Contrast test of thermal properties of suspended kang and traditional landed kang

Abstract: Winter heating is the basic energy demand in the northern China. As the most common heating device, kang is popularly used in Northern China. However, there are a lot of shortcomings for the traditional landed kang, such as large thermal inertia, low temperature increase rate, high energy consumption, low thermal efficiency, and so on. Therefore, it is of great significance to develop and spread a new structured and high-efficient kang. Suspended kang is raised above the floor on columns, which is different from the traditional kang on the ground. Many researches showed that suspended kang took many advantages over the traditional landed kang, such as small thermal inertia, fast heating, low energy consumption, and so on. Meanwhile, tests have not been carried out to study the increasing temperature characteristics and thermal efficiency of the suspended kang in comparison with the traditional landed kang at home and abroad. Therefore, according to the national standard, the contrastive experiment was conducted to investigate the thermal performance of the traditional kang and the newly promoted suspended kang in Lintao County of Gansu province in 2016. The temperature of kang, exhaust gas and the indoor and outdoor, as well as other parameters were measured. The heating rate and thermal efficiency and other relative property parameters of two kinds of kangs were analyzed. The two kinds of kangs were respectively set in different experimental rooms. The size of the two kangs and houses were similar, as well as the layout and the orientation of two houses were same. The experiment was operated from November 4th to November 18th, the two kangs burning the same amount of fuel were heated 2 times every day at 09:45 and 16:30, respectively. The Agilent's Bench Link data logger was used to record and storage the experimental data with interval 10 s. The research results showed that the thermal efficiency of suspended kang and traditional kang were 66.8% and 37.1%, respectively. Every year each suspended kang saved standard coal 540 kg than that of the traditional kang, saving firewood rate was 45%. In addition, the faceplate average temperature of the suspended kang and the traditional kang were 58 and 48.3 ℃, respectively. Suspended kang with precast concrete block was instead of the traditional kang with clay material or mud bricks, due to the difference of material thermal inertia and heat storage properties and structure of kang, which caused suspended kang warming rapidly. The average heating rate of heating stage of the suspended kang and traditional kang was 2.2 and 0.9 ℃/h, respectively. The average cooling rates of cooling stage of suspended Kang and traditional Kang were 0.8 and 0.1 ℃/h, respectively. The suspended kang flue pipe design was very reasonable and the heat of exhaust gas was fully utilized, the average temperature of exhaust gas was lower 36.1 ℃ than that of the traditional kang. During the test, the outdoor mean daily temperature was 5.4 ℃, mean daily room temperature with suspended kang was 12.6 ℃, while mean daily room temperature with the traditional kang was 10.8 ℃. Compared with the traditional kang, suspended kang has obvious effect of energy saving and emission reduction in China's rural areas.