www. refrigerationandaircon. co. za RACA Journal I July 2025 43
Technical of the energy for hot water production to come from environmentally friendly sources requiring verification.
CASE STUDIES IN ACTION The following two case studies by Prousalogou showcase successful implementations of AHI Carrier’ s solutions. These realworld examples provided insights and inspiration for architects, engineers, and developers looking to integrate into their projects sustainable and holistic hybrid HVAC solutions- which combine energy efficiency while catering to environmental issues.
PROJECT ONE: PLOT C397, ABU DHABI, UAE The first case study centres around a ground and 12-floor residential building in Abu Dhabi, housing 230 apartments of various sizes, from single to three-bedroom units. AHI Carrier was called in to‘ comment and advise’ in order to optimise an already designed HVAC solution, in the hope of significantly enhancing energy efficiency and environmental sustainability.
The pre-existing design was robust, including air-cooled screw chillers with fixed-speed compressors and traditional electric water heaters for apartment sanitary water production. AHI Carrier proposed a substantial upgrade by replacing these systems with:
• Space cooling: air-cooled screw chillers with highefficiency variable speed compressors and heat reclaim features – terminal fan coil units( TFCUs) and fresh air handling units( FAHUs)
• Sanitary hot water: instantaneous heating unit interfaces utlising the energy reclaimed from the cooling system
The upgraded chillers not only cater to the building ' s cooling demands year-round but also recover waste heat for hot water production through integrated energy storage tanks. This innovative approach harnesses energy that would otherwise be wasted, resulting in significant energy savings. AHI Carriers ' simulations estimate a reduction of 50 %+ in total system energy consumption, translating to approximately 2.3 million kilowatthours saved annually.
AHI Carriers ' approach started with a thorough understanding of the building ' s requirements and environmental conditions in Abu Dhabi. Detailed analysis of weather patterns and solar irradiation informed their HVAC simulations, crucial for accurately predicting cooling and heating loads throughout the year.
The design process involved creating detailed 3D representations and simulations using advanced tools like HAP( Hourly Analysis Program). This enabled AHI Carriers to visualise the system layout and calculate precise energy requirements, ensuring optimal performance under Abu Dhabi ' s climatic conditions. This revealed that cooling in this environment was a mandatory requirement.
Project Two: Plot C396, Abu Dhabi, UAE
Central to this innovation strategy was the Heating Unit Interfaces( HUIs), compact heat exchangers designed to instantaneously heat water from 15-17 ° C to target temperatures of 55-60 ° C. By utilising reclaimed energy from the chillers, AHI Carrier replaced 780 traditional electric water heaters with 230 HUI units which utilise no energy, thereby significantly reducing energy consumption for water heating in the project.
The environmental benefits of this upgrade are substantial. Through simulation and analysis, AHI Carrier estimated a 60.5 % reduction in CO2 emissions for the building. This equates to an annual reduction of approximately 1.3 million kilogrammes of CO2 emissions, representing its positive impact on climate change mitigation.
Beyond environmental gains, the upgraded system offers operational efficiencies and cost savings. The system ' s Energy Efficiency Ratio( EER) of 5.45 represents high performance and economic viability, providing significant long-term savings in operational costs for building owners and residents alike. This is double the ratio of the previous design.
Moreover, AHI Carrier ensured seamless integration and monitoring through a Building Management System( BMS), which oversees the entire HVAC system ' s operation. This centralised control not only optimises performance but also enhances reliability and responsiveness to varying environmental conditions.
The project ' s impact extends beyond energy and environmental realms. By replacing traditional water heaters with HUIs, AHI Carriers eliminated stagnant water issues, reducing potential microbial risks and minimising the need for additional water treatments. The compact design of HUIs also translates into space savings and simplified installation, further streamlining building operations and reducing construction complexities.
Photos from the installation and commissioning process highlight the effective application and success of AHI Carriers ' solutions. As they work to enhance and expand their sustainable HVAC offerings, AHI Carriers continues to play a leading role in
www. refrigerationandaircon. co. za RACA Journal I July 2025 43