Thermal Comfort and Energy Consumption in a Residential Building: An Experimental Comparison Between a Heat Pump and Gas Boiler Employing Low-Cost Microcontroller-Driven Sensors

Many buildings in Southern European countries are equipped with both gas boilers and air source heat pumps. The present work concerns an experimental evaluation of indoor comfort in an apartment within a residential building, comparing a gas boiler with cast-iron radiators to an air-to-air heat pump. The comfort conditions inside the apartment are assessed at set-point temperatures of 20 °C and 21 °C and with different water supply temperatures from the gas boiler. Energy consumption data for both heating systems are recorded during the tests. The measurements inside the apartment are conducted using inexpensive, widely accessible sensors and Arduino-like microcontrollers, calibrated before use. As a result, comfort indices for the heat pump are between those for the gas boiler at 20 °C and 21 °C. Additionally, to understand the impact of occupancy, an analysis of local discomfort and air quality was conducted by measuring CO2 levels, which rose significantly without air exchange. Lastly, the experimental results are compared with previous dynamic and Computational Fluid Dynamics (CFD) analyses, showing the limit of the computational approach. Indeed, the comfort indices derived from the experimental study are superior to those obtained from dynamic simulations and CFD.