"Detail the intricate workings of an HVAC (Heating, Ventilation, and Air Conditioning) system in a luxury hotel. Explore the complexities of temperature regulation, air quality management, and energy efficiency. Highlight the integration of state-of-the-art technology, such as smart climate control, and emphasize the system's role in ensuring a comfortable and inviting atmosphere for guests while also prioritizing sustainability and cost-effectiveness in the hotel's operation."