住宅用太阳能加热和冷却应用技术简介（英文版）_42页_3mb

Summary of Solar Heating and Cooling for Residential Applications

Core Content

Solar thermal systems (STS) are a mature technology that has been successfully implemented in residential applications for over three decades. These systems convert solar radiation into heat, which can be used for domestic hot water, space heating, and even cooling. Despite their effectiveness, global deployment remains limited, with only 1.2% of residential heating and cooling demand met by solar thermal energy.

STS are particularly beneficial in countries that rely on imported gas or oil for heating, in growing economies where electric boilers strain the electricity grid, and in regions with high cooling demands during sunny hours. The technology has been widely adopted in countries like Cyprus, Israel, and China, where government mandates and local manufacturing have played a key role in its success.

Main Views

• Technology Maturity: STS are a well-established technology with a wide range of applications, including domestic hot water, space heating, and cooling.
• Market Penetration: While some countries have achieved up to 90% penetration of solar water heating systems in new construction, globally STS only cover 1.2% of residential heating and cooling demand.
• Cost and Quality Variability: The cost of STS varies significantly across countries, influenced by local manufacturing, labor costs, and climate conditions. Chinese systems are notably cheaper than American ones, though their lifespan may be shorter.
• Government Role: Government policies, including subsidies and mandates, have historically been crucial in promoting STS adoption. However, support has often waned after oil crises, leading to market stagnation in some regions.
• Integration Challenges: In existing housing, integrating STS can be complex and costly. Additionally, competition from heat pumps and solar PV panels poses a challenge.
• Technological Variants: There are two main types of solar collectors: flat-plate (FPC) and evacuated tube (ETC), with ETC being more common due to their superior efficiency in cold climates.

Key Information

Technology Overview

• STS use solar radiation to heat a transfer fluid (air, water, or special fluid) for heating and cooling purposes.
• The system can be direct (fluid used directly) or indirect (fluid passes through a heat exchanger).
• Thermosyphon systems (passive) are popular in warm climates, while pumped systems (active) are more common in cooler regions.
• Integral Collector Storage (ICS) systems are less common due to heat loss during non-sun hours, though they are cost-effective in certain contexts.

Market and Deployment

• Thermo-syphon systems account for 75% of installed capacity globally, with ETC making up 65% and unglazed systems 8%.
• Solar domestic hot water (SDHW) systems are the most common residential application, with some countries achieving 85% installation rates in new buildings.
• Solar combi-systems provide both hot water and space heating, with a solar share typically around 25%, but capable of reaching up to 60% in energy-efficient homes.

Cost and Performance

• The cost of STS varies by country and is influenced by the quality of the solar collector, labor, and climate.
• In Central and Southern Europe, STS are already more cost-effective than gas and electric heating.
• In the US, STS need to reduce costs by 3–5 times to be competitive with gas boilers.
• Solar thermal cooling is still in early stages, with absorption chillers being the most common technology used.

Future Developments

• Solar cooling is growing, with over 1000 systems installed by 2013. It is especially promising in regions with high summer cooling demand.
• District heating is a promising avenue for large-scale deployment, with some systems achieving up to 50% of heating demand in urban areas.
• Solar plus combi-systems allow for the integration of cooling with existing solar heating systems, improving efficiency and reducing peak electricity demand.

Barriers to Deployment

• High upfront costs in developed countries remain a challenge, especially when compared to conventional systems.
• Lack of regulatory frameworks and quality assurance standards hinders widespread adoption.
• User inertia and lack of awareness among architects and the construction industry limit market growth.
• Competition with other technologies like heat pumps and solar PV systems further complicates adoption.

Policy Recommendations

• Mandates for STS in new construction are effective in driving adoption.
• Subsidies and low-interest loans can support deployment in low-income areas.
• Local manufacturing can reduce costs and create jobs.
• International standards and certification schemes are essential for ensuring quality and facilitating trade.
• Integration with other renewables and advanced R&D will be key to future growth and efficiency improvements.

Conclusion

Solar thermal systems have significant potential to reduce energy demand for heating and cooling in residential buildings. Their deployment is influenced by local policies, economic conditions, and technological capabilities. As the technology continues to evolve and become more cost-effective, it is expected to play a larger role in sustainable energy solutions, especially in regions with high heating or cooling demands and growing economies.