The inhabitants of towns and small cities in northern China used to put coal stoves in their living rooms. The stoves would heat the room and cook food in the traditional way. The problem with these stoves was that they used large amounts of coal and created a lot of smoke. Sometimes, the stoves would release carbon monoxide gas into the room and this would seriously affect people's health. In the 1980s, China began to research coal stoves for cooking and heating purposes. The stoves were redesigned so that they could be used in the kitchen instead of the living room. Heat was transferred to the living room through water pipes, and the carbon monoxide danger was reduced by redesigning the stove. Now, more than 500 000 of these stoves have been distributed in China and there are dozens of coal stove manufacturers. Because of an increase in the population, the number of cooking and heating stoves sold annually is increasing. At first, some coal stove factories suffered from low skill levels and poor management, which resulted in poor quality goods entering the market. This resulted in lack of confidence among consumers and economic losses for the country. Urgent measures were needed to formulate a method for testing cooking and heating coal stoves.

In 1992, the Chinese Academy of Agricultural Engineering Research and Planning was requested by the Ministry of Agriculture to set a National Standard for testing household cooking and heating coal stoves. Institutes and stove manufacturers were required to test the thermal performance of products and to improve the quality of the stoves so that they meet set requirements.

Features of the improved stove

  • Water flows through the heating system without a water pump or electricity. This is especially useful in regions that use the stoves but are without electricity (Figure 1).
  • The heating system is simple and can be operated and maintained with ease.
  • The average temperature of water in the radiators is around 70°C. This makes people feel comfortable.
  • When the stove is closed during the night, the water in the heating system is still flowing slowly. The room temperature therefore does not drop too steeply.
  • The stoves can also provide hot water for baths.

Figure 1: Schematic drawing of heating system and (inset) improved coal stove
!!A new kind of cooking and heating stove
Figure 2: Schematic drawing of stove

Model AIYI High Efficiency Household Stove is a patent product that was designed and developed by the AIYI Development Corporation, Beijing, China (Figure 2). It is designed to optimize conduction, radiation and convection using heat transfer principles. This product has the following advantages:
  • High efficiency and large capacity. When compared to ordinary stoves, it saves about one ton of coal for each family for a winter in northern China.
  • Good thermal insulation.
  • The system is clean. The coal is held in a closed inner compartment, so that the kitchen environment can be kept clean without dust from the stove.
  • Long lasting. The water tank is made of thin cast iron that transfers heat quickly. It has a good resistance to water erosion and high temperature. The life of this type of water tank is two to three times longer than its equivalent made of steel plate.

Evaluation of the stove

The stove must satisfy the following requirements. If any part of the stove or the stove's thermal performance does not reach the set requirement, it cannot be sold on the market. The national standard requirements are as follows:
  • The stove must be durable and convenient to use.
  • It must last for more than five years.
  • No smoke must escape from the stove when it is either on or off.
  • Cooking and heating stoves must have the following performance:

  • Temperature increase of the water in the heating pipes with the stove open during the day must increase by at least 0.8°C/min
  • Available power for cooking ≥1.0kW
  • Temperature increase of the water in the heating pipes with the stove closed at night must be less than 0.8°C/min
  • Efficiency of stove without cooking facility ≥ 55%
  • Efficiency of stove with cooking facility ≥ 50%.


Applying standards across the country has made the quality and performance of the stoves improve dramatically. As a result, the amount of fuel used has decreased and environmental pollution has been cut; an economic and social benefit. This standard became the National Standard across China in February 1996.

The stove described above was tested by the Testing and Supervising Centre on Firewood & Coal Saving Stoves, Ministry of Agriculture, China, and is considered to be an advanced and practical product.
Last edited by Miriam Hansen .
Page last modified on Thursday September 30, 2010 15:48:32 GMT.
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