduced temperature settling time, two 94 gallon tanks were added to the water recirculation loop. Th e overall system is shown in Figure 3 4 Data Acquisition Ambient d ata as well as performance data from the ICS sy stem were acquire d as part of the investigation. A Campbell Scientific model HMP45C weather probe

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31 measured the ambient temperature. A pyranometer from Eppley was installed on the same plane as the ICS to measure the solar ir radiation available. Thermocoupl es from Omega Engineering were installed on the inlet and outlet of the ICS and also on the inlet and outlet of the auxiliary domestic water heater. A n additional thermocouple was installed on the supply water line. A piping and instrumentation diagram (P &ID) is shown in Figure 3 5 The thermocouples are labeled TCS for the supply line and TCP # for the passive system with the # representing the corresponding assigned number. A positive displacement flow meter mode l C700 from AMCO (labeled FMP) measured the incoming cold water from the water supply line to the system. A power transducer that measured voltage and current was installed in the electrical meter can. The power transducer from CR Magnetics was used to mea sure the electrical power consumption of the resistive elements in the auxiliary water heater. A Campbell Scientific CR5000 data logger collected data every minute and recorded average values every fifteen minutes. The data was logged to a one gigabyte mem ory card and was downloaded onto a laptop periodically for review and analysis. The data logger is shown i n Figure 3 6 Controls Three sprinkler timers were programmed to open a solenoid valve for certain times and durations, thu s allowing flow through the system. The times and duration s were based on the ASHRAE 90.2 [32] water draw profile which is shown versus the projected draw profil e in Figure 3 7 The use of the timers facilitated a completely automated flow program representing the hot water use of a typical family. In conjunction with the solenoid valve a manual valve was set in a stationary position to

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32 throttle the flow so that the totals for the hours and days corresponded to the scaled system. The sprinkler timers are shown in Figure 3 8

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33 Figure 3 1 PROGRESSIVTUBE ICS syst em cutaway. ( Source: [28] http://www.thesolarenergycenter.com/page/391300215 PROGRESSIVTUBE passive solar water heating system.)

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34 Figure 3 2 Integral c ollector s torage solar water heating system mounted on the lower wooden platform support structure

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35 A B C Figure 3 3 Pipework connecting the ICS system. A) Copper pi pe soldered to ICS, B) EPDM hose connected to copper pipe, and C) pipe insulation reducing losses and protecting against freezing.

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36 A B Figure 3 4 Water supply infrastructure. A) 94 gallon water stor age tanks and B) water filtration and recirculation system

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37 Figure 3 5 Piping and i nstrumentation d iagram (P&ID) of the ICS s olar system with i nfrastructure and d ata a cquisition

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38 Figure 3 6 Campbell Scientific CR5000 data logger and relay with AC/DC rectifier for water draw controls.

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39 Figure 3 7 ASHRAE 90.2 hot water draw profile versus the projected draw profile.

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40 Figure 3 8 Sprinkler timers for water draw control strategy.

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41 CHAPTER 4 EXPERIMENTAL RESULTS The main area of interest for this investigation was the effect of an ICS system on wint er peak demand. W inter peak demand typically is between 6 AM and 10 AM on the coldest winter mornings. Recreating residential usage was critical to appropriately measure the hot water available from the ICS under normal loading conditions. To appropriately quantify the effectiveness of the ICS, the temp erature differential across the collector and across the complete system at a set flow rate was evaluated Ambient Conditions To determine the effect of solar water heating on winter peak electrical demand, d ata was collected during the colde st section of the winter. Reviewing the data set collected from January 14 to January 27, 2012 shows th at January 15 w as the coldest morning. [33] (Typical Meteorological Year data set 2), which is explained further in the modeling chapter, the experimental weather data needs to be relatively similar to the published data that feeds the model. The ambient con ditions collected and the TMY2 data for the same time period have a very similar pattern with very close high and low temperatures as shown in Figure 4 1 Figure 4 2 shows that t he solar ir radiation data for both the collected and published data are very similar from January 14 to January 17. Temperature Data Using January 14 to January 17 as the focal data of this analysis, the thermocouple data from the inlet and outlet of the collector is presented in Figure 4 3 The data presented has been averaged and grouped into hourly sections. The graph

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42 reveal s that at no point is the o utlet temperature lower than the inlet temperature which is evidence that the collector was transferrin g heat to the water. There is potential for the inlet to the collector to be colder than the ground temperature due to convection and radiation losses to the co ld ambient air from the long inlet piping runs Figure 4 4 shows that the temperature of the inlet piping to the collector is never more than 2 C less than the water supply temperature durin g the 6 AM to 10 AM time window, indicating minimal heat loss. The water supply temperature measured is 15.3C. This is lower than the published literature. Parker measured tap water in February at 19.4C [20] Colon measured the average supply temperature to be between 17C and 18C during the January and February months [23] There is potential to lose heat through the piping runs from the collector to the inlet of the conventional electric water heater but the hose was insulated to reduce losses. Figure 4 5 reveals that the temperatures between 6:00 AM and 10:00 AM for all three mornings are higher at the water heater inlet than the ICS outlet. This difference is approximately 5C during the morning peak for January 14th and 15th and is attributed to conduction through the pip ing connecte d to the water heating tank The temperature rise across the electric water heater show n in Figure 4 6 indicates that the outlet exceed ed the inlet temperatures during 6:00 AM to 10:00 AM This data suggests that the electric water heating element is heating the water during the peak times. Flow Data The flow was controlled by open ing a solenoid valve at the top of the hour in response to the sprinkler timers. The flow meter data is the number of gallons used

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43 during the course of each hour and is therefore in units of gallons per hour. Reviewing the flow meter data for January 14 to January 17 shows that the flow meter was unresponsive. A parallel test for another solar exper iment was also collecting flow data, so a correlation was made to replace the lost data. The calculated data was plotted against the projected flow plan from the ASHRAE 90.2 [32] standard draw profile in Figure 4 7 and shows a close compar ison E nergy Data The electrical power data measured by the CR Magnetics power transducer is shown in Figure 4 8 The data indicates that the electricity usage is w eighted more towards the morning particularly on January 14 and 15 where t he magnitude of the average power along with the frequency of the cycling is greater than any other time during the day. During th e time of the experiment of greatest interest the average power draw is 2006.6 watts. At this rate, the electric w ater heater is consuming approximately 8 kWh of electricity between 6 AM and 10 AM The rate of energy within the system was calculated using the fl ow rate and temperature differentials across various components. This calculation required the specific hea t of water and the energy equation. ( Watts ) = (1 hr/3600s) ( 4 1 ) (grams/hour) =(X gal/hr)(3790 grams/gal) ( 4 2 ) (4.181 J/g K) ( 4 3 ) (K) ( 4 4 ) Using Equation ( 4 1 ) the average energy rate of the solar collector for the morning of Januar y 15 was calculated and is shown in Figure 4 9 plotted with the

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44 electric power draw of the electric water heater. The temperature differential used for the calculation was the difference between the measurement at the inlet and ou tlet of the collector ( TCP3 and TCP2 on the P&ID in Figure 3 5 ) The calculation show s the collector on average is producing 1605.4 watts per hour which over the course of 4 hours is a 6.4 kWh contribution.

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45 Figure 4 1 for January 14 to January 17

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46 Figure 4 2 MY2 data for Jacksonville for January 14 to January 17

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47 Figure 4 3 Measured temperatures at inlet and outlet of ICS for January 14 to January 17.

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48 Figure 4 4 Measured temperatures of water supply and inlet to ICS for January 14 to January 17.

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49 Figure 4 5 Temperature measurement comparison between the outlet of the collector and the inlet of the e lectric water heater from January 14 to January 17.

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50 Figure 4 6 Comparison of the inlet and outlet temperature of the electric water heater from January 14 to January 17.

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51 Figure 4 7 F low m eter data compared to ASHRAE 90.2 draw profile from January 14 to January 17

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52 Figure 4 8 Electricity consumed by the auxillary water heater as measured by the power transducer

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53 Figure 4 9 Energy rate calculations based on the flow rate and temperature differential on the morning of January 1 5.

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54 CHAPTER 5 MODELING TRNSYS is a robust modeling platform with a long hi story of providing reliable performance predictions [21,22] The software model for this solar application opens up opportunit ies to test the effectiveness of the experiment in varying location s wi th a different system size s and at other time s America program in conjunction with National Renewable Energy Lab (NREL) released a software program built on a TRNSYS platform to model solar water heating system installations for the purpose of evaluating the effects of solar water heating on electrical and gas consumption. Permission from NREL has been granted to use this model for the research presented [17] Weather, Hot Water Draw and Simulation Model The graphic user interface for the model is made up of tabs with selectable options and cells to adjust the default numbers. The first step in the model is to set the simulation parameters for a given duration. There ar e multiple options ranging from one day to one year. For specific simulations, month and day selections can be input. The second variable is the weather station locations. Weather data from 239 cities collected from 1961 to 1990 is organized in a series of files that make up the NREL TMY2 data of published weather data. The water draw profile is the third input for the simulation. A user input profile is an option, so t he hot water draw profile from the ASHRAE 90.2 standard was entered. Lastly, the daily hot water consumption was input. To most closely model the experimental setup, the duration was set to run for one week

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55 beginning January 14, using the data set from Jac ksonville, Florida with the ASHRAE 90.2 profile and a hot water consumption total of 39 gallons System Model The second section of the model requires system information input There is flexibility to operate basic systems with default settings or to enter into the user input selection to further customize the model. All of the ICS models have user adjustable inputs for the following : collector top surface area, height of enclosure, water storage volume and the number of collectors plumbed in series. Figure 5 1 shows the performance of the system when modeled as a selective surface ICS with predominantly default settings. The user input values for the basic model include the collector size of 32 square feet, 40 gallons of internal storage and a total depth of 8 inches. The installation variables include orientation parameters, namely the slope of the collector (0=horizontal and 90=vertical) and the azimuth of the collector (0=south, 90=due west, 90=due east). In this case the slope was set at 40.20 degrees and the azimuth was set to zero because the experimental setup was Latitude plus ten (30.2+10=40.2) and was facing due south. At first glance the modeled results seem very optimistic compared to the experimental data. The first mo del run with the basic inputs performed with a 15 to 20 Celsius higher value on the collector return during the peak temperature output. To better match the system in the experiment, the User Input ICS was selected for the second iteration. The User Inp ut ICS adds absorptance, index of refraction, cover extinction and thickness, air insulation space between top layers and emissivity variables. Using the specifications from the data sheet from the manufacturer [34] and [35] the inputs were

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56 adjusted to better represent the specific ICS. Figure 5 2 shows the updated model per formance. The added variables helped close the gap between the model and the experiment, but the differences were still about 20%. An audit of the system was undertaken to better understand this difference. Anchoring the Model The first variable consider ed was in regard to the installation. The experiment uses a collector mounting structure from a flat roof installation kit. This variable leaves the back of the collector exposed to the ambient air and the potential for heat loss due to free convection is much greater. The model does not have an input for this installation variable. To test whether heat loss to convection could make up the 20% difference, a series of calculations were completed Using Equation s ( 5 1 ) through ( 5 5 ) provided a basis for a basic free convection analysis [36] ( 5 1 ) ( 5 2 ) ( 5 3 ) ( 5 4 )

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57 For the calculations the average solar collector temperature at the peak of January 14 was considered the surface temperature ( T s ) T he free convection calculation revealed a 32 C reduction from the outlet as a result of the back of the collector being exposed. Due to the severity of the reduction a more specific heat transfer resistance network was calculated using E quations ( 5 6 ) through ( 5 9 ) [36] ( 5 6 ) ( 5 7 ) ( 5 8 ) ( 5 9 ) The resistance calculations revealed that the conduction through the insulation and aluminum combined with the free convection only account for slightly more than a 3 C reduct ion in output An investigation of the source code from the model revealed insulation assumptions and values. This series of calculations disproves free convection to be the predominant difference between the experiment and the model. The next variable ex plored was the degradation of performance as a result of collector surface residue. Further review of the public literature [37] revealed a claim of 30 40% reduction in performance can be expected as a result of s alt, dirt and birds. Th e author of the publication recommends a panel be cleaned ideally every 3 months and at ( 5 5 )

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58 the least every 6 months. The panel under test was purchased in 2007, has been in a variety of environments, and has never been extensively clean ed The test location is in Jacksonville Beach and is located at ground level in an environment near gravel parking lots. Both salt air and gravel dust have the potential to be strong contributors to performance degradation T dation and estimated losses, as well as the installed environment, led to operating the model with degraded absorptance values. The published absorptance value from the manufacturer is 0.91. At a 25% reduction, the modeled output and the experimental data for the collector output was within 2C of each other on the peak outputs and within 5C on the low outputs. On the high value outputs, that is about a 3.5% difference. The collector return pipe length was adjusted from 50 feet to 125 feet due to increase d losses from outdoor installation versus an attic or garage space. The model results closely match the experimental temperature values. The added length lowers the temperature as a result of the increased losses through the increased surface area. Figure 5 3 shows the updated m odel temperatures for January 15 to January 17. Figure 5 4 represents the sam e model, but displays January 15 solely. Figure 5 5 is the ex perimental data for the same time period. The ICS inlet temperatures from the experiment are consistently lower than the expected or modeled inlet temperatures therefore the ICS average temperature is lower. T he peak ICS out let temperature and the collect or delivery temperature of the model and experiment follow each other closely, so the current set points create the baseline for predicting performance using the model

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59 Auxiliary Heat In a typical installation an ICS is plumbed upstream in series with a conventional electric resistance water heater. To appropriately model the effects that a solar water heater has on the electrical usage, the model requires some auxiliary heat information. In this case, the unit is an electric storage tank, as opposed to g as or tankless, and has 40 gallons of storage. The energy factor is 0.92. The unit has a height of forty six inches and has two electrical resistant heating elements. Each heating element has 4500 watt capacity. The set point for each element was input. To match the experiment, both units were set at 41 C. The setting on the actual unit was for 52 C, but the measured temperature was 41 C Th e difference is attributed to the voltage f eed of 208VAC instead of 240VAC. Figure 5 6 shows the modeled water heater cycles on and off very frequently during the morning peak time and comes on once in the evening. The model has summarized data that writes to excel files to create graphs. Figure 5 7 shows on an average January day the ICS is detrimental to the morning peak between 6 AM and 8 AM, but begins to contribute from 8 AM to 10 A M.

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60 Figure 5 1 Selective s ur face ICS m odel t emperatures. Temperature (Deg C) 80 60 40 20 0 01/15 06:00 01/16 00:00 01/17 00:00 Date and Time ICS Model Temperatures Outlet ICS Average ICS Pipe from Coll Bottom Tube Pipe to Coll Mains Ambient

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61 Figure 5 2 User i nput ICS m odel t emperatures. Temperature (Deg C) 80 60 40 20 0 01/15 06:00 01/16 00:00 01/17 00:00 Date and Time ICS Model Temperat ures Outlet ICS Average ICS Pipe from Coll Bottom Tube Pipe to Coll Mains Ambient

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62 Figure 5 3 User i nput ICS m odel t emper atures with reduced absorption and lengthened return pipe. Temperature (Deg C) 70 50 40 20 0 01/15 06:00 01/16 00:00 01/17 00:00 Date and Time ICS Model Temperatures 60 30 10 Outlet ICS Average ICS Pipe from Coll Bottom Tube Pipe to Coll Mains Ambient

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63 Figure 5 4 User i nput ICS t emperatures for January 14 Temperature (Deg C) 80 60 40 20 0 01/15 06:00 12: 00 01/16 00:00 Date and Time ICS Model Temperatures 18:00 Outlet ICS Average ICS Pipe from Coll Bottom Tube Pipe to Coll Mains Ambient

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64 Figure 5 5 Expe rimental d ata t emperatures January 15.

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65 Figure 5 6 Electric w ater h eater m odel for January 15 On or Off (1/0) 0 01/15 06:00 12:00 01/16 00:00 Date and Time 18:00 1 Electric Water Heater Model

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66 Figure 5 7 Consumed energy for an avera ge January day.

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67 CHAPTER 6 CONCLUSIONS Conclusions from Experiment The impact of solar water heating on reducing peak electrical demand has gained interest as many utility companies in the south have experienced infrequent but severe peaks during cold winter mornin gs. Solar water heaters due to the inherent thermal capacitance, store energy for the times of low solar input. A review of published literature demonstrated limited success with solar water heating as a means for winter peak reduction, but the particular s of the systems and the tests as well as the transferability to other areas was not accessible Due to t his knowledge g ap the effectiveness of an ICS system was investigated. ICS was chosen because it is a modestly pr iced passive system included in the i ncentives program by JEA and Beaches Energy To determine t he effectiveness of winter peak reduction, a test plan was developed and successfully implemented. The test system include d a support structure for an ICS system ambient and performance sensing an d recording instrumentation and the infrastructure and control s to recreate the hot water load profile of a residential home. The data showed that the ICS system contribute d approximately 44% of the energy required to meet the water heating load thus exi sts the potential to reduce the winter morning household peak electrical load by greater than 10%. This energy comes nearly all from the stored thermal capacitance. Th is benefit to the utility companies can justify the solar installation incentives program and also combat the negative effects associated with peak demand.

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68 Further Work Due to the electrical resistance elements of the auxiliary water heaters, the instantaneous power requires bursts of high current with varying frequency and duration. Without a control strategy or timer to intentionally stagger the electricity draws, even with an ICS system reducing the overall electricity needs, there is still potential for high peaks. Further study and experimentation with demand side management, timers and/o r other control strategies and devices open opportunity for optimizing a hybrid arrangement to maximize the effects of solar water heating on peak demand. Based on the installation and maintenance variables that affected the experimental and modeling perf ormance, t here are opportunities to further research the effects of collector angle and orientation and how routine collector cleaning effects solar absorption The current solar collector sizing standards do not account for system design or overnight ene rgy storage capacity and the effects on peak demand There are opportunities to further research these variables as well as other ICS systems and active systems such as active drain back design Based on the outcome of the further research there are opp ortunities to tailor the incentives according to the reduc tion of winter electrical peak ing

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69 LIST OF REFERENCES [1] JEA Sets New Record for Winter Electric Peak. 2010; Available at: https://www.jea.com/Media/News_Releases/News_Archive/JEA_Sets_New_Recor d_for_Winter_Electric_Peak.aspx [2] R. Huber, USA Today, (2010). [3] McMahon M. What is electricity demand? 2013; Available at: http://www.wisegeek.org/what is electricity demand.htm [4] Richmond R, et al., American Solar Energy Society, (2003). [5] B. Moore, (2007). [6] T. Merrigan, D. Parker, Amer ican Council for an Energy Efficient Economy, (1990). [7] L. Craig, Earth Techling, (2011). [8] L. Sherwood, (2011). [9] DOE, (1996). [10] W. Beckman, J. Duffie, Solar Engineering of Thermal Processes, 3rd ed., John Wiley & Sons, Inc., Hoboken, New Jersey; 2006, pp. 238,498. [11] M. Smyth, P.C. Eames, B. Norton, Renewable and Sustainable Energy Reviews, (2004). [12] JEA's Solar Incentive Program. Available at: https://www.jea.com/Manage_My_Account/Ways_to_Save/Rebate_Programs/Shop Smart/Solar_Water_Heating.aspx [13] Instructions for Solar Water Heater Rebate. Available at: http://www.beachesenergy.com/documents/Rebates_Solar_Water_Heater.PDF [14] J. Koomey, R. Brown, Energy Analysis Department, (2002). [15] KUA Sets Third Consecutive Winter Peak Demand Record. 2010; Available at: http://www.intelligentutility.com/article/10/01/kua sets third consecutive winter peak demand record

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70 [16] Southern Company Sets Wi nter Peak Demand Record Again; Third Record in Seven Days Tops Summer Peak Demand. 2010; Available at: http://www.prnewswire.com/news releases/southern company sets winter peak demand record again third record in seven days tops summer peak demand 81159202.html [17] Thermal Energy System Specialists, 1.03 (2009). [18] C. K ettles, T. Merrigan, (1994). [19] M. Bouchelle, D. Parker, M. Anello, (2000). [20] D. Parker, (2002). [21] A. Gravagne, K. Van Treuren, (2008). [22] J. Haberl, S. Cho, (2004). [23] C. Colon, D. Parker, (2010). [24] SRCC, (2013). [25] D. Parker, M. Mazzara, J. Sherwin, Florida Solar Energy Center, (1996). [26] J. Lutz, et al., (1996). [27] SRCC, (2008). [28] PROGRESSIVTUBE passive solar water heating system. Available at: http:/ /www.thesolarenergycenter.com/page/391300215; [29] Sizing a new water heater. 2012; Available at: http://energy.gov/energysaver/articles/sizing new water heater [30] Silicon Solar, Inovative Solar Solutions, (2008). [31] Roof Slope. 2013; Available at: http://www.buyerschoiceinspections.com/Roof Slope [32] American Society of Heating, R efrigerating and Air Conditioning Engineers, (1993). [33] U.S. Department of Energy's Office of Solar Energy Conversion National Solar Radiation Data Base 1961 1990: Typical Meteorological Year 2 (TMY2) Available at: http://rredc.nrel.gov/solar/old_data/nsrdb/1961 1990/tmy2/

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71 [35] Florida Solar Energy Center, Summary Information Sheet. 1995; Available at: http://www.solar water heater.com/pdf/pt 40 cn.pdf [36] F. Incropera, et al., Introduction to Heat Transfer, 6th ed., John Wiley & Sons, Jefferson City, MO; 2011. [37] Reflections Cleaning Services. 2013; Available at: http://www.reflections cleaning.com/solar panel cleaning.htm

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72 BIOGRAPHICAL SKETCH Benjamin Spencer Swanson was born in Lexington, Kentucky to Jeremy and Bethaney Swanson. In 1999, Benjamin moved to Jacksonville to pursue a Bachelor of Science degree from the University of North Fl orida. During his undergraduate studies Benjamin worked as a co op for Smurfit Stone Conta iner and was highly exposed to the thermal science aspects of mechanical engineering. Soon after graduation, Dr. James Fletcher offered Benjamin a position to help de velop the JEA Clean and Renewable Energy Lab. This experience proved to be invaluable and was a springboard into a full time research engineering position and the opportunity to do funded research at UNF as a University of Florida graduate student. Benjami n graduated with his Master of Science in mechanical engineering in the fall of 2013.