Table of Contents

Self-consumption optimization

1. Self-consumption Optimization

The Climkit optimization system allows for increasing the self-consumption rate of a photovoltaic installation by controlling certain devices based on solar energy production.

The surplus fed back to the electricity grid is thus limited, and autonomy is also gained by producing, for example, hot water using solar energy.

Devices (water heaters, heat pumps, radiators, pool pumps, etc.) are controlled via a relay.

It is also possible to control certain electric vehicle charging stations (via Wifi or Ethernet).

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Detailed connection of a relay to the I/O module

The relay I/O module has 4 relays.

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2. Algorithm Operation

The system evaluates the electrical power fed back to or drawn from the grid every minute.

In case of surplus fed back, it activates the various configured and connected devices.

For example, if there is a surplus greater than or equal to 1000 W, it activates the 1000 W water heater.

Conversely, if there is no longer a surplus and energy is being drawn from the grid, the system deactivates the necessary devices to limit the draw.

Devices are activated and deactivated according to the selected operating modes, for example in "Solar only" or "Solar and timer" mode. See Configuration below.

It is not possible to set activation or deactivation priorities among the devices; they are only controlled based on their nominal power to maximize self-consumption.

To be as flexible as possible, it is recommended to connect devices with the lowest possible power so that they activate with even a small surplus.

For example, each phase of a 3000 W water heater can be connected to an independent relay to benefit from three 1000 W steps.

Specific Notes

Minimum power and number of phases of a station

Generally, an electric vehicle requires a minimum of 6A to start charging. Some vehicles require 8A or 10A. A lower minimum can cause an error on the vehicle.

This minimum of 6A is the same for single-phase and three-phase connections: i.e., 1380 W for single-phase 230V or 4140 W for three-phase.

Consequence for optimization: A vehicle connected to a three-phase station requires a minimum solar surplus of 4140 W for the system to start charging.

For small photovoltaic installations (5-8 kWp), the surplus required to activate the station will only be available during summer and mid-day.

In these cases, it is recommended to connect the 3 phases of the station to 3 independent relays or at least to 3 independent switches so that the user can easily switch from one to three phases. See the diagram above.

When changing the number of phases for the station, the main circuit breaker of the station must be turned off, the connection phases engaged or disengaged, and the station turned back on.

The optimization system does not allow for controlling phases and automatically switching from a single-phase to a bi- or three-phase load.

Vehicle Standby

When a vehicle is plugged into the station but the solar surplus is insufficient to initiate charging, the vehicle goes into standby mode until the station supplies it with electricity.

In some cases, the vehicle may go into full standby after some time, and when the station provides it with electricity again, charging will not start until the vehicle is "woken up" by the user.

This case is common when the vehicle is plugged in the evening and the solar surplus will only be available the following morning.

Some vehicles can be updated to prevent these unexpected standbys. Consult the vehicle manufacturer.

The system has been tested on a limited number of electric vehicles, and as each manufacturer has its own specificities, Climkit cannot guarantee the functioning of its optimization system with all vehicle types.
Older Vehicles

Some older vehicles (pre-2012-2014) do not support varying power during charging and are therefore not controllable via the optimization system.

Heat Pumps (SG-Ready)

Most modern heat pumps (HP) are equipped with a potential-free contact which, when closed, sends an instruction to the HP's internal management system.

Generally, it is possible to configure the HP to increase its heating setpoint or produce more hot water when this contact is closed.

By connecting a relay from the optimization system to this contact, it is possible to force the HP to activate when the photovoltaic installation produces surplus energy.

Consult the HP manufacturer.

Connecting a Three-Phase Water Heater

Many water heater elements are connected with 3 wires without a neutral. Therefore, a neutral connection is necessary to control each phase individually.

Otherwise, a minimum of two phases is always required for it to engage.

Two relays can then be used to control: phase 1 and 2 with the first relay, and 1 and 3 with the second.

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