Section E1 Ι No future without digitisation!

Thursday, 14 September 2017, 09:10-09:20h/E1.2

Networking of photovoltaics, electromobility, heat pumps and power grid: First operating experience

Ralph Lingel und Thomas Nordmann, TNC Consulting AG, Switzerland Prof. Harald Thorwarth, University Rottenburg, Germany

In Switzerland about 50% of the overall final energy demand is consumed by private households, considering electricity, heat and private mobility. With increasing sales of PV systems, heat pumps and electric vehicles energy efficient residential buildings are becoming more and more able to cover their energy demand for these three sectors, at least on an annual basis. Residential homes are becoming "prosumers", producers and consumers. Mostly production and demand do not occur at the same time and are not coordinated. Further deployment of electric cars and PV systems can lead to challenging production and demand peaks in power grids.

To coordinate the different energy related components in a residential building an electronic building automation “conductor” was developed, acting as the mastermind. It dynamically and continuously adapts the power demanding loads such as charging stations for EV’s and heat pumps to the available PV production while ensuring user needs.
2016 two pilot projects were realised to verify the capabilities of a smart energy and load management and were equipped with a comprehensive monitoring system.
The first pilot project is a low energy “Minergie” single-family house near Zurich, Switzerland. The house, built in 1999, was renovated with newest building technology including a 6 kWp PV system, a modulating heat pump (2.5 kWmax el.) and a controllable charging station for EV (11 kWmax). The charging station is primarily used for charging a car with 85 kWh battery capacity. Individual room temperature control and thermal management are also part of the system.
The second pilot project is an office building equipped with a 12 kWp PV system and a controllable charging station for EV (11 kWmax). In this project the focus is on charging the company's own electric car with 22 kWh battery capacity with PV.

In Summer 2016 the control algorithms of the conductor were activated for both projects with the main features “PV-Charging” and “Fast-Charging” for the EVs. It could be shown that virtually no energy is exchanged with the grid during daytime when PV charging is selected.
At the office building the EV was almost exclusively charged with PV excess energy till Mid November 2016 and from the beginning of February 2017. Over a long period of time, a significantly greater mileage with PV energy for the vehicle would have been possible than actually demanded.
At the residential house the car was mainly charged on weekends with PV excess energy. This was sufficient, due to the large storage capacity of the vehicle and the rather low mileage driven during typical workdays. When plugged in, almost all PV energy produced could be absorbed in the battery of the vehicle due to the large battery capacity and the rather small PV plant.

The heat pump of the residential home was operated with standard settings in the period January - June 2016. Starting from July 2016 the water heating system, also provided by the heat-pump, was adapted to the PV production. With the start of the heating season at the beginning of October 2016 a control algorithm for the heat pump was implemented to adjust the load profile for heating to the PV production. It could be shown that most of the PV energy produced could be consumed within the building during heating season due to this mode of operation. Especially the controlled charging and discharging of the buildings thermal energy capacity is an essential advantage.