Final Report by Electric Refrigerator Criteria Standard Subcommittee, Energy Efficiency Standards Subcommittee of the Advisory Committee on Energy May 11, 1999
Table of Contents Text of Report 2 (Attachment 1) Targeted range...5 (Attachment 2) Target fiscal year...8 (Attachment 3) Categorization for target setting and target standard values...9 (Reference 1) Differences by storage room forms...22 (Reference 2) Differences of energy consumption in cold air natural convection methods and cold air forcible circulating methods...24 (Reference 3) Total cost comparison in the case of having used Category VI Refrigerator-freezer (Those which used specific technologies in cold air forcible circulating method ones) and Category VII Refrigerator-freezer (Those other than Cateogry VI in cold forcible circulating method ones) for 12 years...25 (Reference 4) Energy savings and transition of monthly energy consumption per 1 L of the electric refrigerator...26 Energy savings and transition of monthly energy consumption per 1 L of the electric refrigerator 28 (Reference 5-1) Target standard value calculation equation every segment (graph) (as of the end of September,1998)...29 (Reference 5-2) Target standard value calculation equation every segment (graph) (at the time of final report)...36 (Reference 6) Relations between the rated internal volume and the adjusted internal volume in the Category VI Relations between the rated internal volume and the adjusted internal volume in the Category VII...43 (Reference 7-1) Product list every category (as of the end of September,1998)...45 (Reference 7-2) Product list every category (at the time of final report)...53 (Reference 8) Trial Calculation Related to Improvements for Energy Consumption...61 (Attached 4) Energy consumption test (New JIS C9801)...62 (Attached 5) History of Electric Refrigerators Criteria Standard Subcommittee...67 (Attached 6) Electric Refrigerators Criteria Standard Subcommittee, Energy Efficiency Standards Subcommittee of the Advisory Committee on Energy...68 1
The subcommittee deliberated on the criteria electric refrigerators (Electric refrigerators and electric refrigerator-freezers are included. Same as below) with respect to energy efficiency for manufacturers or importers (Hereinafter referred to as manufacturers ) of them, and summarized as follows. 1. Targeted scope Of electric refrigerators (A generic name of refrigerators and refrigerator-freezers) and electric freezers (Hereinafter referred to as Freezer ) specified in the revised JIS C 9607, the horizontal freezer is excluded. Furthermore, refrigerator-freezers having freezing compartments of one-star and two-star room types are included. (See Attachment 1) 2. Items of the standard criteria for manufacturers (1) Target year: Fiscal year 2004 (See Attachment 2) (2) Target standard value Concerning the electric refrigerators to be shipped domestically in the target fiscal year by the manufacturers, energy efficiency measured in (3) and shall be weight-averaged by the shipped quantity of each manufacturer in each segment in the following table. Then the weight average shall not be above the value obtained from weight-averaging target standard value by the shipped quantity of each manufacturer in each segment. (See Attachment 3) Category Target standard value calculation equation I refrigerator (Cold air natural convection method) E=0.427 (kwh/year L) x Vadj (L) +178 A refrigerators II refrigerator (Cold air forcible (kwh/year) circulating method) III freezer (Cold air natural convection method) E=0.281 (kwh/year L) x Vadj (L) +353 B freezer IV freezer (Cold air forcible circulating (kwh/year) method) V refrigerator-freezer (Cold air natural E=0.433 (kwh/year L) x Vadj (L) +320 convection method) (kwh/year) VI refrigerator-freezer (The one having C E=0.507 (kwh/year L) x Vadj (L) +147 used a special technology with cold air refrigerator-freez (kwh/year) forcible circulating method) er VII refrigerator-freezer (The one other E=0.433 (kwh/year L) x Vadj (L) +340 than VI with cold air forcible circulating (kwh/year) method) Note 1) E: Annual energy consumption (kwh/year) Note 2) Vadj: Adjusted internal volume (Unit: L) 1) In the refrigerator-freezer and the freezer with three-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =2.15 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 2.15 of was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -18 C and the refrigerators inside temperature of 5 C. 2
25 C - (-18 C) 43 2.15 = = 25 C - 5 C 20 2) In the refrigerator-freezer with two-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.85 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.85 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -12 C and the refrigerators inside temperature of 5 C. 25 C - (-12 C) 37 1.85 = = 25 C - 5 C 20 3) In the refrigerator-freezer with one-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.55 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.55 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -6 C and the refrigerators inside temperature of 5 C. 25 C - (-6 C) 31 1.55 = = 25 C - 5 C 20 (Reference) Three-star room: Freezing compartment in which the average freezing load temperature is -18 C or less Two-star room: Freezing compartment in which the average freezing load temperature is -12 C or less One-start room: Freezing compartment in which the average freezing load temperature is -6 C or less Note 3) Special technologies of category VI mean the inverter technology and the vacuum insulation technology, and the refrigerator-freezer having used either or both technologies shall be classified into the segment VI. (3) Measuring methods The annual energy consumption shall be the value measured by Energy consumption test (New JIS C 8901) (See Attachment 4), and this value shall be the energy efficiency. (4) Display items Display items are according to specifications in Household Goods Labeling Law. The main items are subject to the following. 1) Display items: Rated internal volume, annual energy consumption (Display unit shall be kwh/year), outer shape dimension 3
2) The name of person who is responsible for these display items shall be described in the display, and it shall be displayed on the product main body where consumers easily locate. 3) The annual energy consumption shall be expressed in an integer. (Note) To display Rated internal volume and Annual energy consumption, the revision of rules in the quality display of the electrical machinery and apparatus is required. 3. Recommendations towards energy savings (1) Efforts to be made by Users Users shall select electric refrigerator with high energy efficiency when purchasing and make efforts to reduce the use of energy by means of an appropriate and efficient use of them. (2) Efforts to be made by Manufacturers 1) Manufacturers shall make efforts to facilitate the technological development in order for energy savings of electric refrigerators, and to develop the products with high energy efficiency. 2) In order to disseminate electric refrigerators with high energy efficiency, manufacturers shall make efforts to facilitate the understandings of users about this. (3) Efforts to be made by the Government In order to disseminate the electric refrigerators with high energy efficiency, the government shall make efforts to take necessary measures for political supports and proliferation enlightenment to facilitate the approaches of users and manufacturers. 4. Others A history of holding the subcommittee meetings (See Attachment 5) Subcommittee s member list (See Attachment 6) 4
Targeted Scope (Attachment 1) 1. Targeted scope Targeted electric refrigerators shall be electric refrigerators and electric freezers specified in the revised JIS C 9607. Furthermore, at present, since clear explanation about the measurement method for the annual energy consumption of electric refrigerators does not exist in other than New JIS C 9801, this time targeted range is applied to electric refrigerators and electric freezers specified in the above-mentioned JIS. 2. About exclusions 1) Horizontal type freezers of freezers specified in the revised JIS C9607 In our country, the upright type electric refrigerators are occupied as a mainstream in its use for the reasons of small floor space. The horizontal type freezer has a special form, and a few unit productions have been continued for supply to the specific users. However, looking at its domestic production unit number in the table below, the horizontal types are 9,000 units comparing with 5.4 million units of the upright types. Thus, it accounts for only 0.16% in small percentage. In addition, even taking the import products into account, it is expected that the figure is less than 0.5%. As to the horizontal type freezers, judging from such actual conditions, we excluded it from the targeted range based on the view of Principle 1 planned by the criteria group. Domestic production unit number of electric refrigerators relevant to revised JIS C9607 (Survey of Japan Electrical Manufacturers Association in fiscal year 1997, the estimation included in a part) Electric refrigerators Classification Upright type Horizontal type freezer Production unit number (1,000 units) 5,455 9 Percentage (%) 99.84 0.16 (Note) The horizontal type freezers are in general called a chest freezer. 5
2) Absorption type There are three types using electricity, gas and petroleum as drive source, but any absorption types are used for special application such as for camping and for on-vehicle. There is no established measuring method of energy efficiency, and the production unit number is extremely limited. Therefore, they shall be out of the targeted range. (Domestic production: N/A, number of imported unit: 17,000 in fiscal year 1997) 3) Peltier type This type utilizes thermionic elements for cooling, and is used for the specific applications such as hotels. There is no established measuring method of energy efficiency, and the production unit number is extremely limited. Therefore, they shall be out of the targeted range. (8,000 units in the production unit in fiscal year 1997) Workings of absorption type Condenser (Heat dissipation) Absorption type which becomes cold when heated Evaporator (Endothermic) Ammonia liquid Concentrated ammonia gas Heater Gas and electricity can be used as heat source. Refrigerant is ammonia. Absorber is water. When ammonia liquefied by a condenser is vaporized by a evaporator, the surroundings are cooled by the endothermic action. This type is for camping and for outdoor movables because it can use in places where there is no electricity. Rare aqueous ammonia Workings of Peltier type [Structures] COLD side (Inside of freezer) Manifold (Peltier elements) HOT side (Outside of freezer) Manifold Radiator Fan motor Fan motor Radiator Pump 6
4) Commercial electric refrigerator As to commercially-used electric refrigerator, approximately 190,000 units have been produced in 1998 (Statistics of The Japan Refrigeration and Air conditioning Industry Association). However, these are typical products of small production with large variety, and there are many custom-made productions with versatile applications. For such circumstances, the measuring method of energy efficiency is difficult to be set for them. At present time, the measuring method, such as measuring and calculating energy consumption, has not been prepared. Therefore, as to commercially-used electric refrigerator, in the future, whether they should be designated as target equipment or not is examined separately while grasping the circumstances of energy consumption and considering the upgrading conditions of the measuring method of energy efficiency. 7
Target fiscal year (Attachment 2) The target fiscal year for the standard to be achieved shall be fiscal year 2004 according to the following. 1. In the light of the target of global warming gas reduction in 2010, it needs for consideration for the periods that the models, which accomplished this time s standard, disseminate. 2. In order to accomplish this time s standard, extremely large number of models needs to be re-designed. Therefore, it is necessary to consider the product development cycle of each manufacturer. For this reason, listening on the actual situation about general design development period, the development cycle of a lineup including the major models was roughly 3-5 years. 3. In addition, since it is required to abolish foaming agent (HCFC-141b) used in the insulating materials at present in order for the ozone layer protection measures by the end of 2003, each manufacturer has been replacing with other foaming agent by that time. At that time, since it is expected that newly used foaming agent may lead to increase energy consumption, the technological development and the introduction to the technology to cope with this increased portion are required. Thus, considering such circumstances, it is desired to set the target fiscal year from 2004 onward. 4. As a result of considering the above-mentioned factors, it is considered to be appropriate that the target accomplished period will be roughly 5 years later from the implementation of this system. 8
Categorization for Setting Target and Target Standard Values (Attachment 3) 1. Basic concept of categorization In the electric refrigerators, considerable differences on the energy efficiency are produced depending on the difference of structures and the difference of the introduced technology. For this reason, in setting the segments, we decided to deepen the examination considering the principle and discussions planned in the criteria group about the matters which those differences have a certain influence on energy efficiency. 2. Specific categories (1) Categorization by storage rooms The form of the storage room is roughly classified into refrigerator room and freezing room, but this form s difference will give extremely large influence on energy efficiency. For this reason, in measuring the energy efficiency, in order to reduce the amplitude of this degree of influence, the correction is performed focusing attention on the difference of the ambient temperature and the inside temperature of refrigerators, and it is converted into comparable volume (adjusted internal volume). However, this correction is stationery one so to speak, the difference in number of opening and closing doors in both storages in operating conditions, changes of ambient temperature, the degree of influence on energy efficiency by the control errors are not fully corrected. For these reasons, we decided to classify the refrigerator room and the freezing room separately, and classified into refrigerators, freezers and refrigerator-freezer. (See Reference 1) Refrigerators: Storage room of the structure which maintains the temperature (5 C or so) necessary for food other than frozen foods. Freezers: Storage room of the structure which maintains the temperature (in the case of three-star room: -18 C) necessary for storage of frozen food. (2) Categorization by cooling methods The cooling method has two main methods in the following. Since these differences of methods bring the use and disuse of exhaust heat due to the presence or absence of fan motors and the difference of thermal conductivity in principle cause the difference to energy consumption, these methods were classified. (See Reference 2) 1) Cold air natural convection methods (Direct cold type) A method which cools by circulating cold air from a cooler by natural convection in a refrigerating room and transferring the heat from the cooler in a freezing room, after equipping the cooler it the refrigerating room and the freezing room. 2) Cold air forcible circulating methods (Fan type) A method which cools by forcibly circulating cold air made by a cooler to a refrigerating room and a freezing room by a fan, after equipping the cooler in the place other than refrigerating room and the freezing room. 9
(3) Categorization by using specific technologies 1) In recent years, our country s electric refrigerators have been getting larger from the changes of the lifestyle. Also, at the same time, the products having high convenience in both functional and performance facets have been developed, and these dissemination has been progressing by acceptance from the standpoint of consumers lives. On the other hand, since such products cause much consumption of energy, manufacturers have been advancing the technological development and introduction to reduce energy costs as the product value together, considering perspectives of the prevention of global warming. As a typical technology, the inverter technology, conversion to DC of motors, high performance insulators, high efficiency of cooling ducts and the optimum control technology are included. 2) However, the large sized products which introduced such technologies are high cost, thus are high price comparing to the products which these technologies are not introduced. Studying the relationship between raising portions of prices and the reduced running cost (Reduced portions of electricity bill), it found out that the running cost reduced amounts occupying the price raising portions were roughly 35-50% (Japan Electrical Manufacturers' Association). That is, it fount out that a decrease of electricity bill can not cover the amounts of rising price by introduction to the specific technology. 3) For this reason, the segmentation focused attention on the above-mentioned technological differences shall be provided from the principle 5 planned in the criteria group. Furthermore, there exist many technical items and convenient function items, but technological inputs are duplicated, and convenient functions are basically based on those technologies. Therefore, by eliminating these technologies as much as possible to simplify the segmentation, we classified the technological difference depending on the presence or absence of the inverter technology and the presence or absence of the vacuum insulation materials. 4) Furthermore, manufacturers make efforts to accomplish the target standard value determined for each segment; as a result, many products reach the target level. Then, it is expected that the products not reaching the target level will disappear from in the market. For this reason, in comparing the price of the above-mentioned 1) and 2), it is more appropriate that the comparison is made with the current top runners (Products near the target level) from each segment, but not with arbitrarily selected models. At the same time, we also considered the agreement of adjusted internal volume in the specific work. In addition, many of the products having adopted the inverter technology and the vacuum insulation materials have additional functions which are not included in products without these technologies. In comparing the price, from the viewpoint of the fair comparison, it is important to match the functional level deducting such additional functions, and we paid fully attention to this point. * Comparison of total cost when Category VI refrigerator-freezers (those utilize the specific technology with cold air forcibly circulating methods) and Category VII refrigerator-freezers (those other than ones in Category VI with cold air forcibly circulating method) had been 10
used for 12 years (See Reference 3) (4) Summarizing the above-mentioned (1) - (3), the segmentation for the target setting become as follows. Category I: Refrigerators (Cold air natural convection method) Category II: Refrigerators (Cold air forcibly circulating method) Category III: Freezers (Cold air natural convection method) Category IV: Freezers (Cold air forcibly circulating method) Category V: Refrigerator-freezers (Cold air natural convection method) Category VI: Refrigerator-freezers (Those used the specific technology with cold air forcibly circulating method) Category VII: Refrigerator-freezers (Those other than VI with cold air forcibly circulating method) Note) The limitation by the adjusted internal volume should not be set. 3. Setting of target standard values (1) Basic concept for setting target standard values The target standard values shall be set by the target standard value calculation equation every category based as the follows. 1) We compiled an interim report based on the actual value of the annual energy consumption obtained from the new measuring method at the end of September 1998. However, in the target standard value, the latest data shall be incorporated as much as possible, and they shall be set adding the modification to the interim report from the data at the time of March 1, 1999. 2) For the products which improvements by progress of the future technology by the target accomplished year can be surely expected, the target standard value expecting the improvements shall be set at the utmost. 3) The target standard value shall be set using the relational expression setting the adjusted internal volume as variable for each category. 4) The target standard value shall not have contradiction between categories. (2) Future technological developments and development space 1) Energy savings technologies related to electric refrigerators basically constitute three technological improvements of cooling technology, insulation technology and control technology. To date, various improvements for drive motors, structures of compressors and forms of heat exchangers have been made, but improvements for these element technologies are getting near the limit, and in the future, even if a little improvement have been performed, it is a situation where an innovative technological development can not be expected. On the other hand, the products, which are the results of these various energy savings technologies reaching near limit, have realized the maximum energy efficiency at the present in each category. 11
Therefore, in the future, even if the demand trends and constraints due to manufacturing costs are available, it is important task to input these various energy savings technologies to many products wherever possible. Improvements for each fundamental technologies and prospects of the future are as follows. A. Introduction to inverter technology Improvements for the motor efficiency are attempted by changing the motor for compressor drive from the conventional AC induction motor to DC brushless motor of variable rotation number. The DC drive compressor are enabled to process more much information in digital directly through the high performance microcomputer, thus high accuracy control is realized for the purpose of efficiency improvements. However, the DC brushless motor forming the center of these efficient improvements reaches the maximum level as the efficiency of the motor in size adopted to electric refrigerators. It is a situation that development of the motor better than current level becomes difficult including the cost facets. B. Conversion to DC motor of fan motors The cold air blast fan motor and the fan motor to cool the heat exchanger for condensation are mounted to electric refrigerators. These fan motors give a large influence on energy consumption as heat load. For this reason, reduction of heat load is attempted converting AC motor being conventionally utilized to DC brushless motor. Motor for cold air blast fan Motor for condenser fan AC motor AC motor DC motor (Conventional) (Conventional) DC motor Input (W) 5.7/6.8 1.2/1.2 6.9/5.6 0.8/0.8 (50/60Hz) 12
However, development of small sized DC motor used in the condition under freezing points reaches the limit, development to improve further efficiency is difficult. Stator Rotor Stator Coil Magnet Coil AC motor DC motor C. Performance improvements of heat exchangers Improvements for heat exchange efficiency is attempted by adopting the tube with internal grooves to the refrigerant pipes of heat exchanger. However, the grooved structure of internal tubes face is also getting near the limit in terms of processing, and it is a situation that further improvements become very difficult in the future. With internal grooves (Inner line) 13
D. Optimization of cold air trunk An appropriate cold air distribution has been attempted by installation of electronicallycontrolled damper (Flap controlling cold air flow), as well as by smoothing a flow of cold air, which is achieved by reducing pressure loss due to optimizing the forms within the cold air trunk. Also, we have addressed a large increase of air volume by optimizing the fan forms. However, the request of users expecting a product with large internal volume to the utmost for a certain outer dimension; as a result, it is difficult to further expand the cold air trunk. Therefore, it is also difficult to reduce the draft resistance more than the present level. Optimization of cold air draft (Motor damper) Motor damper (Stepping motor) E. Adoption of cooler specific to refrigerating room and freezing room Providing coolers for both refrigerating room and freezing room, it is possible to improve the efficiency of compressors by increasing the evaporation temperature of the cooler of refrigerating room than that of cooler of the freezing room. This technology is possible to apply to a part of high price zone products. Since the production cost will rise sharply, it is difficult to apply to all products. Cold air blast fan (variable) Air volume adjustment by a damper Cooler for refrigerating room only Refrigerating room Refrigerating room Cooling mode switch valve Refrigerating room Refrigerating room Refrigerating room only cooler Inverter compressor Inverter compressor 14
F. Heat leak reduction from peripheral packing Packing is equipped for sealing between the door and the box body. The material, thickness and forms of this packing will give a large influence on the condition of heat leak and heat intrusion. Basically effective measures that make it difficult to leak cold heat by means of adjusting the packing form which can be achieved by decreasing insulation area between the door and the box body. Up to the present, the heat leak of this part is largely reduced by reduction in thickness of packing and the adjustment of the forms. Also, the load to the freezing cycle has been reduced. However, thickness and durability of packing are getting near the limit, and also the adjustment of forms have been conceived in various ways up to the present. It is in a difficult condition to improve further. Example of heat leak reduction by changing forms Intrusion heat volume difference by presence or absence of fins of packing No fins Fins available Packing intrusion heat volume (W) 4.7 4.4 Ratio (%) 100 93.6 G. Insulation technology (i) Thermal conductivity is desired to be small to the utmost in the gaseous phase condition of rigid polyurethane insulation materials, and the insulation performance has been improved by miniaturizing bubble diameter and by decreasing the convective heat transfer within bubbles. However, as to thermal conductivity of foaming agent which is the largest factor to determine the insulation performance, since the global environmental protection measures (Reduction of ozone depletion materials and global warming materials) are given priority, thermal conductivity are undergoing a transition as the following table. Used periods 1970 1990 1997 Name of foaming agent CFC-11 HCFC-141b Cyclopentane Boiling point ( C) 24 32 49 Gaseous phase thermal conductivity (mw/m/k (40 C)) 9.1 11.3 15.3 (60 C) ODP 1.0 0.11 0 GWP 4000 630 3 (Note) ODP: Ozone layer depletion potential, GWP: Global warming potential As the above table shows, the gaseous phase thermal conductivity of usable foaming agent has been decreasing. Also, making high boiling point of foaming agent gases is to facilitate the deterioration of thermal conductivity due to liquefaction in cooling. In this way, the situation is stringent in the field of the insulation technology, but it is not necessarily obvious that there is a prospect of a new technology to break through such circumstances. 15
(ii) Adoption of vacuum insulation materials In combination with the complex insulation system of vacuum insulation materials having high insulation properties and conventional urethane insulation materials, it is possible to largely reduce heat load. However, since the vacuum insulation materials can not be used in single unit to maintain the box body strength and also the production cost is high. Although this material has been adopted in a part product, it is in a difficult condition to apply to all products. Top face Laminated aluminum evaporated film Adhesion Vacuum insulation materials Arrow direction Side face Cross section magnified drawing Cross section drawing Rear face Outside box General urethane insulating materials Inner box 2) Decrease of efficiency associated with substitution requests for Freon as refrigerant and insulating material Manufacturers are pressing for development of refrigerant and insulating materials in replace of currently used HFC, HCFC refrigerant and HCFC insulating materials in response to protection of ozone layers and global warming. The products having used insulating materials without Freon have been developed in part. If the substitute refrigerant and insulating materials are used, a decrease of the energy efficiency of products is expected. The decrease degree is roughly 10-15% or so. 3) Improvements for energy efficiency As shown in the above, it is considered that the development of the element technology for energy savings reaches the maximum level, and at present time. If these energy savings technology which are applicable beyond those categories can be smoothly applied to as many products as possible, large improvements for the energy efficiency can be expected. In addition, a decrease of the energy efficiency can be expected through facilitation of conversion into new refrigerants and new insulating materials in the future as indicated in 2), but further improvements for the energy efficiency are considered to be severe in such a situation. Considering such circumstances in a general viewpoint, since it can not be expected surely to largely improve the present energy efficiency by the technological development, it is appropriate to 16
make efforts towards achievement of target standard values which are set according to the products with the most excellent in energy efficiency in each category. * Transition of energy savings technologies and monthly energy volume per 1 L of electric refrigerators Major energy-saving technologies contribution to reduction of power consumption of refrigerator-freezer mainly in Category VI and VII (Compared with conventional machine) (See Reference 4) (3) Setting of target standard values In order to understand the characteristics of the product distributions, based on the concept of (1) and (2), first of all, the target standard value is set as below using the data as of the end of September 1998. (See Table 1-1, Reference 5-1, Reference 6, Reference 7-1) 1) In the target standard value calculation equation, since annual energy consumption correlates with the adjusted internal volume, the annual energy consumption is expressed as a linear equation with the adjusted volume as a variable. As a principle, this equation is determined for every category according to the following procedure. Classify the adjusted volume by every 50 L, and set the energy efficiency of the most efficient product as the top value in the category. Then, simply recurs these top value group (As to the category I, take the whole values since the model number is few), and determine a slope of the equation. Next, after fixing this slope, determine the intercept so that any top values do not exist below the line generated from the equation. The target standard calculation equation shall be set. 2) As to Category II and V, the above-mentioned principle can not be applied because there is no input of products at present, or there is few. For this reason, the equation of the relevant category is set considering the difference of the equations and the cooling methods between the categories of the products with the most similar storage room forms. Equation of Category V Looking at the approximate categories focusing attention on the form of storage room of the products in Category V, it seems that the similar refrigerator-freezer in Category VI and VII are referable. Next, looking at the cooling method of products in Category VI and VII, it seems that products in Category VII is relatively the most approximate to ones in Category V, because both are not using specified technologies, from the viewpoint of the presence or absence of the technologies. For this reason, the slope of the equation for Category V is set as 0.487. Find the tangent to the top value (Top value is only one classification) of Category V with this slope, and the target standard value calculation equation for Category V is set (as indicated in the table below). Equation of Category II Since the products do not exist in this category, the method for fixing the intercept by using 17
the tangent, which is adopted for products in Category V, can not be utilized. Estimating the product input to Category II, it is expected that it will be relatively small as in Category I. It is because the product input conditions in Category I of products with the same form of storage room as ones in Category II is few as 16 in the number of product, and because the adjusted volume of products in Category I focuses on roughly 50-100 L. Since to plan a new calculation equation by estimating in the range of such limited small internal volume is considered to unnecessarily appropriate, as a second best policy, the target standard value calculation equation of Category I shall be applied as it is to Category II.. 3) As for freezers in Category III and IV, when determining the target standard value calculation equation with the procedure described in 1) above, the equations will be E =0.253 Vadj + 360 for Category III, and E=0.709Vadj +251 for Category IV. However, since these calculations have little basic value numbers in order to determine the volume distribution of the products and the regression equation, it can not be judged that it is an appropriate equation. Also, there is extremely few of 6 in the product number in Category III, it seems difficult to set a reliable calculation equation based on these numerical values. For this reason, as a second best policy, as to Category III and IV, it is adopted to determine the calculation equation according to the procedure of 1) by means of putting together the product group of both categories. (Table 1-1) Category Target standard value calculation equation I refrigerator (Cold air natural convection method) E=0.427 (kwh/year L) x Vadj (L) +178 A refrigerators II refrigerator (Cold air forcible (kwh/year) circulating method) III freezer (Cold air natural convection method) E=0.281 (kwh/year L) x Vadj (L) +353 B freezer IV freezer (Cold air forcible circulating (kwh/year) method) V refrigerator-freezer (Cold air natural E=0.487 (kwh/year L) x Vadj (L) +324 convection method) (kwh/year) VI refrigerator-freezer (The one having E=0.626 (kwh/year L) x Vadj (L) +181 C used a special technology with cold air (kwh/year) refrigerator-freezer forcible circulating method) VII refrigerator-freezer (The one other than VI with cold air forcible circulating method) E=0.487 (kwh/year L) x Vadj (L) +382 (kwh/year) Note 1) E: Annual energy consumption (kwh/year) Note 2) Vadj: Adjusted internal volume (Unit: L) 1) In the refrigerator-freezer and the freezer with three-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =2.15 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 2.15 of was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -18 C and the refrigerators inside temperature of 5 C. 18
25 C - (-18 C) 43 2.15 = = 25 C - 5 C 20 2) In the refrigerator-freezer with two-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.85 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.85 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -12 C and the refrigerators inside temperature of 5 C. 25 C - (-12 C) 37 1.85 = = 25 C - 5 C 20 3) In the refrigerator-freezer with one-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.55 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.55 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -6 C and the refrigerators inside temperature of 5 C. 25 C - (-6 C) 31 1.55 = = 25 C - 5 C 20 (Reference) Three-star room: Freezing compartment in which the average freezing load temperature is -18 C or less Two-star room: Freezing compartment in which the average freezing load temperature is -12 C or less One-start room: Freezing compartment in which the average freezing load temperature is -6 C or less Note 3) Special technologies of category VI mean the inverter technology and the vacuum insulation technology, and the refrigerator-freezer having used either or both technologies shall be classified into the segment VI. Next, in order to reflect the data of new products after October 1998, the final target standard value is set by means of modifying the above-mentioned target standard value with using the data as of March 1, 1999. (See Table 1-2, Reference 5-2 and Reference 7-2) 4) As for Category I, II, III and IV where new Top Runners did not emerge during October 1998 to March 1, 1999, the calculation equation obtained from the above process was provided as a final target standard value calculation equation as it is. 5) As for Category VI and VII where new Top Runners emerged during October 1998 to March 1, 1999, the calculation equation shall be set so that improvement ratio of the most improved 19
product can be determined in all adjusted internal volume segments. It is adopted as the final target standard value calculation equation. 6) As for Category V, new Top Runner did not emerge, but according to the concept described in 2), determine the tangent to the top value (Top value is only one breakpoint) of Category V with the slope of the new calculation equation for Category VII. It is set as the final target standard value calculation equation for Category V. (Table 1-2) Category Target standard value calculation equation I refrigerator (Cold air natural convection method) E=0.427 (kwh/year L) x Vadj (L) +178 A refrigerators II refrigerator (Cold air forcible (kwh/year) circulating method) III freezer (Cold air natural convection method) E=0.281 (kwh/year L) x Vadj (L) +353 B freezer IV freezer (Cold air forcible circulating (kwh/year) method) V refrigerator-freezer (Cold air natural E=0.433 (kwh/year L) x Vadj (L) +320 convection method) (kwh/year) VI refrigerator-freezer (The one having C E=0.507 (kwh/year L) x Vadj (L) +147 used a special technology with cold air refrigerator-freez (kwh/year) forcible circulating method) er VII refrigerator-freezer (The one other E=0.433 (kwh/year L) x Vadj (L) +340 than VI with cold air forcible circulating (kwh/year) method) Note 1) E: Annual consumption electric energy (kwh/year) Note 2) Vadj: Adjusted internal volume (Unit: L) 1) In the refrigerator-freezer and the freezer with three-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =2.15 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 2.15 of was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -18 C and the refrigerators inside temperature of 5 C. 25 C - (-18 C) 43 2.15 = = 25 C - 5 C 20 2) In the refrigerator-freezer with two-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.85 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.85 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -12 C and the refrigerators inside temperature of 5 C. 25 C - (-12 C) 37 1.85 = = 25 C - 5 C 20 20
3) In the refrigerator-freezer with one-star room type of freezing compartment, the numerical value is determined by the following equation. Vadj =1.55 x V (Rated internal volume of the freezer) + V (Rated internal volume of storage room other than freezing room) The coefficient 1.55 was determined by the following calculation considering the respective difference of the outside air temperature of 25 C and the freezers inside temperature of -6 C and the refrigerators inside temperature of 5 C. 25 C - (-6 C) 31 1.55 = = 25 C - 5 C 20 (Reference) Three-star room: Freezing compartment in which the average freezing load temperature is -18 C or less Two-star room: Freezing compartment in which the average freezing load temperature is -12 C or less One-start room: Freezing compartment in which the average freezing load temperature is -6 C or less Note 3) Special technologies of category VI mean the inverter technology and the vacuum insulation technology, and the refrigerator-freezer having used either or both technologies shall be classified into the segment VI. 4. Improvement effects in the target fiscal year In the improvement of energy consumption from the actual results in fiscal year 1998 when the target standard value of 3 above was set, given a calculation under the certain assumption, approximately 30% improvements are estimated in the target fiscal year (2004). (See Reference 8) 21
Differences by storage room forms (Reference 1) Thickness of insulating materials Defrosting device Anti-icing system Evaporation temperature of cooler Number of opening and closing doors Refrigerator 30mm N/A N/A -5 C Many Freezer 50mm Available Available -27 C Few 30mm Refrigerator-fre ezer (Refrigerating room) 50mm (Freezing room) Available Available -27 C Many (For thickness of the insulating material and the evaporation temperature of cooler, the average values are adopted.) Used purposes Refrigerator: mostly to store food for the short period Freezer: mostly to store frozen food for the long period Refrigerator-freezer: Suitable for large sized and large capacity storage Insulating materials: Freezer: Thick insulating materials are required to prevent dew from attaching to the outer surface Refrigerator: Thinner insulating materials are possible comparing to freezers Freezer Refrigerator Selection standards for thickness of insulating materials: Thinner wall insulating materials are required to use in order to secure the internal volume as much as possible in view of the Japanese house circumstances under the condition that condensation does not occur on the outer surface. Defrosting devices Refrigerator: Since the inside of refrigerators is plus temperature (5 C), it is the off cycle defrosting (Natural defrosting is general during the operation stops). Freezer: Since the inside of refrigerators is minus temperature (-18 C), forcible defrosting by using a heater or the natural defrosting (foods has to be removed) in several times a year is required. Refrigerator-freezer: A periodical forcible defrosting by a heater is required for freezing room. Various Anti-icing systems Refrigerator: Special systems are not required. Freezer: Freezing prevention is required. 22
Refrigerator-freezer: A heater to prevent frost for safety is required because there are boundary areas between the plus temperature and the minus temperature in the freezing cycle. Cooler evaporation temperature Refrigerator: Refrigerant compression ratio is low and efficiency is good. Freezer: Refrigerant compression ratio is high, and efficiency is disadvantageous comparing to that of refrigerator. Refrigerator-freezer: Same as freezers (Forcible circulating methods are controlled by a volume of cold air flow). Frequency of opening and closing doors Refrigerator: The number of opening and closing doors is frequent. However, since the difference in the temperatures between the inside and outside of refrigerators is relatively small, there is little influence from it. Freezer: The difference in the temperatures between the inside and outside of freezer is large. However, since the frequency of opening and closing doors is relatively few, there is little influence from it. Refrigerator-freezer: In the forcible circulating method, since cold air circulates, frosts are easy to attach to coolers of freezing room. The influence from the frost formation due to opening and closing doors and humidity is large. 23
(Reference 2) Differences of Energy Consumption Volume in Cold Air Natural Convection Method and Cold Air Forcible Circulating Method The following is the general difference of energy consumption according to cooling methods, taking an example of the 200 L class of rated internal volume involved in refrigerator-freezers in Category V and VII. 1. Power consumption requiring for driving fans Input 4.5~9.0W x 2 (Input heat exhaust for the input portion) x 24h/day x 0.5 (Operation rate) =108 ~216Wh/day x 365 days/ year = 40~80 kwh/year 2. Power consumption requiring for defrosting heaters Input 130~150W x 2 (Input heat exhaust for the input portion) x 0.5h/day (Energization time/day) =130~150Wh/day x 365 days/year = 48~55 kwh/ year 3. Annual energy consumption differences on theory between cold air natural convection method and cold air forcible circulating method 88~135 kwh/year Category V refrigerator-freezer (Ones with cold air natural convection method) Category VII refrigerator-freezer (Ones with cold air forcible circulating method, except those in Category VI ) Draft port Cooling pipes Wind inlet Wind inlet Fin tube cooler Fan Fan motor Damper thermo Draft port 24
(Reference 3) Comparison of Total Cost in the case of having used Category VI Refrigerator-freezer (Those which used specific technologies in cold air forcible circulating method ones) and Classification VII Refrigerator-freezer (Those with cold forcible circulating method, except ones in Category VI) for 12 years Methods of cost comparison In comparing the cost, we compared after adjusting the technological and functional levels wherever possible by deducting the additional functions in order to make efforts for a fair comparison of these categories. To be more specific, the comparison is performed according to the following procedure. Furthermore, the reason why to set the used periods as 12 years is subject to the Consumers' behavior survey by the Economic Planning Agency in 1997. 1) At first, performing the first adjustment of technological and functional level, it is estimated that the top runner product of each category is the product having mounted energy savings technologies and convenience functional technologies other than the inverter technology and the vacuum insulating technology wherever possible. Therefore, it is considered that roughly levels about the technology other than the inverter technology and the vacuum insulating technology can be integrated by selecting the top runner product from each category. 2) Next, focus attention on the presence or absence of the automatic ice machine and the differences of door numbers as the functions which the above adjustment could not be made, the cost level is adjusted in order to attempt the level integration. Then, the comparison between total costs shall be made. 3) Furthermore, in other than the above-mentioned functions, the functions such as independent vegetable rooms, specific low temperature rooms, freezing corners, folded shelves, antimycotic, antimicrobial and silent running are included. With some exceptions, since such functions have been adopted widely regardless of the top runner product and regardless of these two categories, complex adjustment regarding these functions is no adopted. Adjusted internal volume (L) 401-450 Category Order of energy efficiency in the category Manufacturers Specific technologies Inverter Vacuum insulation Adjusted internal volume (L) Energy consumption volume (kwh/year) (2) Annual energy consumption per 1 L of adjusted internal volume (kwh/year/l) (2)/(1) Suggested retail price (Yen) Functions Automatic ice machines Number of doors Prices after adjusting the functional differences (Yen) Price differences after adjusting the functional difference (Yen) (3) Cost differences in energy consumption after 12 years (Yen) (4) VI 1 Company A (x) 406 520 1.28 190,000 4 a 188,000 - - - - VII 1 Company B (y) 429 620 1.45 120,000 3 b 120,000 (a-b) 68,000 27,600 40,400 29.6 (3)-(4) Number of year (Year) 451-500 501-550 551-600 VI 1 Company D 496 550 1.11 220,000 4 c 212,100 - - - - VII 1 Company E 472 650 1.38 160,000 4 d 160,000 (c-d) 52,100 27,600 24,500 22.7 VI 1 Company D 534 570 1.07 240,000 4 e 229,000 - - - - VII 1 Company C 515 680 1.32 160,000 3 f 160,000 (e-f) 69,000 30,360 38,640 27.3 VI 1 Company A 589 550 0.93 350,000 3 g 337,400 - - - - VII 1 Company G 557 690 1.24 265,000 4 h 262,400 (g-h) 75,000 38,640 36,360 23.3 (Prepared by the data of the end of September 1998) (Note) Suggested retail price: As to the products which are open price at present, original suggested retail prices are adopted. Prices after adjusting the functional differences : In order to adjust the automatic ice machine and number of doors, manufacturing costs for these functions are subtracted from suggested retail prices. Price difference after adjusting the functional differences: Differences between prices of category VI and VII products after adjusting the level as much as possible. Cost differences in energy consumption after 12 years: Differences of cost for energy consumption after 12 years of use between the two products compared (Calculation example by model name (x) and (y)) Differences of annual energy consumption volume: (620-520) (kwh/year) = 100kWh/year Differences of energy consumption volume after 12 years: 100kWh/year x 12 years =1,200kWh Differences of cost for energy consumption after 12 years: 1,200kWh x yen 23 / kwh =Yen 27,600 * 23 Yen /kwh: Unit price specified in Fair competition rules related to the labeling of household electric appliances authorized based on the Act against Unjustifiable Premium and Misleading Representation by Fair Trade Commission 3)- 4): Within price differences after adjusting the functional difference (the cost difference at first), the amounts which are not covered by the decrease of electricity bill. Number of year: For two products compared, it is the number of years to use Category VI products in order to resolve the original price. (Calculation example by model (x) and (y)) Price differences after adjusting the functional difference (the cost difference at first) Difference in annual cost for electricity = Number of years Yen 68,000 [(620-520)kWh/year x 23 Yen /kwh ] =29.6 years 25