One Bangkok (Suanlum) District Cooling Plant

Scope of works

District cooling plant c/w thermal energy storage, external chilled water loop and energy transfer stations, powered by 2 × 69 kV feeders with energy billing metering.

One Bangkok is district cooling done at city-block scale: a central plant with thermal energy storage, an external chilled water loop crossing a dense mixed development, and energy transfer stations at each plot where cooling changes hands commercially. The design questions were the classic ones — plant staging against a load that builds over years, storage sized to shift the afternoon peak, and a loop that must accept future connections without being rebuilt.

Power arrives over two 69 kV feeders, and every transfer station carries energy billing metering, because in a scheme like this the meter is the revenue instrument. Our involvement spanned the plant, the reticulation and the transfer stations as one hydraulic and commercial system.

Technical particulars

Plant type

District cooling plant

Thermal storage

Thermal energy storage system

Distribution

External chilled water loop + energy transfer stations

Power intake

2 × 69 kV feeders

Metering

Energy billing meters

What this kind of commission involves

A district cooling or co-generation commission runs from load modelling and commercial feasibility through to a plant that has to hold its output for twenty-five years. The engineering divides into three parts that are usually contracted separately but must be designed as one system: the central plant, the reticulation between plant and buildings, and the energy transfer station inside each connected building where the cooling is measured and sold.

Disciplines engaged

• Cooling load modelling, diversity analysis and plant staging strategy
• Chiller selection — electric centrifugal, steam or hot water absorption
• Thermal energy storage sizing and charge/discharge control (ice or chilled water)
• Primary, secondary and condenser water hydraulics; pump selection and speed control
• External chilled water reticulation — routing, sizing, expansion and thermal loss
• Energy transfer station design, heat exchanger selection and control valve authority
• Energy billing metering, measurement boundary and tariff structure
• High voltage intake, standby generation and plant electrical distribution
• Plant automation, sequencing, trending and operator interface
• Testing, commissioning and performance verification against contract kW/RT

What we watch for

The failures that recur on this building type, and where we look for them.

• Low delta-T on the consumer side, which quietly destroys plant efficiency and loop capacity
• Optimistic connected-load forecasts leading to plant that spends its life at part load
• Metering boundaries left undefined until the first disputed invoice
• Storage sized in tons instead of ton-hours, so the peak is never actually shifted

The following describes the standard engineering scope for this sector. The specific scope of any individual commission is set by its brief and contract.

Project location