Building 6 — Central Thermal Facility

[IMAGE: Two-storey industrial building with a taller central high-bay section, pale concrete cladding, and an adjacent fenced electrical substation. Louvred panels run along the upper section]

Figure 1: Exterior of Building 6, viewed from the south-east service road. The high-bay section (centre) houses the main thermal systems. The electrical substation is visible on the left. Note the louvred ventilation panels at upper level and the personnel access door (ground floor, right of centre).

Overview

Building 6 serves as the Institute's central utility plant, supplying process steam and hot water to all campus buildings via an insulated underground distribution network. It also houses on-site electrical generation equipment and provides a platform for thermal systems research at industrially relevant scales.

Completed in 1998, the building was designed with a high-bay central hall to accommodate tall process equipment and to facilitate maintenance access using the installed overhead crane.

Thermal Input Systems

Primary thermal input is provided by a bank of high-capacity electric immersion heaters arranged in three parallel arrays. Each array is independently controllable and fed from the site's dedicated 11 kV supply via step-down transformers located in Substation B6, adjacent to the building.

The decision to employ electric heating rather than fossil-fuel-fired boilers was made on the basis of operational flexibility, reduced on-site fuel storage requirements, and the availability of firm electrical supply capacity. Combined nominal thermal rating of the heater arrays is [redacted] MW_th.

[IMAGE: Technical cross-section drawing of an industrial building interior showing a large overhead crane, turbine set at floor level, pipe runs, heat exchanger vessels, and an underground heater vault]

Figure 2: Schematic cross-section of the Building 6 high-bay hall showing major equipment. The 50-tonne polar crane, turbine-generator set, heat exchangers, and heater array vault are indicated. (Some details omitted.)

Electrical Generation

A back-pressure steam turbine coupled to a synchronous generator provides a portion of the site's electrical demand during normal operations. The turbine is rated for approximately 3.5 MW_e and operates on steam raised by the electric heater arrays. This arrangement, while unusual for a conventional steam plant, permits precise control of steam conditions and isolates the thermal system from external fuel supply considerations.

Electrical output from the turbine-generator set is synchronised with the site supply through switchgear located in Substation B6. Under normal conditions the campus operates islanded from the external grid for extended periods.

Overhead Crane

The high-bay hall is serviced by a 50-tonne electric overhead travelling crane of polar configuration — that is, the crane bridge rotates about a central column, providing 360-degree coverage of the hall floor. This arrangement was selected to maximise hook coverage within the circular footprint of the high-bay area and to facilitate the lifting and positioning of heavy equipment components during installation, maintenance, and (if ever required) decommissioning activities.

All lifting operations are conducted in accordance with ISOCTA Lifting Operations Procedure LOP-6.2.

[IMAGE: Interior view from an elevated gallery showing a large rotating crane bridge spanning a circular industrial hall, with turbine equipment visible below]

Figure 3: View of the polar crane from the operating gallery. The rotating bridge is visible above the turbine casing. The central column and slewing ring are indicated. (Photograph taken during commissioning, 1998.)

Heat Transfer Loops

Two independent closed-loop thermal transfer systems operate from Building 6:

Primary Loop — High-temperature circuit supplying process steam at 1.2 MPa saturated conditions to Buildings 1, 4, and 5. This loop includes shell-and-tube heat exchangers for steam condensation and condensate return.
Secondary Loop — Medium-temperature hot water circuit serving building heating, domestic hot water, and the cryogenics facility's pre-cooling heat exchangers in Building 2.

Both loops are instrumented for flow, temperature, and pressure monitoring. Data is logged to the Site SCADA system at 1-second intervals.

Substation B6

The adjacent electrical substation (designated Substation B6) provides 11 kV / 415 V transformation and distribution for Building 6 systems and serves as the campus interconnection point. It is equipped with:

Two 11 kV incoming feeders (one normally open)
11 kV / 415 V cast-resin distribution transformers (3× 2.5 MVA)
Generator synchronisation and protection switchgear
Reactive power compensation (switched capacitor banks)
Single-line diagram (restricted)

Research Use

Beyond its utility function, Building 6 provides a platform for thermal hydraulics research at scales not achievable in laboratory settings. Current and past projects include:

Two-phase flow characterisation in large-diameter pipe geometries — project summary
Heat exchanger fouling studies under extended operation — project summary
High-temperature materials compatibility testing in flowing steam environments — project summary
Transient thermal response of multi-loop systems under load-following conditions — project summary

Specifications Summary

Parameter	Value / Description
Building footprint	~1,200 m²
High-bay height (to crane rail)	18.5 m
Overhead crane	50 t SWL, polar configuration, 360° rotation
Heater array thermal rating	[Redacted] MW_th (combined)
Turbine-generator	Back-pressure, ~3.5 MW_e, 11 kV synchronous
Primary loop conditions	Saturated steam, 1.2 MPa, 188°C
Secondary loop conditions	Hot water, 0.4 MPa, 85–110°C
Substation transformers	3× 2.5 MVA, 11 kV / 415 V
Construction completed	1998