Petra Evaporative Condenser Rooftop System
Petra’s evaporative condenser rooftop systems provide substantial energy savings by operating at lower condensing temperatures than air cooled condensers which enhances the performance and conserves energy consumed by the compressors.
Petra’s PPHE rooftop package unit have significant energy savings in comparison to air cooled alternatives with an added efficiency of over 30% at AHRI conditions.
- Capacities ranging from 25 tons to 160 tons
- Petra's evaporative condenser rooftop is provided with environmentally friendly R-410A refrigerant.
- Double wall construction made form 18 gauge galvanized steel, with 2" thick (3 pcf density) injected foam insulation minimizes heat loss for
additional energy saving.
- Weatherproof construction for the entire unit exterior with applied polyester powder electrostatic paint, oven baked which ensures durability
by complying with a 5000 hour salt bath test in accordance to ASTM A117 and ASTM B1117.
- Centrifugal backward or airfoil supply fans with premium efficiency motors are provided which are more energy efficient and quieter than forward
curved fans. Double width, double inlet (DWDI) or single width, single inlet (SWSI) plenum fans are provided.
- Blow through or draw through cooling
- Factory assembled and tested packaged units minimize field installation and commissioning costs.
- Multiple filter, fan, and coil options and sizes to match system requirements.
- Extended face area filters and coils reduce system pressure drops and improve efficiency.
- Multiple high efficiency Copeland scroll compressors feature excellent reduction in noise and vibration, provide higher redundancy, reduced
maintenance costs and enhance integrated part load values (IPLV)
- Dual independent refrigerant circuits include manual shut off valves on the suction, discharge and liquid lines, accessible sight glass, filter
drier and solenoid valves and high and low refrigerant pressure protection switches. (expansion valves are included in the air handler section).
- Condenser fans are of the axial type, sickle shape blades statically and dynamically balanced selected for optimum efficiency and for maximum
sound power reduction. Fan blades are direct driven by external rotor motor type and protected by steel wire guard coated with electrostatic
polyester powder coating oven baked.
- Three-phase, severe duty, totally enclosed condenser fan motors with current sensing overload protection and permanently lubricated
bearings support extended product life.
- Standard chemical free water treatment system is factory installed and commissioned and eliminates the use of hazardous chemicals,
including scale inhibitors, biocides and corrosion inhibitors. The chemical free water treatment system works on the principle of pulsed
electromagnetic fields that neutralize the charge on particles suspended in water, causing them to attract to each other rather than to form scale
on condenser coil heat transfer surface.
- Walk- in service compartment containing Lights, chemical free water treatment system, spray pump, water connections, single field
connections to make-up water and drain lines and refrigerant service components.
- Up to 30% savings in condensing unit energy consumption in comparison to air cooled alternatives.
- Factory installed variable frequency drives on condenser fans for head pressure control at lower ambient operations
- Open access to compressors and refrigeration piping and condenser tube bundles which reduces service and maintenance costs
- Stainless steel sump and stainless steel spray enclosure, copper tube bundles and PVC spray water distribution tree provide long term corrosion
- Provision made with ample space in the walk-in service compartment for the addition of water treatment equipment to prevent scale
build up and microbial growth
- Unique stainless steel slide out frame enclosure for the spray nozzles and drift eliminators are designed to provide
easier maintenance accessibility and easier cleaning and replacement of spray nozzles reducing service costs and down time
- Corrosion resistant PVC drift eliminators designed with stainless steel slide out frame enclosures limit carry over and significantly reduce drift
rate to less than 0.001% of the recirculation water rate
Evaporative Condensing Energy Saving:
In an air cooled condenser the heat-transfer rate is proportional to the temperature difference between the condensing refrigerant and the dry-bulb temperature of the entering air. The heat transfer mechanism for the evaporative condenser is due to the vaporization of water from the condenser tubes, and the rate of this vaporization is proportional to the difference of water vapor pressure of the liquid water on the tube and the water vapor pressure in saturated air that surrounds the tube. This indicates the performance of the evaporative condensing packages is greatly influenced by the wet bulb temperature of the entering air rather than the dry bulb.
Evaporative condensers work at lower condensing temperatures than air cooled alternatives which reduces compressor work and energy consumption resulting in lower electrical demand and consumption. The efficiency of the Petra’s PPHE evaporative package unit can reach 0.88 KW/ton at AHRI conditions (95⁰F dry bulb/75⁰F wet bulb) in comparison to air cooled alternatives with an efficiency of 1.15 KW/ton at AHRI conditions.