Comfort Heat Index – Thermostatic Control of Air Conditioning Units

This work is related to Heat Index in the context of thermostatic control of air conditioning units. Heat Index is the temperature equivalent of the discomfort caused by the air temperature and the relative humidity (RH). Usually, the air conditioning systems are set to a much lower temperature than needed, resulting in overcooling (which for many people causes discomfort and health hazards) and waste of energy. This work determines the Heat Index which is comfortable enough and does not waste energy for overcooling, called here “Comfort Heat Index”. The Comfort Heat Index is 26.6°C (79.9°F). Setting air conditioning systems to a Comfort Heat Index (CHI) will provide air conditioning that is comfortable enough for those suffering from heat and much better for those suffering from cold. The work also introduces the Optimum Comfort Air Conditioning (OCAC), the thermostat setting that achieves thermal comfort with minimal cooling hours, reduced energy consumption, and a Heat Index (HI) that remains below the Comfort Heat Index (CHI = 26.6°C). Based on the analyzed data for Jerusalem and Tel Aviv, the Heat Index remains below the Comfort Heat Index at cooling setpoints below 25.5°C in Jerusalem and 25.7°C in Tel Aviv. The work applies the Building Energy Simulation and Optimization Online program (BESOO) version 522 which, in addition to previous versions, also calculates the Heat Index of air conditioned room.