How to compare ammonia refrigeration suppliers: design, safety, equipment, controls and total cost

1. Evaluating system design

System design is where supplier quality diverges first. Two bidders given the same cold store will rarely propose the same plant — the differences live in suction levels, charge, and how the plant behaves at part load, which is where it will spend most of its life.

• Duty stated per suction level at your design ambient — not a single headline kW figure
• Evaporating and condensing temperatures the design is built around, with margins stated
• Refrigerant charge in kg, and whether a low-charge or pumped overfeed architecture is proposed and why
• Part-load efficiency: compressor staging, VSD strategy and expected COP at 50–70 percent load, not only at design point
• Redundancy philosophy: N, N+1, or an explicit accepted downtime window
• Heat-rejection type (evaporative, air-cooled, adiabatic) matched to your water availability and climate
• Expansion provision: whether a second phase can be added without replacing the machine room

2. Evaluating safety scope

Ammonia is a safe industrial refrigerant when the safety scope is complete — and an expensive liability when it is value-engineered out of a bid. Safety scope is the most common place where a cheap quote is simply a smaller quote.

• Named design code: IIAR-2, EN 378, or local equivalent, stated in the proposal
• Machine-room ventilation: normal and emergency rates, and who supplies the emergency fans
• NH₃ detection: number and location of sensors, alarm thresholds and integration with ventilation and shutdown
• Pressure relief and discharge routing, including where relief vents terminate
• Documentation package: P&IDs, HAZOP participation, PSM/RMP or Seveso documentation support where applicable
• Commissioning safety: pressure testing, tightness testing and charge procedures included in scope
• Operator training and handover documentation in your working language

3. Evaluating compressors and evaporators

Compressors and evaporators are the heart of the plant and the easiest part of a bid to compare badly. Brand names tell you little; configuration and selection at your duty tell you almost everything.

• Compressor type and count: screw versus reciprocating, and how many machines share the duty
• Selection point: each compressor's efficiency at your evaporating and condensing temperatures, from the manufacturer's selection software output
• Part-load method: slide valve, VSD, or cylinder unloading — and the efficiency penalty of each
• Oil management: separator efficiency, oil cooling method and expected oil carryover
• Evaporator type per room: ceiling units, dual discharge, blast cells — with airflow and throw matched to the room
• Defrost strategy: hot gas, electric, water or air, and the energy penalty of the chosen method
• Materials and hygiene class suited to your product and washdown regime

4. Evaluating controls and monitoring

Controls decide what the plant actually costs to run. Two identical compressor packages can differ by double-digit percentages in annual energy purely through control strategy, floating head pressure and suction optimisation.

• PLC/SCADA platform named, with local panel and remote access scope defined
• Floating condensing pressure and suction-pressure optimisation included, not optional extras
• Energy metering and reporting: kWh per compressor, per room and per suction level
• Alarm philosophy: which alarms dial out, to whom, and with what response workflow
• Integration interfaces: BMS, warehouse management or production systems, with protocols stated
• Data retention and cybersecurity approach for remote connections
• Who owns the software licences and source access after handover

5. Comparing total project cost

Headline CAPEX is the least comparable number in an ammonia bid. Normalise every offer to the same design basis, then compare installed cost and 10-year operating cost side by side.

• Installed cost per kW at the same duty, ambient and redundancy level
• Exclusions listed explicitly: civils, machine-room construction, electrical supply, water treatment, cranes, permits
• Annual energy from each bidder's stated COP at your operating profile and electricity tariff
• Maintenance: contract price, expected overhaul interval and cost, and spare-parts pricing basis
• Commissioning, performance testing and training stated as line items, not assumptions
• Warranty duration and what voids it
• Payment milestones tied to verifiable delivery stages, not calendar dates

Best for

Commercial and industrial cold chain projects, typically from USD 250,000 upward: cold rooms, refrigerated warehouses, blast freezers, processing plant refrigeration and distribution hubs.

Not a fit: domestic refrigerators, household or office air conditioning, small repair call-outs, or spare-parts-only enquiries.

Typical cold chain project types

• Fruit, vegetable and horticulture cold storage with pre-cooling
• Meat, poultry and fish chilling plus blast freezing
• Dairy and beverage process cooling
• Pharma and vaccine GDP cold chain (2–8 °C, −20 °C, −70 °C)
• Refrigerated warehouses, 3PL hubs and mobile cold rooms

Cold room vs refrigerated warehouse

A cold room is a single insulated chamber, usually under ~500 m³, serving one process or storage step. A refrigerated warehouse is a multi-zone facility with racking, docks, air locks and a central refrigeration plant, sized by pallet positions and daily throughput rather than by room volume.

What affects project cost

• Storage volume, pallet positions and daily throughput
• Target temperature and ambient design conditions
• Refrigerant choice (NH₃, CO₂, HFC) and plant redundancy
• Panel thickness, doors, air locks and civil works
• Backup power, solar, freight, duties and commissioning

Temperature range checklist

• +12 to +16 °C — bananas, potatoes, curing
• +2 to +8 °C — pharma GDP, dairy, fresh produce
• 0 to +4 °C — meat, fish and chilled distribution
• −18 to −25 °C — frozen storage
• −35 to −40 °C — blast freezing and IQF

RFQ checklist

• Product, temperature and daily intake
• Room dimensions or required pallet positions
• Site location, ambient conditions and power supply
• Backup autonomy and redundancy level
• Budget range, timeline and scope exclusions

Build your RFQ →

Project type cluster

Agriculture and horticulture cold storage

Pre-cooling plus storage for fruit, vegetables and flowers, usually +2 to +12 °C with high humidity control and fast pull-down after harvest. Sized by daily intake in tonnes, not only by room volume.

Meat, poultry and fish cold storage

Chilling at 0 to +4 °C combined with blast freezing at −35 to −40 °C and frozen holding at −18 to −25 °C. Hygienic panels, drainage and separate dirty/clean flows are part of scope.

Pharmaceutical and API cold storage

GDP-compliant 2–8 °C rooms, −20 °C and, for some active pharmaceutical ingredients and biologics, −70 °C. Requires mapping, IQ/OQ/PQ, N+1 refrigeration, backup power and alarm escalation.

Refrigerated warehouse and 3PL distribution

Multi-zone facilities sized by pallet positions, dock doors and daily throughput. Typical scope covers racking, air locks, dock levellers, a central plant and an energy strategy.

Food processing plant refrigeration

Process cooling, chillers, spiral or tunnel freezers and glycol loops integrated with production lines. Usually specified alongside ISO 22000 and HACCP food safety requirements.

Mobile and containerised cold rooms

Plug-and-play 20 ft or 40 ft refrigerated units for seasonal peaks, remote sites and temporary capacity, typically −25 to +8 °C with optional solar or generator support.