About HMU and their role in Smart-Pumps

The Hellenic Mediterranean University (HMU), based in Greece, acts as the project coordinator and a key technical partner in Smart-Pumps. Its primary mission is to translate advanced design concepts into functional, high-performance heat pump hardware.

To achieve this, the HMU research team has developed two innovative heat pump configurations: an air-to-water and a water-to-water system. Both setups utilise R290 (propane) as an eco-friendly refrigerant, directly aligning with strict European environmental sustainability targets. 

Figure 1: Air – to – Water Heat Pump.

Figure 2: Water – to – Water Heat Pump.

HMU’s technical contribution is divided into two operational streams:

  • The Design and Manufacturing Team: focuses on advanced heat exchanger concepts, topology optimisation, TPMS/gyroid lattice geometries, and consolidated components. This work is strictly guided by Design for Additive/Hybrid Manufacturing principles to ensure that these complex shapes are genuinely manufacturable.
  • The Computational Modelling Team: supports the development through high-fidelity numerical evaluation, including Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), and thermodynamic comparisons against commercial benchmark systems.

Current focus and contributions

Building on these dual streams, HMU is moving away from optimizing isolated parts. Instead, the team is redesigning critical components around full system needs, balancing heat transfer performance, compactness, and digital control.

A primary output of this approach is the development of Triply Periodic Minimal Surface (TPMS) gyroid-based heat exchangers. These highly complex geometries maximize surface-area-to-volume ratios, achieving exceptional thermal performance within highly compact physical spaces.

Figure 3: Design of Gyroid Heat Exchanger in scale for heat transfer analysis.

Figure 4: Results of heat transfer analysis of Gyroid Heat Exchanger.

In parallel, the team has developed:

  • An advanced internal heat exchanger (IHX) with a bio-inspired beehive geometry to optimize refrigerant superheat and subcool control.
  • A consolidated distributor-collector device that integrates smart valving and embedded temperature sensors into a single component.

Figure 5: Consolidated Distributor – Collector Device.

Figure 6: Consolidation of Distributor – Collector and Temperature Sensor Embedment.

Challenges and Solutions

However, making these new designs a reality poses great challenges. Integrating advanced simulation models with strict manufacturing constraints requires massive computational resources and flawless data exchange between design environments.

From a production standpoint, additive processes impose strict limitations regarding build volume, material compatibility, and thin-wall integrity. At the operational level, accurately controlling the two-phase flow of R290 demands precise local liquid-gas tracking, which conventional sensors simply cannot capture.

To address these specific barriers, HMU implemented a data-driven, iterative workflow. They combine conceptual design with high-fidelity simulations, followed by physical verification using FFF-printed PETG prototypes. This practical step allows the team to assess flow behavior and resolve structural uncertainties safely before moving to final metallic production.

Figure 7: Prototype of Gyroid Heat Exchanger printed by FFF method (PETG material) using Prusa PRO HT90 3D Printer.

Impact on heat-pumps’ technology

Ultimately, this continuous technical iteration bridges the gap between theoretical laboratory research and industrial reality. HMU’s work demonstrates how additive and hybrid manufacturing can transition the HVAC sector from geometry-limited design to performance-driven, lifecycle-aware engineering.

By validating these technologies in a real heat pump context, the project establishes a scalable methodology for producing resource-efficient thermal components. In the long term, integrating embedded sensing and digital connectivity will allow these advanced systems to act as flexible, grid-interactive energy assets, capable of responding dynamically to user demand and renewable energy availability on the European grid.