Control Strategies for Efficient Use of Heat Pumps in Non-residential Buildings

Development and testing of novel control strategies for the efficient use of bivalent compression heat pumps with earth probes for heating and cooling purposes in production facilities, taking seasonal influences into account

Project duration:
09/2011 to 02/2014

Project funding:

Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR), Forschungsinitiative Zukunft Bau

Description:

In Germany, buildings cause a significant part of the total primary energy consumption. In order to reach the planned CO2 savings, the energy required for buildings must be reduced. Apart from optimizing the building envelopes, primary energy-efficient production methods can help to reduce the total energy consumption. Heat pumps can serve to reduce primary energy consumption by employing renewable geothermal energy – but the resulting reduction of CO2 emissions and the efficiency of a heat pump are highly dependent on the seasonal performance factor, which is essentially determined by the heat sink and heat source temperatures. Both temperatures are subject to seasonal variation and inconstant user habits.

Non-residential buildings are mostly built and operated under economic aspects – which is why the respective energy production systems are designed from an economic point of view. Heat pump systems require a relatively high investment, which, due to lower energy costs, pays off during operation. Amortization periods of up to 15 years are not uncommon; a value that has been proven critical regarding client decisions. As part of the research project, novel control strategies have been developed and analyzed using simulation technology. These control strategies serve to optimize the bivalent use of a heat pump – in such a way that uneconomic periods are detected automatically, allowing to switch to less expensive producers and to optimize the overall performance over the course of a year.