VWV

Petra Variable Water Volume System

Petra Variable Water Volume System

Since 2003, Petra has committed itself to be an innovator in the energy saving HVAC systems with the introduction of the Petra VWV system. The system offers large savings in energy and initial costs. The system may be used in multi-story buildings, office complexes, hotels, villas or any other type of project where high energy savings are required. The system is comprised of air-cooled water chillers (cooling + heating), indoor units with three way valves, a control package, pumps, expansion tanks, storage tanks, water piping and integrated complete system control

High Efficiency System
Safe system, since water is used inside the building as the cooling media
Refrigerant is only used in outdoor units, No refrigerant leak hazards in occupied areas
No oil return problems
Design to work at 55 °C ambient conditions ensures durability at high ambient temperature
Capacity control modulation, down to 1% of load
Easy to install; no special costly skills required
No distance or elevation restriction allow more reliability with no limitations (compared with refrigerant flow systems)
Friendly to operate: no complication system involve
Central plant allow up to 60% diversity from indoor connected load
Available with R407C and R410A (Soon will be available with low GWP refrigerants)
From smallest capacity up to any range allow more flexibility while selection from 35 up to 1,400 kW (from 10 up to 400 Tons)
Available pumping system including Primary-only or Conventional primary-secondary system
Quick and easy installation and maintenance
Standard parts ensure availability of replacement anywhere every-time
Utilize the benefits of new green refrigerant ensure compliance with green regulations
No reduction in capacity along with long piping ensure better design
Modification any time will not change system effectiveness allowing more flexibility
Integrated System Control
Suitable for future Refrigerants (meets the safety requirements)

Welded structural base painted with mono component catalyzed primer sprayed paint
Base is equipped with welded brackets for heavy duty lifting lugs
High performance hermetic scroll compressor
Condenser coils are copper tubes copper aluminum type
All coils are air pressure tested by dry air up to 2,900 kPa (420 Psi) under water. They also undergo dry cleaning after manufacturing for optimum system cleanness
Condenser fans of the external rotor type with many attractive features such as space saving, compact design, optimum cooling, full speed controllability and low starting currents
Brazed plate heat exchanger consists of stainless steel plates permanently brazed with pure copper filter (for small models)
High efficiency direct expansion (DX) shell and tube type coolers with inner grooved tubes to optimize the cooler’s efficiency (for large models)
Coolers are tested and stamped for refrigerant side design pressure of 1,000 kPa (145 Psi) and for a maximum water side working pressure of 1,500 kPa (220 Psi)
Liquid, discharge and suction pipes are all hard copper pipes. They are formed using automated CNC pipe bending machines in order to minimize pipe-brazed joints which in turn increases system reliability
Epoxy paint for all exposed copper piping system of the refrigeration circuit
Components of each refrigeration circuit include liquid line solenoid valve, liquid line shut off valve, high safety pressure switch and disposable core type filter
Unit is fully charged unit with R410a/R407c refrigerant
Thermostatic expansion valve
Free terminal for remote ON/OFF connection
Free terminal for general alarm output
Control voltage is 220-240V for all components
Single point power connection for each electrical panel
Starting contactors for compressors and condenser fan motors
ON/OFF switch for each compressor
Control circuit breaker for short circuit protection
Short cycling protection for compressors (time delay)
Control transformer mounted & wired that shall supply all unit control voltage from main unit power supply to internal components such as (not limited to) solenoid valves, compressor motor protector, compressor crank case heater and microprocessor controller
Microprocessor controller for full management of chiller operation and safety circuits
Power supply monitor (phase failure relay) used to protect the power circuit against over or under voltage conditions and against phase loss or loss reversing conditions
Nema 3X with IP54 minimum enclosure standard electrical panel. Two separate panels, one for power & the other for control

Digital scroll / VFD scroll compressor
Copper tubes copper fins coil
Coil corrosion protection including polyurethane pre-coating (for aluminum fins) and polyurethane post-coating (for aluminum & copper fins)
Sound reduction options including low rpm condenser fan and compressor jacket
Electronic expansion valve
Pressure gauges for monitoring of refrigeration discharge and suction pressure
Water flow switch installed to prevent operation of unit without evaporator water flow
Cooler cladding of aluminum, stainless steel or painted galvanized steel {made from gauge 22 [0.7 mm (0.03 inch)}
Cooler can be insulated with closed cell foam insulation of 25 mm (1 inch), 38 mm (1.5 inch) & 50 mm (2 inch) The insulation density is 48 kg/m3 (3 lb/ft3) with a K-factor of 0.035 W/(m.°K) [0.0203 BTUH/(ft.°F)
Main disconnect switch used to de-energize the power supply to the chiller during servicing or repairing works because of the door interlock with an external handle that is installed on the electric panel door
Power factor correction used to improve the power factor level which improves system reliability, minimizes voltage drops and gives better power quality
Earth leakage relay used in electrical installations with high earth impedance to prevent shock
Control transformer to supply power input to auxiliary components at 120 or 220 volts, such as (not limited to) bulk head light and GFI outlet
Ampere-meter & volt-meter used to measure the power current & voltage consumption Ampere-meter is used for each phase
120 volt power supply connected through the transformer to provide a 120 volt single phase circuit that is used to operate the electric appliances at site such as laptops, tablets and cell phones
Speed regulator for condenser fan motors used to permit the unit to operate in low ambient temperature
Dual power connection, one power entry for compressors & the second for the rest of the unit
External over load for each compressor
External over load for each condenser fan motor
Circuit breaker for each compressor
Circuit breaker for each condenser fan motor
Nema 4x electrical panels made from galvanized steel
Nema 4x electrical panels made from stainless steel
Cooler tape heater protection down to 0°C (32°F), -18°C (0°F) & -29°C (-20°F)