Renewable energy is a rapidly growing sector of the energy market in today’s modern world. Current small scale renewable energy systems offer advantages to the environment, as well as disadvantages, such as location restrictions and constant power output. Large scale operations currently only produce a small amount of the total energy used in the United States [1].

An energy solution is needed that can overcome the challenges of location and costs, as well as offer reliability and a constant, uninterrupted power supply. Cold temperature geothermal energy production, operating at temperatures of 60° to 75° Fahrenheit, is a solution to these problems.

This proposal will discuss cold temperature geothermal energy production and outline the objectives set by the Geothermal Energy Generation team to research and develop a working prototype of this technology. It includes the schedule for research and objective deadlines, as well as the methods by which we plan to reach success.

Problem Definition

In the past decade the United States Department of Energy, Department of the Interior, Department of Defense, as well as many state governments, has issued grants for millions of dollars for research into renewable energy. This drive for renewable energy solutions has come as the world begins to approach crises in fossil fuel shortages, global warming and enormous amounts of carbon emissions.

The overall power consumption in the United States in 2010 was approximately 2.9 x 10¹³ kilowatt-hours (kWh) [1]. Of that power, 83 percent was produced by fossil fuels, coal and natural gas. 9 percent was produced with nuclear power plants. This overwhelming use of non-renewable, environmentally unfriendly energy sources has created environmental impacts that will resonate, not only in the near future, but for centuries to come.

Current renewable energy technologies present many advantages, but also many disadvantages. Solar, wind, water and geothermal energy production technologies are all required to be within proximity of their respective resources. Solar energy is only viable in a region that gets sufficient sun light year round. Wind power requires ideal geological and weather conditions, which must stay within a range to allow generation without damages to turbines. Water systems are required to be where there is flowing water with enough volume to drive turbines at a reasonable rate. Geothermal energy is currently only possible in regions where ground water is heated by geothermal resources.

Figure 1 - Solar panels and wind turbines [1, 2]

Due to these disadvantages, as well as costs associated with each solution, renewable energy is only 8 percent of the United States total power consumption, as seen in Figure 2, below. Of that, a significant portion is from burning biofuels, which still causes harm to the environment in the form of carbon emissions.

Figure 2 - Overall U.S. energy consumption by type. [3]

In the realm of geothermal energy production, current technologies rely heavily on ideal locations where ground water temperatures are above 300° F. Low temperature systems rely on water in a range of 150° to 300° F, which still provides a formidable restriction on source locations. Only regions with sufficient ground temperatures and water supplies are viable for these power plants. In addition, because these systems are open, in that they use ground water from the environment, there are disadvantages associated with energy losses.

In addition to the proximity restrictions, modern geothermal energy technologies are aimed at large scale facilities producing mass power outputs on the scale of megawatts (10 x 10⁶⁾. This means that only end users within a sufficient distance from the facilities, as well as those able to connect to the source, are able to use this energy. Homes, farms and businesses in remote locations face considerable cost increases to gain access.

For those end users who are within reasonable distance from large power plants, energy costs are still owed to the energy producers. Over time, the return on investment for grid tied power is often less than that for onsite energy production systems. For individuals and businesses that own renewable energy production systems, costs can be significantly reduced. In addition, these users need not rely on grid power. When grid power faces blackouts or cost hikes, individual users are not subject to these impositions.

In contrast to large scale facilities using low or high temperature ground water resources, this proposal suggests cold temperature geothermal production on a small scale reasonable for small homes or individual business buildings. This system would allow individuals to purchase systems at sizes for their homes that would be independent from the grid, as well as allow for placement in almost any region, regardless of geological conditions.

Cold temperatures, in the context of this system, refers to temperatures in the range of 60° to 75° F. The term closed loop refers to a system that would be completely sealed from the outside environment. This system configuration will allow for the reduction of losses associated with binary systems, in which a heated fluid is used to transfer its heat to a working fluid, which is vaporized before being pushed through a turbine. Examples of binary systems can be seen in Figure 3.

Figure 3 - Binary geothermal system examples [4, 5]

The proposed system will pump a working fluid in a closed system under ground to be heated to 60° to 75° F, at which point the fluid will flash boil and the vapor will be driven through a turbine in order to generate electricity.

Project Requirements and Specifications

This project will be conducted in phases, in order to reach research goals by steps before a final prototype is constructed. Following is a list of project requirements and specifications.

1) In order for the proposed geothermal system to function feasibly, the system must operate at a 10% efficiency, or greater. If the system is unable to operate at this efficiency, secondary heat systems may be employed to increase the amount of heat entering the system. Examples of secondary systems would be solar heating, wind generation, and the like.

2) As a cold temperature designated geothermal system, the system will be required to produce power in the temperature range of 60⁰ to 75⁰ F.

3) For 10% efficiency in the temperature range outlined above, the system will need to be capable of producing power equivalent to that of an average U.S. home. This output was determined to be 3.8kW for the average home in the United States [6].

4) The proposed system will operate without the use of external fluids, as is defined by a closed system.

5) To be reasonable, a system in operation would need to be installed in the back yard of an average urban home. For home owners to be agreeable with the installation, the above ground portion of the system must be scaled to a size that will fit within a 10 foot square area.

Phases and Responsibilities

A Gantt chart for these phases can be viewed in the Appendix. Tools for the following phases are listed within each phase step.

Responsibilities of each team member are listed under each step of the phases outlined below. Overall, Ryan Ziegler will be the acting Technical Lead, Lief Kirsch will be the acting Virtual Drafting and Procurement Lead, and Josh Drake will act as the Documentation Lead. While each team member will be responsible for individual responsibilities associated with these titles, they will also work together to complete objectives as necessary.

1. Phase Ia: Project Administration 50 days Mon 10/10/11 Fri 12/16/11

In this phase all documentation for submittal to grant agencies will be completed. Joshua Drake will act as the primary documentation editor. Documents will be submitted for review to Dr. Tim Becker and Bryan Cooperrider in order to insure the highest level of quality before official submission.

a. Project Proposal (10/10/11-10/24/11)

i. The project proposal is this document. It has been completed as a joint effort by the team. Joshua Drake, as the team secretary, did the primary document writing with support from Ryan Ziegler and Lief Kirsch.

b. Executive Summary (10/24/11-11/1/11)

i. The Executive Summary will be drafted as a team effort and will be formatted and edited for final draft by Joshua Drake.

c. Grant Application (10/10/11-12/16/11)

i. Grant Applications for submittal to granting agencies, such as the Department of Energy (DOE), the Defense Advanced Research Projects Agency (DARPA) and similar private or government entities, will be completed as a team effort. Formatting and final draft editing and finalization will be completed by Joshua Drake.

d. Phase Ia Deliverables

i. Project Proposal

1. In class, assigned Project Proposal (This document)

2. Professional Project Proposal for issue to grantors

ii. Executive Summary

1. In class, assigned Executive Summary

2. Professional Executive Summary for issue to grantors

iii. Grant Application(s)

1. Grant applications with inclusion of professional documents listed above

2. Phase Ib: System Analysis 64 days Tue 10/25/11 Fri 1/20/12

This phase consists of a complete system analysis prior to moving forward on the development of a virtual model. This information flow must be computed in order to insure that the proposed project is viable as an energy solution and will assist in computational analysis in order to simplify steps that will be completed in the SolidWorks Professional environment. During this process, Ryan Ziegler will act as the technical lead with support from Lief Kirsch and Joshua Drake.

a. Thermodynamic Analysis (10/25/11-11/11/11)

i. Thermodynamic analysis will aid in understanding the overall GTG system energy consumption and output. This information is integral for computing the system efficiency, as well as understanding what materials and fluids will be more likely to lead to project success.

b. Heat Transfer Analysis (11/1/11-11/18/11)

i. Heat Transfer analysis will aid in understanding further specifications, such as the needed pipe lengths to absorb required heat, ideal system materials and fluids, as well as overall system requirements.

c. Fluid Analysis (11/8/11-11/25/11)

i. Fluid flow analysis is necessary for sizing critical system components, such as pumps and turbines, as well as pipe and fluid specifications.

d. Final Report (10/25/11-12/9/11)

i. The final semester report will encompass all reporting requirements as specified by the instructor. Detailed information regarding this report is not available at this time. As this report will likely include all of the formal data gathered during the semester, Joshua Drake, Ryan Ziegler and Lief Kirsch will each contribute portions of this assignment.

e. Component Specifications (11/14/11-12/9/11)

i. Once each area of system analysis as listed above has been completed it will be necessary to define the system components’ specifications for modeling in the virtual environment. Ryan Ziegler will act as the technical lead with support from Joshua Drake and Lief Kirsch.

f. Reanalyze Thermodynamics, Heat Transfer and Fluids based on component specifications (12/19/11-1/20/12)

i. Once data has been compiled concerning the specifications of the system components, these data will be run through the system analyses in bullets a-c in order to confirm their validity.

g. Phase Ib Deliverables

i. System Analysis Report

1. A section by section report summarizing each system analysis listed above, including a section on component specifications

ii. Semester Final Report (as assigned)

3. Phase II: Virtual System Build 49 days Mon 1/23/12 Thu 3/29/12

With the system components analyzed and the specifications for each of them defined, the virtual GTG system can be assembled. Prior to system assembly, individual, virtual, critical system components must be procured from vendors or built in the SolidWorks environment.

a. Size and Acquire Virtual Pumps, Turbines, and additional complex components (1/23/12-2/9/12)

i. System components matching the specifications discovered in Phase Ib will be sized for use in the system and virtual models will be procured for use in SolidWorks. Lief Kirsch will be responsible for researching and procuring these components.

b. Build Virtual Components: 28 days Fri 2/10/12 Tue 3/20/12

Components that are not of a complex nature, such as those described in 3.a, will be modeled in SolidWorks. Lief Kirsch will be primarily responsible for drafting these components within the specifications of the components acquired above.

i. Pipes (2/10/12-2/23/12)

ii. Pressure Vessels (2/24/12-3/8/12)

iii. Fittings, Accessories (3/9/12- 3/20/12)

c. Assemble Complete System ( 3/21/12- 3/29/12)

i. With all of the system components compiled, the virtual system model can be assembled in SolidWorks. Lief Kirsch will act as the lead drafter on this step with support from Ryan Ziegler and Josh Drake.

d. Phase II Deliverables

i. Assembled virtual GTG system

ii. Complete Bill of Materials with parts and components specifications

4. Phase III: Virtual Simulation 31 days Fri 3/30/12 Fri 5/11/12

The virtual simulation will be the final phase in developing a functional virtual proof of concept. This virtual prototype will be the basis for building a small scale prototype for demonstration of the system, as well as a demonstrable technical model for use in further grant procurement.

a. SolidWorks Virtual Analysis: 21 days Fri 3/30/12 Fri 4/27/12

The virtual model will be analyzed in SolidWorks Professional for system optimization and as best practices in proof of concept.

i. Thermodynamic Analysis (3/30/12- 4/9/12)

ii. Heat Transfer Analysis (4/10/12-4/18/12)

iii. Fluid Analysis (4/19/12-4/27/12)

b. Compilation of data and final system assembly (4/28/12-5/02/12)

i. At this point all of the system components and data necessary to complete a final system prototype will have been compiled, computed and organized. The system will be completely virtually assembled and run to demonstrate its viability. Ryan Ziegler will act as the technical lead. Lief Kirsch will act as the lead drafter. Josh Drake will be responsible for support and documentation of the process(es) involved.

c. Final Reporting ( 4/30/12- 5/11/12)

i. The final report for this project will be written, covering all of the information required by the class instructor. Detailed information regarding this report is not available at this time. Joshua Drake will act as the lead editor and writer for the final report. Ryan Ziegler will assist in providing technical data and Lief Kirsch will provide SolidWorks virtual data.

d. Phase III Deliverables

i. Completed virtual prototype as proof of concept, fully assembled, analyzed and functioning in the SolidWorks environment

ii. Final comprehensive project report

1. At least one full report of findings and conclusions

2. If required, a separate final report as assigned for the class

Budget

A preliminary budget for this proposal, including the possible construction of a full sized working prototype is listed in Table 1, below.

Table 1 - Projected project budget with inclusion of cost for building a full scale prototype

Item	Individual Cost	Number of Items	Total Cost
SolidWorks Professional	$5,495.00	1	$ 5,495.00
Pumps	$55.00	3	$165.00
Turbines	$10,000.00	1	$10,000.00
Piping Al (per 96")	$167.26	103	$17,227.78
Total	$15,717.26	108	$32,887.78