Case Study #18:
Plastic Heat Exchangers in Commercial Fish Farming – Culiacán, Mexico
Initial situation
Maintaining strict water quality and temperature control is critical in modern aquaculture, especially in saltwater fish farming. Metal contamination and corrosion are key concerns, as even trace amounts of metal ions can harm sensitive fish stocks and disrupt breeding programs. As a result, leading fish farms increasingly require equipment that is non-metallic, highly durable, and safe for continuous use in seawater.
Challenge
A major fish farming operation in Culiacán, Mexico, set out to upgrade its rearing systems for premium fish species. The customer needed high-capacity heat exchangers for three separate installations, totaling 15 units. The application required cooling of recycled ocean water across a network of fiberglass tanks and pools, with each system designed to maintain stable, low water temperatures ideal for fish health and growth.
Specific technical requirements included:
- Non-metallic, corrosion-resistant construction: To prevent metal ion leaching and withstand continuous seawater exposure.
- Integration with existing fiberglass tanks: Including open-top tanks and pools, some serving multiple fish tanks.
- Large heat transfer capacity: Aiming for a total cooling load of 15,000,000 BTU/hr.
- Consistent temperature control: Capable of cooling water from 84°F to 77°F (or as low as 75°F) over a 24-hour period, with continuous circulation.
- Sanitary operation: The seawater is filtered via sand and UV sterilization before recirculation.
Solution
CALORPLAST supplied modular Immersion-Type Heat Exchangers, constructed from high-performance PE-RT (Polyethylene of Raised Temperature resistance) for all wetted components. This plastic material offers robust corrosion resistance and complete immunity to seawater-induced degradation, ensuring no metal ions are released into the aquatic environment.
Key project highlights:
System Design:
- Each heat exchanger was suspended directly in the process tanks and pools, maximizing contact with circulating seawater for efficient heat exchange.
- Units were sized to fit the unique dimensions of each tank, with special consideration for compact integration and easy future servicing.
- The system accommodates open-top, fiberglass-insulated tanks, allowing for simple installation and compatibility with existing infrastructure.
Performance:
- Each installation is capable of handling significant cooling loads, with rapid cooldown cycles designed to maintain water temperatures critical to fish health.
- PE-RT construction ensures long-term reliability, zero metal contamination, and low maintenance even in harsh marine conditions.
Result
The customer was able to achieve reliable, consistent cooling of all fish tanks, maintaining optimal temperature and water purity without risk of metal leaching or equipment failure. The modular plastic heat exchanger solution delivered:
- Improved fish health and yield thanks to precise temperature control and the elimination of metal ions.
- Reduced operational costs due to the low-maintenance, corrosion-free nature of the plastic systems.
- Seamless integration with existing tanks and filtration systems, with flexibility for future system expansions.
By selecting CALORPLAST plastic immersion heat exchangers, the Culiacán project demonstrated a scalable and sustainable solution for demanding aquaculture environments.
