District cooling reaches Hong Kong

The government of Hong Kong’s major project to redevelop the old Kai Tak Airport site is to incorporate district cooling technology. This will be the first use of DC in the territory but, already, more projects may be lined-up to follow, as David Hayes reports.

A consortium of Hong Kong’s Hip Hung Construction Co along with Young’s Engineering Co and Singapore-based Dalkia Asia has won an eight-year Hong Kong government contract to design, build and operate the territory’s first district cooling system.

Construction on Phase 1 is under way as part of the initial infrastructure building stage of the government’s Kai Tak Airport Redevelopment Programme, which involves building residential, commercial and public service facilities ” including a new cruise line terminal ” on the old airport site next to Victoria Harbour.

‘All investment in this project is from the Hong Kong government,’ said Li Kwok Keung, assistant director of electricity and energy efficiency in the government’s Electrical & Mechanical Services Department.’ The consortium will design, build and operate the district cooling system. After eight years beginning February 2011, there will be an option to extend the contract. Construction is in three phases and will take five years in total, so we have added three years to this time period, making eight years, to make sure all the plant is running properly and efficiently.’

Tenders for the contract were invited in mid-2010, with the contract being awarded earlier this year. Bidding attracted a good level of interest, with most bids from consortia of Hong Kong and foreign companies, said Li. Standard Hong Kong government tender practice was followed, with bidders first submitting technical design proposals and details of experience. Fee proposals were submitted in the second stage.

UP TO 80,000 RT OF COOLING

Under the Kai Tak Airport Redevelopment Programme about 1.73 million m2 of floor area in various buildings will use district cooling (DC) when the three construction phases are finally completed. Government buildings make up about one third of the DC cooled floor area. The rest includes hotels, offices and retail outlets.

‘The exact share of the district cooling that private buildings use will depend on the private developers. The land available at Kai Tak will not be sold for hotel or office or commercial developments if there is no demand for any of these,’ said Li. ‘If there is no demand for hotel space, then offices and commercial developments can be built instead, or vice versa. The actual change in land demand for various possible uses that could happen will not change our overall project design.’

Maximum demand for district cooling once all buildings are completed is expected to total about 80,000 refrigeration tonnes (RT), supplied by two chiller plants with an estimated 28 chillers of 5000 RT, 2500 RT and 2000 RT capacity. But the size of chillers could vary change if larger units become industry standard over the next five years, said Li. The number of chillers installed will also depend on the load once all buildings have been constructed. The Electrical & Mechanical Services Department projects that demand for district cooling will fall to about 30% to 50% of maximum demand during the cool season, when demand will fluctuate with daily temperatures.

Hong Kong’s first district cooling project has been a long time in the planning, due partly to the protracted finalization of the Kai Tak Airport Redevelopment Programme. Originally, when planning began more than 10 years ago, the government proposed a land reclamation scheme for the water channel that separates the Kai Tak Airport runway and the East Kowloon shoreline, and to reclaim land along the harbour side of the runway. But this approach was abandoned as Hong Kong residents opposed further land reclamation in Victoria Harbour.

Hong Kong's first district cooling project
Photo: Marc Worrell

SHOWCASE PROJECT ” BUT NO CHP

The decision to choose district cooling was influenced by government and public concern that Hong Kong should play its part in reducing global warming. Hong Kong already imports electricity from China as no more suitable sites are available in the territory to build new power stations.

‘Our district cooling system will use seawater. The efficiency gain will reduce the electrical energy used for air cooling the commercial developments in the Kai Tak Redevelopment Area,’ said Li. ‘Also, this will help achieve synergies in the overall plant construction programme. The government wants to develop Kai Tak as an environmentally friendly green hub. The government wants to provide district cooling as a showcase pilot project to show that district cooling is applicable in Hong Kong.’

Chillers installed for the Kai Tak district cooling system will be powered with electricity drawn from China Light & Power Company’s distribution grid, which serves Hong Kong’s New Territories and the Kowloon peninsula. Maximum electricity demand for the chillers is likely to be about 284 MW.

Although a CHP option has not been selected, the government had studied the feasibility of building a new gas-fired CHP power plant to supply electricity to the two chiller plants, one of which will be built underground, said Li. Building a power plant on the Kai Tak site would require a chimney to be built, which had raised concerns about smoke emission. Also, the government’s financial analysis of the proposed district heating option indicated that buying in electricity would be more cost effective than building a CHP power plant.

‘That’s the reason there is no CHP for this project,’ said Li. ‘Also, there is no heat load in Hong Kong so what would we do with the CHP heat output, as it’s not efficient to use the heat for the chillers. In fact, we will have one or two heat reclaim chillers for the plant rooms. If possible we will feed the hot water to hotels that will be built on the development site and maybe to the public hospital that will be built there. However, the hot water temperature will not be high enough for use in sterilizing as with a normal CHP system. In our project the heat discharge is just for air conditioning.’

The Kai Tak project’s environmental credentials could be further enhanced by plans to use green energy powered bus services or a monorail to transport people around the new district. For the moment, these proposals are still at the consultation stage.

A SMALL NEW TOWN

The Kai Tak redevelopment scheme is similar to building a small new town, said Li. The first buildings due for completion are a cruise liner terminal at the end of the old Kai Tak Airport runway and a combined office/commercial development that will include entertainment facilities for tourists.

Phase 1 infrastructure construction including large diameter district cooling pipe work already is underway at Kai Tak for completion in 2013. Two 1000 mm pipelines are being built in parallel over a 2 km stretch to cope with expected seasonal changes in cooling demand ” rather than building a single larger diameter pipeline. ‘We wanted to build in flexibility for different cooling loads in the different seasons,’ said Li. Constructing pipework is at an early stage because the large diameter district cooling pipes run under roads being built to provide vehicle access in the development zone.

Phase 2 of the district cooling project includes the start of the design, build and operate contract that will be completed in 2017 when all new buildings will have been completed in the development area and the district cooling fully installed. But the district cooling system is scheduled to serve its first customers in 2013 when the cruise liner terminal is due to enter use, along with commercial facilities such as shops, supermarkets and restaurants in some government housing blocks.

Installing district cooling will be a new venture for the property developers involved in constructing the various buildings planned for the Kai Tak development project. While commercial properties in Hong Kong are often installed with central air conditioning, most residential property is built without, leaving tenants and apartment owners to purchase and install their own air conditioning units.

GREENER ENERGY FOR BUILDINGS

Buildings expected to use district cooling in the development include hospitals, hotels and commercial buildings.

‘All government buildings in the Kai Tak development must connect to the district cooling system to show the government’s commitment to green energy,’ said Li. ‘These will include schools, hospitals, government offices and the planned multi-purpose stadium.’

Meanwhile, the start of the district cooling system design, build and operate contract this year coincides with construction of the two DC chiller plant rooms. One in the old airport apron area is expected to require a 162 MW electricity supply and will be cooled with a seawater pump room. Another, expected to require 122 MW, will be mid-way along the old airport runway.

Government buildings at the new development will have to connect to the district cooling system
Government buildings at the new development will have to connect to the district cooling system
Photo: David Hayes

The actual buildup of chiller capacity will depend on Hong Kong’s economy over the next five years and the economy’s impact on property development at Kai Tak. The overall project has been divided into many property development phases to allow flexibility to respond to the impact of economic changes, said Li.

‘We will build about 5 km of parallel pipework to meet cooling demand in 2013. There will be 3 km of 500 mm and 800 mm pipework running along the runway and 2 km of 1000 mm in the old airport apron area,’ said Li.

Phase 1 pipework will be completed by the end of 2012 to match with road works. Phase 2 site preparation and investigation has already started. The first chillers must be installed before the cruise liner terminal opens in 2013 so the chillers must be commissioned in 2012. Phase 3 will involve constructing the remaining pipe work and installing the remaining chillers and pumps to meet future DC demand.

MORE DISTRICT COOLING PROJECTS

Meanwhile, district cooling has already been identified as a potential energy efficient solution for two other future developments in Hong Kong, including the West Kowloon cultural district development proposed for a reclaimed area in West Kowloon on the opposite side of the Kowloon peninsula to the Kai Tak development scheme. Completion currently is expected in 2015 or 2016.

Now under planning, the West Kowloon cultural hub will include performance venues and high grade residential housing developments. In addition, West Kowloon will be served by Hong Kong’s MRT railway system and in future is expect to be one of the station halts on the proposed Hong Kong to Guangzhou high speed railway line.

Another possible site is a proposed new town with science parks proposed for construction in Hong Kong’s New Territories near the border with Shenzhen in China. The new town project is at the feasibility study stage, with completion due sometime after 2020. The new town will consist of various districts with teaching buildings, R&D facilities and residential housing for students and lecturing staff and their families.

David Hayes writes on energy matters from Asia. Email: cospp@pennwell.com

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