Nelson Fumo

This study evaluates the performance of evaporative cooling (EC)-assisted residential HVAC systems within the broader context of improving energy efficiency in U.S. housing. Using whole-building energy simulation in OpenStudio, a representative single-family house was analyzed across multiple climate zones under three configurations: (1) a baseline air-source heat pump, (2) EC applied at the outdoor air intake, and (3) EC applied at the heat pump inlet. Annual energy use, indoor temperature and humidity, thermal comfort (PMV), water consumption, and economic performance were assessed. Results indicate that system configuration exerts a stronger influence on performance than climate variability. Specifically, the EC at the heat pump inlet configuration reduced annual energy consumption by up to 5.1%, whereas the EC at the outdoor air intake configuration yielded negligible or inconsistent savings (generally within ±1%). The heat pump inlet EC configuration consistently reduced annual energy consumption and showed favorable economic performance in 10 of 16 climate zones, whereas outdoor air intake configuration yielded limited energy savings and was not economically viable. Indoor temperature control remained stable across all cases, while relative humidity increased with EC operation but remained within acceptable limits under appropriate control strategies. The findings indicate that EC integration can improve residential HVAC performance when properly configured, with system placement and humidity control being critical determinants of effectiveness.

Humidity control in residential buildings is fundamental to ensuring indoor comfort, health, and energy efficiency. This study evaluates the relationship between indoor relative humidity and its impacts on thermal comfort, HVAC energy performance, biological activity, and material durability during the cooling season. Through literature and thermodynamic analysis, the results suggest that moderately higher RH levels to the common 50% recommended can improve thermal comfort and reduce cooling energy consumption without increasing health or material risks. The analysis concludes that humidity itself is not inherently detrimental; rather, condensation is the critical mechanism behind health and material degradation. Consequently, operating residential cooling systems within a controlled upper humidity at 60% offers measurable energy benefits while maintaining occupant well-being and building integrity.