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Study of Swimming Pool Heat Pump System in a Villa in Southern France

8 PVT Panels + 1 Heat Pump = Zero Electricity Bill for Pool Heating

Nice, France | 40 m³ Outdoor Pool | No Thermal Cover | May–October

Without PVT

3,786 kWh

Grid electricity / season
With PVT

–982 kWh

Net export to grid
Annual Saving

€931

Bill saving + feed-in revenue

1. System Configuration

Component	Specification	Key Parameters
PVT Hybrid Panels	8 x PVT600M	4.8 kWp electrical + 11.3 kW thermal (peak) 316L stainless steel heat exchanger, 6 bar max pressure
Heat Pump	ESBYC-016TJ1	R290 inverter, 15.9~6 kW heating COP 10.6~6.6 (Air 26°C)
Inverter	5kW Hybrid Inverter	DC side: PVT array \| AC side: heat pump + grid export
Pool	40 m³, ~25 m² surface	Target 28°C, no thermal cover Season: May–October (180 days)
Location	Nice, France (43.7°N)	Mediterranean climate, ~5.0 kWh/m²/day solar Electricity: €0.22/kWh \| Feed-in: €0.10/kWh

2. Why It Works — Dual Benefit

A standard PV panel only generates electricity. A PVT panel does two things at once:

1. Electricity Generation

Offsets heat pump compressor power directly.
2. Thermal Harvesting

Preheats pool water, boosting heat pump COP from 6.6 to 7.8.

The second channel is the game-changer. Pool water first circulates through the PVT array, where solar energy raises its temperature by 3–5°C before it reaches the heat pump. With warmer inlet water, the heat pump's temperature lift shrinks — the compressor works less, and COP jumps.

This is the fundamental advantage of PVT over "regular PV + heat pump": the heat pump runs less not just because PVT generates electricity, but because PVT supplies free heat.

3. Monthly Performance

Month	Air Temp	Pool Heat Loss	PVT Heat	PVT Power	Grid (No PVT)	Grid (PVT)
May	17°C	180 kWh	49 kWh	22 kWh	32 kWh	–2 kWh
June	21°C	135 kWh	54 kWh	24 kWh	23 kWh	–13 kWh
July	24°C	100 kWh	55 kWh	25 kWh	15 kWh	–19 kWh
August	24°C	95 kWh	49 kWh	22 kWh	14 kWh	–17 kWh
September	21°C	130 kWh	41 kWh	18 kWh	22 kWh	–5 kWh
October	17°C	175 kWh	27 kWh	12 kWh	32 kWh	13 kWh

Negative grid values = net export to grid. From May through September, the meter runs backwards for five consecutive months.

4. A Day in July — Hour by Hour

Let us zoom into a typical July day to see how PVT and the heat pump interact in real time:

Time	PVT Activity	Heat Pump Status
06:00–08:00	Starting up. Generating ~0.5–2 kW power, water warming slowly.	Standby — pool temperature still acceptable.
09:00	700 W/m² irradiance. 2.8 kW power + 6.0 kW heat.	Low-speed start. COP 7.8. Consuming 1.2 kW.
10:00–15:00	Peak sun. 2.8–4.0 kW power + 6.0–8.5 kW heat. Water reaches 28.5–29.3°C.	COMPLETELY OFF. PVT thermal output covers all heat loss.
16:00–18:00	Irradiance declining. Output tapering down.	Low to medium speed. COP 6.8–7.5.
19:00–21:00	Sunset. No more output.	Full speed. Making up residual heat loss from daytime.
22:00–05:00	Night. No output.	Low speed maintenance / standby.

Daily total: PVT generated 25.0 kWh electricity + 55.2 kWh heat. Heat pump consumed only 13.3 kWh. Net result: 11.7 kWh exported to the grid — while keeping the pool at 28°C.

5. PVT vs. Standard PV — The Difference

Metric	8 x PVT600M	8 x Standard PV 550W
Total Power	4.8 kWp	4.4 kWp
Daily Power (July)	25.0 kWh	22.9 kWh
Daily Heat Output	55.2 kWh	0
Heat Pump COP	7.8	6.6
Heat Pump Daily Usage	5.7 kWh	15.2 kWh
Net Grid (Daily)	–19.3 kWh	–7.7 kWh
Annual Saving	€931	~€370

PVT saves €561 more per year than standard PV — because thermal harvesting reduces the heat pump's workload by 55%. The small premium for PVT over standard PV pays for itself in under one year.

6. Investment & Payback

Item	Cost (€)
8 x PVT600M panels	3,200
ESBYC-016TJ1 R290 Inverter Heat Pump	2,500
5kW Hybrid Inverter	800
Mounting, piping, pump, controller	1,400
Installation labour	1,000
Total Investment	8,500
Return	Value
Annual saving + feed-in revenue	€931
Simple payback period	~9 years
With French MaPrimeRénov' subsidy (20–30%)	6–7 years
Lifetime net benefit (15–20 yr)	€5,500–10,000

7. The Bottom Line

8 PVT panels on a South-of-France rooftop. One R290 inverter heat pump. 180 swimming days. The electricity meter runs backwards for 150 of them. The sun supplies the power, the PVT supplies the heat, and the owner pays nothing for pool heating.

The old logic was: pool loses X kWh of heat, heat pump makes up X kWh with electricity.

PVT rewrites the formula:

Pool heat loss − PVT free thermal supply = what the heat pump actually needs to do.

When the sun shines hardest — exactly when the pool loses the most heat — PVT generates both abundant electricity and heat. The heat pump rests during peak sun hours. During off-peak hours, it operates with preheated inlet water at a significantly higher COP.

Get a Custom PVT + Heat Pump Analysis for Your Project

Windfull provides complete swimming pool heat pump system solutions — from system design and equipment supply to installation guidance. Contact us at [email protected] or WhatsApp: +86-13306217982

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