Photovoltaic sanitary water heater from Belgium


Belgian startup Wanit has developed a solar water heater that purportedly reduces the cost of domestic hot water by 85%. The PV water heater solution includes a main dual tank and a solar connector that links the tank with a rooftop PV system and residential battery.

The solar connector relies on maximal power point tracking, which ensures that the maximum output from the solar array is always captured, claimed Wanit. 

“According to the power demand, the connector converts the electricity to the right voltage with no loss and conveys it to the main boiler, the satellite boiler or the batteries,” Christian Bayet, the company's founder, told pv magazine.

The solution can be installed vertically or horizontally and is available in four versions: a 65-liter water heater for off-grid applications, an 80-liter device for off-grid applications, and two on-grid heaters with capacities of 65 liters and 80 liters. The smallest water heater measures 1,066 mm x 275 mm x 506 mm and weighs in at 28.4 kg. The largest solution measures 1,251 mm x 275 mm x 506 mm and weighs 32.3 kg.

“We offer different versions depending on the size of the household, the available space and the number of panels that can be placed,” Bayet said. “The 65-liter product is suitable for smaller households, with very little space, and the 80-liter is more suitable for larger households. But the main difference between the two models, the DC (off-grid) and the Hybrid, is that the second has two additional heating rods that are connected to the grid at 230 V.”

Bayet said the DC model is suitable for those who wants to add the system to their heating system, as would people who opt for thermosolar systems.

“The hybrid model is a compact boiler where everything is integrated. When the free heated water reserve is exhausted, the boiler can heat, according to different programs, all or part of the tanks and thus ensure to cover the need for hot water at any time, while maintaining all the capacity to store the free energy production of the panels,” he explained.

The system heat storage capacity ranges from 5.9 kWh to 7.2 kWh, with all devices relying on two dry heating rods and IP22-rated protection. They also all feature DC power of 1,300 W.

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Every watt installed gives benefits but we recommend at least 400 W per person. For a household of four people, the ideal configuration is four new generation PV panels and a hybrid boiler of 80 liters, and batteries to offer more storage and more flexibility,” Bayet said.

The Solar Connector

Image: Wanit

The solar connector operates with a maximum input current of 20 A, a minimum PV voltage of 60 V, and a maximum system voltage of 200 V. Its efficiency is 97.5% and it can be connected to up to 1,700 W which can be done with four solar modules.

For less powerful PV panels, depending on their characteristics, a six-panel configuration is also possible,” Bayet said. An internal sensor regulates the charging voltage according to the room temperature. “With an external sensor, as an option, adaptation is carried out continuously,” he added.

For the SolarConnector, the 80-liter Hybrid boiler, and four PV panels, the price is around €4,000 ($4,230), installation costs included. 

“This is an additional cost of €3,000 compared to a classic electrical boiler,” Bayet said. “The payback of this difference will be delivered after four to six years, depending on the local electricity tariffs.” Additionally, the company can offer batteries at less than €1,000 for a storage capacity of 3.2 kWh.

Wanit currently has operations in Brussels and Tournai, Belgium.

“We serve zones located 100 km around these two cities, North of France included, and we are planning to reach other cities before our products can be available anywhere in Europe and in the world,” said Bayet, noting that it is handling assembly at an unspecified location in Belgium. “We are working every day to improve our producing capacity in order to meet the demand.”

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