Search Results (3)

It has been shown that heating methods have a large impact on rural indoor air quality. Previous studies on indoor air quality in rural houses involved a limited number of heating methods and lacked comprehensive comparative research on the three heating methods: coal-fired boiler radiator heating, air-source heat pump radiator heating, and Chinese stove–kang heating. In this paper, subjective surveys and objective tests were conducted on indoor air quality in rural houses using these three heating methods in northern Shanxi, China. The gray relational analysis method and the comprehensive index method were used to evaluate the indoor air pollution levels of the three heating methods. The results were as follows: The subjective evaluations of most rural residents were overly optimistic about the indoor air quality of coal-fired boiler radiator heating and Chinese stove–kang heating. The indoor TVOC concentrations from these two heating methods far exceeded the standard limit of 0.6 mg/m³ at night. The indoor PM_2.5 and PM₁₀ concentrations from Chinese stove–kang heating varied greatly over a day and showed intermittent peak fluctuations that far exceeded the standard limits in the initial period of fuel combustion. The pollution levels from coal-fired boiler radiator heating, air-source heat pump radiator heating, and Chinese stove–kang heating were evaluated as light pollution, non-pollution, and medium or heavy pollution, respectively. Full article

High heating expenses are observed in numerous Chinese rural houses located in severe cold regions due to the high heating demand, inferior envelope performance and low-efficiency heating equipment. The local traditional heating methods include Chinese Kangs and coal boilers with water-based radiators. The intermittent operation and manual regulation of these systems result in significant temperature differences and inadequate thermal comfort. This study presents the cost-optimal envelope renovation solutions with the minimized lifecycle cost (LCC) during a 20-year discount period and CO₂ emissions of annual delivered energy consumptions. A single-family detached rural house in Harbin was used as a case building, illustrating the typical state of comparable houses in this climate context. Simulation-based multi-optimization analysis was conducted in this study using the building simulation tool IDA ICE and its integrated optimization tool AutoMOO. The results indicate that the cost-optimal renovation solutions with intermittent and continuous heating can cut CO₂ emissions by 30% and 40%, respectively. The LCC with intermittent heating is still 7% greater than its pre-renovation case, which may require external financial support to encourage the renovation conduction, while the LCC with continuous heating decreased by 8% after renovation. According to the comparison results, cost-optimal solutions have significant advantages in both reductions of LCC and CO₂ emissions over standard-based solutions. Moreover, utilizing intermittent heating is more effective than continuous heating in demonstrating the positive impacts of envelope renovation on increasing average temperature, decreasing temperature differences and lowering occupied time at low thermal comfort levels. Full article

The intermittent heating mode of Kang plays an important role in the heat storage and release in cave dwellings. However, research on the effect of Kang heating on the thermal process of traditional buildings is rare. Therefore, based on long-term monitoring of cave dwellings, regular conclusions about the influence of Kang heating on the thermal environment were obtained. Furthermore, an unsteady heat transfer model of the envelope was proposed for the first time. Then, based on this model, the thermal storage performance of cave dwellings during the period of Kang intermittent heating was explored. The results showed that, due to Kang heating, the indoor air temperature of cave dwellings could be increased by an average of 3.1 °C. Furthermore, the inner walls had a large thermal mass and the maximum heat storage in a single day was 487.75 kJ/m², while the maximum heat release was 419.02 kJ/m². The heat release at night could reach 87%. In this paper, the law of thermal storage and release characteristics of earthen building envelopes under intermittent heating was firstly obtained. Results can enrich the thermal process theory of earthen buildings and provide a theoretical basis and technical support for building thermal environmental construction. Full article