Electric Storage Tank Boiling Water Heaters:

Energy Efficiency Criteria and Labeling Method for Electric Storage Tank Boiling Water Heaters

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Energy Efficiency Criteria and Labeling Method for Electric Storage Tank Boiling Water Heaters

No. En-Tech 10205017171
Promulgated and in effect on October 2, 2013

I. Electric Storage Tank Boiling Water Heaters(“products”) applying for Energy Label Certification shall meet the following requirements on scope, energy consumption test conditions and methods, and energy consumption criteria:

1. Scope: Products shall meet the requirements of CNS 3765-15, and the following specifications:
Voltage: 250 Volt (V), Single-Phase
Current: 60 Ampere (A)
Storage Capacity: under 500 liter (l)

2. Test Conditions:
(1) The ambient temperature shall be at 25±1℃. All surfaces of the machine to be tested shall keep a distance of over 300 mm from surrounding walls of the test chamber.
(2) The wind speed during the test shall be less than 0.5m/s. The relative humidity shall be less than 85%.
(3) Test voltage: 110V±2% or 220V±%

3. Test Methods:
(1) Container effective capacity test: Turn on the electric water machine, and add water into the container until the water reaches the high level mark. Measure and record the mass (kg) of water added, and convert the data to container effective capacity V (liter, l) using the following formula:
V=(M/ρ)×1,000
where ρ is the water density (kg/m³)

(2) Average water temperature measurement:
i. Turn on the electric storage tank boiling water heaters, and add ambient temperature water into the container until the water reaches the high level mark. Insert the thermometer into the container through the vent hole or water level detector installation port.
ii. Location for temperature measurement: The location for temperature measurement varies according to the shape of the water container. For cylindrical or cuboidal container, the thermometer shall be placed at two-third of the height of container from the bottom. For spherical container, the thermometer shall be placed at the center of the sphere.
iii. Keep the water in the container at high level mark for temperature measurement, and set the thermostat to maintain the water temperature at 97℃±2℃.
iv. Turn on the heater and wait for the water temperature to reach set temperature. Let the hot water machine operate steadily in the warm-keeping mode, and record the following data which cover several complete temperature cycles during the test period.

A. Test period t₁ (hr): t₁ shall be greater than 24.
B. Average water temperature T_i(℃) as the heater is switched on
C. Average water temperature T_f(℃) as the heater is switched off
D. Average water temperature of the container TW (℃): TW =(T_i+T_f)/2。
E. Electricity consumption during the test period Et₁(kWh)。

(3) Calculation of standardized 24-hour warm-keeping electricity consumption:
i. 24-hour warm-keeping electricity consumption E₂₄(kWh):

where t1 is the total time used for measuring electricity consumption in warm-keeping mode.

ii. Standardized 24-hour warm-keeping electricity consumption E_st,24 (kWh):

where TW (℃)is the average water temperature of the container in the warm-keeping mode; and Tamb (℃) is the average ambient temperature.

4. Energy consumption criteria: Standardized 24-hour warm-keeping electricity consumption E_st,24shall not be higher than E=0.0329×V+1.0839, where V is the measured container effective capacity.
5. Storage-type electric hot water machines applying for the Energy Label Certification shall submit the continuous water temperature records. The water output temperature shall be higher than 95℃.

II. Notes on product labeling

1. The name and address of the label user shall be clearly displayed on the product or product packaging.
2. If the label user is an agent, the name and addresse of the manufacturer shall also be displayed on the product or product packaging.
3. The product catalog shall display the container effective capacity V (l) and usable capacity (L) and standardized 24-hour warm-keeping electricity consumption E_st,24.
4. The value of the container effective capacity shall be rounded to one decimal place.
5. The value of the standardized 24-hour warm-keeping electricity consumption E_st,24shall be rounded to four decimal place.