Carbon-Smart Buildings Tackling Energy Efficiency in Hong Kong s Commercial Buildings
Introduction Hong Kong buildings consume a massive 89% of the SAR s electricity and make a sizeable contribution to greenhouse gas emissions. Retrofitting is the answer, but designing the optimal retrofit raises a myriad of questions. Recognizing these challenges, the Climate Change Business Forum (CCBF) set out to tackle the toughest part of the problem: energy inefficiency in Hong Kong s commercial building stock. Every Building a Powerhouse, published by CCBF in 2010, analyzed 29 energy conservation, generation and storage technologies with the potential to substantially reduce carbon and energy use in Hong Kong s existing commercial building stock. The promise of this report inspired further inquiry to identify technologies with the greatest impact. Carbon Smart Buildings (CSB) started by computer simulations to pinpoint those technologies combining cost effectiveness, carbon efficiency and fit with local needs. This summary report draws from data amassed from trials of the key technologies in Hong Kong commercial buildings. Its primary aim is to help landlords make informed, practical investment decisions to upgrade their buildings energy performance. It can also guide tenants in planning and negotiating green office space. The study s methodology comprised Capturing from computer modelling the most promising technologies for upgrading the energy efficiency of Hong Kong s commercial building stock; Performing detailed analysis and modelling, which quantified savings against the agreed baseline using a whole-building approach; Trialling the most promising technologies on site in existing commercial buildings in Hong Kong; Every Building a Powerhouse Desktop analysis Existing & emerging technologies for energy conservation, generation and storage Carbon-Smart Building Modelling Computer modelling to identify most promising technologies Quantify potential savings & performance Carbon-Smart Building - Technology trials Trials in Hong Kong commercial buildings Practical evaluation of procurement, installation and use Chiller Dynamic Control Low Energy Lighting Design Façade Treatment Ultra-Efficient Air-conditioning Plant Small and Medium Enterprises Office Refurbishment What Why How When Perceived Challenges Key Findings Carbon-Smart Beneficiaries All results and recommendations presented in this report were obtained from trials carried in existing building in Hong Kong. The recommendations included herein, and the technical report available on the CCBF web site, are designed to inform the business case and increase uptake of effective building efficiency technologies in Hong Kong s commercial building stock. Landlords investors in building energy efficiency upgrades For details on the studies and the findings please refer to the main technical report. w w w. c l i m a t e c h a n g e b u s i n e s s f o r u m. c o m 2 Tenants seeking to lower their energy bills and carbon emissions
Total Hong Kong Energy Consumption 40% of the total energy in Hong Kong is consumed by the commercial sector including offices, hotels and retail buildings Residential 19% Figure 1: Hong Kong Total Energy Consumption Energy Consumption within the Commercial Sector Within the commercial sector the large energy consumers are space airconditioning (54%) and lighting (14%) Space Conditioning 54% Others 19% Office Equipment 13% Commercial 40% Lighting 14% Electricity Rate Variation Transport 32% Figure 2: Hong Kong Commercial Sector Energy Consumption Industrial 9% As energy prices rise, the business case will only get stronger. Although it is difficult to predict accurately how much they could rise over the lifetime of the building upgrade, the simple payback period will reduce proportionally to the increase of electricity cost. Technology At-a-glance Technology Technology Description Savings Chiller Dynamic Control Low Energy Lighting Façade Treatment Ultraefficient Airconditioning SME Office refurbishment Chiller Dynamic Control involves applying advanced control strategies in order to operate building systems according to changing building loads, profiles and external weather conditions. One area that can provide significant energy savings is chiller plant controls. It involves variable speed drives and controls for all components including chillers, pumps and cooling towers. Integrated controls of chiller plant equipment deliver efficient operation of each component following the varying cooling demand. Low Energy Lighting involved two strategies: 1) Reducing the general ambient lighting and unnecessary lighting while keeping adequate working lighting levels. 2) Using high efficiency lighting such as LED, T5 fluorescent lamp, compact fluorescent lamp. The lighting power consumption can be reduced significantly while maintain the sufficient lighting level. Façade treatment with solar film is an efficient way to improve the Shading Coefficient value of the glazing. It reduces heat entering the building and improves the thermal comfort. Ultra-efficient chiller plant focuses on high-performance chillers with COP of 6 or above that use less energy to provide cooling. This can be achieved by installing water-cooled chillers with oil-free magnetic bearing compressors or with a central control variable speed systems. The major energy consumers in Small and Medium Enterprises offices are lighting and office appliances. Significant energy savings can be achieved by using efficient lighting, integrating controls for occupancy, daylight, smart energy metering systems and energy labelled appliances. 20-35% of cooling plant energy use over water-cooled constant speed plant baseline (typical for existing commercial buildings in Hong Kong) 15 40% of lighting energy use compared to standard 500 lux design (typical for existing commercial buildings in Hong Kong) 1 5% of cooling energy use compared to a not optimized façade (clear glass) 20 30% of chiller energy use compared to a constant flow water-cooled plant (typical existing commercial building) 20 40% of SME office energy use compared to a standard design with no daylight and occupancy controls (typical for small and medium tenants) 3
Chiller Dynamic Control What Chiller Dynamic Control involves applying advanced control strategies in order to operate building systems according to building loads, profiles and external weather conditions. One area which can provide significant energy savings is chiller plant controls involving variable speed drives and controls for all components including chillers, pumps and cooling towers. Why By integrated control of chiller plant equipment efficient operation of each component can be achieved according to the actual cooling demand. How Design the system with chiller dynamic control. Ensure the proper commissioning after installation, and consider re-tuning during the lifetime of the building. When When the existing chillers reach the end of their lifespan or for a major refurbishment. Overcoming Perceived Challenges Figure 3: Chiller Plant with variable speed drives Control Schematic Government Approval Technical Maintenance Dynamic building control implemented on a chiller plant or on a whole building does not require additional government approval. Modern chiller design and controls now allow variable flow in both chilled and condensing water circuits reducing total plant energy. The feedback from the project sponsors was that the benefits outweigh the additional management costs. 4
Cost : Simple Payback Period: Savings: Added cost for CDC is 30-60 HKD/m 2 Within 8 years Up to 13% of building total energy consumption Key Findings 100% 90% Degree of fine-tuning Up to 37% building chiller energy reduction Water-cooled Baseline Project 1* Project 2 Project 9 Chilled water pump, kw/ton 0.116 0.078 0.064 0.044 Chiller, kw/ton 0.513 0.410 0.551 0.429 80% 37% Condensing water pump, kw/ton 0.174 0.254 0.085 0.055 70% Cooling Tower, kw/ton 0.077 0.059 0.021 0.022 60% Total Plant, kw/ton 0.88 0.80 0.72 0.55 50% Saving against water-cooled baseline 9% (25% last 2 months*) 18% 37% 40% 30% 20% 10% 0% Water-cooled Baseline Project 1 Project 2 Project 9 Cooling Towers Chilled Water Pumps Condensing Water Pumps Chillers Table 1: Dynamic Chiller Plant Control Savings Breakdown by Component The water-cooled plant used for the baseline has constant speed components. Projects 1, 2 and 9 demonstrate different levels of optimized dynamic control operation due mostly to the different level of fine tuning completed. Refer to the main technical report for details. Project 1 has mostly constant speed operation during the trial period since it covered the initial commissioning and fine-tuning. The chiller Plant in project 9 has been fully set up, tested and refined, while those in projects 1 and 2 need further fine tuning. Figure 4: Chiller Plant Energy Consumption Comparison Showing Reductions Achieved against Baseline * The percentage improvement on annual basis includes constant speed operation of CDWP and the initial period of fine tuning. The last two months of the period demonstrated full VSD operation and the savings for this period were 25%. 5
Low Energy Lighting What Low Energy Lighting involves two strategies: 1. Optimized illuminance Reducing the general ambient lighting and unnecessary lighting while keeping the lighting level adequate at the work place. No added capital cost is required. 2. Efficient lighting By using high efficiency lighting such as LEDs, T5 fluorescent lamps, and compact fluorescent lamps, the lighting power consumption can be reduced significantly while maintaining a sufficient lighting level. Why Low Energy Lighting saves energy by reducing unnecessarily high illuminance levels and when artificial lighting is not required. This strategy can save up to 40% of building lighting energy. 600 500 400 300 200 100 0 Lux Standard Lighting Design Optimized Lighting Design Figure 5: Standard design of lighting is around 500 600 lux, with computer based office work the optimized lighting level can be achieved at 300 400 lux. How Set appropriate energy targets, for example 300-400 lux, 8-10 W/m 2. Engage office occupants to ensure they can accommodate the lower illuminance levels. Consider incorporating dimming control now this is more cost effective. When When the existing lighting reach the end of their lifespan or are in need of major renovation. Overcoming Perceived Challenges Hong Kong Office Culture Standard Design Practice HK office are often designed with very high lighting levels. Occupants acceptance has to be considered for each separate office population. The trials showed high acceptance rates. > 500 lux Very high illuminance for computer based office tasks Standard practice 500 lux Installed capacity 600+ lux 6
Optimized Illuminance (Strategy 1) Efficient Lighting (Strategy 2) Cost : No additional cost if carried out during a retrofit or new installation Cost : 190 HKD per m 2 Simple Payback Period: N/A Simple Payback Period: Within 6.5 years Savings: 6% of building total energy consumption Savings: 6% of building total energy consumption Key Findings 1. Optimized illuminance Illuminance tenants find acceptable: Perimeter Office Zones: 300 lux Interior Office Zones: 400 lux Appropriate for both new building design and existing building refurbishments Over-sizing of installed lighting power Two approaches to optimize illuminance: Reduce the number of lamps in each luminaire Dim lamps (if dimming is available) 2. Efficient lighting Appropriate for existing building refurbishments Main features: DALI central control system, T5, compact fluorescent lamp (CFL), daylight sensors, reduced illuminance target of 400 lux 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Up to 40% building lighting energy reduction 40% Typical 500 Lux 400 Lux 350 Lux 300 Lux 12+ W/m 2 8-9 W/m 2 7-8 W/m 2 6-7 W/m 2 Figure 6: Total Lighting Energy Consumption Comparison with Different Illuminance Levels, taking Standard 500 lux as 100% 7
Façade Treatment What Façade treatment with solar film is an efficient way to retrofit glazed facades of existing buildings. Solar film reduces the radiation entering the building, reducing the heating effect within the building. Why This reduces the cooling load of the building which leads to energy savings at the central cooling plant. Additionally, thermal comfort is improved in the premises where solar film has been retrofitted since the radiant heat is reduced. How Investigate existing glazing performance and assess if solar film is applicable and likely to provide benefits. When For buildings with clear or low performance glazing and high solar loads. Overcoming Perceived Challenges Figure 7: Solar Film Schematic Government approval Climate Regional Issues There is no government approval required for façade treatment by application of solar film. Appropriate for HK climate Solar façade treatments and professionals to install them are available on the local market. The materials need to have the appropriate fire safety approvals. 8 * RT Abbreviation for a Ton of Refrigeration a unit of power equal to 3.52 kw.
Cost : Simple Payback Period: Savings: 515 HKD/m 2 of filmed glazing Within 4.2 years 123 HKD/m 2 of filmed glazing/year Key Findings Appropriate for existing offices that have clear glazing. Significant thermal comfort improvement Direct measurement of savings is not feasible. Indirect methods might be inconclusive for some projects Total Energy Savings against Pre-Upgrade Baseline Shading Coefficient* Pre-Upgrade: 0.82 380 3% building cooling energy reduction Shading Coefficient Upgraded: 0.42 370 9% Saving from Solar Film 62,000 kwh 360 Saving from per m 2 Solar Film 100 kwh/m 2 x 100,000 350 340 330 320 Saving Contribution to the Building Total Energy Consumption Simple Pay Back Period (at the time of retrofit) 1.5% 4.2 years 310 Table 2: Building Total Energy Savings against Pre-Upgrade Baseline (Calculated) 300 kwh Pre-Upgrade Upgraded Figure 8: Energy Saving From Solar Film * Shading Coefficient typically varies from > 0.8 for clear glass to < 0.3 for high performance double glazing. 9
Ultra-Efficient Air-Conditioning What Ultra-efficient air-conditioning plant focuses on high-performance chillers with Coefficient of Performance (COP) of 6, or above, that use less energy to provide cooling. This can be achieved by installing water-cooled chillers with optimized condensing and chilled water temperatures and flow rates. Also technologies, new to Hong Kong, should be explored, such as oil-free compressors. Why Cooling dominates the energy consumption in HK buildings and focusing on its efficiency provides some of the greatest single reductions in building energy consumption. Air Conditioning 54% Others 19% How Set targets for coefficient of performance (COP). Ensure that operations and maintenance staff receive adequate training. When When the existing chillers reach the end of their lifespan or need major renovation. Overcoming Perceived Challenges Benchmarks Water Cooled Option Ultra Efficient COP > 6 Conventional COP 5 ~ 6 Office Equipment 13% Figure 9: Energy Consumption by Office Segment 2009, Source EMSD Fair COP 3 ~ 5 Lighting 14% Poor COP < 3 Oil-free Chillers Suppliers Maintenance Reference Projects No longer limited, there are now more than 3 local suppliers for oil-free chillers. Feedback from the project sponsor was that good maintenance support has been provided and they expect less maintenance than a conventional chiller. Previously limited but now growing number of local reference projects. Air Cooled Option Ultra Efficient COP > 4 Conventional COP 2.5 ~ 3.5 Fair COP 2 ~ 2.5 Poor COP < 2 10
Added Cost : Simple Payback Period: Savings: 4000 HKD per RT* 3 years to recover the added cost 18% of building total energy Key Findings 100% Up to 30% chiller plant energy reduction Two aspects of ultra-efficient chiller plant have been tested during this study: 1. Oil-free Chiller 90% 30% The study has shown exceptional performance of the cooling plant 30-40% better than conventional water cooled chillers especially in part load, mid-season and winter. Feedback on the availability of adequate local maintenance from the operators has been very positive and less of a concern now multiple suppliers and more installations are now in HK 80% 70% 60% 2. Water Cooled Plant with Primary Variable Flow 50% Appropriate for all kinds of commercial buildings Main features: water cooled chillers, chilled water pumps, condensing water pumps and cooling towers, all of them equipped with variable speed drives. One project successfully used a performance-based contract provider which led to more emphasis on continuously fine tuning the operation. 40% 30% Conventional Water Cooled Chiller Plant Ultra-efficient Chiller Plant Figure 10: Energy Consumption Comparison between Typical Building and Ultra-Efficient Chiller Plant Building, taking Conventional Water Cooled Chiller Plant as 100% 11
SME Office Refurbishment 12 What The SME Office refurbishment consists of the following energy reducing features: Efficient lighting (see also section on Low Energy Lighting) Integrated controls for occupancy sensors and daylight sensors. Energy metering Energy-labelled appliances Why Significant energy savings Relatively short payback period Providing feedback on energy usage allows tenants to review behaviour to reduce consumption. 20,000 18,000 16,000 14,000 12,000 10,000 kwh Up to 14% total tenant energy reduction EMSD Baseline ASHRAE Baseline Installed Figure 11: Potential Annual Energy Savings For Office Tenants 14% How Low energy design ethos for fit out projects. Adopt best practices, including the HK mandatory and voluntary energy efficiency labelling schemes. When On change of tenancy or when the existing installation reaches the end of its lifespan, or is in need of major renovation. Overcoming Perceived Challenges Government approval Local Standards Availability of Suppliers Local Reference Projects Office refurbishment does not require government approval EMSD Code of Practice for Energy Efficiency 2012 (BEC) Various suppliers of lamps, control gear, daylight and motion sensors and luminaires Abundant references from suppliers
Tenant Lighting Renovation Added Cost : 65 HKD/m 2 Simple Payback Period: Savings: Within 2.4 years 14% of total tenant energy consumption. Further savings can be achieved by operational and housekeeping measures Key Findings Small and medium enterprise (SME) office refurbishment can provide 14% savings of total tenant energy consumption. For comparison the local lighting efficiency standards (by EMSD) and international lighting efficiency standards (by ASHRAE/IESNA) were used. Case study shows that savings of 15-25 HKD/m 2 /year can be achieved. Payback period is approximately 2.4 years. Appropriate for existing small office refurbishments. Time for Implementation: Upon moving in to a new office location or when a lighting refurbishment is due. Energy Efficient Appliances Hong Kong Mandatory Energy Efficiency Labelling A mandatory scheme covers room air conditioners, refrigerators, compact fluorescent lamps, washing machines and dehumidifiers Hong Kong Voluntary Energy Efficiency Labelling The voluntary scheme covers a wide range of products including photocopiers, laser printers, TV sets, LCD monitors, fax machines and water dispensers. Energy Star Labelled Products Produced by the US Environmental Protection Agency, Energy Star is a well-regarded international energy labelling system and it covers a wide range of products. Energy labelled appliances can provide savings in the range of 10% to 50% compared to non-energy labelled products depending on the type of equipment. 13
General Recommendations for Landlords Landlords control basic building systems that extends to tenant spaces. Landlords seeking to increase energy efficiency should: Set O&M Targets Carry out Audits Indentify Improvement Opportunities Setting Project Specific Targets Carry out Improvement Projects Measurement and Verification Recommended Improvement Opportunities The greatest opportunities for savings are from upgrading air conditioning and lighting. Variable speed drives on pumps and cooling towers should be prioritized during upgrades. Make provisions for equipment controls and monitoring. When replacing air conditioning, consider high-efficiency VSD or oil-free magnetic bearing chillers. Reference international energy efficiency standards (e.g. ASHRAE 90.1) when sourcing equipment. If current glazing does not sufficiently block incident radiation, consider solar film to both reduce heat gain and improve thermal comfort. When replacing existing lighting or designing new, design at 350 Lux. Provide dimmable lighting control gear for tenant spaces. When refurbishing lighting, replace lamps with T5 and LED fittings. Sub-meter the main systems to allow detailed monitoring of energy consumption. 14
General Recommendations for Tenants When selecting an office space to rent, inquire if the landlord can provide: Evidence that the property is certified under a green building system (such as BEAM Plus or LEED) or that an application for such certification is underway. Lighting with dimmable control gear. This will allow for more efficient use of natural daylight. Lighting fittings with potential for de-lamping. This provides flexibility to reduce illuminance and operational cost. Access for tenants to control the fresh air supply. High performance glazing* or alternatively, solar film on clear glazing. Energy audit results according to the Building Energy Efficiency Ordinance. As a tenant you can also install or request: Daylight sensors, especially in the perimeter of rooms, within 5 metres of windows. Occupancy sensors for ambient lighting. LED or T5 (highly efficient) lamps for lighting. Energy metering with real time feedback to tenant/occupants. Appliances with the highest efficiency rating (certified on the label). 15
The Climate Change Business Forum (CCBF) convenes some of Hong Kong s most astute businesses to collaborate on tackling climate change. As a think tank on the transition to a low-carbon economy, the forum seeks to be a resource to Hong Kong s business community and government. CCBF was established in 2008 by the non-profit Business Environment Council. Climate Change Business Forum c/o The Business Environment Council Room 201, Jockey Club Environmental Building, 77 Tat Chee Avenue, Kowloon, Hong Kong Tel: +852 2784 3900 Fax: +852 2784 6699 Web: www.climatechangebusinessforum.com Printed on Recycled Paper using Soy Ink CCBF would like to thank our research partner Cundall is an international organisation providing multi-disciplinary engineering and sustainability consultancy. They provide clients with practical advice and solutions, which reduce the environmental impact of developments, and provide better spaces for building users and occupiers, as well as for the wider community.