Providing a complete HVAC system for an office building in Germany

Daikin supplied a Professional air handling unit (AHU) connected with VRV units with R-32 refrigerant using dedicated kits, to meet the ventilation, cooling and heating needs of a five-floor office building in Bochum, Germany. The ventilation system is centralised, with the AHU installed on the roof of the building.  

 

PRODUCTS 

1 x Professional AHU with integrated Daikin control solutions.  

Total cooling capacity: 88kW  

Total heating capacity: 47kW 

Both heating and cooling are provided by a changeover DX coil for R-32 refrigerant, connected with the VRV units.  

 

NEEDS & SOLUTIONS  

One of the main focuses for the project was to ensure that the air handling unit was energy efficient and had low pressure drops. To meet these requirements, Daikin supplied a Professional Series ahu with additional components, in particular filters designed to minimise pressure drop. The unit was also selected for its low airflow speed design (1.28 m/s), which results in more efficient operation and lower energy consumption. The fans were also selected for their IE5 Ultra-Premium efficiency, in line with the latest standards in fan technology. 

From a technical point of view, the main highlights of this project are the factory-installed controls and the integration with the newly launched VRV5 units by means of the EKEA dedicated connection kits for DX coils when R-32 refrigerant is employed. 

In addition, the AHU complies with all relevant regulations and meets the requirements of the German hygiene guideline VDI6022 as well as the ERP EcoDesign 2018 standards.   

 

 

The Daikin AHU-DX unit integration kit 

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 designed the AHU-DX outdoor unit integration kit, which can bring several advantages. This plug-and-play system has Daikin specialized selection software integrated, so one factory-fitted single control box controls the whole system, simplifying the communication wiring. The parts are factory pre-assembled providing an additional guarantee of installation reliability. The kit also helps the decarbonization process, allowing easy management of both cooling and heating operating modes without the need for gas boilers and allows operating with both R-410A and R-32, thereby increasing opportunities for decarbonization of space heating in residential and commercial buildings. Lastly, DX kit selection rules are integrated into Astra Web, the Daikin AHU’s selection software, which results in easy selection.  

 This scheme shows the 5 elements system:  

 

 

 

  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  

  5. A factory-mounted Plug&Play Daikin control system Thanks to this combination are possible to provide ventilation, air conditioning, cooling and controls in a single package. 


 

 

Daikin Professional series 

The Professional series offers a tailor-made AHU solution with over 1,000 possible combinations to precisely meet all customer requirements, making it suitable for many different applications.  

The AHU is designed to the customer's requirements, always optimising the unit for the most cost-effective selection and manufacturing standardisation. The plug-and-play control provides excellent operational flexibility. The factory-fitted electrical control panel, complete with Direct Digital Control (DDC), integrates built-in temperature, humidity and CO2 sensors to manage mixing dampers, heat recovery wheels, water valves, pressure switches for filters and fans, fan motors and inverters. The control system can manage the chilled water coil, hot water coil and DX cooling and/or heating coils (in conjunction with ERAD-E-/ERQ/VRV) of single or multiple refrigerant circuits (up to four circuits per DX coil). 

To ensure that Daikin Applied achieved the best fit for this project, the custom-made AHU was externally mounted and sized to the engineer's precise criteria, while meeting the site's technical specifications. 

 

 

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