The impact of ventilation parameters on thermal comfort and energy-efficient control of the ground-source heat pump system

This study focuses on the concurrent changes of the PMV-power demand triggered by the two common control variables of the ground-source heat pump (GSHP) system, namely the ventilation rate and supply water temperature from the compressor, to explore their potentials to achieve energy saving while maintaining indoor thermal comfort level. Using the two variables as the intermediate parameters, a set of full-scale experiments was conducted to obtain the resultant changes of indoor environmental conditions and power demand across design space. Statistical models for heat supply and coefficient of performance (COP) of the GSHP system were constructed from the Gaussian process regression (GPR) to derive the PMV and power change separately. Afterwards, the response surface of PMV-power demand were calculated with different configurations of the two control variables. It is identified that the system COP significantly changed from 1.7 to 6.6 due to parameters variations. Such a change in the COP results in non-linearity for the PMV-power demand curves where lowest power demand can be determined with improvements in the PMV level by properly tuning both ventilation parameters. The projection of the PMV-power demand response surface creates the frontier of the power demand for a given PMV level indicate a potential strategy for the GSHP system. For instance, we identified that under the thermally-neutral condition criteria the GSHP system is operated at a power demand of 1.77 kW. However, by changing the ventilation rate and supply water temperature, 20% energy consumption reduction can be achieved with a nearly-same thermal comfort (−0.07 PMV). Finally, the potential efficient control for the GSHP system with the help of the PMV-power demand curves tool is revealed and discussed.