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Project Information Center

STATEMENT OF WORK

Project Title:

Reliability Development and Field Demonstration of CO2 Heat Pump Water Heaters

Contractor:

University of Maryland, College Park

Office of Research Administration and Advancement
3112 Lee Building

College Park, MD 20742
(301) 405-6276

Program Area:

Building Technologies

Partners:

United Technologies Research Center
Tennessee Tech University
Maryland Energy Administration

Project Description:

Aimed at improving the reliability of CO₂ heat pump water heaters and demonstrating the results at field test sites in Maryland and Tennessee. The development work will concentrate on the bearing/lubrication system, CO₂ solubility in the lubrication system, compressor testing at the limits of the operational envelope, field endurance testing, and the development of a load sharing algorithm for multiple unit installations.

Management Plan (Approach):

The unique nature of STAC requires that projects be supported by multiple State entities, and to the extent necessary any other entity. As indicated in the STAC Agreement, it is the Contractor’s responsibility to coordinate the execution of work under the Contract, incorporated by reference hereto. Contractor, in conjunction with the other State entities, and to the extent necessary any other entity, shall conduct the project in accordance with the Management Plan (approach) described below.

Task 1 - Design of Facility and Software

This task shall encompass the designs of the experimental test facilities at UTRC and UMD, as well as the selection of the appropriate modeling software for use in Tasks 3 and 5.  The kickoff meeting of the project will also be held within this task.

Deliverables:

• UMD Deliverable: UMD will complete design of its facility for oil retention measurement in the hot water heater heat pump.
• UTRC Deliverable: UTRC shall provide assistance and consultation for test facility design and software tool selection.
• TTU Deliverable: TTU will familiarize itself with the existing software in preparation for its modeling task.

Task 2 - Oil Circulation Testing Improvement

During this task the test facilities from Task 1 will be built and the compressor shall be tested within test stands and within a representative CO₂ heat pump system to characterize the lubrication flow as well as develop a deeper understanding of the underlying mechanisms behind this flow.  Through this testing, design changes which will lead to enhanced reliability and performance shall be developed.

Deliverables:

• UMD Deliverable: UMD will report test data of oil distribution in the heat pump system and compressor for a wide range of likely operating conditions.
• UTRC Deliverable: UTRC shall perform lubricant circulation tests on a series of CO₂ compressors, with data to be used in Tasks 3 and 5.
• TTU Deliverable: -none-

Milestones:

• November 2007 - Compressor lubrication testing completed.
• February 2008 - Compressor redesign to optimize lubrication circulation completed.

Task 3 - Software Verification

The software used to perform the lubricant transport modeling shall be acquired, installed, and validated with prior data.

Deliverables:

• UMD Deliverable: UMD will provide support to TTU and UTRC in software implementation and verification runs.
• UTRC Deliverables: UTRC shall coordinate with TTU on the software to be used as well as perform software validation runs.
• TTU Deliverable: Verification results from using and tuning software for oil circulation and retention.

Milestones:

• May 2007 - Software installed and validated.

Task 4 - Expander Evaluation

In this task, expansion work recovery devices (expanders) shall be tested within representative CO₂ heat systems at UMD and UTRC.  The testing shall reveal the extent of performance improvement possible, at design as well as off-design conditions.  The teask shall also evaluate potential reliability issues.

Deliverables:

• UMD Deliverable: Expander performance test results including oil circulation issues related to expander use.
• UTRC Deliverables: UTRC shall test an expander in a representative heat pump system as well as coordinate with testing and evaluation conducted at UMD.
• TTU Deliverable: -none-

Milestones:

• December 2007 - Expander installed in system.
• February 2008 - Expander performance evaluation completed.

Task 5 - Data Evaluation

During this task, the lubrication system modeling capabilities shall be expanded through further development and validation using the experimental results from Task 2.  At the end of this task, the models shall be used to feed into Task 6 the information necessary to create redesign options to optimize the efficiency and reliability of the system.

Deliverables:

• UMD Deliverable: Support provided to UTRC for redesign of system.
• UTRC Deliverables: UTRC shall validate, improve and exercise the lubrication system models.
• TTU Deliverable: Support provided to UTRC for redesign of system.

Milestones:

• December 2007 - Design parameters necessary for optimal redesign identified.
• December 2007 - Interim Report.

Task 6 - System Redesign and Final Report

Based on the output from Task 5, the optimal design parameters shall be exercised in the modeling tool using a design of experiments (DOE) process to develop an optimal compressor and system redesign for efficiency and reliability.  The results shall be coordinated among the team members.  The final report will also be part of this task.

Deliverables:

• UMD Deliverable: Final report for UMD portion of project and the overall project.
• UTRC Deliverables: UTRC shall provide information from Task 5 to TTU on the optimal design parameters as well as coordinating and contributing to the final report.
• TTU Deliverable: Completed, updated and verified model and its portion of final report.

Milestones:

• March 2008 - Design parameters for redesign passed to TTU.
• May 2008 - Final Report.

Project Tasks, Status, and Deliverables

Last Updated: 12/22/06