Powerstream Screw Inverter

PRECISE CAPACITY CONTROL

Powerstream’s compact semi-hermetic screw compressors are distinguished by a further improvement in energy efficiency at full and part load conditions. Accordingly, these compressors exceed the international efficiency standard of compact screws with respect to the seasonally weighted energy requirements to an even higher degree than before.

Each unit in the range equipped with a pair of compressors on a single circuit and starts with the one driven by the inverter-fed motor. As the cooling demand exceeds its capacity, the control system of the chiller starts up a fixed-speed compressor and adjusts the speed of an inverter-driven compressor accordingly to the actual load. When the cooling demand decreases, the control system stops a fixed-speed compressor and regulates the speed of an inverter compressor as required. Additionally, the chillers feature low in-rush current, hence lowering the installation costs.

CENTRALIZED CHILLED WATER PLANT CONTROL

The control hub of Powerstream chillers is a sophisticated controller with advanced software developed for efficient operation of water-cooled chillers. It manages and optimizes the chiller’s performance, giving complete control over the system for plant operators.

Control software can be directly linked to the existing building management system. Integration with a BMS allows collecting and analyzing operating data of chilled water plant and helps to maintain optimal equipment settings, saves energy, identifies trouble-prone areas, provides maintenance schedules and generate safety and security alarms.

For the efficient operation of multiple units on a single chilled water plant, the sequencing software permits interlinked operation of the complete system, thus providing optimal temperature control and minimal energy consumption.

Chillers can be configured for constant or variable flow depending on a configuration of a chilled water system. For the systems with a primary-only circuit, constant pressure differential or constant temperature differential flow control can be selected, while constant temperature differential control is available for primary/secondary systems. Flow control logic dynamically adjusts the pump speed based on the actual load, thus optimizing pump energy consumption and ensuring the stable operation of the chilled water plant. The control system is able to operate with a single chiller or multiple chillers.

ADOPTED FOR PART LOAD CONDITIONS • ENABLES HIGH EVAPORATION TEMPERATURES

​Flooded shell-and-tube evaporator used in Powerstream design offers extremely high evaporating temperatures for a given supply water temperature and optimized for R134a refrigerant. The heat transfer rate of the evaporator enhanced with internal refrigerant side tube grooving and optimally positioned baffles. Internal baffles in the water circuit optimize the flow while keeping pressure drop to a minimum. Reduced baffle spacing ensures high heat transfer at low flow rates, as well as for brine operation.

EASY OF MAINTENANCE/CLEANING • R134A-OPTIMIZED

Powerstream chillers feature newly developed shell-and-tube water-cooled condensers optimized for refrigerant R134a to provide the best possible efficiency. With high-grade finned tubes, the new design of the internal baffles and shell, these condensers provide lower condensing temperatures and maximum efficiency with a low cost per kW, as well as the shorter length and reduced weight.

Optimized water flow also reduces the risks of fouling and erosion of the heat exchanger, while reduced pressure drop enables savings on pump energy. New heat exchangers allow the extended range of condensation temperatures, making the chiller suitable for almost any kind of application.