Optimizing PV-Driven Heat Pump Systems for Cost Savings & Energy Independence

Researchers have conducted an extensive study analyzing 30,912 unique scenarios to optimize heat pump systems powered by photovoltaic (PV) energy. Using mixed-integer linear programming (MILP)-based multi-objective optimization (MOO), the team evaluated cost efficiency and self-sufficiency under day-ahead spot market pricing.

Led by scientists from Austria’s Technical University of Leoben, the study introduces a novel approach to flexible heat pump operation in residential settings, enhancing renewable energy integration while reducing grid strain.

Key Findings & Methodology

1. MILP-Based Optimization for Household Energy Management

The researchers developed a Python-based MILP-MOO model, chosen for its ability to:

• Guarantee global optimality in energy cost reduction.

• Integrate demand response programs and renewable energy forecasts.

• Optimize heat pump flexibility to improve self-sufficiency.

“No prior research has comprehensively integrated these objectives within a MILP-based MOO framework at the individual household level,” said Christopher Gradwohl, the study’s corresponding author.

2. Scenario Testing: Variables & Configurations

The study examined six living conditions, including:

• Single-family homes vs. apartments

• Rented vs. owned properties

• Households with 1-2 occupants

These were combined with four building types, accounting for different thermal energy demands based on construction age and heating efficiency.

Additional variables included:

3. Simulation Setup

• Location: Leoben, Austria (1,200 kWh/m²/yr solar irradiation).

• PV System Assumptions:

  • 10% system loss factor

  • 35° tilt angle, south-facing orientation

• Heat Pump Efficiency:

  • Air-source: 0.4

  • Geothermal: 0.35

4. Key Results

• Reduced Grid Load: Flexible heat pump operation lowered peak grid imports/exports.

• Thermal Storage Outperforms Batteries: Systems with thermal storage + heat pumps achieved higher self-sufficiency than those with battery storage, at lower costs.

• Cost vs. Self-Sufficiency Balance: The model successfully minimized energy costs while maximizing self-sufficiency through price-based demand response signals.

Why This Matters for Homeowners & Energy Systems

• Lower Energy Bills: Optimized heat pump + PV systems reduce reliance on grid electricity.

• Grid Relief: Flexible operation eases stress on low-voltage networks.

• Higher Renewable Utilization: More efficient use of solar power decreases fossil fuel dependence.

Final Thoughts

This research highlights the untapped potential of heat pump flexibility in decentralized energy systems. By integrating thermal storage and PV-driven heat pumps, households can cut costs and boost energy independence—without always needing expensive battery storage.

For more details, the full study is available in Energy Conversion and Management:
🔗 "Unlocking heat pump flexibility: A multi-objective optimisation approach for self-sufficiency and energy costs."