27. Sep 2023
Nicolas Colombi explains how monitoring household power usage and managing self-generated electricity can lead to 90% savings.
Given inflation, rising energy prices and the need to reduce our carbon footprints, the pressure is on to lower our consumption and decrease our reliance on energy suppliers. Self-generation is a logical way forward, but before doing so, the existing set-up should be checked to ensure that it is as efficient as possible.
Having received requests from several upscale villa owners to reduce their energy bills by implementing a photovoltaic (PV) panel system, we developed a solution that would first monitor their current usage and then optimise their proposed PV set-ups.
Image - monitoring: The first step in saving energy is to find out how much power your devices are consuming and establish a baseline from which to make improvements.
Most solutions on the market are single-purpose. For instance, you might buy panels to power your pool filtration and heat pump.
Or you might purchase panels for self-consumption without knowing which appliances will be used during production, and having to manually start them. When inverters are equipped with relays for load management, they only provide on-off relay control.
This approach falls short when you have systems such as room-by-room heating/cooling regulation, variable-speed pool pumps, or thermodynamic heat pumps.
With KNX, we have the capability of controlling a wide range of heating and cooling products by adjusting the temperature of each room, or to raise or lower the hot water tank's temperature. We can even command the pool (heat pump and filtration) to start when production is sufficient, and get instant power readings for each piece of equipment, enabling real-time impact assessment when modifying parameters.
The luxury villas who contacted us were already equipped with KNX automation for lighting, heating, hot water, pool, and charging stations, so we decided to augment this by adding energy storage using batteries and energy management software. Prior to the installation of PV panels with storage, we recommended using energy monitoring in order to establish who is consuming what and see if any initial savings could be made.
Image - Grafnx: (Left) Example of a Can’nX Graf'nX dashboard used with (right) the Can'nX Emergy'nX gateway. This combination allows monitoring and then optimisation of energy consumption.
We used the Can’nX Graf’nX system, that integrates KNX, Modbus, or IP (MQTT) meters into an online energy dashboard, in order to understand consumption patterns and identify abnormalities caused by equipment due to malfunctions or incorrect settings. For example, in previous projects, we found a thermodynamic hot water tank that was constantly running on electric resistance (50kWh/day); pool filtrations operating 24/7 (120kWh/day) even in mid-season due to incorrect water quality set up; and a pool heat pump left on during unoccupied colder months, consuming 50kWh versus 15kWh in warmer months.
At this initial stage, the gains were substantial for the projects in question, as nearly 25MWh per project could be saved, resulting in a reduction of 2.5 tons of CO2 emissions.
Moreover, the energy dashboard calculates crucial installation values, such as the base load of the installation, apparent power (drawn power in kVA), and peak power draw. This allows for proper verification of the electrical subscription size, enabling adjustment for subscription cost and kWh pricing savings. In some projects, clients have decided to reduce their subscription size to benefit from cheaper per kWh energy costs thanks to tariff shield mechanisms.
After analysing consumption patterns and a few adjustments to the electric hot water tank by a plumber, we set up a script in a Kloud'nX cloud account that enabled us to implement a load shedding system. This avoids certain consumption peaks without sacrificing comfort, thereby decreasing the client's subscription power use.
After several months of consumption monitoring, we proposed a tailored solution using PV panels and storage combined with the Can’nX Emergy’nX energy optimisation software. Hybrid inverters for PV panel production, combined with energy storage batteries were integrated into the existing KNX installation comprising hot water tanks, HVAC, pool filtration, pool heat pumps and electric vehicle charging stations.
The energy optimisation software allows automatic control of major power consumers to be finely tuned, with priority orders chosen by the occupant, all without compromising their comfort.
Based on fluctuating energy costs and PV production levels, it finely manages battery charge and discharge cycles and automatic operation of necessary equipment to create energy surplus, thereby minimising usage during periods of high electricity pricing.
- Chart showing energy savings growing as PV panels, battery storage and
optimisation are introduced.
The implementation of energy management combined with renewable energy sources leads to significant savings:
In the context of the aforementioned projects, we are dealing with villas having subscriptions ranging from 50-120kVA, with annual consumption of 50-100MWh. The resulting gains in energy savings are significant, reaching tens of MWh, which translates to several tons of CO2 reduction.
Implementing basic energy monitoring results in approximately 15% savings in most installations. Within the first year of installation we were able to detect malfunctioning and highly-energy-consuming electrical appliances, which were then optimised. That makes the installation have an ROI of 1-2 years.
The use of photovoltaic panels allows for a 30-40% reduction in consumption based on the installed power. With a ROI ranging between 8-11 years, for an installation with peak power equivalent to the subscribed power.
The additional installation of a battery, with a storage capacity of about 2 x the maximum produced power in kWh, leads to an additional energy savings of 15-30%. The return on investment for this setup is approximately 12-15 years.
KNX-based energy management enhances the return on investment by enabling precise ongoing load control and equipment control based on dynamic energy pricing, photovoltaic production, energy storage, and priority set by the occupant. Indeed the Can’nX EMergy’NX system can save up to 90% of the energy bill, and by slightly scaling up the panels and the battery, achieving autonomous usage even becomes feasible.
Nicolas Colombi is the CEO of Can'nX, provider of KNX and IoT solutions for designing, implementing, and optimizing connected building systems.