Ludmilla energy-plus housing estate, Landshut
|Location of local community||Stadt Landshut, 84034 Landshut, Niederbayern, Bayern|
|Settlement in figures||65.79 km² area, 62,700 residents|
|Developer, organizer||Ludmilla-Wohnbau GmbH|
|Settlement||mixed development comprising apartment buildings and single family homes|
|Utilisation type||purely residential|
|Gross floor area, after (according to DIN 277)||0,73 ha|
|Area used for residential purposes, after||7.600 m²|
|Number of residential units, after||7.600 m²|
|SOI (Site Occupancy Index)||0.34|
|FSI (Floor Space Index)||1.05|
|Age structure||new buildings|
|State of construction and refurbishment||new buildings|
|Heating system||single family homes: heat pumps. Apartment buildings: local heating network, heating centre with CHP power plant and peak load boiler (biogas fuel)|
|Ownership structure||freehold apartments and homes|
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.
Another aim of the project is to develop guidelines and recommendations for action for designers of energy-plus housing estates. These should highlight important issues and requirements already during the design phase that need to be considered in future energy efficient building projects. Because, thanks to their excellent physical characteristics, very little energy is required for heating energy-plus buildings in order to achieve a positive energy balance, heating these buildings with heat pumps provides an interesting alternative. For this reason, a simulation tool is being developed as part of this project that is intended to prevent design errors when designing geothermal heat exchangers.
Building and system concepts
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. The following technologies are used in the construction project being investigated:
Building services technology in 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
• 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.
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.
State of the project work (beginning of 2011)
The last apartment buildings are currently under construction. The measurement technology is currently being installed in the buildings that have already been completed and the display and data recording systems are being integrated. The simulation tool for using shallow geothermal energy is being programmed.