22 May 2008
The energy demand for heating is decreasing significantly in modern highly-insulated
dwellings. In a research project several heating and cooling variants with ground-coupled
heat pumps, passive cooling with borehole heat exchanger and cooling by night-time ventilation
have been evaluated.
A parametric study with MATLAB/Simulink simulations using a residential low-energy building
has been carried out with the objective to estimate energy demand for heating and cooling
versus thermal comfort and economical feasibility of the overall system.
Beside the most suitable hydraulic scheme the appropriate control providing an optimal thermal
comfort with a minimum of additional energy in comparison to heating-only had to be optimised
to avoid intermittent heating and cooling in autumn and spring yielding an increase in
heating energy demand, since the cooled concrete structure has to be heated-up again, if
space heating is required.
As a result of the simulations a proven hydraulic scheme, smart control strategies and guidelines
for system design could be derived. The project is a national contribution to IEA HPP
Annex 32 on economical heating and cooling systems of low energy houses.