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.

Coastlines on Earth always change due to both natural and human causes. Scientists concerned the position of coastlines as it can provide useful information for coastal zoning plans, coastlines position prediction and environmental managements. Extraction coastlines from remote sensing image became a common and effective method as it can save money and human resources to some extend and provide more accuracy results. DSAS, one plug-in in ArcGIS, is another popular analysis tool to calculate the change rates of coastlines. In this report, the author chose the Pearl River Estuary in China as the study area and analyzed spatiotemporal changes during the past 40 years by using Landsat data. In 1978, total length was 788.13km and increased to 980.57km in 2018. The proportion of artificial coastlines occupied 0% in 1978 and soared to 67% in 2018. The speed of coastlines change rates reached to 13.82 km/yr in artificial ones and nearly stable in natural types.

The prolonged duration of winter season and the occurrence of extreme low temperatures present significant challenges when implementing mechanical ventilation systems in severe cold regions. These challenges encompass substantial requirements for heating supply air and frequent operations for defrosting. Heat stored in the ground has the potential to be harnessed for pre-conditioning supply air through the utilization of an earth-air heat exchanger (EAHE). This study focuses on evaluating the heating performance of the EAHE when integrated into a heat recovery ventilation system. The energy model of a case building in Harbin and the proposed ventilation system were simulated in IDA ICE. The results show that as the outdoor temperature drops, the proportion of heat supplied by EAHE increases, leading to a decrease in reliance on reheater to heat supply air. This underscores the advantages of applying EAHE to preheat fresh air in colder climates.