This project will develop a techno-economic and thermodynamic evaluation for integration of heat pump technologies into Alumina refineries and other potential HILT CRC industries. First, a thorough review of heat pump technologies including commercial compressors and working fluids will be conducted. Based on technology assessments and the industrial heat demand, i.e. the relevant temperatures of waste and process steam, the most suitable configurations of heat pumps for integration into the process will be selected and assessed in terms of technical feasibility, and thermodynamic and economic efficiencies.

New technology to accommodate multiple energy sources and offer flexibility in switching between them

Using computer simulations and thermodynamic modelling, the project compared several heat pump technologies, including mechanical vapour recompression (MVR), thermal vapour recompression (TVR), vapour compression heat pumps (VCHP), and cascaded heat pump (CASHP) systems.

The project included a technoeconomic analysis of the levelised cost of heating (LCOH) for these technologies in steam generation using waste heat sources with temperatures ranging from 50°C to 100°C.

Key findings included:

• MVR systems are most effective for recovering clean water vapour at temperatures above 80°C, particularly for temperature lifts below 40°C.
• TVR systems demonstrate the lowest capital cost but require a source of motive steam. Economic viability is significantly affected by whether motive steam is generated using gas or electricity.
• CASHP systems are more suitable for contaminated heat sources but with higher LCOH due to increased capital and operational costs.
• Hybrid MVR-VCHP systems offer the best balance between cost and performance, particularly when handling contaminated or liquid-phase waste heat sources.

HILT CRC Project Summary RP2.011 Thermal Energy Recovery using High-Temperature Heat Pumps