Meeting comfort cooling & heating needs for an Office building in London


Daikin recently supplied 5 Inverter Screw units to an office building in London. The main goal of this project was to provide the office building with an efficient and comfortable solution for cooling and heating.  


4 x EWYD-4Z 

1 x EWAH-TZ 

Total cooling capacity: 3076 kW 

Total heating capacity: 2370 kW 


Project needs 

The project requirements posed a challenge in finding the best solution to meet energy-efficiency and heating and cooling needs that could meet the building's load profile, managing to maintain low operating costs. To satisfy these needs, Daikin provided an air-cooled system including 4 polyvalent (or multi-purpose) units and 1 chiller, which can ensure absolute reliability and efficiency. 

Furthermore, the system was expected to cope with NABERS' requirements. NABERS UK is a system for rating the energy efficiency of office and commercial buildings across England, Wales, Scotland, and Northern Ireland. It indicates the environmental performance that buildings must meet, measuring greenhouse gas emissions, and energy and water efficiency. 

For these reasons, the units supplied were four multi-purpose units from the EWYD-4Z Series and a screw inverter chiller from the EWAH-TZ Series. With full inverter technology, the five units were able to meet energy efficiency targets. Specifically, the EWYD-4Z units, thanks to their multi-purpose nature, represented a valuable solution in terms of building efficiency, as they allowed to design of a more energy-efficient HVAC system compared to traditional systems which integrate a higher number of components. 

Moreover, given the importance of the project,  all four units went through stringent factory acceptance testing before shipping. All units were tested at full load cooling mode, heating mode and mixed mode. Besides, partial load conditions were tested as well, both in cooling and heating mode. Cooling operating conditions have been tested with ambient temperature rising from 35 °C to 40 °C, whilst heating conditions at ambient dropping from - 5 °C to - 10 °C. The test sessions also included defrost conditions and acoustic testing to prove compliance with requirements.  


Variable Frequency Drive Technology by Daikin 

Part load efficiency is particularly important when it comes to HVAC systems. It is well known that HVAC systems spend most operating hours in conditions outside of design. When looking at a typical cooling load profile, units mostly operate at part load. This results in different HVAC system components running at off-design operation. Therefore, they must perform efficiently and reliably in these conditions too. That can be managed using variable frequency drive (VFD) or inverter technology – an electronic power component that, by varying the frequency of the motor power supply, modulates the compressor rotational speed and in such a way controls the compressor capacity. Operating costs reduction is usually associated with the ability of the hydronic system to deal with part-load demand. 

VFD is an electronic power component that allows the compressor to perfectly match the different loads requirements a building might have, through the capacity control of the compressor, providing outstanding part load efficiency, and allowing great energy saving opportunities. Daikin has its own VFD technology, mounted onto Daikin own single screw compressors, also equipped with Variable Volume Ratio (VVR) to furtherly adjust compressor operations at any condition, allowing for higher efficiency and lower operating costs. 

Daikin VFD differentiates from others for being refrigerant cooled, hence not being affected by environmental conditions such as ambient temperature, altitude, or air quality, thereby ensuring outstanding reliability. 


Polyvalent units working principle and why to choose them 

A polyvalent system can provide chilled and hot water all year-round facing variable climatic conditions, operating both in “Air to Water” and in “Water to Water" modes according to the plant’s needs. When a type of application requires energy for both heating and cooling or at the same time, multi-purpose technology is perfectly suited. Its feature is that, regardless of the season, cooling and heating are required simultaneously on two different water circuits. The multipurpose unit does not need a seasonal changeover as the reversible heat pumps, and it can control the two refrigerant circuits independently according to the actual demand for cooling and heating.  




About Daikin on Site (DoS) 

Daikin on Site (DoS) is a cloud-based remote monitoring and control system that provides 24/7 real-time data, monitoring the operations of cooling and heating plants and their proper functionality. It is an innovative tool for HVAC plants providing not only remote monitoring but also periodic reports for in-depth plant analysis, energy analysis, and intelligent maintenance. The information provided by this solution offers a unique level of detail by offering a continuously evolving service, enabling plant owners to take preventive measures and avoid the additional costs associated with breakdowns and downtime. 

Facility managers can easily recognize the problem and find the right solution whenever an alarm occurs. Thanks to the fact that this platform allows parameters to be evaluated in real-time if an adjustment of settings is needed, it is possible to intervene remotely. All this makes it possible to improve the performance and management of the units, planning preventive maintenance and increasing the reliability of the systems. 

Read more here about Daikin on Site (DoS).


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