Residential property Allerheiligen

Description

The ELWA from my-PV ensures optimal energy management not only in single-family homes but also in multi-family buildings. By using the ELWA, the central building technical systems in the project in Allerheiligen, Austria, were minimized to the essentials.

The hot water preparation takes place entirely decentralized in the individual apartments using electric water heaters (ELWA) built into the hot water storage tanks.

This eliminates the need for pipe-based hot water distribution. In addition to the heating connection, each apartment only has a cold water supply.

By using the ELWA, the high energy losses from hydraulic pipes can be completely avoided. Solar energy is converted into heat precisely where it is needed.

How the ELWA works

During the day, DC current is transported from the PV modules to the ELWA via power cables, which heats the hot water in the storage tank. On days with low solar radiation, household electricity automatically heats the water when needed. The hot water supply is always guaranteed with the ELWA. Thanks to the integrated MPPT tracker, the ELWA can also be used with different PV orientations.

Inverters and grid connection permits are not required as no electricity is fed into the grid. Installation or retrofitting is extremely simple.

With the ELWA, the typically complicated grid coupling of PV systems in large residential buildings is no longer necessary. Thanks to the storage option, solar power becomes an efficient solution for this building type.

ELWA Modbus Interface

Thanks to the Modbus interface used by my-PV, continuous functional monitoring and operation parameter tracking are also possible remotely. The Modbus interface communicates with the ELWA via the integrated infrared interface. Additionally, a further temperature sensor can be integrated into the control.

Due to the ability to monitor all devices in the system, this solution is particularly well-suited for residential construction.

ELWA Sizing Guide

The recommended size of the PV system is based on the number of people in the household or their hot water consumption. For each resident, an average of 50 l/day can be assumed. This corresponds to an energy requirement of about 1,000 kWh/year.

The annual yield of a photovoltaic system in Austria is approximately 1,100 kWh/kWp. With a recommended solar hot water coverage rate of 50%, a system size of 2 kWp is required for a four-person household.

ELWA Product Details

• 0 – 2,000 W stepless

• Set target temperature with rotary knob

• Works even during power outages

• Suitable for hot water storage tanks with 100 – 1,000 liters

• Self-consumption: 2 W

• Efficiency: >99% at nominal power

• Hot water guarantee: 750 W