How do you calculate cooling system energy use?

Multiply connected load in kW by runtime in hours. A 12 kW cooling load running 8 hr uses 96 kWh. Multiply by the rate ($0.12/kWh) for a total cost of $11.52 for the shift.

What is the cost per unit of advance for cooling?

Divide total cooling cost by advance output. Here $11.52 across 1000 units of advance is about $0.0115 per unit, a small but trackable slice of the drive's energy cost.

Should I use connected load or measured draw?

Measured average draw is far more accurate. Connected (nameplate) load assumes the compressors run flat out; real chillers modulate with ground temperature and duty, so nameplate over-states energy unless the plant is fully loaded.

Why track cooling cost per unit instead of per hour?

Per-unit cost ties energy to production. The hourly figure here is $1.44/hr, but if advance slows while cooling keeps running, the per-unit cost climbs and exposes a productivity or fouling problem the hourly number hides.

What raises cooling system load on a TBM?

Higher ground and groundwater temperatures, fouled heat exchangers, degraded coolant, and long conveyor runs all push the cooling plant to work harder, raising average draw above the design figure.

Does this include the main drive's own power?

No. This isolates the cooling plant load so you can budget and benchmark it separately from cutterhead drive power, which is a much larger and more variable consumer.

Tunnel Boring & Heavy Civil Equipment calculator

Cooling System Load Calculator

Cooling system load estimates the energy a tunnel boring machine's cooling plant consumes over a shift and what that costs per unit of advance. On a TBM the main-drive chillers, hydraulic coolers, and gantry HVAC run continuously to keep bearing and fluid temperatures in range, and that power draw is a real line item on long civil drives. Site electrical engineers and cost planners use this to allocate cooling energy against production and to spot when a fouled heat exchanger is quietly inflating the power bill. It turns a nameplate load and an electricity rate into shift energy, total cost, and a cost-per-output figure you can benchmark.

What this calculator does

Estimate cooling system load for tunnel boring and heavy civil equipment using production-ready inputs so teams can budget energy cost, compare equipment settings, or include electricity in the quote.
Use it when cooling system load in tunnel boring and heavy civil equipment is up for an upgrade and you want a defensible savings story.
It computes energy used from connected load and runtime, multiplies by the electricity rate for total cost, and divides that cost by advance output for a per-unit energy cost.

Formula used

Total cooling system load energy cost = cooling system load connected load × cooling system load runtime × blended electricity rate
Energy cost per kWh = total energy cost ÷ units processed during runtime

Inputs explained

Cooling system connected electrical load:
Cooling system runtime this shift:
Blended underground electricity rate:
Advance output during runtime:

How to use the result

Use it to budget cooling energy for a shift, allocate power cost against advance, or flag a rising per-unit cost that signals fouling or a control fault.
Connected load is not the same as actual draw; chillers cycle and modulate, so unless you use a measured average kW the energy figure will run high.

Current U.S. benchmarks

As of Apr 2026, industrial electricity averages 8.7 cents per kWh across the U.S. (EIA), up 5.5% from a year earlier. State averages range widely, so plants should confirm against their own tariff.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate cooling system energy use? Multiply connected load in kW by runtime in hours. A 12 kW cooling load running 8 hr uses 96 kWh. Multiply by the rate ($0.12/kWh) for a total cost of $11.52 for the shift.
What is the cost per unit of advance for cooling? Divide total cooling cost by advance output. Here $11.52 across 1000 units of advance is about $0.0115 per unit, a small but trackable slice of the drive's energy cost.
Should I use connected load or measured draw? Measured average draw is far more accurate. Connected (nameplate) load assumes the compressors run flat out; real chillers modulate with ground temperature and duty, so nameplate over-states energy unless the plant is fully loaded.
Why track cooling cost per unit instead of per hour? Per-unit cost ties energy to production. The hourly figure here is $1.44/hr, but if advance slows while cooling keeps running, the per-unit cost climbs and exposes a productivity or fouling problem the hourly number hides.
What raises cooling system load on a TBM? Higher ground and groundwater temperatures, fouled heat exchangers, degraded coolant, and long conveyor runs all push the cooling plant to work harder, raising average draw above the design figure.

Last reviewed 2026-05-12.