Thermal Management & Cooling System

Revision D Thermal Design Basis

GA-D07 Thermal Rack

The Revision D thermal-management equipment is consolidated within the GA-D07 thermal-rack zone.

The radiator and fans occupy the upper portion of the thermal rack, positioned above the plate heat exchanger, circulation pumps, reservoir and associated lower-level thermal equipment.

A minimum 600 mm free radiator-face clearance is retained to support airflow and prevent discharge-air recirculation.

T01 — 40 kW Air-Cooled Radiator

Final fin density, tube construction, coolant-side pressure drop, fan static pressure, sound power, motor power, environmental rating and exact mounting remain vendor-controlled.

T02 — EC Variable-Speed Radiator Fans

Two EC fans are integrated with the radiator assembly and provide modulated airflow according to actual heat-rejection demand.

Fan operation is coordinated with coolant temperature and the three-way temperature-control valve rather than operating continuously at maximum speed.

Fan status and fault feedback are incorporated where supported by the selected radiator/fan package.

T03 — 40 kW Plate Heat Exchanger

Final plate count, channel pattern, approach temperature, pressure drop, fouling factor and construction are subject to the final thermal model and selected vendor.

T04 — Duty / Standby VSD Cooling Pumps

T05 — 50 L Diaphragm Expansion Tank

T06 — 80 L 316L Coolant Reservoir

T07 — Cooling Filter

The main cooling loop incorporates a 100 micron filtration baseline to protect the motor, VFD/electronics cooling passages and other thermal equipment.

Differential-pressure indication is required so restriction and filter condition can be monitored.

T08 — DN40 Three-Way Temperature-Control Valve

Exact Cv/Kv, actuator configuration, fail position and control characteristic remain validation/vendor controlled.

316L Cooling Piping

High-point venting and low-point drainage are provided where the physical arrangement can trap air or liquid.

Motor, VFD & Power-Electronics Cooling

The primary motor uses a closed-loop water-jacket cooling interface. Volume 11 supplies coolant within the main cooling-loop envelope, while final branch flow, pressure and permitted temperature limits remain controlled by the selected motor OEM.

Liquid-cooled VFD/AFE and converter branches are integrated into the DN40 loop where required by selected equipment. Air-cooled equipment remains outside the liquid-loop heat allocation and must be addressed through the applicable ventilation architecture.

The 15 kW recovery PMG remains air cooled with a 1 kW thermal-loss allowance and is not a locked main-loop liquid load.

Independent BESS Thermal Systems

Revision D maintains two independent BESS cabinet thermal systems. They are not connected to the main liquid loop unless the selected battery supplier explicitly certifies a shared cooling arrangement.

Final internal battery cooling hardware, refrigerant system, condensation control, module thermal interfaces, temperature setpoints and fire-response interaction remain battery-supplier controlled.

Thermal Instrumentation

Demand-Controlled Thermal Operation

Revision D specifically replaces unnecessary fixed-speed cooling operation with demand-controlled thermal management.

Duty-pump speed and EC-fan command follow actual thermal demand, minimum stable flow, equipment cooling requirements and validated control margins.

At low heat load or cold ambient conditions, the three-way valve may bypass or mix flow to avoid overcooling. As coolant temperature rises, radiator exposure and EC-fan demand increase.

Cooling Failure Management

Real-World Thermal Installation Sequence

1. Verify GA-D07 / SP-13 thermal-rack footprint, structural supports and service clearances.
2. Fabricate and install the S355 thermal rack with required stainless-to-carbon-steel isolation.
3. Install the T01 radiator and two T02 EC fans in the upper rack with at least 600 mm clear airflow space.
4. Install the T03 PHE, T04 duty/standby pumps, T05 expansion tank, T06 reservoir, T07 filter and T08 three-way valve.
5. Install the L-401S/R DN40 316L supply and return piping and the L-402 DN20 fill/vent service.
6. Install FT-401, temperature sensors, pressure sensors and LT-401 reservoir-level instrumentation.
7. Connect the motor water-jacket and approved liquid-cooled power-electronics branches using OEM connection requirements.
8. Integrate any liquid-cooled recovery active rectifier only after the selected converter cooling arrangement is confirmed.
9. Install the two independent BESS thermal systems according to battery-supplier requirements.
10. Complete pump changeover, EC-fan, three-way-valve, thermal alarm, trip and status wiring.
11. Flush and clean the main cooling circuit and inspect or replace the filter as required.
12. Pressure/leak test the loop using an approved procedure within installed component ratings.
13. Fill and vent the loop, establish expansion pressure and verify reservoir level.
14. Commission temperature regulation, standby-pump takeover, fan modulation and valve control.
15. Perform worst-case heat-rejection FAT/SAT and archive final measured flow, pressure, temperature and heat-balance data.