GB 24849-2017Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades for Household and Similar Microwave Ovens (English PDF)

Foreword

This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard replaces GB 24849-2010, Minimum Allowable Values of Energy

Efficiency and Energy Efficiency Grades for Household and Similar Microwave Ovens.

Compared with GB 24849-2010, the major changes are as follows, in addition to

editorial changes.

-- the definition of efficiency for microwave ovens is added (see 3.1);

-- the off mode (see 3.4; 3.5 of edition 2010) and standby mode (see 3.5; 3.4 of

edition 2010) are redefined;

-- the basic requirements are deleted (4.1 of edition 2010);

-- the definition of and requirements for "evaluating values of energy conservation"

are deleted (3.2 and 4.7 of edition 2010);

-- the calculation formula of microwave ovens is moved to the text part (Article 4;

A.2.2 of edition 2010);

-- the energy efficiency grades are adjusted from 5 energy efficiency grades in the

original standard to 3 energy efficiency grades (see 4.1; 4.2 of edition 2010);

-- the expression of heating time t in the calculation formula of efficiency for

microwave ovens (see 4.2) and the determination method for heating time (see

A.2.1) are explained;

-- the method for the determination of the geometrical centre of the chamber of

microwave ovens is added (see B.3);

-- the test methods for the off-mode power and standby-mode power are modified

(see Annex C; Annex C of edition 2010).

This Standard was proposed by the National Development and Reform Commission

Resource Saving and Environmental Protection Department and the Ministry of

Industry and Information Technology Energy Saving and Comprehensive Utilization

Department.

This Standard shall be under the jurisdiction of the National Standardization Technical

Committee on Energy Base and Management (SAC/TC 20).

The drafting organizations of this Standard. China National Institute of Standardization,

Guangdong Midea Kitchen Appliances Manufacturing Co., Ltd., China Household

Electric Appliance Research Institute, China Standard Certification (Beijing) Co., Ltd.,

Ningbo Fotile Kitchen Ware Co., Ltd., Hangzhou Robam Electrical Appliances Co., Ltd.,

Guangdong Glanz Group Co., Ltd., Panasonic Appliances Microwave Oven (Shanghai)

Co., Ltd., Whirlpool (China) Co., Ltd., Vkan Certification and Testing Co., Ltd., China

Quality Certification Centre South China Laboratory, Shanghai Institute of Quality

Inspection and Technical Research.

1 Application Scope

This Standard specifies the minimum allowable values of energy efficiency, efficiency

grades, test methods and inspection rules for household and similar microwave ovens

(hereinafter referred to as microwave ovens).

This Standard applies to microwave ovens of maximum rated input power 2 500 W

and below, including combination microwave ovens, which heat materials and foods in

the chamber with the electromagnetic energy of ISM frequency band, 2450 MHz, and

resistive electrical heating elements.

This Standard does not apply to commercial microwave ovens, industrial microwave

ovens and microwave ovens with range hoods.

NOTE ISM frequency band is the electromagnetic frequency range which was decided by the

International Telecommunications Union (ITU) and adopted in the standard numbered CISPR

11 The standard was developed by the International Special Committee on Radio Interference

(CISPR).

2 Normative References

The following referenced documents are indispensable for the application of this

document. For dated references, only the edition dated applies to this document. For

undated references, the latest edition of the referenced documents (including all

amendments) applies to this Standard.

GB 4706.21, Household and Similar Electrical Appliances – Safety – Particular

Requirements for Microwave Ovens Including Combination Microwave Ovens

GB/T 18800, Household Microwave Oven – Methods for Measuring Performance

3 Terms and Definitions

For the purposes of this document, the following terms and definitions and those

defined in GB 4706.21, GB/T 18800 and IEC 62301 apply.

3.1

efficiency for microwave ovens

The ratio of the effective output energy to the input energy of microwave ovens,

expressed in %.

3.2

minimum allowable values of energy efficiency for microwave ovens

The minimum allowable values of energy efficiency of microwave ovens under the

testing conditions specified in this Standard, provided that the standby power, off power

and maximum allowable values of energy consumption for grill-function are met.

3.3

maximum allowable values of energy consumption for grill-function

The maximum allowable values of energy consumption for the grill function of

microwave ovens under the testing conditions specified in this Standard, in W·h.

3.4

off mode

The mode in which microwave ovens are connected to power supply but do not provide

any standby or main functions. The indicator lamps only used to indicate microwave

ovens are also in the off mode.

4 Energy Efficiency Grades

5 Technical Requirements

The minimum allowable values of energy efficiency for microwave ovens are of energy

efficiency grade 3 specified in Table 1.

6 Test Methods

The test conditions and methods for the determination of the efficiency values of

microwave ovens are as specified in Annex A.

7 Inspection Rules

The samples for the type inspection of efficiency are 3 sets for each batch, including 2

sets for test and 1 set as standby.

Annex A

(Normative)

Test Method for Efficiency for Microwave Ovens

A.1 Test conditions

A.1.1 Test environment

The test shall be conducted in a site. there is no forced-convection air; the

environmental temperature is 20°C ± 5°C; the relative humidity is 45% ~ 75%.

A.1.2 Test power supply

The microwave ovens to be tested are powered at the voltage 220 × (1 ± 1%) V and

the frequency 50 × (1 ± 1%) Hz; the total harmonic distortion shall not be greater than

5%.

A.1.3 Measuring apparatus

When water temperature is measured, the accuracy of the temperature measuring

system used shall be ± 0.5°C within the temperature range of 0°C ~ 50°C.

A.1.4 Arrangement of microwave ovens to be tested

The microwave ovens to be tested shall be placed on a horizontal platform of plywood,

which is about 20 mm in thickness and coated with matt black paint.

A.2 Test method

A.2.1 Microwave output power

During the measurement, pour water into a glass container as the load with the initial

water temperature lower than the environmental temperature; use the microwave

ovens to heat to approximately the environmental temperature. The step shall ensure

the minimum effects on the heat loss and heat capacity of the container. Therefore,

consideration shall be given to correction factor. In a word, the step requires accurate

measurement of water temperature.

......