Alternative Energy Supplement System Design



Alternative Energy Supplement

System Design

Dec07-04

Design Report

Client:

Mary Elizabeth and Colin Chinery

Faculty Advisors:

Professors John W. Lamont and Ralph E. Patterson III

Team Members:

Matt Kelly

Aaron Kulow

Daniel Rathe

Joshua Riley

DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer engineering course at Iowa State University, Ames, Iowa. This document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

March 30th, 2007

Table of Contents

Page

List of Figures…………………………………………………………………... ii

List of Tables…………………………………………………………………... iii

List of Definitions……………………………………………………………… iv

Introductory Material……………………………………………………………….. 1

Executive Summary……………………………………………………………... 1

Acknowledgment……………………………………………………………….. 1

General Problem Statement…………………………………………………….. 2

General Solution Approach…………………………………………………….. 4

Operating Environment………………………………………………………... 4

Intended Users and Uses………………………………………………………... 5

Assumptions and Limitations…………………………………………………… 5

Expected End Products and Other Deliverables………………………………... 5

Approach and Design……………………………………………………………….7

Approach Used……………………………………………….…………………7

Design Objectives……………………………………………………………….7

Functional Requirements……………………………………………………… 10

Design Constraints……………………………………………………………..12

Technology Considerations…………………………………………………….13

Testing Requirements Considerations…………………………………………. 16

Project Continuation…………………………………………………………... 16

Detailed Design...………………………………………………………..…….. 17

Resources and Schedules…………………………………………………………... 19

Estimated Resources…………………………………………………………... 19

Project Schedules……………………………………………………………… 21

Closure Materials………………………………………………………………….. 24

Project Team Information…………………………………………………….. 24

Closing Summary……………………………………………………………… 25

References……………………………………………………………………... 26

List of Figures

Page

Figure 1: Overhead Photograph of Chinery Acreage……………………………… 3

Figure 2: Monthly Energy Data and Predictions…………………………………… 8

Figure 3: Design Layout of RES…………………………………………………... 18

Figure 4: Project Schedule from Project Plan..……...………………………….…... 21

Figure 5: Revised Project Schedule……………………………………………….. 22

Figure 6: Deliverable Schedule…………………………………………………….. 23

List of Tables

Page

Table 1: Estimated Personnel Effort from Project Plan…………………………. 19

Table 2: Revised-Estimated Personnel Effort…………………………………….. 19

Table 3: Estimated Project Costs………...………………………………………… 20

Table 5: Revised-Estimate Project Costs…….……………………………………. 20

List of Definitions

Alliant—Alliant Energy provides gas for the Chinery acreage

F—Fahrenheit

Geothermal—An underground system that extracts heat from the ground and uses it to heat a home or other building

IRR—Internal rate of return

kWh—kilo-Watt hours.

MARR—Minimum attractive rate of return

Midland—Midland Power Cooperative is the electricity provider for the Chinery acreage.

Net metering—Selling back to the power utility excess power generated by the RES

PV—Photovoltaic. An array of solar panels that convert solar energy into electrical energy.

RES—Renewable energy system. The combination of wind turbines, solar panels, and other power generating or energy storage devices

Turnkey—a complete renewable energy system from one vendor.

WT—Wind turbine. A wind turbine is a machine that converts mechanical energy in the wind into electrical energy.

Introductory Material

The following introductory material provides an overview of the project and puts the design of the system into context. The reader can use this material to become familiar with the Chinery acreage, the purpose of the project, the goals of the project, and specific problems that affect the design of the RES.

Executive Summary

The Chinery family lives on a small acreage west of Ames. Over the past few years, they have suffered from power-outages lasting up to several days. This creates an immense problem for them because they have four horses. When they lose power for long periods of time, they are forced to carry buckets of water from the bathtub to the horses. In addition, this is inconvenient for them because most of their appliances and entertainment equipment rely on electricity. Even though the power company has become more reliable over the last year, there is still a need for a source of power if the utility company fails to provide it. In addition, having unique sources of energy on the acreage would be a source of enjoyment and pride for a retired engineering professor.

The design team is researching various technologies to accomplish the goal of finding the best alternative energy sources for the Chinery family. The design team is looking for renewable technologies that are practical, economic, and amenable to the Chinery Acreage. The design includes what renewable technologies are being used, why those technologies are best, and where the technology can be purchased. In addition, the design includes an economic analysis of the RES. The economic analysis covers a broad range of scenarios for energy dynamics on the Chinery Acreage; the client can choose different living conditions, renewable technologies, and modes of operation. The end design will allow the client to choose between several systems, and the client will be presented with the respective benefits and drawbacks of each system, along with the group’s recommended best system.

Work is being done on the design project. The original design strategy was to research individual components that make up an RES; for example, wind turbines, solar cells, and batteries. The best individual components would then be combined into an RES. However, the client wants a turnkey system: a system that can be purchased entirely from one vendor. A turnkey RES will be more reliable, will be covered under a vendor’s warranty, and will be easier for the client to use. Notwithstanding, the RES could still use individual components from multiple vendors subject to approval from the client. Clarifying that the system is to be a turnkey system has helped to narrow research and design efforts.

Acknowledgements

The team would like to thank the faculty advisors, Dr. Lamont and Dr. Patterson. They have contributed a great deal of time to ensure the project is a success. In addition, the team would also like to thank the Chinery family. They have provided ideas and data for planning the project.

General Problem Statement

Mary Beth and Colin Chinery own an approximately 1700 square foot rural farmhouse and horse barn occupying four acres approximately five miles west of Ames, Iowa. The current layout of the acreage can be seen in Figure 1. The rural farmhouse is almost one hundred years old and is in need of some renovation. The roofing and siding on the house will likely be replaced sometime in the near future. The house is currently heated by natural gas. All electrical loads will be considered for the house. The horse barn currently holds four horses. Horses do not require heat in the winter; however, heating elements are used to thaw the horses’ drinking water in the winter.

There is a possibility of additions to the load from both the house and horse barn portions of the farm that must be taken into account in the design. In the near future either an addition to the existing farmhouse or a new smaller house will be built on the property for Professor Patterson. Additions to the horse barn such as a horse grooming station will also need to be considered.

Electric power is currently supplied to the acreage by Midland Power Cooperative; this power is both expensive and unreliable. The purpose of this project is research alternative energy and energy saving measures that could possibly be applicable to this specific farmhouse.

There also exists the problem of predicting the energy dynamics on the Chinery Acreage. The energy supply comes from renewable sources: wind, solar, and geothermal heat. Historical data describing energy from these sources must be collected and analyzed. The analysis includes how much energy is available daily, weekly, or monthly; it also includes the probability that this energy will be available in the future. Historical data describing monthly energy demand on the Chinery Acreage is available for the past three years: December 2003—December 2006. More data describing daily or weekly energy use needs to be collected. The energy supply and demand analyses need to be combined to show whether there is scarcity or an energy surplus on the Chinery Acreage.

[pic]

Figure 1: Overhead Photograph of Chinery Acreage

General Solution Approach

After researching alternative energy and energy savings measures, a cost-benefit analysis will be done on all of the possible improvements to determine the ones that would be best suited for this particular farm.

There are five different alternative energy configurations that will be considered.

• No alternative energy sources are used, energy from the power grid will be stored in a battery bank for use during outages.

• The alternative energy sources supply all energy for both the house and horse barn with no connection to the power grid.

• The alternative energy sources supply primary energy for both the house and horse barn with connection to the power grid for distribution of excess energy from alternative energy sources, and the power grid will also supply back-up for the system.

• The power grid will be the primary source of energy with backup from the alternative energy sources.

• No alternative energy sources are used, current configuration is not changed

Once all cost-benefit analysis calculations have been completed and the most appropriate alternative energy configuration has been determined, the best suited alternative energy and energy savings measures will be chosen. The group will then design a complete alternative energy system for the rural farmstead. Specific parts, such as a certain model of a wind generator, will be chosen for the alternative energy design. All information needed to build the actual alternative energy system will be provided in the final report.

Operating Environment

The design will be for an outdoor system exposed to the severe weather conditions of Iowa, including snow, wind, rain, and ice. The system will need to operate between the temperatures of -30 degrees F and 120 degrees F. There will be approximately 1500 kWh per month of power flowing throughout the system, so it will need to be placed so that no faults will occur in foreseeable circumstances. The system will also have to be placed in such a way that it does not interfere with activities on the acreage; for example, the system components should not be in the way of vehicles.

Intended Users and Uses

The users for this project are the Colin and Mary Beth Chinery family and Ralph Paterson III. Professor Paterson will have a basic understanding of the system, and be able to perform some limited simple maintenance if the installation takes place. Colin and Mary Beth will have limited technical knowledge of the RES; any information that they want or need about the RES must be provided by the design team. The design of the RES considers the Chinery children: the system components cannot interfere with their activities and cannot present hazards to their health and safety.

The uses of this project will be the design of a system to power the acreage and possibly heat the house. The electrical system may supply the main power, backup power, power for farm uses, or power for odd jobs. The designed heating system will provide heat for the house.

Assumptions and Limitations

This section details the specific assumptions and limitations relevant to this project thus far.

Assumptions

The following decisions have been made before execution of the project in order to complete the project definition.

Regarding the economic analysis, preliminary research indicates that the acreage is in a class three wind resource area. This information will be used to determine the energy output of a WT over a period of time. Readily accessible wind and solar resource data is accurate to within plus or minus ten percent; so this accuracy will be assumed for all wind and solar resource data.

The assumed usable life of the project is 25 years. The life expectancy of any batteries that may be implemented is 5-10 years.

Limitations

The physical size of the RES cannot exceed the area of the acreage. The design must develop a bill of materials and plan of procedure that operate within a finite budget. All codes and regulations will be considered throughout the design. Industrial power quality standards will be met.

Expected End Products and Other Deliverables

This section will describe what will be delivered to the client prior to the conclusion of the project.

The end product will consist of the recommended options for energy savings and alternative energy sources. This will include the products that should be included in the various operating modes. Moreover, the vendors from whom the products can be purchased will be included. In addition, the justifications for why particular vendors were chosen will be included.

The final product will also include recommendations concerning how the largest savings can be attained. Safety and other considerations will be included in our recommendations. In addition, technical information pertaining to each item will be included. Maintenance tasks that are required over the lifetime of the product will be specified.

In addition, the end product will include a rigorous economic analysis of the possible systems to determine the payback period and return on investment of the project. The economic analysis will include the initial capital investment required for each part of the system, maintenance costs over the RES lifetime, taxes, depreciation of the equipment, and interest expenses. Also, rebates or other incentives offered for energy saving products will be described that are offered by the utility company, state, or federal government. The time-value of money will be taken into account for all of the cash flows related to each product.

Approach and Design

This section details the approach that is being taken to accomplish the team’s goals; it includes work that has been done so far, current work being done, and work that will be done later in the project.

Approach Used

Work is being done on the design project. The original design strategy was to research individual components that make up an RES; for example, wind turbines, solar cells, and batteries. The best individual components would then be combined into an RES. However, the client wants a turnkey system; a system that can be purchased entirely from one vendor. In contrast, the RES could be made of individual components from multiple vendors that are made into a system as part of the project; however, this approach is not being taken. Clarifying that the system is to be a turnkey system has helped to narrow research and design efforts.

Design Objectives

Steps are being taken to gather data about energy use at the Chinery acreage. Initially, monthly electricity and gas usage data was obtained from Midland. The data is not useful for describing daily or weekly energy usage. Daily and weekly energy usage is needed in order to specify how large to design the storage unit, for example, a battery bank. For a good design, it will be necessary to optimize the size of the storage unit. Renewable energy from wind and solar is not constant, but varies daily. Knowing how much energy the Chinery acreage needs on a daily or weekly basis is necessary to specify component sizes in the RES.

Seasonal daily and weekly energy use data will be compared with typical wind and solar energy density available during the same time of year. Energy density describes how much energy is available in a certain space, for example the swept area of a wind turbine rotor or the exposed area of a solar panel, and in a certain amount of time, for example one day or one week. For a given time of year, if the energy density is low, then either the storage unit must be large or energy will need to be purchased from a provider. If the energy density is typically high in a season, then the storage unit may be designed to be smaller. Dr. Lamont is procuring a recording amp clamp that can collect daily or weekly energy use data. If the daily and weekly data is obtained, then it will be compared with energy supply predictions from the RES. The energy supplied by the RES is being predicted based on the acreage’s wind and solar resource, the overall system design, and the size of the RES.

There exists the problem of determining how large to design the RES. The size of the RES depends on the short term energy dynamics on the Chinery Acreage. As seen in Figure 2, the monthly energy data was plotted against time using dark blue dots. As much as possible, the design will meet the demand of future load increases on the Chinery Acreage. The increases in load may include Professor Patterson living on the acreage, a new barn, additions to the house, a new house, a well, geothermal electrical loads, and other loads that may be presented by the client. The updated model of future energy use will be compared with energy available from wind and solar energy on the acreage and used to design the RES.

[pic]

Figure 2: Monthly Energy Data and Predictions

Monthly wind speed data was obtained from the Iowa Energy Center’s online Wind Turbine Output Calculator. The theoretical power available in the wind is as follows: P =0.5(air density)(swept area)(wind speed)3. The monthly wind speed data from the Iowa Energy Center and a reasonable amount of swept area were used in the power equation to estimate monthly power available in the wind on the Chinery acreage. A reasonable amount of swept area is between about six square meters and sixty square meters. This range of swept area is based on the characteristics of small WTs available in Paul Gipe’s Wind Energy Basics, A Guide to Small and Micro Wind Systems; the book was considered credible because it is endorsed by the National Renewable Energy Laboratory.

The monthly kWh of energy available in the wind was then calculated. WTs are theoretically limited by the Betz Limit: any horizontal axis WT cannot extract more than 16/27 ~ 0.59 of the power available in the wind. Small and micro WTs manufactured in 2007 do not approach the Betz Limit, and for modeling purposes 0.2 will be used; this means that a WT will extract only twenty percent of the power, and twenty percent of the energy, available in the wind. The monthly energy, kWh, available in the wind was multiplied by 0.2 to obtain the monthly energy output, kWh, of a WT. The monthly energy output, kWh, of a WT was appended to the graph of energy usage on the Chinery acreage in Figure 2; the WT output is the light green x on the plot and is described as “WT Output kWh” in the legend in Figure 2. This is a preliminary comparison of the energy supply and demand dynamics on the Chinery acreage. The monthly energy usage on the Chinery acreage was subtracted from the monthly supply of energy from the WT; this difference is displayed in yellow in Figure 2 and identified as “WT Output – Usage” in the legend. The difference between energy supply and demand on the acreage is an estimate of energy storage demand or the amount of energy that needs to be provided by other components of the RES such as solar panels or energy purchased from Midland. This information is being used to determine the size of the RES.

Below is a list of the objectives that the team is beginning to accomplish.

Bill of materials—the bill of materials will include a list of all equipment necessary to implement and operate the RES. Each item on the list will include the item’s cost, quantity, and vendor. The bill of materials will follow industrial standards so that an electrician can use it. This will no longer be required because the design has been changed to a turnkey system. The reasoning for this is that the system as a whole will provide better warranties, with more reliable service and accountability. The client has specified that a turnkey system is what they want.

• Working drawings—the working drawings will be used by the Chinerys and electricians to understand the RES and the plan of procedure. These may be provided by the company contracted to install the selected equipment. Some drawings may include block diagrams that show macroscopic relationships in the RES but hide details, electrical circuit schematics showing how items in the RES are connected to each other and the grid, maps showing locations of RES items on the acreage, multi-view drawings showing two-dimensional surfaces of RES items such as electrical cabinets, electrical parts, primary sources, storage elements, and others, pictorial drawings showing three dimensional representations of RES items, and others.

• Plan of procedure—the plan of procedure will describe how the end user is to go about contacting the correct company, acquiring the recommended system, and having it installed. It will describe the vendors to contact to procure the system. The installation will be done by the vendor, because this is what the client has requested.

• Financial analysis—the financial analysis shall include capital expense of all RES items, maintenance expense, interest expense, utilities expense, labor expense, shipping expense, tax expense, subsidies, revenues due to offsetting original utilities, payback period, and expected rate of return. The salvage value of the selected system will be taken into account.

• Electrical characteristics—shall describe the electrical behavior of the RES. The report will include plots of electrical parameters as functions of load, supply, storage level, and temperature. Electrical parameters shall include current, voltage, power, frequency, power factor, total harmonic distortion, and other power quality metrics. The report will also describe each plot and its relevance to the RES.

Functional Requirements

Previous energy use data has been collected from the electricity provider, Midland Coop, and the gas provider, Alliant. The data has been analyzed to observe changes and averages, but projections about additions and increases in the load must still be made. In addition, a recording device is going to be used to collect daily energy use data. The future increases will be predicted based on the children growing up, additions to the house, building a new barn, and Professor Patterson moving to the acreage. The spreadsheet that will be used to analyze increases in energy consumption will include several variables which will be used to model multiple circumstances. The variables are additional load due to Professor Patterson, the children, a new barn, a well, geothermal, and the base load. The spreadsheet analyzes all of the scenarios by month.

The RES will operate in one of the following modes of operation. The mode of operation will be chosen based on a number of factors, such as the savings that each mode of operation provides, the future energy demands of the Chinery acreage, and cost. The initial cost and payback period of each mode of operation will be calculated and compared. If the payback period of the RES primary mode of operation is shorter than twenty years, then it will be recommended. Otherwise, the mode of operation with the shortest payback period will be the best choice:

Stand alone—The RES will be the primary power source without Midland Coop utility backup, and the RES does not interconnect with the grid. The RES will supply any predictable load at all times through a primary source or storage element. This option is not feasible. This mode of operation does not provide a level of reliability that is adequate for the client. For example, if the wind turbine or solar cell breaks down, the client will be out of electric power for several days.

• RES with net metering—The RES will be the primary power source with Midland Coop as a backup source of power, and the RES shall interconnect with the grid for the purpose of backup and net metering. Any load that is not met with the RES will be met with power from Midland Coop. The RES will supply any predictable load at all times through a primary source or storage element. In addition, the RES shall provide power to the electric power grid when all loads are met, all storage elements are fully charged, a primary source is available, and the electric power grid is in a state to accept power. Multiple sizes of RES will be considered with costs and payback period taken into effect. RES and Midland will operate as a joint power supply. The goal of this mode of operation is for the RES to provide approximately half of the demand; Midland Coop will provide for all remaining load demands.

RES backup—Midland Coop will be the primary power source with the RES as backup. Midland Coop will supply any predictable load at all times. The RES will supply power when energy is available either through a primary source or storage element and Midland Coop is unable to meet the load. The RES must interface safely with the grid; it must meet any regulations for interconnection with the grid.

• No change—There will be no changes made to the current system.

Load—Based upon operating mode selected, the RES must be capable of meeting the demands of some of the following loads:

• Barn—Some loads in the barn will include water pumps, two 1.7 kW water heaters, lights, and fans. In addition, the design must include capacity for any potential additions to the barn’s load.

• House—The RES must also provide heating and cooling to the house if it proves to be cheaper than the current gas heating. In addition, the design will include capacity for any potential additions to the house and the house’s load.

The project will not implement the RES. Equipment will not be purchased.

The RES will not meet unpredictable loads. The RES will not provide for additional loads that are not considered additions to the acreage or predictable increases in load. Such additional loads may include any large motor not accounted for in final design specifications, any electrical equipment used in the barn that is not part of the predictable load, and any electrical equipment used on the acreage that is not predictable or expected.

The design will not consider disassembly of the RES. A scrap value will not be determined, and the design will follow the principle of going concern.

Design Constraints

Financial—The RES and design meet the following financial constraints:

• The RES is designed to break even with less than or equal to twenty years of operation.

• The RES is designed so that the design process, implementation, and operation all fall within the budget of having a payback period of 20 years or less.

• The client has limited the design to that of turnkey systems only.

Physical—The RES and design meet the following physical constraints:

• Any photovoltaic (PV) system being considered withstands the environment of central Iowa. Also, the PV system must have maximum exposure to the sun. Thus, the PV system will be located away from obstructions such as buildings, trees, crops, and any other temporary or permanent objects that block the sun. The PV system must not be in the way of vehicles, family recreation, and other activities on the acreage. Finally, the PV system shall be located somewhere near the load or storage elements.

• The wind energy system must withstand the environment of central Iowa. The WT will be located in a place that minimizes turbulence from obstructions, minimizes the distance to the load or storage elements, and, if connected to the grid, minimizes distance to interconnection with the grid. Finally, the WT must be located on an appropriate type of soil that is amenable to the WT’s foundation.

• If implemented, the geothermal system will not interfere with existing buried equipment on the acreage: cable or piping; septic system; water well; footings for additions to the house, barn, or other additions; or other structures and landscape that currently exist. The geothermal system shall be constrained by existing driveways, roads, and waterways.

• All work must meet the approval of the client.

• All electrical codes must be met

• All industrial, governmental, and residential standards and regulations regarding wind, solar, geothermal, and other equipment used in the RES will be followed. Many of these regulations may be found online.

• All operating equipment must coexist with the neighbors.

Technology Considerations

The possibilities being considered are wind turbines, solar cells, batteries, geothermal and other heat pumps. In the following section design considerations of each of these technologies are considered.

Wind Turbines: In the initial research of WTs, the most important factors to consider will be power output and initial costs. These two criteria will allow the team to screen out WTs that are cost prohibitive. If a WT meets the cost requirements, the group must then determine if the WT can be reasonably installed on the farmstead. Besides installation costs, one should consider:

• The physical size of the wind generator.

• The electrical output of the wind generator.

• The amount of clearance required around the wind generator.

• The impact on the farm animals

• The relative mass of the wind turbine(mass per swept area). This is a measure of the robustness of the turbine.

• Over-speed Control, which determines how the turbine reacts to dangerously high wind speeds.

• Rotor Diameter

The designer should evaluate the possible locations for installation of the wind generator based on the size of the wind generator and the amount of clearance required for the wind generator. Depending on the amount of space available, there are possible limitations on the size of the wind generator. The WT will have to be installed clear of obstructions, with significant clearance for the spinning blades of the turbine.

There are additional considerations that may need to be investigated if the WT must be installed close to the house. One should consider the effective lifetime of the wind generator. The designer will also look at the noise that is created by the WT, the possibility of electromagnetic interference from the spinning blades of the turbine, and shadow flicker, which is the strobe effect caused by the shadow of the spinning blades on the WT.

The designer must also learn how the WT will supply power to the farmstead. For example, will the WT convert the AC power created by the generator to DC current that can be stored in a battery and converted back to AC power when supplying power for the house and horse barn. Besides the method of supplying power to the farmstead alone, the group must explore the ability of the wind generator to connect with the distribution grid to possibly sell extra generated power.

Besides the specifications for the individual WTs, factors that are applicable to all wind generators must be explored. For example, wind data must be found so that the group can calculate the capacity factor of the wind generators. The wind data will need to be correlated with the cut-in wind speed for the wind generator, so the group may do a cost benefit analysis of the wind generators.

Solar Energy: The group will investigate at least two types of solar energy: solar heating and photovoltaic electricity.

Solar heating will be evaluated in terms of cost savings. The first thing the group must consider with solar heating is feasibility of installation. This will involve both initial costs and the ability to install solar heating into a century old farmhouse. If solar heating is able to be both cost beneficial and feasible to install, the group will investigate specific solar heating systems. The estimated cost will be around eighteen cents per kilo-watt-hour, according to Dr. Dalal. He also stated that the warranty on these is typically 30 years. The group will first analyze the heating capabilities of solar heating systems. The designers will need to know how much heat solar heating can provide to the house, and how much hot water can be provided with solar heating. The mechanisms for solar heating must be investigated. Stationary solar panels and panels that track the sun shall be examined.

Photovoltaic energy will be evaluated initially in terms of initial costs and power output. This information will be used as a screening to ensure that PV can be cost-beneficial. If PV passes the initial screening, feasibility of installation will be looked at. Photovoltaic cells could possibly be installed either on the ground or on the roof. For roof installation, the weight of the PV cells needs to be known to determine whether the roof can support that much weight. Different sizes will be looked at to see which can be installed on the roof. Other alternative such as PV shingles will be looked at.

Photovoltaic cells could also be installed on the ground. For ground installation the team will again need to look at the size of the PV cells, but weight should not be an issue. Ground installation has the benefit that ground installed PV cells can track the sun. The team will investigate the benefits of fixed orientation versus the ability for the PV cell to track the sun. The costs are considered to be the largest factor in making this decision.

For either roof or ground installation, the effective lifetime of the PV cells will be considered. The group must also consider the degradation in power output as the PV cells age. Possibly the most important consideration will be the efficiency of the solar cell versus the initial cost of the solar cell.

Heat Pumps: The considerations for heat pumps will be similar to the considerations for solar heating. Heat pumps will not create electrical energy, rather they will reduce the amount which the client would normally spend heating the house. There are two kinds of heat pumps which will be considered: air source heat pumps and geothermal heat pumps.

For both types of heat pumps, the initial costs of the system will need to be known, including the cost of installation as well as the amount of energy the heat pumps will save. To determine the energy savings, the energy savings in heating costs as well as the additional electrical load from running the heat pumps will have to be known. The efficiency of each pump will also have to be known.

For air source heat pumps, the efficiency of the heat pump will need to be known. For both air source and geothermal heat pumps, the team will need to know if the heat pumps can interface with the current heating and cooling system in the house, and whether it uses air ducts or something else.

For geothermal heat pumps, the most important factor after costs will be the feasibility of installation. The team will look at whether vertical or horizontal loops will be better for this particular farm. For geothermal heating, the lifetime of the above ground as well as the below ground portions of the heating system will need to be taken into account.

Storing Energy or Interfacing with the Distribution Grid: For wind and solar electrical energy, as well as any other type of alternative electrical energy sources the group might consider, how the system will interact with the grid will need to be known. Any system connected to the grid will have certain requirements such as frequency. The team will need to investigate these requirements and make sure each electrical system could meet these requirements. If the system cannot meet these requirements, there is still a possibility of using the electrical energy without being connected to the distribution grid.

The team must also consider the problem of back feeding to the power grid during an outage. The electrical system should not back feed into the power system during an outage because the electricity could harm electrical workers that are possibly repairing a downed power line.

Besides considering the possibility of feeding the electricity into the power grid, the team will also consider storing any excess electrical energy for later use. The most likely form of storage will be battery storage. For battery storage, the storage capacity of the batteries must be known. The team will need to investigate the methods for charging the battery and the methods for converting the DC power stored in the battery to AC power that can be utilized by the various electrical devices in the house.

The team will need to know the temperature ranges and operating environments in which the batteries can be used. The team will also need to know the lifetime and initial costs of the batteries.

Unique Alternative Energy Sources and Cost Saving Measures: Besides the previously mentioned alternative energy sources, the senior design team will also investigate other alternatives that may not have been considered yet. For example, the team could look at alternative heating sources such as wood, pellet, or corncob heating. The technical considerations for these alternatives will be very similar to the technical considerations for solar and wind. The group must know the initial costs and either the cost savings or the power output. The team will also need to know if the system can be feasibly installed and the team must make sure it will work with the other proposed cost saving measures.

Testing Requirement Considerations

Since the team is not actually implementing the design, the physical system cannot be tested. The team will run a simulation of the expected output and load. The focus of this simulation will be to test whether the output of the system and the stored power can supply ample power to keep the system running at the peak load for extended periods of time. The amount of power that is produced by the system will be considered and estimated, along with how much of that power is consumed by the client as compared to being sold back to the power coop. The simulations on the Iowa Energy Center website will also be used to estimate the monthly power output. The equations and inputs for how they make the estimate has been requested. This procedure could be used to model monthly power output in other turnkey systems. The team will also determine and resolve any design flaws that would prevent the installation or proper operation of the system.

Project Continuation

The end product should be completed by the end of this project, so continuation will not be necessary. A continuation project could be used to finish any grant applications started as part of this design project. Also, related alternative energy projects may surface in the future. Additional projects could use the information from this project, and analyze the installed system to aid in the decisions that their team must make.

Detailed Design

The major components of the design include:

• A design of the RES

• A design of the geothermal system

• An economic analysis of the RES

• Sources of energy savings

• Predicted outputs necessary to cover increased energy usage

• Predicted output from the RES

Components of the RES are shown in Figure 3. These parts will come with the selected turnkey system. The purpose of the project is to select the turnkey system that best meets the energy supply and demand on the Chinery acreage, is industrially sound, and is financially viable.

The chosen system will be based on our economic analysis of the best turnkey systems. The economic analysis will include revenues from the output of the RES, savings due to the RES and geothermal system, and expenses. The expenses include the capital costs the RES and the geothermal system, taxes, maintenance, depreciation, and interest. The economic analysis will also include grants or other subsidies that could be used to finance the project. In the economic analysis, the financial situation on the Chinery acreage will be calculated assuming no RES or geothermal system is installed; this will be the basis of comparison for alternative systems.

In scenario analysis, different implementations of the RES and geothermal system will be analyzed economically and compared to the base case. For example, the scenario that includes a stand alone RES system and geothermal system will be compared to the base case scenario. The base case and each implementation will include the effects of the time value of money, present worth analysis, MARR, and IRR. The MARR and IRR will not be the deciding factor in the economic analysis because the client is not pursuing the project solely as a financial investment. The different modes of operation will be compared on the basis of their IRR, with the higher IRR being the more financially sound project. However, the client would like to implement the system as the primary source if possible. This means that if the RES as primary source has any rate of return on the money, it will be recommended.

The economic analysis will include estimates for future energy prices, and scenario analysis will also be used. The system will also be selected based on the desired output by using the estimated increase in power demand. The mode of operation decided upon will determine the turnkey system used. If it is feasible to select the RES as a primary source, this will be done. The design will also include the options for any available grants or discounts. A separate economic analysis will be done concerning the geothermal system. To find sources of energy savings, an energy audit will be performed.

The design will include a forecast for the increased energy use on the Chinery acreage. The forecast will include Dr. Patterson moving out to the acreage, the children growing up, additions to the house, a new barn, a well, and maybe a new house. The forecast will be used in the model of the power demand curve. Estimates will be made for the output of the WT and solar panels, and this will be compared to the demand curve to forecast how much energy needs to be supplied by the utility. The supply and demand forecasts will also be used to estimate how large to design the storage system. The forecasts will be used to determine how large the WT blades, generator, and tower need to be. For a given WT capacity factor the forecasts can be used to determine how large to design components of the WT: how long the blades need to be, how large the generator should be rated for, and how tall the tower needs to be. The forecasts will also be used to determine the area necessary to capture enough energy with the PV array.

[pic]

Figure 3: Design Layout of RES

Resources and Schedules

Estimated Resources

Personnel Effort—Table 1 is based on the Statement of Work from the project plan. It shows the major tasks of the project and the estimated time each member of the group will commit to those tasks.

|Table 1. Estimated Personnel Effort |

|Team member |Josh |Aaron |Matt |Dan |Total |

|Task 1—Problem Definition |19.0 |17.5 |10.0 |6.0 |52.5 |

|Task 2—Technology Selection |144.5 |142.0 |144.0 |136.0 |566.5 |

|Task 3—End Product Design |22.5 |27.0 |31.5 |27.0 |108.0 |

|Task 4—Project Reporting |56.5 |61.5 |57.5 |82.3 |257.8 |

|Total |242.5 |248.0 |243.0 |251.3 |984.8 |

Table 2 is the revised version of the estimated personnel effort to include additional hours for the problem definition. The problem definition has been expanded to include the additional hours needed to determine the preferred mode of operation and RES final design. The mode of operation depends on how the RES is designed to meet the supply and demand of energy on the Chinery acreage. After completing research and preliminary modeling, it was determined that the modes of operation could not be selected until a better energy model was constructed and the size of the RES needed was determined.

|Table 2. Revised-Estimated Personnel Effort |

|Team member |Josh |Aaron |Matt |Dan |Total |

|Task 1—Problem Definition |49.0 |47.5 |40.0 |36.0 |172.5 |

|Task 2—Technology Selection |119.5 |117.0 |119.0 |111.0 |466.5 |

|Task 3—End Product Design |22.5 |27.0 |31.5 |27.0 |108.0 |

|Task 4—Project Reporting |56.5 |61.5 |57.5 |82.3 |257.8 |

|Total |247.5 |253.0 |248 |256.3 |1004.8 |

Financial Requirements—Table 3 reflects the design nature of the project. The table shows that the costs of the project include the poster and the labor expense that would be included if the group members were being paid.

|Table 3. Estimated Project Costs |

|Item | | |Without Labor |With Labor |

|Poster | | | $ 50.00 | $ 50.00 |

|  | |Subtotal | $ 50.00 | $ 50.00 |

|Labor at $15.50 per hour: | |  |

|a. Kelly, Matthew | | | $ 3,758.75 |

|b. Kulow, Aaron | | | $ 3,844.00 |

|c. Rathe, Daniel | | | $ 3,766.50 |

|d. Riley, Joshua | | | $ 3,895.15 |

|  | |Subtotal |$ 50.00 | $15,264.40 |

|  |  |Total |$ 50.00 | $15,264.40 |

Table 4 is the revised version of the estimated project costs to include the additional labor described in Table 2.

|Table 4. Revised-Estimated Project Costs |

|Item | | |Without Labor |With Labor |

|Poster | | | $ 50.00 | $ 50.00 |

|  | |Subtotal | $ 50.00 | $ 50.00 |

|Labor at $15.50 per hour: | |  |

|a. Kelly, Matthew | | | $ 3,836.25 |

|b. Kulow, Aaron | | | $ 3,921.50 |

|c. Rathe, Daniel | | | $ 3,844.00 |

|d. Riley, Joshua | | | $ 4,316.75 |

|  | |Subtotal |$ 50.00 | $15,574.40 |

|  |  |Total |$ 50.00 | $15,574.40 |

Project Schedules

Project Schedule—the project schedule is based on the statement of work. It shows which tasks happen in series and which tasks happen concurrently. Figure 4 is the original project schedule from the project plan.

[pic]

Figure 4: Project Schedule from Project Plan

Figure 5 is the revised project schedule to show the additional time being spent on the Problem definition. The “Meter Power Consumption” subtask under the problem definitions shows that, if a recording device is obtained, daily energy use data will be collected throughout the spring and summer of 2007.

[pic]

Figure 5: Revised Project Schedule

Deliverable Schedule—the deliverable schedule is based on the statement of work and EE 491 class requirements. It shows when the major deliverables are due in the course of the project.

[pic]

Figure 6: Deliverable Schedule

Closure Material

Project Team Information

Client Information

Client: Mary Elizabeth and Colin Chinery

Address: 1254 W. Ave., Ames, IA 50014

Contact Person: Dr. Ralph E. Patterson III

Phone: 515-294-2428

Fax: 515-294-6760

Email Address: repiii@iastate.edu

Faculty Advisors

Dr. Ralph E. Patterson III

326 Town Engineering, Ames, IA 50011

Phone: 515-294-2428

Fax: 515-294-6760

Email Address: repiii@iastate.edu

Dr. John W. Lamont

324 Town Engineering, Ames, IA 50011

Phone: 515-294-3600

Fax: 515-294-6760

Email Address: jwlamont@iastate.edu

Team Members

Aaron Kulow

2212 Friley Pearson, Ames, IA 50012

Major: Electrical Engineering

Phone: 515-520-1069

Email: akulow@iastate.edu

Josh Riley

4912 Mortensen Rd. #1032, Ames, IA 50014

Major: Electrical Engineering

Phone: 515-708-2407

Email: rileyj1@iastate.edu

Matt Kelly

528 Billy Sunday Rd. #203, Ames, IA 50010

Major: Electrical Engineering

Phone: 515-956-7790

Email: mwkelly@iastate.edu

Daniel Rathe

169 University Village Apt. H, Ames, IA 50010

Major: Electrical Engineering

Phone: 515-520-1094

Email: rathed@iastate.edu

Project Website:

Closing Summary

Building a renewable energy system to provide for the energy needs of a home demonstrates the family’s initiative and independence. The first step in building such a system is its design. To start, research is being done to find the type and best combination of renewable energy sources to use: wind, solar, geothermal, or others. Concurrently, data is being collected and analyzed to assess the dynamics of energy supply and demand on the Chinery acreage. As an improved model of energy supply and demand on the Chinery acreage is constructed, renewable energy sources are being chosen that best meet the supply and demand dynamics. Equipment is being chosen that will best implement the system; all of this equipment will be listed in the bill of materials. In addition, the final design will include a plan of procedure for the user to contact vendors as well as electrical and construction contractors, if necessary. The design presents working drawings describing the physical layout, electrical characteristics, and performance of the system. Finally, the RES is described and the project’s cost, time, and resources are presented in the design report. Once the design is done the system may be installed to provide clean, renewable, and independent energy to the family.

References

1. American Wind Energy Association. Retrieved January 30, 2007, from

2. Bergey Windpower Co. Retrieved February 1, 2007, from

3. Econar. Retrieved February 3, 2007, from

4. Gipe, Paul. Wind Energy Basics. 1999 Chelsea Green Publishing Company.

5. Google Maps.

6. Iowa Energy Center.

7. National Renewable Energy Laboratory. Retrieved February 5, 2007, from

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