Duluth, MN2023Ammonia refrigeration + heat recovery

Harbor District cold-storage warehouse

Waste heat now warms 42,000 sq ft of office and shipping bays year-round.

Harbor District cold-storage warehouse

The challenge

The original scope came in as a straightforward replacement. Once we opened the mechanical rooms and pulled twelve months of BAS data, the picture shifted. What looked like an aging system was actually a design mismatch — the loads had drifted over two decades of tenant fit-outs, and the equipment was fighting the building.

The solution

A phased conversion. New equipment sized to the actual load, not the load stamped on the drawings. Controls rewritten. Sequences of operation rebuilt from scratch. The old system stayed live through six months of installation so tenants never lost service.

The result

First full winter: 41% reduction in energy cost against the prior year, normalized for weather. Peak demand down 32%. Zero occupant complaints for four straight months. And a client who is now on year three of a continuing maintenance contract.

What it cost

Flat-rate project pricing, quoted before work began.

$2.71M
Total investment
Ammonia compressor package and evaporators
$1.24M
Heat-recovery loop and hydronic distribution
$611,000
Insulated envelope penetrations and dock seals
$302,000
Safety systems, detection, and PSM documentation
$328,000
Controls, commissioning, and operator training
$229,000

Utility efficiency rebate of $214,000 applied at final billing.

Estimated annual savings
$468,000 / yr
Simple payback
5.8 years

Figures reflect this project's scope and conditions. Your building will price differently — get a scoped estimate.

Ready when you are

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