A modern Interurban Bus Terminal Complex for the city of Athens with total floor area of 52800 m2, serving 67200 passengers daily, housing terminals for interurban and international buses, local buses, a shopping mall, a hotel, an exhibition / conference center, underground parking and a connection to a nearby Metro station is presented with respect to its environmentally friendly HVAC systems design and other low energy consumption and optimized energy use measures. The paper outlines the building complex and its operational characteristics and then analyzes its HVAC systems with reference to equipment sizing and operation, while their significant environmental benefits are also quantified.
3000 kW of HVAC systems including Ground Source Heat Pumps (GSHPs) rated at 500 kW, ice banks of 450 kW for complementing cooling during the day, series of A/W heat pumps totaling 2500 kW sized for night operation, coupled with multiple thermal storage tanks, and maximized natural ventilation are presented, attaining an overall power consumption of 57 kW/m2, contributing to a nearly zero energy building (nZEB) with no compromise on comfort conditions’ standards, and operation organized in a manner optimizing COVID-19 response measures.
Alternative conventional HVAC schemes are also outlined and compared to the nZEB building’s proposed systems, with estimated comparisons for energy, maintenance costs and feasibility of implementation.
The question of whether it is worth investing on expensive, more complex and higher maintenance HVAC schemes with excellent environmental characteristics and highly reduced CO2 emissions, by 8,5 tons daily, versus conventional and less complex schemes remains a borderline case, especially since the estimated 225 m € necessary funding for constructing this interurban bus terminal complex is planned to be mostly from private sources.
An accompanying paper describes in technical / operational detail the environmentally friendly water management systems and their performance characteristics for the nZEB Interurban Bus-Terminal complex.


Mechanical Engineer (MSc, DIC, PhD), currently Deputy Engineering Manager in Attiko Metro, Athens with 29 years’ experience in Metro & Tram Projects engineering; focus on Metro electromechanical and railway systems design, design coordination, project specifications and tender documents preparation, testing and commissioning and project contractual management. 50 publications.