Presented at the First International Conference on Energy Efficiency in Household Appliances, Florence, Italy. Nov 10-12 1997.

Alan Meier

Lawrence Berkeley National Laboratory

University of California

Berkeley, California USA

Synopsis

Energy test procedures will require revisions in order to accommodate microprocessor controls and linkages to energy efficiency regulations.

Abstract

An energy test procedure provides manufacturers, regulatory authorities, and consumers a way of consistently evaluating energy use and savings across different appliance models. Three trends will force radical changes in the creation and maintenance of energy test procedures. First, the appliance industry is becoming increasingly international. As international trade in appliances rises, firms will seek to reduce trade barriers, including local test procedures. Second, "ownership" of test procedures is shifting from test-setting organizations to government agencies in charge of efficiency regulations and labels. This suggests a different role for standards-setting organizations. Finally, the introduction of microprocessors to control appliance operation is causing an increasing discrepancy between energy test procedures and actual operation. Current test procedures test mechanical efficiency of appliances but ignore the "software" aspects. Most energy test procedures will need to be revised soon or become obsolete. The next generation of test procedures will need to address all three trends.

1. Introduction

An energy test procedure is the foundation for energy efficiency standards, energy labels, and other related programs. It provides manufacturers, regulatory authorities, and consumers a way of consistently evaluating energy use and savings across different appliance models. The relationship among these components is illustrated in Figure 1. A well-designed test procedure services the needs of its users economically and with an acceptable level of accuracy and correspondence to actual conditions. On the other hand, a poorly-designed energy test procedure can undermine the effectiveness of everything built upon it.

Energy test procedures have typically been developed and maintained by test-procedures organizations in each country or region. The largest such organizations include the International Organization for Standardization (ISO), the International Electro-technical Commission (IEC), the American Society for Testing and Materials (ASTM), and the Japan Industrial Standards (JIS). Most procedures-setting organizations have a unique status in which they have near law-making authority but are operated mostly by the industries affected by the procedures and standards.

Figure 1. The relationship between energy test procedures, labels, efficiency standards, and other efficiency programs.

In the last decade, three major trends have emerged that will force radical changes in the way in which energy test procedures are established and maintained. These three trends are:

• internationalization of the appliance industry and reductions in trade barriers;
• adoption of energy efficiency regulations and labels in several countries
• major technological innovations do not show savings in test procedures

This paper discusses the implications of these trends with special emphasis on the energy test procedures. The goal of this paper is to call attention to a growing problem and stimulate further discussion rather than to present a tidy solution.

2. Internationalization of the Appliance Industry

The home appliance industry is becoming increasingly multinational. Large, international firms are buying out the small, regional manufacturers and joint ventures are now common. As a result, there is a gradually increasing flow across borders of both components and finished products. This is further encouraged by reductions of tariffs and quotas. One of the obstacles to increased flow are the barriers created by the costs of meeting local energy test procedures and energy efficiency standards. An internationally recognized testing laboratory charges roughly US$2000 to perform the U.S. Department of Energy (DOE) test procedure on a single refrigerator and US$6000 for a central air-conditioning unit. (Meier and Hill 1997) The laboratory tests and administrative work needed to create a European Union energy label for a clothes-washing machine cost about US$3800. Manufacturers (and some countries) have begun to regard country-specific test procedures or standards as trade barriers that should be removed in accordance with World Trade Organization (WTO) agreements.

It would be best to harmonize the different test procedures so that a single procedure for each appliance applied throughout the world. And in fact there are numerous efforts underway to harmonize appliance test procedures in order to stimulate international trade and reduce trade barriers. For example, in 1995 Japan revised its refrigerator energy test procedure so that it resembles the ISO test. Several Latin American countries are also examining procedures to harmonize their test procedures. But the present international situation still consists of many different energy test procedures for each appliance.

3. Minimum Energy Regulations and Ownership of Energy Test Procedures

When countries establish minimum energy efficiency regulations, the organizations responsible for the test procedures lose control and "ownership" of the test procedure. This has already occurred in the United States and will begin to occur in Japan and the European Union.

The United States introduced minimum energy efficiency regulations ten years ago but individual states have had regulations for almost twenty years. These standards covered most of the major appliances, including refrigerators, air conditioners, and heating equipment. This gradual transfer of ownership of a test procedure is that of refrigerators has already occurred in the United States for refrigerators.

For many years, refrigerators manufactured in the United States were measured with a test procedure developed by the Association of Home Appliance Manufacturers (AHAM), HRF-1. (Association of Home Appliance Manufacturers 1988) In 1978, the state of California established its own minimum energy efficiency regulations. For the first time, energy test procedures were codified into a law. In this case, however, the law simply referred to the test procedures established by AHAM, Air Conditioning and Refrigeration Institute (ARI) and other test-setting organizations.

In 1987, the U.S. federal government established national minimum energy efficiency regulations which went into effect in 1990. The Department of Energy was assigned responsibility for managing the regulations and selecting the subsequent levels. The minimum energy efficiency levels as well as the test procedures were published in the Code of Federal Regulations. (U.S. Department of Energy 1997) Even though the test procedure was virtually the same as the original HRF-1, the energy test for the American refrigerators had essentially changed names from the "AHAM test" to the "DOE test".

The federal government is also responsible for energy consumption labels that appear on all new appliances. These "EnergyGuide" labels originally appeared in the early 1980s, and were originally based on test procedures established by the test-setting organizations. Starting in 1990, however, the labels relied on "DOE test" procedures.

The most important aspect of this transfer of ownership of test procedures was the process to modify the test procedure or create alternative tests. The need to modify the test arises when a manufacturer develops a new energy-saving design whose benefits do not appear in the test. In the past, the test-setting organizations maintained committees to consider changes. The procedure of proposing a change was relatively simple and quick. These decisions would not affect the manufacturer's ability to sell the appliance. Now, a manufacturer must appeal to the DOE for an alternative testing procedure. The DOE is required to notify the public of a rule-making, hold hearings if deemed necessary, and wait a legally-required period before announcing a final decision. Many more groups can participate in this process, including the government agencies, non-government organizations (NGOs), and other manufacturers. Thus, a manufacturer may wait up to two years for the whole process to be completed. Together, the collection of these modifications, alternative test procedures, and exemptions have created what is, in effect, a new test procedure. If the manufacturer does not receive permission to use an alternative test procedure or an exemption, then the appliance cannot be sold in the United States. Thus, the details of the test procedure will have greater financial importance to a manufacturer.

Japan also has minimum efficiency regulations for several products and expects to soon introduce stricter versions, covering more products. (Turiel 1997) Other countries, such as the European Union and Korea, are introducing minimum efficiency rules soon. Europe does not yet have minimum efficiency standards, but it does have an EU-wide labeling system. The local test-setting organizations have maintained control over the test procedures in both Japan and the EU. But both countries are less advanced in the process than the United States, so the need for changes in test procedures, alternative tests, or exemptions to accommodate new technologies has not yet appeared. Changes are likely to be requested when the existing test procedure prohibits a manufacturer from selling a product or getting a favorable energy rating.

4. Existing Energy Test Procedures Fail to Capture Benefits of New Technologies

Consumer appliances are always being improved and some of these improvements lead to reduced energy use. In other cases, the improvements lead to increased energy use. The savings or increased use are not always revealed in the test procedure, as is described in the examples below: For the most part, these examples are drawn from the ISO or DOE test procedures.

• Variable-Interval Defrost in refrigerators: The automatic defrost feature in refrigerators can be responsible for as much as 15% of a refrigerator's total electricity consumption. Most refrigerators use a clock to initiate defrost at a regular interval. The heater is switched on even if no frost has accumulated. The energy test measurement period runs from defrost to defrost so as to capture exactly one energy-intensive defrost cycle. Recently, a manufacturer developed a sensor to detect accumulation of frost in refrigerator-freezers. When a specified level of frost accumulates, the defrost heater is switched on and the frost melts. A refrigerator with this sensor will never defrost during the test because not enough frost accumulates.

• Variable-Speed Motors in Air Conditioners, Heat Pumps, and Refrigerators. Variable speed motors in appliances offer many benefits to consumers, including better temperature regulation, higher de-humidifcation, and quieter operation. There are also substantial energy savings when the appliance is operating at part-load. Most appliance energy test procedures, however, measure performance at steady-state. The variable-speed motor performs worse than single-speed alternatives at full-load because of small losses in the inverter. The seasonal energy savings from variable-speed operation, however, can easily be 30% when compared to single-speed units. These savings will not appear in most tests.

• Soil Sensors in Dishwashers and Clotheswashers. The DOE tests do not use dirty dishes or clothes. Several manufacturers have introduced dishwashers and clotheswashers with soil sensors. These sensors measure the amount of dirt and a microprocessor adjusts the water temperature, amount of water, and dose of detergent to match the needs. They cut washing time, save water and detergent, and avoid needless over-washing. They also save energy through reduced hot water consumption and motor operation. The sensors and logic needed to make successful cleaning selections is complicated but most test procedures ignore the existence of the microprocessors unless they completely defeat the conventional test.

• Moisture and Temperature Sensors in Clothes Dryers. Clothes dryers waste considerable energy by over-drying clothes. Two strategies have been used to minimize over-drying: temperature sensors and humidity sensors. The DOE test for clothes dryers does not attempt to measure the efficacy of the different approaches; instead it assigns an arbitrary "field use factor" to each sensor. Both sensors receive 1.04 regardless of their effectiveness.

• Switch to Control Anti-Condensation Heater in Refrigerators. Some refrigerators are equipped with a switch to control the anti-condensation heaters. How should the switch be set during the energy test? This anti-condensation heater can increase a refrigerator's energy consumption by 10%. The ISO test requires the heater to be switched on if it is necessary to maintain certain performance criteria. The DOE test is not linked to performance criteria, so the DOE had to select a switch setting for the test. After changing its mind at least once, the DOE requires that the manufacturer report the energy use based on the setting when the unit leaves the factory. ISO may be forced to confront the switch issue if manufacturers decide to install condensation sensors. The heaters will be switched off until the sensors detect formation of condensation. Thus, the heaters may be off a significant fraction of the time. The potential energy savings will not be reflected in either the ISO or the DOE test.

• Automobile Emissions Control. In the United States, the auto "highway" fuel economy and emissions test measures emissions up to a speed of 100 kph and with auxiliary equipment, such as the air conditioner, switched off. On-board microprocessors minimize emissions by continually adjusting the fuel-air mixture. A sensor in the tailpipe measures oxygen concentration in the exhaust and the microprocessor adjusts the fuel-air mixture entering the engine cylinders to minimize engine emissions (and improve fuel economy). General Motors designed certain Cadillacs to go "open loop", that is, switch off the feedback from the tailpipe sensor, when the car exceeded 100 kph. The microprocessors were also programmed to go open loop when the air conditioners were switched on. Neither of these programming instructions will be observed in the emissions test, even though they are both very common situations. The U.S. Environmental Protection Agency (EPA) fined Cadillac $46 million and subsequently rewrote the regulations to prohibit all open loop operation. This blanket prohibition forecloses various design options where limited use of open-loop operation would reduce overall emissions and improve fuel economy.

The combined use of sensors and a microprocessor to control the operation of the appliance is a common feature in all of these examples. Automobiles are the extreme case-a typical vehicle now contains at least ten microprocessors-but already the more expensive models of refrigerators, air conditioners, clotheswashers, and dishwashers use microprocessors to control some features of their operation.

The energy test procedures were developed before microprocessors appeared and, in effect, measure the mechanical, or "hardware", aspects of an appliance's performance, such as amount of insulation, quality of the compressor, or water consumption per cycle, but fail to measure the "software" aspects of an appliance's energy performance. The examples described above demonstrate that clever use of sensors and microprocessors can significantly reduce energy use. Furthermore, it is impossible to ignore these innovations; the automobile example demonstrates that the test procedure can easily be subverted.

A few test procedures have been modified as a result of microprocessor controls. Both the DOE and ISO refrigerator test procedures include an alternative test for variable-length defrost controls. There are many different algorithms (and sensors) that could be used to control defrost intervals, and some are more efficient than others. Unfortunately, neither test assesses the quality of the software, only if this kind of control is being used. For central air conditioners with a similar type of defrost control, the DOE test simply adds 3% to the seasonal performance efficiency factor. Again, the test does not evaluate the quality of the software and performance of the control, only that a sensor and control are present. For clothes dryers, the DOE test gives a credit for units with temperature or moisture controls, regardless of the sensors' design, accuracy, or the logic in which the information is used.

The present energy test procedures often discourage manufacturers from introducing new, energy-saving technologies. Such innovations may have obvious energy-saving benefits during actual use in homes but no measurable savings in the test procedure. Manufacturers have no incentive to use those innovations (unless they provide other non-energy benefits, too). A discrepancy between field and laboratory conditions will always be the case, but it appears that innovations make the discrepancy particularly large now. Essentially all major energy-consuming appliances can benefit from innovations in microprocessor control (including variable-speed drive and use of sensors). The examples above demonstrate that the energy-saving potential is still large.

Obsolete test procedures also encourage manufacturers to design and optimize for inappropriate conditions. The appliance may appear efficient in the test procedure but perform poorly in actual use. For example, US manufacturers size refrigerator compressors to perform best at 32°C rather than more common household temperature range of 20 - 25°C. In another case, an air conditioner manufacturer raised efficiency by sacrificing latent heat removal capability (which is not measured in the test). Finally, a manufacturer of washing machines set the "normal" wash setting to abnormally low-energy conditions in order to improve the unit's apparent efficiency. While optimization to unrealistic conditions is probably not a major problem, it is crucial to maintain a good correspondence between the energy test procedure and actual usage conditions.

5. The Next Generation of Energy Test Procedures

The discussion above demonstrates that current test procedures cannot accommodate important energy-saving innovations and changing international conditions. These shortcomings appear in nearly all energy test procedures, from autos to refrigerators. This suggests that the procedures should be revised en masse rather than piecemeal. The next-generation test procedures should have the following features:

• better correspondence between test procedure and actual conditions
• measurement of appliance's mechanical efficiency (insulation, compressor COP, sensors, etc.)
• measurement of an appliance's logical efficiency (software)
• increased reliance on performance-based measurements
• inclusion of standby energy consumption for intermittently-operated equipment
• recognition that the test procedure will be linked to national efficiency regulations or labels
• consistent procedures for adjustments to local conditions

It may not be possible to include all these features in every test procedure but a set of guiding principles such as those above is a reasonable first step. These principles will alert manufacturers that new, energy-saving technologies will receive more recognition which will stimulate greater activity. The systematic revision of the test procedures is a major undertaking and probably beyond the regular capabilities of ISO and other standards-setting organizations. In addition, the links to world trade and government regulations will raise coordination to a new level. For this reason, other international organizations, such as the International Energy Agency, may be needed to assist. The revision of test procedures has an important side benefit: it allows countries to harmonize to a new, single test procedure. This may encourage international harmonization activities because it avoids the awkward situation of countries surrendering their test procedures in favor of another procedure that is technically no better than the original (but is internationally accepted).

6. Conclusions

Energy test procedures generally receive very little attention from anyone besides manufacturers. Test procedures were developed and periodically modified by committees consisting primarily of manufacturers. The tests were not linked to regulations, so unusually high or low test values did not have major financial implications.

This situation has changed because economic, technological, and environmental developments are forcing new institutions to become involved. The increasing internationalization of the appliance industry, combined with reductions in trade barriers, encourages centralized production and distribution of appliances. The costs of performing a different test procedure for each country or region becomes a real non-tariff trade barrier. Multinational firms will become a strong advocate of harmonized test procedures.

Governments will be more involved with energy test procedures because the minimum efficiency regulations and label programs rely on them. These governments must ensure that all models of appliances can be fairly tested and ranked. They must also develop mechanisms for exemptions or allow alternative tests when the regular test is inappropriate. If the United States is any guide, then the ownership of test procedures will gradually shift from the test-setting bodies, such as ISO, ARI, CEN, and JIS, to government regulatory agencies.

Finally, technical innovations have increased the disparity between energy use determined by the test procedure and typical operation in homes. These are chiefly a result of microprocessor control, which can adjust the operating conditions to more closely match requirements. The existing test procedures fail to capture these savings and therefore discourage manufacturers from introducing new technologies that could reduce energy use.

In the next decade, we will see unprecedented pressure to modify and update test procedures at the same time as there will be pressure to harmonize test procedures. This situation can also be viewed as an opportunity, too. A harmonized test procedure can also be a next-generation test procedure.

Acknowledgments

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

References

Association of Home Appliance Manufacturers (1988). "American National Standard for Household Refrigerators and Household Freezers." AHAM, Rept. No. ANSI/AHAM HRF-1-1988, Chicago IL.Meier, A. K. and J. E. Hill (1997). "Energy Test Procedures for Appliances." Energy and Buildings 26(1): 22-33.Turiel, I. (1997). "Present Status of Residential Appliance Energy Efficiency Standards-An International Review." Energy and Buildings 26(1): 5-15.U.S. Department of Energy (1997). 10 CFR 430 Subpart B-Test Procedures. Code of Federal Regulations. Washington, D.C., U.S Government Printing Office.