January 2013
Publication year: 2013
Source:Building and Environment, Volume 59
An air-to-water heat pump system for the heating of a one-family home is numerically analysed. The influence of the supply temperature on the seasonal performance factor of the heating system is examined by varying the heating curve. Furthermore, an adaptive control algorithm is studied which lowers the supply temperature according to the actual heating demand. The study includes a variation of control parameters. The different configurations are evaluated with respect to their efficiency (seasonal performance factor) and the comfort (room temperature). In systems with correctly parametrized heating curve controlling the room temperature is likely to be too high because of inner loads and solar gains. Instead of dealing with these gains by lowering the mass flow using thermostatic valves, the supply temperature can be dropped. This has a positive effect on heat pump efficiency because it decreases the total temperature lift. The control algorithm adapts the supply temperature in discrete time steps depending on the position of the thermostatic valve. Special attention has to be paid for the resulting room temperature and its deviation. With the control algorithm presented in this paper, the seasonal performance factor can be increased by up to 0.19, depending on the allowed variability of room temperature. Savings in annual primary energy demand compared to a standard controlling are up to 6.8%.
► An air-to-water heat pump system for the heating of a one-family home is numerically analysed. ► An adaptive control lowers the supply temperature according to the heating demand. ► The control strategy leads to savings in annual primary energy demand for heating. ► Control parameters have an influence on primary energy demand and thermal comfort.
Publication year: 2013
Source:Building and Environment, Volume 59