Best practices in LEED projects: a case study from Spain

Daikin recently supplied 4 EWWD-VZ and 32 D-AHUs to meet the cooling and ventilation needs of Caleido Tower, an office complex in Madrid, Spain. The design of Madrid's skyline presented the challenge of maintaining an energy-efficient environment while accommodating its diverse uses. Daikin stepped in with tailored HVAC solutions that were critical to achieving LEED certification.



4 x EWWD-VZ single screw compressor water-cooled chillers with Inverter technology

32 x D-AHU Modular P

Cooling capacity: 4000 Kw



Caleido is a complex located in the financial district of Madrid, consisting of a shopping and leisure area, and a medical center. It is one of the 5 towers that completes the Madrid skyline. The complex, shaped like an inverted T, houses a variety of spaces on its ground floor, among which you can find shops, restaurants, leisure and areas for events. And in the Tower, itself there is the IE, a prestigious educational center with more than 5,000 students. With more than 180 meters high, maintaining a comfortable and efficient environment that adapted to the diversity of uses without losing sight of energy efficiency was a major challenge. On top of that, the building project was under LEED assessment for certification. Thereby, a series of requirements have been posed to satisfy LEED assessment criteria.


Efficient &reliable water-cooled units

Daikin designed a customised solution using advanced EWWD-VZ water-cooled units with variable frequency drives. At the system's core is an exceptionally reliable single-screw compressor with unique performance characteristics. The combination of this compressor with Inverter technology and Daikin's extensive expertise ensures not only the highest levels of energy efficiency but also unmatched durability, making it a truly solid choice for your air conditioning needs.

Daikin single-screw compressor

Daikin develops and manufactures its screw compressor. Different from a standard screw compressor, it uses one main screw mashing with star rotors to produce a volume-matching compression cycle. As the main rotor is balanced in both radial and axial directions, the compressor bearing has extremely high reliability.

The benefits of Inverter technology

Most of the operating time of HVAC equipment is at part load conditions. That means the compressor of a chiller encounters many hours of off-design operation. It is important, though, to look for chiller units that ensure optimal performance at part loads.

This is the case of units equipped with inverter or variable frequency drives (VFD) to modulate the compressor’s capacity according to demand. The inverter technology continuously modulates the speed of the compressor's motor, which is the most efficient way to perform the capacity control of the compressor. This results in outstanding part-load efficiencies, and therefore low operating costs.

Noise attenuation configuration

Caleido Tower is a mixed-use building, visited every day by thousands of people. Hence, the customer also expressed the need to limit the sound power related to the chillers’ operation. Thereby, a compressor soundproof system has been integrated into each unit, reducing sound power by up to -3 dB(A).

Reclaimed refrigerant for lower environmental impact

The units supplied for this project were part of the L∞P by Daikin programme, which means that the chillers are covered within certified reclaimed R-134a refrigerant allocation. Under the reclamation process, refrigerant is recovered and reprocessed to match the performance and quality of the virgin substance. Our reclaimed R-134a meets AHRI700 standard (purity>99.5%), so it can be recovered and reclaimed with no limits. This approach supports Daikin Industries' environmental policy for 2050, avoiding, every year, the production of virgin refrigerants including both R-134a R-410A and R-32 for more than 400,000 kg per year. Specifically on R-134a, a study from Tokyo University, reports that it has a 90% lower environmental impact than virgin R-134a. This is because refrigerant reclamation does not require end-of-life destruction, and reprocessing requires less energy than the production of virgin refrigerant.


Air Handling Units for optimal indoor air quality

As mentioned, Daikin has been supplying air handling units as well, 32 Modular P AHU units. This product range ensures from 700 m³/h to 21,000 m³/h air flow and offers a plug-and-play AHU solution thanks to its modular design. Indeed, Modular P is available in 10 model sizes to accommodate the different building types and needs. As well, Modular P also ensures optimal indoor air quality thanks to a design compliant with VDI 6022 hygiene guidelines. Moreover, heat recovery exchangers are integrated into the unit’s design, to make sure the building can keep running costs low for heating systems operation. Modular P can be integrated in a chilled water system, or a direct expansion system (DX) as well. To this purpose, specific kits have been recently released by Daikin, covering integration with condensing units equipped with both R-32 and R-410A. This and many other design configurations can be set via the AHU selection software Astra Web, also allowing the possibility to import BIM objects in Autodesk® Revit, thanks to a dedicated free plug-in available for download.




Green building, features and specifications


Buildings have a substantial environmental impact, contributing significantly to energy consumption and CO2 emissions. Green building practices aim to mitigate these impacts by adopting resource-efficient and environmentally responsible approaches throughout a building's lifecycle. Certifications like BREEAM and LEED assess environmental performance and promote higher construction standards globally. BREEAM is widespread, with over 200,000 buildings certified, while LEED, popular in the US, is gaining traction in the EU.

The incorporation of Daikin's customised HVAC units with inverter technology played a crucial role in enhancing the Caleido Tower project. This not only improved comfort and energy efficiency, but also highlighted the importance of cutting-edge technology in effective building management. The LEED Gold certification achieved by the Tower validates its compliance with specific criteria in categories such as Energy and Atmosphere and Indoor Environmental Quality. Developed by the U.S. Green Building Council, LEED is an internationally recognised standard for sustainable construction that certifies that buildings exceed national standards for energy efficiency, water savings, CO2 emissions reduction, indoor air quality, resource stewardship and environmental impact reduction.

HVAC systems have a significant effect on a building's environmental impact, accounting for approximately 50% of energy consumption. For this reason, by optimising HVAC systems, buildings can reduce their environmental footprint. Daikin is committed to reducing the environmental impact of the air conditioning sector by developing innovative technological solutions for sustainability in the residential, industrial, and commercial sectors, including chillers and mechanical ventilation systems.

Daikin's air handling units (AHUs) ensure optimal indoor air quality through premium components. Meeting the requirements for LEED and BREEAM certification, Daikin AHUs minimise operating costs by reducing energy consumption. Incorporating heat recovery technology and advanced filtration systems, they exceed local legislative requirements and contribute to occupant comfort by addressing emissions, energy consumption and resource conservation.


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