Week 7 - Energy efficiency and renewable energy Flashcards
What is the Building Energy Efficiency Ordinance (Cap. 610)?
- launched the Hong Kong Energy Efficiency Registration Scheme for Buildings in Hong Kong
- Promotes building energy effeciency
- 3 Key requirements ————————
1. Developers and building owners must ensure 4 key types of building services: aircon, lighting, electrical, and lift & escalator
2. Retrofitting has to have them too
3. Owners of commercial buildings have to have it too
What is HK3030?
- Hong Kong Green Building Council (HKGBC) campaign
- Reduce 30% of absolute amount of electrcity by 2030
- Includes behavioral change and technology advancement and uptake
- Mostly through building itself (48%) but also behavioral (12%) (turning off lights, turning down aircon, cleaning aircon filter)
- Overall change across all aspects of the building
Give me an overview of Hong Kong’s energy saving plan? (2015 ~ 2025+)
- Target: Hong Kong achieves energy intesnity reduction by 40% by 2025 (from 2005)
- Combined effort of public and private sector
- 4 major areas of change: economic, education, regulatory, social
Give me an overview of potential for renewable energy in Hong Kong.
- Solar energy – 17% of annual power demand
- Wind energy – near-short and offshore wind farms recommended, 24%
- Fuel cells (turn a chemical into an energy using reactions) – 7%
- Waste to energy – MSW, sewage sludge, livestock waste
- ## Other tech— biomass, hydropower, tidal and waste power – not so great for Hong kong
What are some renwable energy (RE) demonstration projects that have happened in HK since 2002?
Solar——————-
- Solar water heating
- solar photovoltaic
- other solar tech
Wind ——————-
- large wind turbines
- small wind turbines
- offshore wind farms
Waste-to-energy———————-
- landfill gas
- anaerobic digestion
- thermal treatment
Other—————————–
- marine renewables
- hydroelectric
- biomass CHP
- geothermal
What is Feed-in Tariff?
- helps encourage private/public sectors to cosider investment in RE
- power generated can be sold to power companies at a higher rate for payback of investment
What are some solar energy collectors for buildings?
- Flate plate collector
- Evacuated tubes
- Solar tracking device
- Parabolic concentrator
- Solar air collector
What are some examples of New Generation of Solar Thermal Systems (NEGST)?
- Hamburg Bramfeld, German - flat plate solar panel collectors integrated into roof
- Paris, France - solar panels integrated with building facade
- Leipzig, Germany - solar panels integrated with balcony
What are some of the benefits for solar-thermal energy for building cooling?
- most sun = most solar = most cooling demand
- Direct reduction of primary energy consuption
- Easy to combine with other sources
- Less geographically dependent
- Lower enviornmental life-cucle impact than solar-electric energy from PV
What is the categorization for solar air-conditioning?
- Active ———————————
- Solar absorption cooling system
- Solar adsorption cooling system
- Solar desiccant air-conditioning system
What are some adavancements and case studies in cooling systems?
- Solar absorption cooling system in Wine Store Cooling in Banyuls, France – since 1991, cools 3 million bottles
- Largest solar adsorption cooling system - Inofita Viotias, Greece – since 1999, for cosmetics facotry
- Desiccant Rotary Wheel
- Heat-driven desiccant cooling unit (uses solar enery to drive dehumidification and cooling)
- Solar Desiccant Air-conditioning
System in Freiburg, Germany – first DAC system in germany – since 2004
What does potential for REs for the EU look like?
- By 2020, >25% could be RE generated
- By 2030, 50% of heat supply by new tech
- 2050, biomass and geothermal and solar thermal could satisfy 100% of euro heating demand
- Can also develop hybrid systems
What can combined systems look like for cooling, heating, and power (CCHP)?
- CCHP - trigeneration, CHP - cogeneration
- Rare CCHP/CHP projects for non-industrial application in HK except Zero Carbon building
- Advantages————————-
- Common forms of energy recovery
- Operation cost is saved
- Reduce carbon emissions
- Captures waste heat for heating/cooling purpose, reaching 75% > efficiency against 40% of trad systems <————
- Can be done through——————
- Internal combustion engine
- Gas turbine
- Steam turbine
- Combined gas and steam turbine
- Fuel cells
- Organic rankine cycle
- Stirling engine
What is an example of a CCHP or partial one?
- Shinjuku District Heating and Cooling Center (SDHCC), Tokyo, Japan
- 1997 built, supplied almost all heating and cooling in shinjuku
- Combined CCHP
- District Cooling System (DCS), Kai Tak, Hong Kong
- Serving centralized chilled water
- Needs to focus more on cooling
- Steps
1. Seawater intake
2. Central Chiller plant
3. Underground water pipe network
4. Heat exchangers
5. User buildings
What are the benefits of district cooling system?
- Saving electrcity consumption (20 - 35% reduction as compared to conventional water-cooled and air-cooled systems)
- Better spatial utilization (No chiller plant space required IN building, only one, and heat exchangers are smaller)
- Environemntal merit to buidling (noise and heat not an issue, reduce UHI effect)
- More adaptable for cooling demand
- Enhanced system reliability
