When does the building simulation make sense?
In contrast to the classical analytical heating and cooling load calculation, the building simulation is usually much more complex due to the depth of detail to be taken into account. Its use is therefore particularly profitable for larger buildings or for buildings in series production. A significant benefit is the reduction of the planning risk, especially with new or innovative building concepts.
o Reduction of the planning risk
A relatively frequent misplanning of modern low opaque buildings is the underestimation of the cooling load in warm, sunny summer months. The high-quality simulation provides a multitude of physical results per time step, such as the room air and felt temperature. The calculation of the room temperature shows at an early stage to what extent heating and cooling load peaks can be expected.
By analysing the frequency of the cooling and heating loads that occur, it is not only possible to coordinate the sizes of the heat and cooling generators, but also to dimension their size in relation to each other as a function of the highest possible base load coverage and the lowest possible peak load coverage.
This procedure allows the investments in the producer park and/or the efficiency of the producers to be designed depending on their expected capacity utilisation.
o Economic and ecological optimisation of the refrigeration and heat generation park
Insulating is now standard in new construction. In this context, it should be noted that the increasing insulation thickness does not result in an equal proportional increase in energy savings. The following figure shows an example of the degressive course of transmission savings over the increase in insulation thickness.
The strength of the insulation and its influence on the energy costs can be varied and optimised within the framework of regulatory requirements with the share of renewable energy supply.
o Economic and ecological optimisation of thermal insulation
A frequent weak point of modern buildings is inadequate ventilation with regard to the air tightness achieved in new buildings. In many cases, the air tightness required by law is exceeded. The result is reduced air quality in the residential unit.
The building simulation allows the variation and optimisation of the free and fan-supported air exchange and the necessary measures to compensate for air exchange enthalpy losses. Air quality can be quantified and evaluated taking into account the occupancy function, demand-driven ventilation strategies and the influence of heat recovery efficiencies.
o Evaluation of expected room air qualities from an economic point of view
The efficiency of individual heat and cooling generators varies considerably depending on their type and use. Their evaluation in terms of climate law via the level of the associated primary energy factors makes this even more complicated. Compared to a water/water heat pump, the air/water heat pump is significantly less expensive in terms of total investment costs up to commissioning, and is significantly less efficient for heat input, depending on the outside temperatures and type of heating system. The building simulation can compare such correlations as the demand, the operation-dependent efficiency and thus the operating costs to the investment costs and thus helps to make a decision in the planning process.