This paper presents the design of a power generation system utilizing energy harvested from exercise machines, aiming to convert human mechanical energy generated during physical training into electrical power. Exercise machines produce mechanical energy that can be converted into electricity to supply small electrical loads. The exploitation of this energy source contributes to energy savings, enhances awareness of renewable energy utilization, and supports sustainable development. The study focuses on the mechanical design integrating a generator into the exercise machine, as well as the calculation and selection of system parameters to ensure a stable output voltage. Simulation, prototype fabrication, and experimental measurements of voltage, current, and power were conducted for validation and evaluation. Experimental results demonstrate that the system operates stably, the output voltage meets the design requirements, and the generated power is sufficient for small-scale electrical devices. These findings confirm the feasibility and effectiveness of the proposed system, indicating its potential for practical applications.

The utilisation of low-temperature heating systems has been demonstrated to enhance heat source efficiency and reduce energy consumption, thereby playing a crucial role in the conservation of building energy and the reduction of associated emissions. The present study investigates the application effects of radiator-based low-temperature heating technology across a range of building energy efficiency levels and climatic conditions. The objective of the study is to promote the adoption of low-temperature heat sources in heating systems and to support sustainable building practices. The TRNSYS simulation platform was utilised to develop building models representative of typical climate zones. The feasibility of radiator-based low-temperature heating was evaluated from the perspectives of thermal comfort (PMV index) and temperature stability, utilising scenario analysis methods. This evaluation encompassed various combinations of building envelope performance and radiator supply water temperatures. The findings indicate that enhancing the thermal performance of building envelopes can mitigate the impact of reduced heat dissipation during low-temperature water supply, thereby facilitating low-temperature heating (with water temperatures as low as 40°C) to meet thermal comfort requirements in energy-efficient buildings. In high-performance buildings, high-convection ratio radiators have been shown to maintain minimal temperature fluctuations. The findings of this research provide a theoretical foundation and practical guidance for the optimisation of heating systems in retrofitted buildings, the adaptation of low-temperature heat sources, and the selection of appropriate radiators. This research offers broad engineering application prospects.

Low-temperature heat source heating represents a pivotal technological direction for global energy decarbonization and building heating decarbonization. Its development is deeply integrated with fourth-generation district heating (4GDH) concepts, forming a comprehensive technical framework encompassing top-level design, pipeline systems, terminal equipment, and standardized modeling. This study systematically reviews research advancements in low-temperature heating technologies across conceptual frameworks, network performance, economic viability, intelligent control systems, terminal innovations, thermal comfort, and standard methodologies. It highlights core advantages of low-temperature heating systems in reducing heat and exergy losses, integrating renewable energy and industrial waste heat, and enhancing system flexibility. Research demonstrates that low-temperature district heating networks exhibit significantly superior energy efficiency and cost-effectiveness compared to traditional high-temperature systems. Existing building retrofits require shorter investment payback periods, optimized terminal equipment can reliably adapt to low-temperature operating conditions, and intelligent control coupled with demand response mechanisms further reduce operational costs. Future technological priorities will focus on low-cost deep retrofitting, cross-sector energy integration, market-based incentive mechanisms, and standard upgrades to provide critical support for clean heating initiatives and carbon neutrality objectives.