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Topics: District concepts, Construction of new housing estates, Operational management & energy management, Solar power, Modelling & simulation, Monitoring & balancing
Innovation: Simulation tool developed for using shallow geothermal energy that is based on “Delphin”. Residents can see their current energy consumption displayed online.


  • Simulation tool based on Delphin calculates the geothermal behaviour of the ground
  • Optimising the plant operation reduces the distribution losses and auxiliary energy input
  • Rebound effect leads to higher energy consumption
  • Self-generated electricity from the CHP and PV systems are directly used in the district
  • Development of an online platform for residents to visualise the energy consumption

The energy-plus “Ludmilla-Wohnpark Landshut” housing estate was built on an industrial brownfield site. Close monitoring and the subsequent optimisation of the building operation significantly reduced the energy consumption. Incorrect behaviour by the residents and errors in the operational management initially led to consumption considerably above the planned target values. A new online visualisation of the energy consumption allows each resident to view their own consumption in direct comparison to the housing estate average.

Project context

As part of the "+one" research project, it was intended to gain new insights about energy plus housing estates, which will become increasingly frequent in future. Greater awareness for energy-saving living is fostered among the residents of energy-plus housing estates by showing them how user behaviour impacts on energy consumption, particularly with highly energy-optimised building types. The intention is to raise awareness for the fact that although energy optimised buildings provide the basis for high energy efficiency, user behaviour has a decisive impact on the energy consumption.

Research focus

The aim of the project is to conduct building- and energy-oriented investigations by means of intensive monitoring. In addition to assessing the district concept in terms of the energy utilisation, the impact of energy-plus housing estates on the energy supplier’s electricity grid will also be considered. In addition, it is also planned to conduct building simulations, a simulation tool for using shallow geothermal energy will be developed and an online platform will be provided for raising awareness among the residents. Guidelines will also be drawn up for residents and designers. It is intended to incorporate the knowledge gained from this research project in future construction projects.


District concept

In order to attain the “energy plus” goal, energy savings must form the focus of the building concept. This is also helped by using highly efficient construction materials. In contrast to the thermal insulation composite systems currently used in most new buildings, which consist of concrete components and externally applied thermal insulation, hollow clay bricks with integrated insulation are deployed in the Ludmilla housing estate. This enables the advantages of masonry construction to be combined with very good thermal insulation. The air spaces in the hollow clay bricks are filled with a mineral granulate. Filing the brick holes with mineral granulate also integrates a “noise absorber”. The combination of hollow bricks and mineral granulate with an λR = 0.040 W/(mK) meets maximum thermal insulation requirements with a U-value for the total brickwork equalling 0.18 W/(m²K). In addition, triple-glazed windows are used with a UW value of 0.92 W/m²K. All construction components considerably undercut the minimum values stipulated by EnEV 2009. A further feature of energy-plus housing estates is the use of innovative building services technology.

Energy concept

Detached, semidetached and terraced houses

  • Deployment of mini heat pumps that have been specially developed for low-energy homes
  • The heat pump has reverse operation for the summer, with use of waste heat for heating the domestic water
  • Use of shallow geothermal energy, using different types of installed ground collectors
  • Very good temperature conditions on the heat sources and heating side in order to optimise the coefficient of performance of the heat pumps
  • Indoor heating using underfloor heating with a maximum supply temperature of 35 °C (LowEx)
  • Controlled indoor ventilation with η > 85%
  • Air ducts in the concrete ceiling to ensure optimum air vent locations for the air flow
  • A PV system provides the electricity required for space heating, ventilation and water heating
    Building services technology in apartment buildings

Multi-family house

  • Use of condensing cogeneration system to meet basic loads (domestic water heating)
  • Condensing boiler used as peak load boiler
  • Biogas is used solely as fuel
  • 10,000-litre buffer storage tank to enable the heat volume required for the peak domestic water heating loads (morning and evenings) to be produced and stored during the day
  • Each apartment has its own compact station in which the domestic water is heated as required according to the continuous flow principle (no circulation losses)
  • Compact station also acts as transfer point for the underfloor heating
  • Apartment buildings are supplied with heat via a joint local heating network
  • The compact stations enable the supply temperature in the entire local heating network to be kept to a maximum of 50 °C (which leads to lower losses during the heat distribution)
  • Use of central ventilation units with η > 85% to ensure a minimum air change
  • In addition to the electricity generated by the CHP plant, electricity is also supplied by the photovoltaic systems on the roofs.

    Measurement concept

    The measurement concept for the Ludmilla housing estate encompasses more than 700 measurement points. The gas consumption, the electricity generated and the heat provided will be measured for the heating centre.

    On the electricity side, the electricity produced by the PV systems, the temperature and humidity of the ventilation systems as well as their electricity consumption will be recorded for all buildings.

    On the heat side, the electricity required by the heat pumps and the heat extracted from the ground will be measured for the single-family homes, whereas only the overall heating requirements will be recorded for the apartment buildings. For both building types, the heat requirements for space and water heating will be separately recorded for each residential unit. In addition, the temperature and humidity in the rooms will be measured in the apartments in the second building phase.

    Visualisation of the energy consumption

    The comprehensive measurement technology will be additionally used to inform the residents of the Ludmilla housing estate via an online platform about the current energy consumption for each residential unit as well as for the entire estate. For data protection reasons, each resident is only allowed to view their own consumption. Surveys will be conducted before and after launching the online platform in order to determine how the displayed energy values impact on the behaviour of the residents. The survey findings will be compared with the measurement values and evaluated.

    New simulation tool for shallow geothermal energy

    The “Delphin” simulation program, which has been developed at Dresden University of Technology for calculating the transport of heat and humidity in construction components, provides the basis for a simulation tool for shallow geothermal energy. Essential physical processes such as heat conduction, diffusion, capillary conduction, enthalpy transport and evaporation have already been implemented and tested. The extraction of heat from the ground, the storage of heat in the ground, the influence of the ground water on the distribution of heat in the ground as well as the melting enthalpy (icing) are integrated in the model. The new tool therefore enables the behaviour of the ground to be realistically calculated for several years in advance (ground model). The simulation results are validated with a measurement field that comprises eight different types of installed ground collectors. These are equipped with more than 200 temperature sensors.

    Project data

    District data

    Gross floor area, after (according to DIN 277) 7.600 m²  
    Area used for residential purposes, after 7.600 m²  
    Number of residential units, after 68 WE  
    SOI (Site Occupancy Index) 0,34 GRZ  
    FSI (Floor Space Index) 1,05 GFZ  

    Energy data

    Ultimate energy demand (Heat, after DIN V 18599) 40,00 kWh/m²a  
    Ultimate energy demand (Electricity, after DIN V 18599) 30,00 kWh/m²a  

    Implementation costs

    Reference surface for implementation costs Gross floor area 7.600 m²  
    Building related investments after HOAI (KG 300 und KG 400)    
    KG 400 260,00 €/m² BGF  

    Last Update: 27. July 2017

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