Daikin is announcing the release of the new polyvalent unit EWYS-4Z, equipped with Daikin Inverter-Driven Single-Screw Compressors. Designed for commercial and industrial applications, this unit operates with R-513A refrigerant, whose Global Warming Potential (GWP) is 55% lower than R-134a, while maintaining the same safety classification (A1).
In this article, we will showcase the features of this unit, explain how it works, and guide you on how to choose it according to Daikin's recommendations.
The features
The Daikin EWYS-4Z polyvalent unit features highly efficient Single-Screw Compressors with Variable Frequency Drive (VFD) and Variable Volume Ratio (VVR).
Key information about the EWYS-4Z range:
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Capacity range: from 400 to 800 kW in cooling and heating mode
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Total Energy Efficiency Ratio (TER) up to 7.89
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Operating temperatures: from -18°C to +50°C ambient temperature
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Chilled water temperature range: from -8°C (with water/glycol mixture) to +20°C
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Heating water temperature range: from +30°C to +60°C
As a result, EWYS-4Z can be extensively used over many different applications, from industrial to commercial buildings, hotels, hospitals. As well, it ensures reliable operation and optimal performances in many distinct locations and weather conditions. A reduced noise configuration is also available, featuring noise attenuation achieved through lower fan speeds and a specially designed soundproof compressor cabinet. Enhanced insulation on refrigerant pipes and special connections at the compressor's suction significantly reduce vibration transmission.
How does a multipurpose unit work and when to choose one?
The EWYS-4Z is equipped with two Shell&Tube heat exchangers on the waterside: one always operates as an evaporator (cold heat exchanger) and the other as a condenser (hot heat exchanger). Copper-aluminium (Cu/Al) fin and tube coils are used to dissipate excess cooling or heating energy. As a result of this design, the Daikin polyvalent unit can simultaneously meet cooling and heating requirements by following two setpoints simultaneously all year round, adapting to changing climatic conditions. Unlike reversible heat pumps, it does not require seasonal changeover and can control the two refrigerant circuits independently, based on actual cooling and heating demand.
How to choose a multipurpose unit
As stated, multipurpose units are preferred for applications requiring simultaneous heating and cooling. Hence, the main challenges when to choose one relate on how efficient and reliable operation are guaranteed, to what extent these units can be integrated in a larger HVAC system, and on how to keep their reliability and performance over time. EWYS-4Z offers 10 good reasons for choice, that can be reviewed here below:
Efficient operation to limit running costs
Reason #1: VFD regulation + VVR control. EWYS-4Z range provides chilled and hot water operating in both air-to-water and water-to-water all year round. The VFD modulates unit capacity efficiently at part load, while VVR adjusts compressor operations to match any conditions, minimizing energy losses.
Reason #2: NO starting current. No current spikes at start-up. The starting current is always lower than the current absorbed in the maximum operating conditions (FLA).
Reason #3: High power factor. EWYS-4Z maintains a displacement power factor always greater than 0.95, avoiding power factor penalties and reducing electrical losses in cables and transformers.
Reason #4: Quick comfort conditions & low water content required. The ability to vary the output power in direct relation to the cooling and heating requirements of the system, allows to reach the set-point conditions very quickly. The switch between the different operating modes occurs in less than one minute allowing it to operate properly with the same amount of water as in the loop of a cooling-only inverter chiller.
Outstanding reliability
Reliable operation is ensured considering both product features and control features at the same time.
Reason #5: EWYS-4Z is designed with two separate and independent refrigerant circuits ensuring maximum safety and ease of maintenance.
Reason #6: Daikin refrigerant-cooled VFD technology is not affected by environmental conditions such as ambient temperature, altitude or air quality, ensuring unparalleled reliability.
Reason #7: Thanks to meticulous design and experience, Daikin single-screw compressors feature highly balanced mechanical loads, which reduce component stress, extend the life of the unit, and improve reliability. This design also minimises vibration and noise emissions. The excellent volumetric efficiency of the compressors makes them ideal for variable-speed applications. The compressor geometry is optimised for variable speed operation, even at high speeds.
Referring to controls, Reason #8: Daikin intelligent Chiller Manager (iCM) allows control of up to 8 units within a system, manage the sequencing and capacity of each unit to achieve the overall required capacity while minimizing energy consumption. This ensures proper sequencing and capacity management of the units without the need for an additional control panel, utilizing the unit’s software functionalities. This approach provides a highly cost-effective plant solution, prioritizing reliability over efficiency as it balances the load between units, optimizing the working conditions of the entire group. This approach extends the life of the units in the system.
Integration of multipurpose unit in a larger HVAC system
Reason #9: Daikin iCM ensures proper integration of EWYS-4Z units into a system with distinct types of units, such as:
- A 4-pipe system with EWYS-4Z and a chiller with heat recovery
- A 4-pipe system with EWYS-4Z and a heat pump with a changeover valve for mode-switching
It is worth to mention that in both cases a full Daikin HVAC system can be designed. In the second case, the integration with water-to-water heat pumps (under the same system control) allows for a full decarbonization of heating even where terminals would still be radiators. Indeed, a Daikin cascade system can be designed for provision of heating water up to 75 °C, considering EWYS-4Z in combination with single screw compressor’s water-sourced heat pumps, eventually also equipped with VFD, and available under various refrigerant options (R-1234ze, R-513A, R-134a).
Reliability and performance over time
It is always key to keep HVAC equipment under proper conditions, to ensure HVAC plant targets and related maintenance costs would be fulfilled.
Hence, Reason #10: EWYS-4Z is equipped with Daikin on Site, a cloud-based remote monitoring system that provides 24/7 real-time data, ensuring the proper functionality of cooling and heating plants. This innovative tool for HVAC systems offers not only remote monitoring but also periodic reports for in-depth plant analysis, energy analysis, and intelligent maintenance.
Daikin on Site delivers a unique level of detail, offering a continuously evolving service that enables plant owners to take preventive measures and avoid additional costs associated with breakdowns and downtime. Facility managers can easily identify problems and find the right solutions whenever an alarm occurs. The platform allows for real-time evaluation of parameters, making it possible to adjust settings and intervene remotely when needed.
With Daikin on Site, users have complete access to the unit controller through the cloud. The unit is equipped with a modem and a GSM card, providing an autonomous internet connection.
In conclusion, the Daikin EWYS-4Z polyvalent unit sets a new standard for efficiency in commercial and industrial HVAC applications. With its advanced Single-Screw Compressor technology, this unit ensures reliable and sustainable performance. The ability to provide simultaneous heating and cooling, along with features such as Variable Frequency Drive (VFD) and Variable Volume Ratio (VVR), makes the EWYS-4Z an optimal choice for a wide range of applications. Additionally, Daikin's intelligent control systems iCM and remote monitoring (DoS) guarantee long-term reliability and operational excellence.
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