Combining Building Technologies to Best Effect
The greatest energy efficiency is achieved by combining various energy-efficient technologies. Of course, competent planning and selection of measures, and their careful execution, are absolutely essential. The special provisions in German legislation encourage full utilisation of the scope and potential of these technologies and promote diversity in the approaches used. As a result, German engineers are driving the energy-efficient merging of insulation and heating technology and the development of the necessary control systems. German companies are global leaders in energy-efficient boiler technology, renewable energies and control systems, offering the greatest number of solutions and the most advanced.
Buildings with optimised insulation, such as passive houses, are virtually air-tight. In these buildings, ventilation systems provide the hygienically required air renewal and maintain a constantly optimised quality of air, while minimizing the supplementary heat requirement. A central ventilation system is an ideal solution for utilising the heat in the extracted air to pre-warm the incoming fresh air. Air-to-air heat pumps can reduce the ventilation heat requirement by up to 95%, for example.
Where solar radiation (which is free of charge and of CO2) is used as an energy source, an intelligent combination of technologies involving heat stores and heat generators provides the solution for periods of low sunlight:
- Well-insulated heat storage tanks with a tall and narrow design and minimised heat stratification, used in conjunction with intelligent control technology, enable the use of various levels of heat and the storage of heat from various sources, while keeping heat loss to a minimum. These are used both by the solar heating system and by the secondary heat generator, for example a pellet or condensing boiler or a heat pump in order to reduce partial-load conditions or cycling.
- Other storage solutions are also available. The structure of the building itself can balance day/night differences if the thermal mass of its components is activated (for example, with water pipes in the ceiling). In addition, latent heat storage (with PCM, or phase change materials), such as encapsulated paraffin in the surface of interior walls (for example, plaster, gypsum plasterboard or chipboard) can maintain the desired temperature over longer periods.
In terms of systems engineering, geothermal probes significantly enhance the potential of solar heating systems and heat pumps. During the summer months, the soil around the probes can be regenerated using the surplus heat from the solar heating system. This type of coupling also protects the solar unit against stagnation, which would damage its components. During the summer, solar units can normally provide a building's entire hot water requirement, which saves heating costs and, of course, reduces CO2 emissions.
Pellet boilers and condensing boilers can similarly be used in combination with solar heating systems. By having these boilers provide almost all of the hot drinking water required during the summer months, inefficient partial-load conditions are avoided. This protects the environment, reduces costs and enhances the durability of the boilers themselves.