Ammonia refrigeration

图片16.png

Application, Material Selection, and Advantages of KDP Plate Heat Exchangers in Ammonia Refrigeration Systems

Ammonia (NH₃), as an efficient and environmentally friendly natural refrigerant, is widely used in industrial refrigeration, cold storage, and food processing. Plate heat exchangers (PHEs) are increasingly replacing traditional shell-and-tube heat exchangers in ammonia refrigeration systems due to their high heat transfer efficiency and compact design. Below is a detailed analysis of their applications, plate/gasket material selection, comparisons with other heat exchangers, and key advantages.

Contact Us

Applications of KDP PHEs in Ammonia Refrigeration

Ammonia Evaporator

Function:

Liquid ammonia evaporates under low pressure, absorbing heat to cool secondary refrigerants (e.g., glycol-water or brine).

Applications:

Cold storage (-30°C to +5°C).

Food freezing production lines.

Design Considerations:

Freeze-proof design (e.g., wider plate spacing) for low-temperature operation.

Corrosion-resistant materials for the ammonia side.

aa69cb99cf5176f59c9eb502f88612eb.jpeg
c94dbd09a05f20dedb0e55b188e10ffc.jpeg

Ammonia Condenser

Function:

High-pressure ammonia gas condenses into liquid, releasing heat to cooling water or air.

Applications:

Industrial refrigeration units.

District cooling systems.

Design Considerations:

Pressure-resistant design (typically ≤25 bar).

Anti-fouling measures (e.g., wide-gap plates) for the cooling water side.

Plate and Gasket Material Selection (Ammonia-Specific)

Ammonia is highly permeable and corrosive, and low-temperature conditions impose strict material requirements.

Plate Materials

MaterialApplicationsAdvantagesLimitations
316L Stainless SteelGeneral ammonia systems (evaporators/condensers)Cost-effective, chloride-resistantLong-term ammonia exposure may cause stress corrosion.
Titanium (Ti)High-purity ammonia systems, seawater-cooled condensersExcellent ammonia resistance, 20+ year lifespanHigh cost (3–5× stainless steel).
Nickel Alloy (e.g., 625)High-temperature/pressure systems (e.g., heat pumps)Resists high temps (>200°C) and corrosionVery expensive.
Aluminum (Coated)Ultra-low-temperature evaporators (<-50°C)Lightweight, high thermal conductivityRequires coatings, shorter lifespan.

Gasket Materials

Ammonia causes rubber swelling; specialized materials are required:

MaterialTemperature RangeAmmonia ResistanceApplication Examples
Hydrogenated Nitrile (HNBR)-40°C to +150°CResists ammonia and oil, 5–8-year lifespanAmmonia compressor oil coolers.
Fluoroelastomer (FKM)-20°C to +200°CResists ammonia and high temps, poor low-T elasticityHigh-T ammonia condensers (>100°C).
EPDM-50°C to +150°CGood low-T performance, but degrades with prolonged ammonia exposureLow-T evaporators (cold storage).
PTFE-Encapsulated-200°C to +260°CFully ammonia-proof, but stiff and costlyExtreme conditions (e.g., chemical plants).

Comparison with Other Heat Exchangers (Shell-and-Tube / Brazed Plate)

(1) PHE vs. Shell-and-Tube Heat Exchanger

FeaturePlate Heat ExchangerShell-and-Tube Heat Exchanger
Heat EfficiencyHigh (K-value 4000–8000 W/m²·K)Low (K-value 800–1500 W/m²·K)
Ammonia Charge50%+ reduction (low hold-up volume)High charge, greater leakage risk
MaintenanceRemovable plates, replaceable gasketsRequires professional cleaning
Pressure RatingMedium (≤25 bar)High (≤100 bar)
CostHigher upfront cost, lower energy useLower upfront cost, higher energy use

Case Study:

Cold storage retrofit: A logistics center replaced shell-and-tube with PHE, reducing ammonia charge by 60% and saving 12% energy annually.

PHE vs. Brazed Plate Heat Exchanger

FeatureGasketed PHEBrazed PHE
Ammonia ResistanceRequires specialized gaskets (e.g., HNBR)No gaskets, no leakage risk
MaintenanceCleanable, replaceable gasketsNon-serviceable, must replace if clogged
ApplicationsHigh-flow, fouling-prone systemsClean fluids, small systems (e.g., heat pumps)
CostModerateHigh (complex brazing process)

Case Study:

Ammonia heat pump: Brazed PHEs are used for refrigerant-water heat exchange but cannot be cleaned, limiting them to clean-water applications.

Key Advantages of KDP PHEs in Ammonia Refrigeration

(1) High Efficiency, Energy Savings

Corrugated plates:

Turbulent flow enhances heat transfer, 30–50% more efficient than shell-and-tube.

Case:

A meat processing plant reduced compressor power by 18% after switching to PHE evaporators.

(2) Reduced Ammonia Charge, Enhanced Safety

1/3 the hold-up volume of shell-and-tube, minimizing leakage risks (complies with F-Gas regulations).
Case:

An EU cold storage project avoided safety reviews by keeping ammonia charge <10 tons.

(3) Modular Design, Load Flexibility

Adjustable plate count:

Seasonal adaptations (e.g., adding condenser plates in summer).

Case:

A brewery reduced plates by 20% in winter, cutting pressure drop by 15%.

(4) Easy Maintenance, Long Lifespan

Quick disassembly:

Ideal for ammonia systems with oil/contaminants.

Case:

A seafood cold storage facility cleaned PHEs quarterly, achieving 10+ years without corrosion.

(5) Superior Low-T Performance

EPDM gaskets withstand -50°C, suitable for ultra-low-T freezers (e.g., tuna storage).
Case:

A Japanese -60°C freezer used titanium plates + EPDM, operating flawlessly.

Common Challenges & Solutions

Solutions:

Ammonia Leakage

Use FKM/HNBR gaskets (ammonia-resistant).

Regular leak checks (ammonia sensors + bubble tests).

Freeze Cracking

Use wide-gap plates in evaporators (anti-icing).

Add glycol antifreeze loops.

Oil Fouling

Select nickel alloy plates for oil coolers.

Install CIP (clean-in-place) systems.

Summary

Advantages of PHEs in Ammonia Refrigeration

AdvantagePerformancevs. Shell-and-Tube/Brazed PHE
Energy EfficiencyHigh heat transfer, lower compressor power20–30% more efficient than shell-and-tube
Safety50%+ less ammonia chargeComplies with strict environmental laws
MaintenanceEasy cleaning, gasket replacementShell-and-tube is hard to clean; brazed PHEs are unserviceable
Low-T OperationEPDM gaskets withstand -50°C, titanium resists corrosionShell-and-tube prone to freeze cracks

Selection Guidelines

Choose PHEs for:

Ammonia charge-limited systems (e.g., cold storage).

High-maintenance applications (e.g., oil-laden evaporators).

Choose Shell-and-Tube/Brazed PHEs for:

Ultra-high-pressure systems (>25 bar).

Small-scale or ultra-pure ammonia systems.

With proper material selection (e.g., titanium plates + HNBR gaskets) and design optimization, PHEs deliver high efficiency, safety, and longevity in ammonia refrigeration, making them the ideal alternative to traditional heat exchangers.

Our Core Strengths

In the petrochemical industry, equipment needs to withstand high temperature, high pressure, corrosion, scaling and other multiple tests. We are the preferred supplier of heat exchanger solutions for harsh working conditions due to the following core advantages:

3add9fe2433f4382d7ae4e54ca4451e.jpg
Customized design

Optimized heat transfer solutions according to petroleum/chemical process requirements

bdfa74348693a760e8cba3b877ae1d1.jpg
Diversified products

Full range of plate heat exchangers, condensers, evaporators, etc.

1051bf136be1a28c94f692b87013f93.jpg
High reliability

Strict quality control, adapt to high temperature, high pressure and corrosive environment.

e2563e19e6f2bce6f7de272d873642a.jpg
Full life cycle service

From selection to maintenance, to ensure long-term stable operation.

Top