OPTINERGY

What is it?

Automatically optimise your energy bill without changing your lifestyle.

The end of subsidised renewable electricity may finally have some beneficial effects: it gives us the opportunity to think differently. New possibilities are opening up as soon as it becomes more profitable to use this energy for self-consumption rather than simply selling it back to the electricity distributor.

So this project is developing the simplest possible system for using all the solar energy that exceeds a house’s own consumption, and making use of it.

In practical terms, OPTINERGY is an electronic box placed in the electrical panel or right next to it. This box monitors the direction of the current. Whenever it sees the current flowing back to the grid (when the panels supply more energy than the house consumes), it redirects this excess energy to dedicated electrical appliances.

How does it do this?

The excess kilowatt-hours are automatically converted into heat by automatically heating the household water in summer and the ambient air in winter.

But why not batteries?

Because batteries are fragile, dirty, expensive, bulky and have a limited lifespan.

Why simple heating elements?

For reasons of reliability.

Ideally, of course, this current should be injected into a heat pump or into the batteries. The problem is that these devices require a permanent and constant power supply. A heating element, on the other hand, converts any electrical power into heat, regardless of its stability.

Why a flexible system?

For two reasons:

1) Solar current is never constant. It drops every time a cloud passes overhead and fluctuates constantly.

2) Domestic consumption is extremely volatile. So the direction of the current going to the house or to the grid changes thousands of times every day. (depending on the appliances that are constantly being switched on and off: washing machines, dishwashers, cookers, thermostats, lights, etc.)

The OPTINERGY system has no qualms. It instantly picks up any excess current and directs it where you tell it to. Silently and without human intervention.

Yes, but in practice?

This system allows you to switch off your boiler from March to November, and puts less strain on it during the winter. For example, an old, poorly insulated house with 4500 Watts of solar panels will reduce your heating costs by a factor of 6. (See example at bottom)

When is this vital?

In a house with electric heating and/or an electric water heater.

When is it really useful?

In all cases of heating using fossil fuels such as gas or oil. It’s always a good idea to replace all fossil fuel consumption with renewable energy, which is also free.

When is it less useful?

In the case of a building heated by a heat pump. Conventional electric heating may be 3 times less efficient than a heat pump, but as you sell your electricity for 3 times less anyway… you might as well use it at home. Every calorie supplied by OPTINERGY relieves the heat pump by the same amount. Less wear and tear, so less maintenance.

When is this system not useful?

– When you sell subsidised electricity at a fixed rate.

– In a well-insulated house with water heated by solar thermal energy and a heat pump.

Why use a three-phase system?

Using a single-phase system is inefficient at best, and bad at all other times. You can end up with an appliance that will consume more current than if you hadn’t installed it. Avoid at all costs.

OPTINERGY is three-phase, instantaneous and scalable. Its metering system is radically different. What’s more, it’s open and available for all power ratings. It doesn’t matter whether you want to control a villa or a large building: that’s what it’s designed for.

What about installation?

The installation is not invasive and is grafted onto the existing panel. You also need to add a three-phase heating element to the boiler, as well as one or two electric radiators in the house.

What about maintenance?

No maintenance is required once the system is installed. No wear or maintenance of any kind.

What about use?

A simple switch:

Set to “summer” when the boiler is switched off, and the panels will heat the domestic hot water.

Set to “winter” when the boiler is on, and the solar panels will heat the air.

Set to “in-between seasons” to heat the water in the morning and the air in the afternoon.

What about reliability?

If the OPTINERGY system were to break down in any way, everything would function normally. The system is completely independent of the boiler and does not interfere with it.

And how long does it last?

The systems and software used are conventional industrial components. The overall design is open: any electrician can improve, adapt or modify the software as he sees fit.

Any other advantages?

Yes, OPTINERGY makes it unnecessary to install thermal solar panels, for example.

Thermal panels are expensive in terms of materials, maintenance and installation costs. Their biggest disadvantage is that they are of little use throughout the summer when there is too much energy. OPTINERGY, on the other hand, heats its domestic water, but then sells the electricity back to the distributor when the water is hot. In this way, OPTINERGY offsets the lack of output with efficiency.

What are the real benefits for a house?

Based on a concrete example provided by 10 years of continuous operation with 4 kW of solar panels, the annual consumption of pellets was divided by 6, the wear and tear on the boiler reduced by the same amount and the electricity bill reduced to zero.

There’s another invisible but very real advantage: a boiler that operates for only 8 months of the year will wear out less. The savings are tangible, but difficult to quantify.

Payback over the years..

For simplicity’s sake, we’re not going to talk in kilowatts but in francs, in a system that has been operating since 2015 in a family home.

In 2014 (before the solar panels and the MRCL60 system were commissioned), a year’s worth of pellets cost 1250 Swiss francs, 750 Swiss francs worth of electricity, and the boiler ran all year round. That’s 2000 francs.

Since then, each year’s supply of pellets has cost 200 francs, total electricity (consumed and produced) is around 0 francs and the boiler only operates intermittently during the 4 winter months.

These savings amounted to $1800 per year, or $18,000 over the 10 years that the OPTINERGY prototype was in service. Not to mention the fact that the boiler was switched off for 6 and a half years.