Daikin Air Handling Units in DX plants: new kits for plug & play system installation and control

The rise of energy-efficient building designs increases the need for ventilation systems. In this regard, to ensure optimal climate conditions by providing a fresh, healthy, and comfortable environment for buildings of all sizes and applications, Daikin offers its Air Handling Units from medium to large-scale heat recovery ventilation.

Daikin offers a wide range of AHUs that can be installed in a series of systems including: hydronic systems and DX (direct expansion) systems. In both cases, the AHUs are used for air conditioning, air handling and heat recovery.

Where a DX system has been opted for, the integration with condensing units is needed to ensure the correct system operation. For this purpose, Daikin recently launched the new EKEA expansion valve set and control boxes to facilitate further the connection between Daikin DX outdoor units and Air Handling Units (AHUs). The new kits also operate with the lower GWP refrigerant R-32, providing a low CO2 solution for heating, cooling, and fresh air for maximum comfort in commercial spaces. The unit is a plug-and-play solution which is ready to use and simple to operate, ideal for fresh air treatments.  


The AHU-DX outdoor unit integration kit and related benefits

A series of benefits can be detailed in relation with the integration kit. Specifically, 3 main benefits relating to installation, reliability and potential of decarbonisation.

  1. Plug & play system selection and installation: The whole system is designed within Daikin specialised selection software. No pumps, valves, expansion vessels, buffer tanks etc. are required to complete the installation of the system. One single control box is controlling the whole system. It regulates the expansion valve kit and outdoor unit capacity based on the input of the controller and sensors/thermistors. On top of that, the needed communication wiring is simplified: cool/heat signal is factory wired to the control box directly, eliminating the need to lay any additional wire between AHU and condensing unit on site. As well, DX coil, expansion valve kit and control box are factory fitted.
  2. Reliability: The combination kit ensures the correct operation of the system, according to the design defined during system configuration via Daikin specialised selection software. In addition, the parts are factory pre-assembled providing an additional guarantee of installation reliability. Furthermore, the AHUs already include control logics to guarantee compliance with IEC60335-2-40 (ed. 7) for safe R32 operation.
  3. Decarbonisation: the new AHU-DX outdoor unit integration kit facilitates decarbonization in comfort applications allowing easy management of both cooling and heating operating modes without the need of gas boilers. The kit allows integration with Daikin DX outdoor units equipped with both R-410A and R-32, thereby increasing opportunities for decarbonization of space heating in residential and commercial buildings. 
  4. Easy selection: all DX kit selection rules are integrated into Astra Web, the Daikin AHU’s selection software. Thanks to a direct link with VRV Web Xpress, finding the perfectly matching condensing unit has never been easier

Daikin AHU-DX outdoor unit system description

The scheme below describes the system, composed of 5 main elements.  


  1. A DX outdoor unit (VRV IV, VRV 5 or ERQ)
  2. A Daikin AHU with DX (Direct expansion) heat exchanger
  3. The expansion valve kit that regulates the refrigerant flow (and as such the delivered capacity) to the AHU
  4. The control box that regulates the expansion valve kit and outdoor unit capacity based on the input of the controller and sensors/thermistors. Depending on the type of control, the regulation can be done on the supply, return or room air temperature, thanks to the precise evaporating/condensing temperature control
  5. A factory-mounted Plug&Play Daikin control system which, thanks to its integrated logics and factory-fitted components, will offer a balance between ease of integration and response time to changing loads


Daikin AHUs overview 

Daikin offers a variety of AHU products that can be classified according to size and airflow capacity. One of their main features is modularity, so the possibility to be adapted and customized according to the dimension and type of application. 

Daikin's Modular Series units have pre-defined sizes and are available in both indoor and outdoor versions. This means that several modules can be used to cover a wide range of applications. The operating range is suitable for all types of climates. 

Daikin’s AHU product portfolio can be also classified depending on ventilation typology, which can be centralized or decentralized.  

In centralized ventilation, which implies a single location accommodating the equipment (located outdoors on the rooftop of the building, or indoors in a technical room), the units that are implemented are Professional, Modular R and Modular P. The Professional solution is characterized by infinite variable sizes that can be tailored to the customer's needs,  

For decentralized ventilation, which involves one AHU unit per apartment in case of residential or one per office in an office building, the units that are used are Modular T and Modular L.  


Decarbonization and Green building 

HVAC systems can play a very important role in the decarbonisation process. Air conditioning is one of the main contributors to energy consumption in buildings (around 80%) and therefore to global warming. It is therefore important to have an AHU system contributing to the reduction of CO2 emissions while ensuring wellness of building’s occupants. These are features specifically taken into consideration within green building protocols. Indeed, to be considered as such, Green Buildings undergo a quality assessment based on specific rating systems that certify how the facilities are designed to minimise their impact on the environment. The most popular building certifications today are BREEAM - widely used around the world, with over 200,000 buildings certified and over a million registered for assessment - and LEED certification, which is particularly popular in the US but spreading rapidly in Europe and Middle East as well. The whole Daikin Air Handling Units (AHUs) portfolio is designed to provide outstanding energy efficiency and superior indoor air quality, thanks to the use of premium components and thorough optimization, which allow Daikin technology to provide unrivalled performance, both in terms of energy use and creation of a healthy indoor environment. Daikin AHUs can contribute in BREEAM projects with up to 40 credits from out of 6 categories: management, energy, pollution, waste, innovation, health & wellbeing. As well, Daikin AHUs can allow to achieve up to 16 credits in LEED projects from out of 4 categories: energy & atmosphere, indoor environmental quality, materials and resources, innovation and regional priority.


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