Bivalent Heat Pump Systems
Achieving the Perfect Balance
What Is a Bivalent Heating System?
A bivalent heating system uses two heat sources to meet a building's thermal demand. Typically, this involves a renewable heat source—like an air or ground source heat pump—paired with a traditional boiler or electric heater. The goal is to use the low-carbon, efficient heat source as much as possible while calling upon the secondary heat source only when needed—such as during periods of extreme cold when the renewable source can't meet peak demand on its own.
The "bivalent point" is the outside temperature at which the second heat source begins to supplement the first. Designing this point correctly ensures optimal system performance, energy efficiency, and occupant comfort.
Why the Bivalent Point Matters
Getting the bivalent point right is critical for:
- Efficiency: Ensures the renewable heat source is used to its full potential.
- Cost savings: Reduces reliance on more expensive or carbon-intensive backup heating.
- Comfort: Maintains consistent internal temperatures even in severe weather.
- System balance: Avoids oversizing or undersizing either heat source, protecting both performance and longevity.
How Our Software Supports Bivalent System Design
At Heat Engineer Software, we've integrated advanced features to streamline the design of bivalent heating systems, from initial heat loss assessment to precise bivalent point optimisation.
Accurate Heat Loss Calculations
Our platform ensures that all heat losses are captured—fabric, ventilation, and infiltration—forming a reliable foundation for effective bivalent system design.
Dynamic Bivalent Point Optimisation
Once a full heat loss assessment is complete, our software:
- Calculates the external design temperature using local weather data.
- Models system output curves for both primary (e.g., heat pump) and secondary (e.g., gas boiler) heat sources.
- Pinpoints the bivalent point by intersecting heat supply capacity with building demand across the temperature range.
Custom Load Matching
Engineers can adjust system parameters—including emitter temperatures and system hysteresis—to visualise how changes impact the bivalent point. This allows for:
- Precise specification of heat pump capacity.
- Validation of backup system performance.
- Evaluation of hybrid vs. parallel operation modes.
Reporting and Export
The software provides comprehensive documentation, including:
- Exportable design files for system specification and quotation.
- Graphical overlays showing heat pump output vs. building load.
A Future-Proof Tool for Modern Heating Design
From retrofit projects to new builds, our platform helps heating professionals make smarter, more sustainable design decisions. It removes complexity, reduces risk, and ensures optimal system performance for every property.