Welcome to YODA – Open Digital Archive for CSEM
The YODA archive gives access to CSEM's publications, such as its annual reports and brochures. For technical papers such as scientific publications, bibliographic information is provided, along with the full paper where this is possible.
This comprehensive database is part of CSEM's Open Access Publishing policy. For further information refer to the YODA support guide or contact repository@csem.ch.
Recent Submissions
Item type:Item, Frequency control with aggregated heat pumps in buildings: A comparison of complex and simple control strategies(2026-03-01)As the share of electricity generation from non-dispatchable sources like wind and photovoltaics grows, so does the need for active grid stabilization. For this purpose, we use aggregated heat pumps in buildings as a virtual power plant. Unlike other technologies used to stabilize the grid, such as pumped hydro or natural gas power plants, the aggregation of buildings is not hindered by geography, nor does it incur any additional strain on the environment. However, a large number of buildings is required to reach a substantial level of deployable power. The right trade-off between cost and performance in the aggregation method is essential to be competitive with the more established technologies in this field. To this end, we evaluate simple and complex frameworks for frequency control with a simulated cluster of 1000 buildings, based on real data, and estimate their respective cost-effectiveness. The most complex methods, using full data access and bi-level optimization, yield the highest total flexibility provided and the lowest tracking error. However, the lower system costs of the less complex methods, relying on limited data and simplified formulations of the optimization problem, outweigh their inferior performance in terms of expected profitability. With the assumed tariffs, we only expect a net profit when using the more cost-effective methods with large buildings. To achieve profitability with small buildings within the specifics of our simulations, the remunerations would have to increase by a factor of two to seven.Item type:Item, Predictive control of eV charging for wide-area reduction in grid congestion(2025-06)We present a solution for unlocking the flexibility of electric vehicles (eVs) and ease their integration into the electrical grid. As opposed to most existing solutions that focus on controlling individual charging stations, the proposed solution controls the charging profiles of a group of vehicles to activate their demand-side flexibility. The solution aggregates the eVs into a virtual power plant to alleviate grid congestion, specifically to prevent overloading on a set of grid substations. More precisely, it operates a pool of vehicles that can be charged at any charging point served by grid substations within a given set. The proposed solution implements a model predictive control (MPC) algorithm under constraints to set the optimal charging profile for each eV. This allows the pool to respond to congestion management requests (or constraints) by limiting the peak power at the substations. The solution can also be used to respond to ancillary services requests. The proposed solution was tested on simulated data from 1000 eVs during two weeks in summer in the Greater Paris Area. State of charge (SoC) constraints were respected 99% of the time by the proposed solution compared to 92% by the benchmark approach.Item type:Item, The Impact of Data Availability on Consumption Flexibility Estimation With Heat Pumps(2025-10)Using the inherent consumption flexibility of electrical systems is becoming increasingly important to help with grid balancing, as renewable energy sources are on the rise. This study investigates how data availability impacts the quality of flexibility predictions and the resulting difference in performance in the task of cost minimization under a dynamic electricity tariff. For a building with a Heat Pump (HP) connected to a water tank, we differentiate the cases where only HP power measurements are available and where either one or both indoor temperature and tank temperature measurements are available. The experiments show a clear advantage of the full data availability case over the others, while the simplest case can compete in the task of cost minimization, when additional assumptions are made.Item type:Item, Field demonstration of a scalable predictive energy management approach for multi-family buildings with heat pumps and PV(2026-06-04)The OPERA project demonstrates a predictive energy management strategy designed for multi-family buildings equipped with heat pumps (HPs) and photovoltaic (PV) systems. The project, implemented in a renovated 20-apartment building in Neuchâtel, Switzerland, aimed to develop, deploy, and validate a model predictive control (MPC) strategy that optimizes heat pump operation. It leverages the building’s thermal inertia to minimize electricity costs while preserving comfort. Communication with the heating and domestic hot water (DHW) subsystems is standardized via SmartGridReady (SGR) functional profiles. Across a full heating season (2024–2025), the predictive control achieved an 11.5% reduction in HP electricity costs, primarily by shifting consumption to low-tariff periods and increasing self-consumption. The project confirms the technical and economic feasibility of predictive control for collective housing in a renovation context and puts a strong emphasis on replicability, by 1) providing a blueprint for replication to similar buildings with a communication and control approach relying on standardized interfaces to the heat pump and home automation system to control the valves, and 2) integrating in a commercial energy management system (EMS) with no additional hardware investment required; and 3) formulating recommendations related to design, control and operation drawn from that campaign.Item type:Item, Robustness of nano-electromechanical switches against mechanical shock and vibration loads(2025)Nano-electromechanical (NEM) switches offer significant potential for future computing and memory applications due to their low power consumption and ability to operate in high-temperature and radiation-harsh environments. However, there is a lack of studies on the robustness of NEM switches under mechanical loads. In this study, we investigated the performance of 3- and 7-terminal NEM relays under mechanical shocks up to 5000 g and vibrations up to 70 g. The results demonstrate that devices maintain mechanical functionality, with some variations in the electrical characteristics. These findings underscore the potential of NEMS technology for reliable operation in harsh environments, paving the way for their possible integration into next-generation electronic devices.
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