Waste Heat Recovery from Low Temp Thermal Energy
Project Overview
In an era where industrial decarbonization is critical to meeting climate goals, we partnered with a forward-thinking client, a major ASX listed company that was looking for an innovative heat recovery solution.
The Opportunity
Our client faced a common situation found in many process systems where vast amounts of thermal energy is produced at low temperature. Our client’s facility operated a closed-cycle cooling water system to reject this heat to the atmosphere. At the same time, the facility required continuous heating of potable water from 18 °C to 38 °C, previously achieved using fuel-based heating.
By recovering the waste heat and reintegrating it into the process, the client hoped to significantly reduce both energy use and emissions but had to comply with strict food safety requirements.
The Challenge
To use captured waste heat from the closed-cycle cooling water circuit to reduce our client’s energy consumption and its carbon footprint.
Most critically, absolute separation between the fluid streams that met food safety requirements had to be maintained and a strong financial return was needed to provide a prompt return on investment (ROI) and justify the capital investment.
Key Technical Data:
- Hot side flow: 40°C at 30-12 m³/hr (variable)
- Cold side flow: 18°C at 12-36 m³/hr (variable)
- Temperature target cold side: 38°C
- Low pressure drop
Non-negotiables:
- Zero cross-contamination between fluid streams
- Food-grade hygiene standards
- Acceptable ROI
Technical hurdles:
- Low temperature differential meant conventional heat exchangers would struggle to achieve the required effectiveness
- Variable flow rates on both the hot and cold sides added significant complexity to the design.
The Solution
The solution – a custom designed and engineered FluidEX® Fail-safe plate heat exchanger system from Fluid Dynamics.
Fluid Dynamics’ engineering team utilised advanced thermal design software to simulate performance across the full range of operating conditions. This modelling allowed the heat exchanger configuration to be optimised to provide reliable performance predictions across the entire range of our client’s variable flow scenarios.
The FluidEX® Fail-safe plate design was crucial to this application. Unlike standard plate heat exchangers, FluidEX® Fail-safe plate heat exchangers incorporate a double-wall barrier between the hot and cold fluid streams. Should a leak develop in one plate, the leak will drain between plates and not cross-contaminate – a critical feature which is ideal for food-grade applications.
Technical Specifications:
- Construction: SS316 stainless steel plate and frame technology
- Plate Design: FluidEX® Fail-safe plates with enhanced heat transfer area
- Sealing: Food-grade EPDM gaskets
- Safety Features: Dual-plate barrier to remove the risk of fluids mixing
- Compliance: Full food-grade hygienic components
The Result
The FluidEX® Fail-safe system is installed and the client reports it is operating successfully and delivering impressive environmental, operational and financial benefits from the re-use of waste heat.
Environmental:
- CO₂ reduction: >9 t per year:
- Fuel savings: >36 t per year
- Energy savings: ~1,800 GJ per year
Operational:
- Consistent performance across variable flow conditions
- Zero contamination issues
- Full compliance with food safety regulations
Financial:
- Return on Investment: ~15 months
- Free Heating: ~20,000,000 litres of water per year
The Bigger Picture
This project exemplifies how industrial decarbonization does not require revolutionary technology, just the smart application of proven engineering principles to recover energy that would otherwise go to waste.
Not only does a FluidEX® Fail-safe heat exchanger use no energy itself, by matching it with a low-grade heat source and an appropriate heat demand, it will safely redirect otherwise wasted heat away from atmosphere for re-use as valuable energy.
The success of this project clearly demonstrates that even applications with challenging low temperature differentials and variable conditions can achieve excellent results when properly engineered.
Well-designed waste heat recovery systems by Fluid Dynamics can be installed in most industrial facilities with similar cooling and heating demands such as that of our client and will provide a highly cost-effective pathway to reducing a company’s carbon footprint as well as an impressive and genuine ROI.
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