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STATEMENT OF WORK

Project Title:

Closing the Gap: Getting Full Performance from Residential Central Air Conditioners

Contractor:

New York State Energy Research & Development Authority (NYSERDA)
17 Columbia Circle
Albany, NY 12203-6399
(518) 862-1090

Program Area:

Buildings

Partners:

Florida Solar Energy Center (FSEC)
Advanced Energy (AE)
Energy Center of Wisconsin (ECW)

Project Description:

The field performance of central air conditioning (CAC) falls short of expectations from laboratory-based federal efficiency ratings. On average, these units use 10-30% more electricity than expected. This work will address key factors leading to these shortfalls. The end result of this work effort will be next generation methods and technically feasible climate sensitive designs of air conditioning systems, along with more knowledge of understanding how to optimize systems in the field and installation and sizing of systems in such a way as to transfer the knowledge to HVAC contractors.

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.

Linked Contractors (State Chartered Organizations):
New York State Energy Research and Development Authority
Florida Solar Energy Center
Advanced Energy (North Carolina)
Energy Center of Wisconsin

Subcontractors to Linked Contractors:
American Council for an Energy Efficient Economy (subcontractor to NYSERDA)
CDH Energy (subcontractor to NYSERDA)

Project Participants not receiving STAC funding:
Californi Energy Commission (funding LBNL exclusively)
Lawrence Berkeley National Laboratory (funded by CEC and subcontractor to ACEEE)
Wisconsin Energy Conservation Corporation

NYSERDA will be the Managing Partner for the contract and serve as primary contact to NASEO. NYSERDA will be advised by a Steering Committee. Each State Chartered Organization and ACEEE will designate a representative to the Steering Committee that will meet periodically. The Managing Partner is responsible to NASEO for project execution, and for assuring that the match funds/federal funds ratio remains within the appropriate range during each twelve-month period of the project. The Managing Partner will report and seek resolution to deviations in schedule, funding commitments or other responsibilities of other State Chartered Organizations, first to the Steering Committee and if need be, directly to NASEO. ACEEE will serve as Technical Director for the linked projects. The Technical Director will serve the group and the Managing Partner by providing for quality assurance and task tracking. The Technical Director will be advised by and advise the Project Steering Committee. The Steering Committee will also form an independent Advisory Committee of experts who will meet semi-annually to review progress and suggest improvements that may occur. The Advisory Committee will receive and review copies of all relevant technical reports. The Technical Director will be responsible for maintaining the schedule, including preparing reports for NYSERDA and other members of the Steering Committee and Advisory Committee.

Task 1: Improve central air conditioner performance ratings

The objective of this task is to provide a basis for replacing or supplementing the current federal efficiency measure for central air conditioners with metrics that better reflect field performance, the benefits of new technologies, and the multiple needs of consumers, utilities and different regions. If successful, it will help manufacturers by simplifying testing and emphasizing product differentiation; and will help consumers and utilities by providing energy and peak demand savings as well as reliable guidance on appropriate equipment for varying applications and conditions. For this project element, CEC will fund ACEEE work with assistance from the LBNL to supplement the STAC funded effort. NYSERDA, FSEC, ECW, WECC, ACEEE, and CDH Energy will provide in-kind support. Six sub-tasks will be performed to develop a suite of test method recommendations to DOE and ARI.

Task 1.1: Review present standards and method of testing

Review the present standard and method of test in the light of issues listed above. This work will be led by NYSERDA/ACEEE. WECC in-kind resources will focus on supplemental analyses and testing concepts with industry. FSEC, LBNL, and other partners will review concepts based on their experience. CEC staff will assist, based in part on their experience developing the existing test methods.

Deliverable: White Paper, Quarter 1, by ACEEE for CEC and NYSERDA.

Comments/Dependencies: Work completeness (but not the deliverable itself) dependent on supplemental analyses, and concept review and testing by WECC (in-kind), FSEC (in-kind), LBNL (CEC-funded), and other partners. The deliverable is not dependent on STAC-funded work by others in the project.

Task 1.2: Field performance data review

Review all available field performance data and programs designed to compensate for limitations within the seasonal energy efficiency ratio (SEER). Document methodological defects such as underestimates of external static pressure. ECW, WECC, FSEC, CDH, LBNL, and other partners will help locate data for the ACEEE meta-analysis.

Deliverable: White Paper, Quarter 5, by ACEEE for CEC and NYSERDA.

Comments/Dependencies: Work quality (but not the deliverable itself) dependent on supplemental analyses, field data from Task 3.1 and concept review and testing by WECC (in-kind), FSEC (in-kind), LBNL (CEC-funded), and other partners. The deliverable is not dependent on STAC-funded work by others in the project.

Task 1.3: Develop population weighted temperature bin-hour distributions

SEER is based on a calculated “average” cooling climate for the United States, as measured by the distribution of hours at particular outdoor temperatures (called “[temperature] bin hours”). There have been large population shifts toward the South and West. Also, recent climate data over the last decade suggests increased full load cooling hours in many locations in the U.S. as well as higher summer peak temperatures. Therefore, we will develop population-weighted temperature bin hour distributions for the future, reflecting anticipated population distributions across the country in a year such as 2010 or 2020. Climate data will be revisited. This revised analysis will likely shift upward the heaviest emphasis in the bin hour’s calculation for modulating equipment, and the test temperature for single-speed equipment (now at 82ºF). Ideally, one would also consider further weighting by an appropriate proxy for time-of-day rates. CDH will carry out these tasks, with supplementary work by FSEC and LBNL.

Deliverable: White Paper, Quarter 2, by CDH Energy for NYSERDA (STAC funded and in-kind).

Comments/Dependencies: FSEC (STAC funded) will assist CDH with developing the analysis methodology, and both FSEC (STAC funded) and LBNL (CEC funded) will review the analysis results.

Task 1.4: Preliminary proposed rating procedures

Develop a set of potential metrics to overcome the defects identified. These may include modified seasonal energy efficiency ratings, and evaluation of the multiple EER-based system used by the International Organization for Standardization (ISO). NYSERDA/ACEEE will lead this work, with review by CEC, ECW, WECC, FSEC, LBNL, NYSERDA, and other parties.

Deliverable: White Paper, Quarter 6, by ACEEE for CEC and NYSERDA.

Comments/Dependencies: CEC, ECW, WECC, FSEC, LBNL, NYSERDA and other parties will use in-kind resources to contribute and review the White Paper. The deliverable is not dependent on STAC-funded work by others in the project.

Task 1.5: Simulate benefits of alternative metrics for diverse climates

Use a single, characteristic, single-family house type in each region, and examine four climates – Southwest hot dry, Southeast hot humid, Northern/Mountain short hot, and West Coast temperate. NYSERDA/CDH will lead this work, with FSEC and LBNL supplemental work.

Deliverables: WhitePaper, Quarter 8, by CDH Energy for NYSERDA (NYSERDA and STAC-funded).

Comments/Dependencies: FSEC (STAC funded) to assist CDH with developing the analysis plan, and both FSEC (STAC funded) and LBNL (CEC funded) to review the results.

Task 1.6: Analysis and recommendations

Based on the first five subtasks, develop recommendations for one or more alternatives to be presented to all stakeholders for their consideration. The stakeholders include CEC, DOE, NIST, ASHRAE, and ARI. After this workshop, the analysis and report will be revised to reflect workshop input. Copies of the final report will be provided to the organizations that develop test procedures for this equipment (see list above) for their consideration. ACEEE will lead this work, to be reviewed by all other partners. ACEEE will sponsor or co-sponsor a workshop for stakeholders to explore next steps toward formal test method revision.

Deliverable: White Paper, Quarter 8, by ACEEE for NYSERDA (NYSERDA and STAC-funded) and CEC.

Comments/Dependencies: Other parties named above will use in-kind resources to contribute and review the White Paper. The deliverable is not dependent on STAC-funded work by others in the project.

Task 2: Robust Feature Set for Residential Air Conditioners

The objective of this task is to develop a “robust” feature set for residential air conditioners to improve operating efficiencies. The following features will be considered:

• Performance: Meets current Energy Star specification. Performance self-certified to within 95% of the rated EER95 at 90% and 120% of the specified refrigerant charge; and airflow at 90% of the value specified by the manufacturer.
• Adaptive Capabilities: Variable-speed motor that maintains 400 cfm/ton across a static pressure range such as 0.1–0.8 inches water pressure. Thermostatic Expansion Valve (TXV) or better refrigerant metering device.
• Alarms (on thermostat): Replace or clean air filter, incorrect refrigerant charge, static pressure out of range, and system needs service (other).
• Maintenance: No scheduled maintenance except filter replacements for 5 years if possible.
• Environmental Considerations: Use chlorine-free refrigerants, establish maximum noise level.
• Business Concerns: Consider requiring that all components be provided by a single source; sizing and installation by NATE-certified (or equivalent) technicians; ideally full warranty for 15 years.

Four sub-tasks will be performed to produce the feature set.

Task 2.1: Develop trial specification sets

From trial specification sets developed by ACEEE and other project participants, carry out simulations in four climates to estimate savings achievable with a robust feature set.

Deliverables: White Paper on simulation methods and results, Quarter 4, by CDH for NYSERDA (NYSERDA funded and in-kind).
Memo with trial specification sets, Quarter 2, by ACEEE to CDH for NYSERDA (NYSERDA and STAC-funded).
Memo with trial specification sets, Quarter 2, by FSEC to CDH for NYSERDA (In-kind and STAC funded)

Comments/Dependencies: FSEC will assist CDH with developing the analysis methodology and will review the simulation results.

Task 2.2: Draft specification

Publish and circulate a full draft of the trial specifications (developed in Task 2.1) for review.

Deliverable: White paper on full draft specification for review (modeled on the form of ENERGY STAR® Program Requirement), Quarter 6, by ACEEE for NYSERDA (NYSERDA and STAC-funded).

Comments/Dependencies: Depends on CDH simulations. Will benefit from in-kind reviews by other team members (FSEC, ECW, WECC, AE, etc.).

Task 2.3: Consensus building workshop

Hold a workshop to reach consensus among manufacturers, program sponsors, on the feature set. Work with manufacturers to bring qualifying products to market, and with Market Transformation (MT) organizations such as the U.S. Environmental Protection Agency, the Consortium for Energy Efficiency, regional alliances, and others.

Deliverable: White Paper for NYSERDA and other process participants to summarize process and results, Quarter 7, by ACEEE .for NYSERDA (NYSERDA and STAC-funded).

Comments/Dependencies: Work content product dependent on participation by other stake-holders.

Task 2.4: Coordinate with manufacturers

Work with manufacturers to bring qualifying products to market, and with Market Transformation (MT) organizations such as the U.S. Environmental Protection Agency, the Consortium for Energy Efficiency, regional alliances, and others.

Deliverable: White Paper on activities and results, Quarter8, by ACEEE for NYSERDA (NYSERDA and STAC-funded).

Task 3: Field Performance Data and Innovation

Field performance falls far below predictions from the federal standards that are based on laboratory measurements (See Task 1). The objective of Task 3 is to extend existing field studies to additional climates and house construction types (with particular attention to whether the HVAC systems are outside the thermal envelope (attics) or in conditioned or semi-conditioned (basement) spaces. The studies proposed support Task 1 (new basis for Standards) and Task 5 (helping contractors and others do a better job through information dissemination and training). Three sub-tasks will be performed to extend the body of knowledge about field conditions and air conditioner performance in different regions of the country.

Task 3.1: Comparison of ratings with field performance

Test data on 300 new systems installed under Wisconsin’s Focus on Energy program and the systems evaluated as part of New York’s CheckMe® program will be gathered and compiled in a coordinated fashion by WECC (in-kind) for ECW. These data will include key parameters such as coil airflow per ton, air handler power draw, external static pressure and refrigerant charge. ECW and WECC will also gather similar data for a random sample of 50 households with new air conditioners and employ relatively simple on/off monitoring during the 2004 and 2005 cooling seasons to gather empirical data on cycling behavior of typical new systems. ACEEE will do meta-analyses of these data and existing data from climates where more research has been conducted (e.g., California and Florida). ACEEE and WECC will lead this work, with data as available from Advanced Energy.

Deliverables: Working Paper, Quarter 2 on 300 new systems evaluated as part of Wisconsin’s Focus on Energy program and 2004 subset of 50 randomly sampled households, by ECW and WECC (STAC and in-kind). Working Paper, Quarter 6 for data on 2005 subset of 50 randomly sampled households, by ECW (STAC). Working Paper, Quarter 2, on systems evaluated as part of New York’s CheckMe program, by ACEEE for NYSERDA (both In-kind and STAC-funded).

(The three deliverables will document methods used in the studies, and provide the per house data on system, house, and performance parameters.)

White Paper, Quarter 3, by ACEEE for NYSERDA (both In-kind and STAC-funded), on the influence of construction style, duct location, and system parameters on field performance.

Task 3.2: Benefits of proper sizing

Field tests will be conducted in two states (Florida and Wisconsin) to show the benefits of proper sizing to contractors, customers and utilities. In four case-study houses in each state, existing oversized air conditioners will be replaced partway through the cooling season with new air conditioners properly sized according to Air Conditioning Contractors of America (ACCA) Manual J, the de facto standard for sizing cooling equipment. Energy, demand and indoor comfort benefits of proper sizing will be documented through monitoring and occupant interviews. To the extent possible, Florida homes will be monitored and analyzed in three phases: (1) as-found operation of the existing oversized system, (2) operation of the existing system after system tune-up; and, (3) operation of the replacement (properly sized) system. The changes will be staged such that similar weather patterns are likely during the test periods. Wisconsin’s shorter cooling season will require focusing on the last two conditions.

Deliverables: White Paper for Wisconsin studies, Quarter 6, by ECW and WECC (In-kind and STAC-funded). White Paper for Florida studies, Quarter 6, by FSEC (In-kind and STAC-funded). White Paper, on customer satisfaction with right-sized equipment, Quarter 8, by AE (In-kind and STAC-funded).

Task 3.3: Research strategies for enhanced field performance

ECW and WECC (in-kind) will conduct field monitoring on a total of 20 systems in the 2004 and 2005 cooling seasons to test several strategies to improve field performance of new central systems by altering how the systems are controlled. These include altering the staging control of two-stage systems in order to demonstrate the impact of air conditioner output capacity on indoor comfort, energy consumption and peak demand, and using special thermostats to allow adjusting airflow according to dehumidification need.

Field monitoring and testing will be conducted in an experimental framework in which each home acts as its own control; that is, each home’s air conditioner will be operated in one or more test conditions part of the time and in a control condition the remainder of the time over the course of the cooling season.

Deliverables: ECW White Paper, Quarter 6, by ECW (In-Kind and STAC-funded) on field monitoring and testing.

Comments/Dependencies: Project team members are committed to provide review, but this service is not a critical dependency for this task.

Task 4: Develop New Climate-Sensitive Air Conditioner Designs

Current air conditioners and heat pumps are generally compromise designs that meet equipment-rating conditions (ARI Standard 210/240) cost-effectively and work adequately in a variety of climates. However, greater comfort and energy savings can be gained if units are designed for specific regional climates. In particular, a unit optimized for hot-dry conditions can improve efficiency by reducing dehumidification ability. And a unit optimized for hot-humid conditions can increase dehumidification and comfort without “over-cooling” a space.

CEC is now planning a project to develop a residential air conditioner optimized for hot-dry climates. Some preliminary work by Oak Ridge National Laboratory (with DOE funding) has provided the groundwork for this CEC project. NYSERDA is initiating a project to develop an air conditioner optimized for northern climates (short duration cooling season with relatively high peak loads that strain utilities and electrical distribution systems).

The objective of Task 4 is to evaluate the various methods available for use in providing proper dehumidification across a very wide range of loading conditions, and develop a unit that incorporates the best options while maximizing energy efficiency. Task 4 is intended to complement the CEC and NYSERDA efforts by developing a residential air conditioner optimized for hot-humid climates.

Task 4.1: System Configuration: identification, simulation and cost-benefit analysis

FSEC will lead the overall development effort, identifying best technical options for the climate sensitive air conditioner. CDH will provide technical assistance by evaluating prototype performance through computer simulations and performing cost-benefit analyses to identify the most promising configurations. ACEEE will provide additional technical review and guidance.

This task includes the evaluation of the various methods available for use in providing proper dehumidification across a very wide range of loading conditions, and development of a unit that incorporates the best options while maximizing energy efficiency. Options may include: (1) air-to-air heat exchangers to enhance dehumidification (e.g., heat pipes), (2) air flow reduction, (3) reheat (refrigerant hot gas or subcool reheat), (4) energy recovery ventilators, (5) ability to modulate dehumidification performance as needed to match the loads, and (6) enhanced evaporator coil heat exchange surfaces.

FSEC and CDH will apply the results of U.S.DOE funded work on evaluating the dehumidification performance of cooling coils at part-load conditions to develop an effective hot-humid climate unit under this sub-task.

Deliverables: White Paper, documenting methods, results, and implications for system configurations, computer modeling, and cost-benefit analysis, Quarter 3, by FSEC and CDH for NYSERDA (both In-kind and STAC-funded).

Comments/Dependencies: FSEC work and report are dependent on results of CDH simulations and White Paper.

Task 4.2: Prototype System: design, construction, laboratory and field testing

FSEC will lead the overall effort to construct the prototype unit(s), perform testing in existing laboratory facilities, and monitor system performance at a field test site. ACEEE will provide additional technical review and guidance.

Deliverables: White Paper, documenting prototype unit design and construction, laboratory tests of prototype, and field tests of the prototype, Quarter 8, by FSEC (In-kind and STAC-funded).

Task 5: Information Dissemination and HVAC Contractor Training

The objective of Task 5 is to develop training for HVAC contractors and homebuilders on important HVAC efficiency, sizing and performance issues, and to incorporate findings from the project into existing training programs. The strategy will be to provide several half-day classes consisting of content from existing courses in this area and new information produced from the findings and tools developed under other project tasks. To facilitate use of STAC research in the training, each of the other project elements includes reporting findings in such a way that will allow for easy inclusion into training materials. Fact sheets will be developed and/or revised to incorporate project findings.

The training classes will be promoted through professional organizations and regional mailings. Depending on the class(es) a student attends, he or she should gain the knowledge required to accurately size and select air-conditioning systems, test building and duct air leakage, assess causes of various building moisture problems and/or knowledgably promote high efficiency equipment. Most courses will be organized so students will also receive CEU credits.

Deliverables: FSEC (In-kind and STAC-funded) will provide in-state training courses in some or all of the project areas described above.

AE (In-kind and STAC-funded) will provide in-state and out-of-state (three additional states) training courses in some or all of the project areas described above. WECC for ECW (In-kind) will incorporate project results into existing in-state training courses in some or all of the project areas described above.

ECW (STAC funded) will develop a fact sheet targeted at homeowners to highlight the benefits of proper system sizing based on the results of Task 3.2.

Comments/Dependencies: NYSERDA, FSEC, AE and ECW, where appropriate, will provide training materials developed under this project to other agencies (e.g., state energy offices, ACCA, electric utilities, etc.) for inclusion in their literature and course curriculum, thereby increasing the transfer of project results.

Project Tasks, Status, and Deliverables

The Project Lead, NYSERDA, shall be responsible for compiling all deliverables and submitting them to NASEO with a description of how the various deliverables for that task relate to the work performed on that task.

Last Updated: 10/24/06