Project Description

In ModEMS4Q, modernization concepts for existing residential districts were developed on the basis of a cross-building energy management system (EMS) with renewable energies (RE). Recommendations for existing building owners are summarized in a practical guide. Example districts comprise different building age classes, including some listed buildings.

The basic concept for modernization envisages equipping districts with a heat pump system, always in conjunction with PV systems and a building-wide EMS. The EMS is used to optimize RE consumption in the district through supply-dependent control of heat generation or electricity use and the integration of storage systems (thermal, electric; including electric vehicles). Depending on the initial energy status of the buildings, special modernization measures are required. The economic feasibility of the modernization concepts developed was validated on the basis of three existing residential districts in cooperation with practice partners. The buildings were simulated in TRNSYS. Implementation in at least one district is planned in a follow-up project.

The model-predictive control of the EMS incorporates PV, variable-speed heat pumps, buffer storage, batteries, electric vehicles and weather data. The EMS takes into account the different requirements and needs of users. For utilities, the reduction of peak loads and energy flows is crucial in order to guarantee security of supply. In addition, increased local self-consumption of solar power is desirable to reduce the load on the grid. If the EMS is operated by a consumer, reducing electricity costs is the main optimization criterion. Different constraints and boundary conditions are taken into account in each case. The EMS was implemented in Matlab and the optimization problem was solved using the CasADi solver. To account for the volatility of the energy market, fixed and variable electricity prices were considered.

The model predictive control achieves savings in electricity costs of over 30% compared to a rule-based control in two scenarios (“reduction in electricity costs” and “reduction in energy flows”) under test conditions.

Despite increased energy costs, the high investment costs and long amortization periods continue to be decisive obstacles. Accordingly, in the vast majority of cases, only buildings and building components in need of renovation can be modernized economically (coupling principle).

This leads to the conclusion that a rapid reduction in emissions in the building sector requires either a high financial incentive (or pressure) to accelerate the economically difficult modernization of the thermal building envelope and ultimately achieve a higher modernization rate for the building envelope. The focus should be on the façade and basement, as these typically require the least refurbishment.

Alternatively, the focus can be placed on the technical building services and thus the supply side, such as through the introduction of the 65% RE regulation in the GEG. This is also possible with the contracting model developed in ModEMS4Q in combination with hybrid concepts for existing buildings. According to current estimates, it is possible to enforce rapid emission reductions and avoid the critical amortization period for modernization of the building envelope in buildings that do not require renovation. Existing buildings could thus fall back on hybrid concepts on a transitional basis. The building envelope would then be modernized in the typical refurbishment cycle (coupling principle). Installed heat pumps should be designed accordingly for a phase after modernization so that they can eventually supply buildings independently.

Funding Period

June 2021 - September 2023

Funding

Federal Ministry for Economic Affairs and Climate Protection (BMWK)

Research Partners

Technische Universität Kaiserslautern (now: RPTU):

Prof. Dr. Björn-Martin Kurzrock, Dennis Aldenhoff, M.Sc. (Fachgebiet Immobilienökonomie)

Prof. Dr.-Ing. Sabine Hoffmann, Daniel Schmidt, M. Eng., Katharina Boudier, M. Eng., Stefan Spies (Fachgebiet Gebäudesysteme und Gebäudetechnik)

Prof. Dr. Ping Zhang (Lehrstuhl für Automatisierungstechnik)

Prof. Dr. Steven Liu (Lehrstuhl für Regelungsysteme)

Project Website (Begleitforschung Energiewendebauen)

ewb.innoecos.com

Project Results

Planungleitfaden - für Bestandshalter und Fachplaner - Energetische Modernisierung von Wohngebäuden und Quartieren mit Berücksichtigung des Einsatzes eines Energiemanagementsystems

The Full Research Report (in German) can be downloaded on ResearchGate: Link