New glycol-free option for air-cooled free cooling chillers

Following the launch in 2023 of the TZ D air-cooled chiller series including also Free Cooling configuration, Daikin is now announcing the Glycol-Free option for EWFH/S/D-TZ D free-cooling chillers. This option operates with a “closed loop” system, providing a compliant and efficient solution for applications where avoiding the use of glycol is preferred. 

This option provides several benefits for different types of applications. Firstly, it can lead to significant cost savings as the avoidance of glycol in customer's system makes it easier to maintain and improving overall efficiency. In industrial processes, it reduces the risk of contamination, ensuring that product quality is not compromised. 

 

Overview of Daikin air-cooled TZ D chiller range 

TZ D air-cooled free cooling chillers incorporate the latest technology to deliver top performance across a wide range of capacities from 180 to 2150 kW. The wide range of operating conditions makes the TZ D series the optimum solution for comfort, process and critical cooling applications: 

  • From –20°C up to +55°C outdoor ambient temperature conditions 
  • From –12°C up to +30°C supply water temperature  

TZ D free-cooling chiller series is available with 3 refrigerants: 

  • R-1234ze (EWFH) 
  • R-513A (EWFS) 
  • R-134a (EWFD) 

all available in four efficiency tiers:  

  • Blue (B-) 
  • Silver (S-) 
  • Gold (X-) 
  • Platinum (P-)  

two sound configurations: 

  • Standard Noise  
  • Standard Sound + option 76-b (compressor enclosure) 

 

The 10 main reasons to choose TZ D chillers 

Among all the benefits offered by this unit, here are ten good reasons to choose the TZ D range.  

Reason #1: Daikin Single- Screw Compressor design. This type of technology is designed to be extremely reliable, even in harsh environments. Unlike a standard screw compressor, Daikin's design uses a main screw that meshes with star rotors to create a volumetric compression cycle. As the main rotor is balanced in both radial and axial directions, the compressor bearing achieves exceptionally high reliability.  

Reason #2: Outstanding reliability ensured by Daikin in-house Inverter. The chillers feature one or two independent refrigerant circuits. Each compressor is equipped with a Variable Frequency Drive (VFD), installed directly on the compressor and cooled by the refrigerant itself. Unlike other technologies, such as air-cooled and glycol-cooled drives, Daikin technology offers true independence from outdoor conditions (temperature, humidity, altitude, pollution). The VFDs are designed and manufactured by Daikin to operate continuously under the most extreme conditions. 

Reason #3: Cutting-edge efficiency thanks to Daikin in-house VFD and Variable Volume Ratio. Most of the time, chillers operate at conditions off-design (i.e. part loads). Therefore, it is crucial to ensure optimal adaptation of the unit to varying application loads. Daikin VFD allows the unit to operate at optimum efficiency, resulting in reduced and controlled running costs in every working condition. On top of that, the in-house single-screw compressor is integrated with the Variable Volume Ratio (VVR), a sliding valve which modulates the compression ratio enhancing the efficiency of the compressor with varying ambient conditions, adjusting compressor’s geometry to the real operating conditions.  

Reason #4: Integrated Active Harmonic Filter by Daikin.  Harmonic distortion is caused by nonlinear loads such as power electronic devices, variable frequency drives, and certain types of lighting, which inject harmonic currents into the power system, causing additional power consumption in electrical systems. It can lead to increased energy losses and reduced efficiency, resulting in higher energy costs. Low harmonic distortion helps minimize these losses, improving energy efficiency and reducing operational expenses. Active harmonic filters (AHFs) are electronic devices used to reduce harmonic distortion in electrical systems. They are capable of dynamically compensating for harmonic currents in real time, thereby improving the power quality of the system. AHFs actively monitor the harmonic currents and generate compensating currents that cancel out the harmonics, resulting in a reduction in Total Harmonic Distortion (THD). Daikin offers a unique solution for active harmonic filtration developed by Daikin Power Electronic division. Based on the same proprietary technology used for compressors drive, the active harmonic filter by Daikin is fully integrated on the chiller. The device is installed inside the electrical panel, cooled by the refrigerant from the chiller circuit ensuring temperature control in all operating conditions regardless of environmental conditions.  

Reason #5: Despite the free-cooling mode, Daikin TZ D units are extremely compact. This is due to a special redesign of the condenser section, which results in a significantly lower footprint compared to competing units. This design optimisation not only reduces the space required but also improves the overall efficiency of the system, making it a more space-saving and practical choice for various applications. 

Reason #6: Compact free-cooling configuration, also glycol-free. These units are very compact: despite the free cooling configuration, they do not require any additional space beyond the size of the unit itself, so they do not take up any extra space compared to a standard chiller without free cooling capability.  As a result, Daikin can offer a free-cooling solution that does not require the use of glycol in the user's system, keeping the glycol contained within the refrigeration system. 

Reason #7: Wide operating envelope. The TZ D units can operate in a wide range of conditions, making them suitable for a variety of applications. For example, they can provide chilled water for applications such as ice rinks with temperatures as low as -15°C, while also being suitable for data centers that require higher evaporator outlet temperatures of up to 30°C. This versatility provides exceptional flexibility, allowing TZ D units to operate effectively in a wide range of environments and climates. 

Reason #8: The possibility to integrate the Total or Partial Heat Recovery options, configurations that allow the recovery of some or all the heat produced during the cooling process. This improves energy efficiency and reduces operating costs. With Total Heat Recovery, the unit is equipped with an additional condenser per circuit to produce hot water. Heating is only available when cooling is also required.  With Partial Heat Recovery, the unit is equipped with one desuperheater per circuit to produce hot water. As with total heat recovery, heating is only available when cooling is also required.  This heat recovery system allows the production of hot water that can be used for specific applications needs.  

Reason #9: Performance monitoring option available. The unit's performance information is available directly from its controller, which provides real-time data as well as the historical performance of the unit. This allows to monitor the unit efficiency and make the necessary adjustments to maintain optimum performance. By tracking performance data, it is possible to identify anomalies or deviations early on, allowing to detect and manage potential problems before they lead to failures. 

Reason #10: These units can be integrated into a complex system comprising several Daikin units. Effective management of this group of units is essential to optimise operating hours and ensure proper functioning. This can be achieved with the Intelligent Chiller Manager (iCM) option, which optimises systems of up to 8 units, and the cloud remote monitoring tool Daikin on Site. Specifically, iCM is a control system designed to harmonise the operation of each chiller within a group to achieve the desired performance with minimum energy consumption and mechanical effort. This results in increased durability, efficiency, operational effectiveness and cost savings. Daikin iCM can be connected to Daikin on Site, a cloud-based monitoring platform. This tool enables plant owners to take preventative measures to avoid additional costs associated with breakdowns and downtime. It also generates periodic reports for a more comprehensive analysis of system performance. 

 

Overview of Free cooling solutions by Daikin 

The EWFH/S/D-TZ D chillers are equipped with a fully integrated free cooling system. The unit's control logic enables free cooling operation when the outdoor air temperature is low enough to cool the fluid returning from the system to the chiller. The standard configuration is associated to an open loop free cooling system, in which the fluid from the application passes through the free cooling heat exchanger. An optional closed-loop or Glycol-Free version is now available to allow operation with water only in customer’s premises.  

By selecting the Glycol-Free option, the fluid in the system can be pure water, while the glycol is confined within a closed loop between the free cooling exchanger and the brazed plate exchanger. This means the glycol would not be circulating through the customer's system but is rather contained within the chiller itself. The operating modes remain the same as those of the “open loop” version: 

  • When the ambient temperature is higher than the water temperature returning to the unit, the system operates in "mechanical cooling" mode. 
  • When the ambient temperature is sufficiently lower than the returning water temperature, the system switches to "mixed mode". 
  • When the outdoor temperature is cold enough, mechanical cooling is turned off completely, and the system operates at full capacity in "free cooling" mode.

 

 

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