A PVT panel feeds 25–45 °C low-grade heat from the absorber on its rear side into the source circuit of a brine/water heat pump. The elevated source temperature lifts heat pump COP — roughly 2–3% per kelvin gained — while the heat extraction cools the PV cells and raises electrical yield by roughly 3–8% over a year. The panel effectively replaces the outdoor unit or borehole as the heat pump's energy source.
How does a PVT panel act as a heat pump source?
A PVT hybrid collector generates electricity in its PV cells while an absorber bonded to the module's rear captures the heat the cells would otherwise waste. Connected to the source side of a brine/water heat pump, that absorber replaces the outdoor air unit or ground loop: sunlight — direct or diffuse — warms the glycol in the panel, the heat pump's evaporator extracts the heat and pumps it up to heating temperature, and the cooled fluid returns to the roof, keeping the PV cells cool. One roof field thus supplies both the heat pump's energy source and much of the electricity that drives its compressor.
Why does a warmer source raise heat pump COP?
A heat pump's COP rises as the gap between source and delivery temperature narrows: each kelvin of source-temperature gain improves COP by roughly 2–3% (IEA SHC Task 60). A PVT field running 10–20 K above ambient on a sunny winter day therefore lifts COP by a fifth to a half versus an air-source unit fighting the same weather — and it does so silently, with no fan and no defrost cycles stealing energy in cold, humid conditions. Over a full year the effect shows up as a higher seasonal COP, which is precisely the metric subsidy schemes and energy labels reward.
What does the hydraulic layout look like?
The source loop is a closed propylene glycol circuit: PVT field → heat pump evaporator (usually via a plate heat exchanger) → back to the field, driven by a solar pump station under a solar controller. In summer, when the field runs hot, a switching valve typically diverts heat directly into DHW preheat instead of through the heat pump; a buffer tank or ice store can sit between field and evaporator for extra flexibility. Field area is engineered to the heat pump's evaporator capacity by the system planner — climate, single-source versus dual-source design and building load all enter the sizing, so it is a calculation, not a rule of thumb.
Does a PVT source work at night and in winter?
Yes, within design limits — an unglazed PVT panel is also an air heat exchanger, so wind and ambient air keep feeding the absorber when the sun does not.
| Condition | Typical source temperature | What happens |
|---|---|---|
| Clear sun on the field | 10–30 K above ambient | Peak COP; PV cells actively cooled |
| Overcast daylight | 2–10 K above ambient | Diffuse gain still lifts COP |
| Night with wind | ≈ ambient | Panel works as a silent air heat exchanger |
| Clear, calm night | Slightly below ambient | Controller limits extraction or a second source assists |
This heat-pump-source configuration is the one driving PVT market growth in Germany and the Netherlands, where designers size the field for the winter night case or pair it with a borehole that the PVT field regenerates in summer.
Which subsidies recognise the PVT + heat pump combination in 2026?
Germany's BEG explicitly funds PVT as a heat source for a heat pump — independent of heat pump brand — making it one of the few European schemes that names PVT at all; the panels must be Solar Keymark-certified and BAFA-listed for the solar-thermal route. In mainland France, MaPrimeRénov' has funded hybrid solar panels only as part of a whole-home renovation — no longer as a stand-alone measure — since 1 September 2026, with Solar Keymark or CSTBat certification required. In the Netherlands, ISDE support requires the product to appear on the RVO device lists. Rates moved mid-2026 in several countries, so check the current official rules before committing. Solimpeks has manufactured PV-T hybrid panels since 2008 with exactly this certification base — the pairing of PVT versus separate PV and thermal explains when the combination beats conventional layouts.
Frequently asked questions
Can any heat pump use a PVT source?
No — it must be a brine/water or water/water heat pump designed for an external source circuit. Standard air-to-air and monoblock air/water units have a fixed evaporator and cannot accept a PVT loop. Manufacturers increasingly list approved PVT pairings, and Germany's BEG funds the combination independent of heat pump brand.
How many PVT panels do I need per kW of heat pump?
It is a planning calculation, not a rule of thumb: the field must cover the evaporator's heat demand in the design condition, which depends on climate, whether PVT is the only source or paired with a borehole or outdoor unit, and the building's heat load. Expect the planner to size from the heat pump's source-side datasheet, not from panel count.
Can a PVT field replace a borehole entirely?
In mild climates, a correctly sized PVT field can serve as the sole source. In colder climates the strongest configuration pairs PVT with a smaller borehole: the field carries the mid-seasons and regenerates the ground in summer, cutting drilling metres while protecting the borehole's long-term temperature.
Does the panel still generate electricity while feeding the heat pump?
Yes — better than an uncooled panel. Drawing heat away keeps the PV cells cooler, lifting electrical yield by roughly 3–8% over a year. Both outputs run simultaneously: electricity to the house or grid, heat to the source circuit.