Flexible energy concepts for decarbonization
The climate paths of the housing industry are based on three main pillars:
- Energy-efficient building renovation
- The change of energy source in heating technology
- The decarbonization of energy sources
When implementing individual corporate strategies, areas of tension arise between the various goals, such as the affordability of housing, economic efficiency and climate goals. There are also dependencies on the energy sector and regional expansion plans as part of municipal heating planning. Anyone who wants to develop and ultimately implement the right strategy in this area of conflict must therefore master a variety of tasks.
Energy-related serial refurbishment can make it possible to overcome some of these challenges. With its wide range of configurations of building envelope and energy concepts, it offers a high degree of flexibility. In this way, a wide variety of property strategies can be taken up in the portfolio and maximum CO2-Reductions are realized. What this could look like in practice is discussed in this issue of our newsletter.
Insulated building envelopes:
The key to success
There is a decisive lever for implementing the decarbonization path in particularly inefficient housing stocks in energy efficiency classes E-H: improving the building envelope.
Curb losses and reduce consumption
Professional insulation and replacement of windows significantly reduce transmission heat losses and thus the consumption of final energy for heating. On the other hand, the energy costs saved in this way open up potential for an increase in the basic rent. Lower ancillary costs and higher rental income are powerful arguments. However, reducing final energy consumption also has other benefits. This is how CO also decreases if the emission factor remains the same2-Emissions. This is particularly in view of increasing CO2-Pricing (BEHG and CO2KostaufG) is crucial to avoid significant additional financial burdens for owners and tenants. In addition, lower final energy demand reduces the impact of external factors, such as energy price fluctuations.
Low-temperature capability and supply security
Improving the building envelope therefore reduces the overall energy requirement of the building. It makes it easier to size new generation and supply systems and is a decisive factor for improving the low-temperature capacity of a building. With a reduced heating load, it is only possible to operate a heating system with flow temperatures in the low temperature range (≤ 55°C).
The reduced flow temperatures also mean that heat pumps work more efficiently, which, in combination with PV systems and a green electricity tariff, lay the foundation for CO2-neutral operation of a building. In addition — when connected to a district heating network — the well-insulated building envelope reduces the amount of heat drawn from the network and, accordingly, also reduces CO2-Reduces emissions.
Funding: The best conditions
The combination of building insulation and efficient plant technology is therefore the key to success for CO2-neutral building operation. It is therefore not surprising that the Federal Funding for Efficient Buildings (BEG) also takes into account the building envelope and plant technology with the respective energy source. By combining both areas, final energy consumption can be minimized, the use of renewable energy can be maximized and thus a sustainable solution can be implemented for the existing buildings in the portfolio.
The EcoWorks façade system meets the requirements required for the KfW-55 standard. This means that a high funding rate, including a 15% repayment subsidy bonus, is achieved for serial restructuring by ecoworks. The prefabricated façade elements are combined with suitable energy concepts. This is achieved by installing the necessary components in the façade elements at the factory: Strings for heating, cold water & hot water, electrical/control and ventilation (with and without heat recovery) are therefore integrated from the outset.
Choose a safe energy supply
There are many aspects that must be considered when choosing the right energy supply in order to make it as sustainable and cost-effective as possible. Serial refurbishment offers various options here.
district heating
Under certain circumstances, changing energy sources does not make sense. This can be the case, for example, if a building is already connected to an existing district heating network. In this case, a pure serial shell repair An improvement in the energy efficiency class to A/A+ level has already been achieved. Additional measures reduce heat energy loss even further. The measure is completed by basement ceiling insulation and roof replacement. If necessary, the top floor ceiling can also be insulated while maintaining the existing roof.
The first-time Connecting an existing property to the district heating network In a serial renovation project, the conversion to a perspective CO enables2-free heating. But beware: Energy suppliers play a central role in creating a sustainable and climate-friendly district heating supply. The networks are not yet CO2-neutral. In addition to this aspect, the connection also entails other dependencies, for example with regard to investments and delays in infrastructure expansion. Against this background, early and close coordination with the local energy supplier is necessary. On request, we advise and support our customers in this process.
As already mentioned in the first part, the choice of energy source is also relevant for funding measures. For connection to district heating, this means: If the heating network has a primary energy factor of not more than 0.25 or if there is a transformation plan in place, the EE bonus (+5% repayment subsidy) will be achieved in KfW funding. Compared to the installation costs for new energy sources, the low investment costs for the district heating transfer station are a compelling argument.
A connection as part of a serial renovation by ecoworks allows customers to reuse existing pipeline networks in the building (for heating and cold/hot water) and connect them to the transfer station. If necessary, a strand renovation can be carried out via the façade. If there is no centralized supply in the building yet, the EcoWorks cable elements in the façade offer a minimally invasive installation option. It is therefore possible to switch to district heating and thus a more sustainable supply of residential units with comparatively little effort.
Central heat supply
Die Centralization of heat supply is also the suitable interface for existing buildings that are supplied with decentralized central gas heating systems. The conversion from gas floor heating systems to an air-water heat pump or a district heating connection enables the use of renewable energy and reduces operating costs. The number of fossil-powered energy producers in the inventory is therefore significantly reduced! Centralized control ensures optimized plant operation, which benefits owners and tenants. We have developed an innovative product for this purpose: Here, too, we can minimally invasively retrofit the strings using our external EcoWorks cable elements. Core drilling is only required to connect the new lines to the existing lines in the apartments.
Depending on the type of building and technical requirements, the Central or decentralized hot water treatment be implemented. Thanks to a central solution in the basement, no further devices are required in the apartments, reducing maintenance and repair costs. The prerequisite is the installation or existence of the appropriate hot water distribution network in the building — always in compliance with the Drinking Water Ordinance and hygiene in drinking water installations. Regular reviews are also required.
An existing supply from electric water heaters can be maintained, although higher energy efficiency may be achieved in view of primary energy demand and the targeted KfW funding standard. In decentralized supply situations, therefore residential or fresh water stations, which heat the water from the central heating system using a heat exchanger when required, represent a reasonable alternative. Here, central heating (e.g. district heating or central heat pump) is used to heat water at home level. Since the water is only heated in the apartment, there are fewer losses through pipes. Home stations can also be easily integrated into existing heating systems. Since this hot water treatment system is likely to fall under the 3-liter rule (in accordance with §3 TrinkwV [“Definitions”] paragraph 12), the landlord's obligation to sample is waived.
heat recovery
In accordance with current requirements and KfW Efficiency House standards, we equip the Buildings with suitable ventilation concepts off. They ensure the necessary ventilation to meet hygienic and health requirements as well as building protection when users are present during normal operation and remove excess moisture.
Ventilation concepts can be integrated into systems with and without heat recovery be differentiated. Heat recovery systems use the heat from the exhaust air to heat the incoming air. This reduces heating requirements and saves energy. According to the BEG-WG Directive, the use of a ventilation system with heat recovery in the EE class is mandatory. Centralized, decentralized and mixed forms of centralized and decentralized ventilation systems can be used. Up to the KfW-55 standard, systems without heat recovery can also be used. In these cases, however, the lower investment is also offset by lower funding. As part of project consulting, we therefore show our customers the optimal variant in each case, taking into account customer goals.
Photovoltaic (PV) systems
When implementing serial renovation projects, the Strategic goal of PV expansion be pushed forward. As part of roof renovations with modular trapezoidal sheets, we can install full-surface PV systems. The three most important concepts for operation are tenant electricity models, full feed-in and partial feed-in.
Tenant electricity models make it possible to deliver the solar energy generated on the roof of a residential building directly to tenants. Here, the generated electricity is not completely fed into the public grid, but is consumed locally. However, they require careful legal and technical implementation, including billing and administration of electricity delivery, as well as compliance with regulatory frameworks. We advise our customers on how to implement the appropriate model.
At the Full feed All solar power generated is fed into the public power grid. The operator of the PV system receives a feed-in tariff in accordance with the Renewable Energy Act (EEG). This method is administratively less complex, as no separate billing with tenants is required and all electricity is fed in to the network operator.
At the Partial injection Some of the solar power generated is consumed directly in the building, while the excess electricity is fed into the public grid. A specific application example is the supply of an air-water heat pump. The heat pump uses PV power to generate heat and hot water, which reduces dependence on external energy sources and lowers operating costs. This solution requires an intelligent controller and an energy management system to optimally balance the PV yield and energy requirements of the heat pump.
Are you interested in a serial renovation?
We would be happy to provide you with transparent advice on the options for serial restructuring of your portfolio. Arrange a non-binding Consultation appointment and learn more about our flexible energy concepts for decarbonization.
Meet us at WohZukunftStag 2024 on 26th & 27.06.24 in Berlin
We are pleased to be there on June 26 and 27 when representatives of the German real estate industry will be there under the slogan “Wohnungswirt.Schafft.Zukunft!” Meet in Berlin. At the GdW Housing Future Day in Berlin, our team will be discussing serial renovation with Marc Becker and Sebastian Eck.
Book an appointment with our team now? Then write directly to one of our team members here on LinkedIn or the form Use “WZT 2024” in the “Message” field on our website.
