Long-term analysis of cooling demand and heat recovery in hotel HVAC systems: Implications for sustainable chiller design and operation to reduce CO2 emissions

Abstract

Problem statementThe long-term impact of hotel operations on energy consumption and carbon emissions in cooling demand (CD) and condenser heat recovery (HR) is not well understood. IntroductionThis study aims to analyze the changes in CD and HR over a 20-year period for a hypothetical hotel in Hong Kong to assess the long-term impact of hotel operations on energy consumption and carbon emissions. MethodologyEnergyPlus software is used to simulate CD and HR values, considering architectural features and HVAC system configurations. Long short-term memory (LSTM) models are developed, incorporating indoor temperature setpoint, climatic variables, and historical data. The study assesses building energy simulation from 2003 to 2022 against typical meteorological years and compares the energy and carbon emission performance of various chiller system configurations, including a variable speed chiller system with condenser heat recovery. Salient findings/resultsThe LSTM models demonstrate high performance with an R2 value of 0.979 and an accuracy of 0.946 in the confusion matrix. The simulation results show a significant increase of 3.83 % to 18.93 % in peak CD and 6.04 % to 20.48 % in annual total CD from 2003 to 2022, which was not predicted by the typical meteorological year data. The all-variable-speed chiller system with condenser heat recovery maintains high energy performance despite the rising CD, resulting in a notable reduction in carbon emissions (15.77–17.44 kgCO2/m2). ConclusionsThis study offers valuable insights into the design and operation of sustainable chiller systems, helping to understand long-term trends in cooling demand and condenser heat recovery in hotel operations.